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Symphony in Concrete Studying impact of evolution of tools and techniques of formwork in exposed concrete. Nishita Parmar, UA2311. Guided by: Sankalpa.


“Always reserve a portion of your brain to be lazy�- a piece of thought from an unobstructed mind of, pogo the pug.

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ACKNOWLEDGMENTS: I would like to thank my guide for invaluable guidance; people whom I interviewed for sharing their time and knowledge; my mother for being everything but an unparalleled spirit of love, courage and wisdom; my father for being a trampoline whenever I fell down; Gugs for being sanely insane; Vedanti for always being there; my GANG, Kp, Kishan, Manuni, Babs, Aman, Sagar, Dhwani, Prasik, Hiren, Devashree, for all the help in making this document and for frequent transits to worlds of crazy and imaginations; to all the wonderful souls known to me; my family, friends, professors, colleagues, strangers, for contributing towards encouraging new modes of thoughts and making it possible for each other to live; and lastly COMPARTMENT S4 for being the reason to finish thesis and look forward to a new day.

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CONTENTS 1. Introduction 1.1 Abstract 1.2 Aim 1.3 Objectives 1.4 Scope and limitations 1.5 Method of study 2. 2.1 2.2 2.3 2.4

Concrete and Formwork Defining technology and construction process Definition of formwork and formwork parts and assembly. Concrete and texture Formwork typology and examples

3. 3.1 3.2

Concrete Formwork History History of concrete through innovation in formwork Limitations of tools and technique: Identification of parameters of framework for case study

4. Case Study 4.1 Method of Case study 4.2 L.D Institute of Indology 4.3 IIM-A 4.4 Lilavati library, CEPT 5.

Inferences and Conclusion

6.

Bibliography

7.

Illustration credits

8.

Appendix

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1. INTRODUCTION

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1.1 ABSTRACT “Every man made form and in particular, every architectural formdoes not exist solely as static consequence to an otherwise irrelevant act of production, but conversely, that the nature of form is inlaid in the process of making”. [1]

[1]

“Notes for theory of making in a time of Necessity.” Zambonini, Giuseppe. Notes for theory of making in a time of Necessity. The MIT Press on behalf of Perspecta, volume 24, 1988. 2-23.

The process of transformation requires identification of the material, tools and relationship of the maker to a time in history. And thus the object will carry advances and contradictions of the society in which it is a product of. [1] In architecture, construction is a discontinuous process of putting things together, at any given stage the form is either incomplete or essentially different from the final one. The final form is the result of many forces acting on it such as the availability of material, technological developments, labour, economy etc. Thus, the incompleteness imposes limitations on the final product because of all these factors. In case of concrete buildings, the most important part due to which the plastic material, concrete, becomes unique is formwork. So, the final form is the result of many forces as said above. It gives shape and texture to concrete and also takes up maximum labour cost and time. And therefore, it has its own limitations. Despite this importance very little focus is paid on the formwork system which has caused the divide between architecture and engineering. Thesis will try to re-examine the integral system of concrete formwork in terms of its material, fabrication, construction and its technology; as well as its importance as a potential tool for informing the design of elements and the whole form. Thesis intends to understand the role of tools and techniques in construction by trying to reconstruct formwork and going beyond the surface phenomenon and seeing the significance of deeper relationships. Thereby, bridging the divide.

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1.2 AIM: To understand how has the limitations rising from the shift in tools and techniques in case of concrete formwork affected the construction process and thereby form of elements in the building.

1.3 OBJECTIVES: To understand, • In what manner has the construction process undergone change with respect to the change in tools, techniques and material . • How has the limitations coming from the construction process affected the form of elements in the building. • The ways in which formwork has the potential to inform design. • To know what are the current technologies and their limitations in concrete work systems used in India today.

1.4 SCOPE AND LIMITATIONS • The case studies are chosen on the basis of availability of data and different types of formwork systems used in a duration of every 10-15 years since 1960. • The case studies are limited to public buildings of Ahmedabad in exposed concrete. • The data collected for the case studies through interviews ans site observations • The research will be done from the view point of construction process and not the design process. • The design of formwork in terms of structural design is not studied for the research. • Expression of concrete due to concrete mixture will not be considered

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1.5 METHOD OF STUDY

Introduction

Construction process and built form

Formwork introduction and typologies

Timeline: History of concrete through formwork innovation

Identification of parameters of framework: What are the factors causing limitation of tools and techniques

Formwork Construction What aspects of formwork are to be studied?

Case Studies Reconstructing data for formwork for identified typical building details.

Typical Building Details For what parts of the building is formwork studied?

Studying identified parameters of framework How has limitations from tools and technique of formwork affected building elements and form

Inferences Why is there difference in technique and tools of formwork in three case studies?

Conclusion

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2. CONCRETE AND FORMWORK

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2.1 DEFINING TECHNOLOGY AND CONSTRUCTION PROCESS Technology: Technology, “science of craft” is the collection of techniques, skills, methods and processes used in the production of goods or services in the accomplishment of objectives, such as scientific investigation.[2] It includes different materials, techniques, processes, tools, the building themselves during the course of production and their use. It is in the technique of making that the craft lies and decides the form of the object. “For technique may be interpreted in many various ways. I never regarded technique as atomization of crafts but instead as a whole poetry of action and as a means of achieving metamorphoses. It has always seemed to me that observation of technical phenomenon not only guaranteed a certain controllable objectivity, but afforded an entrance to the very heart of the problem.” [3]

[2]

Hale, William Braham and Jonthan. Rethinking Technology. great Britan: Routledge, 2007. [3] ,[4]

“Notes for theory of making in a time of Necessity.” Zambonini, Giuseppe. Notes for theory of making in a time of Necessity. The MIT Press on behalf of Perspecta, volume 24, 1988. 2-23. [5]

Rastogi, Parth. Role played by materials and building techniques in the development of elemental forms. Ahmedabad: CEPT UNiversity, 1983.

For making something one needs material and tools that are suitable to transform the material. Making of a final form is a combination of materials and appropriate tools to define the technique. The tools and techniques are not something that designers make, but he has to work in a given technological state. The development of these tools and techniques are dictated by many factors such as social and cultural development and development in fields peripheral to architecture. So when a designer is working in a given state, it lies in his vision on how he would want to use the particular set of tools and techniques in order to transform matter into the object he desires, and any changes or shift in technology will therefore play a major role in advancement of architectural elements. Therefore, knowledge of the entire process from conception to execution is essential so that every minute choice involving materials and methods can be bent at the designer’s discretion, to fully address the objectives of production. Such knowledge provides basis for every transformation proposed by the designer. This can be found throughout the construction process as it reveals itself through detail: at the meeting of walls, roofs, beams and other elements. [4] Construction: Construction is a discontinuous process of putting things together in which at any intermediate stage, the form is either incomplete or essentially different from the final form. This signifies problems associated with the incompleteness of the forms during construction and thereby limitations imposed on the choice of the final form due to the very process of construction. [5] Throughout history we see examples of buildings where the expression of building is a true manifestation of its process and limitations offered by the tools and techniques of construction. Construction with centering* and formwork*, the need of falsework* of the form itself during construction have arisen mainly in case of the 11


2.1 construction technique for arch

spanning elements like arches and vaults, initially and more recently in reinforced concrete. The former have not been self supporting until completed , and later not until concrete has hardened completely. [6] Some examples of this manifestation in the form of building are discussed below: Arch and vaulted structures developed in Roman era became self supporting only when completed. The manner in which completed structures fully support itself is dependent on the precise manner and sequence of construction. The true arch became self supporting element when the last stone is inserted at the top, called keystone. In using centering* as a technique, voussoirs* above Romanesque doors and windows [7] have been explained as a technique dictated by the erecting sequence. Temporary wooden centering was required only for first ring of voussoirs, thereafter the first ring acted as a permanent centering for the next order for the arch, whose faces were corbeled out beyond the inner and outer faces of the first ring[8] Similarly, shape and dimensions of formwork also determines the measurements in the space and configuration of part of the structure. Since, timber and steel which was normally used for formwork, comes in flat and straight boards and plates, in order to make economical, the forms therefore had surfaces which are straight lines. In case of concrete, it is the technique of molding concrete that gives form to it. This technique of formwork even when economically designed tends to be more expensive then the cost of what is built. Therefore in designs of modern RC (reinforced concrete), this frequently has resulted in standardizing the forms of beams, columns, walls so to repeat them in every floor.

Falsework*- Falsework consists of temporary structures used in construction to support spanning or arched structures in order to hold the component in place until its construction is sufficiently advanced to support itself. For arches, this is specifically called centering. Falsework also includes temporary support structures for formwork used to mould concrete to form a desired shape, scaffolding to give workers access to the structure being constructed, and shoring which is temporary structural reinforcement used during repairs. (https://en.wikipedia.org/wiki/Falsework) Centering*- a type of falsework: the temporary structure upon which the stones of an arch or vault are laid during construction. Until the keystone is inserted an arch has no strength and needs the centring to keep the voussoirs in their correct relative positions. (https://en.wikipedia.org/wiki/Centring) Formwork*- It is temporary or permanent molds into which concrete or similar materials are poured. In the context of concrete construction, the falsework supports the shuttering molds. (https://en.wikipedia.org/wiki/Formwork) Voussoirs*- is a wedge-shaped element, typically a stone, which is used in building an arch or vault. (https://en.wikipedia.org/wiki/Voussoir) [6] [8]

Rastogi, Parth. Role played by materials and building techniques in the development of elemental forms. Ahmedabad: CEPT UNiversity, 1983.

[7]

refer figure 2.1

But there have been exceptions, where these limitations of formwork in concrete structures has brought innovation in form and expression of the building. Such exceptions can be seen right from roman structures to explorations of molten stone by Kahn. They will be discussed in next chapter in the history of concrete through formwork innovation. Thus, construction of formwork in concrete becomes an important construction process where technological advancements can be studied. 12


2.2 DEFINITION OF FORMWORK AND FORMWORK PARTS AND ASSEMBLY This section introduces formwork systems, clarifying terms and definitions which help to understand the case study drawings.

[9]

Jha, Kumar Neeraj. Formwork for concrete structures. New Delhi: Mc Graw Hill Education (India) Private Limited, 2013.

Formwork is a kind of temporary structure whose purpose is to support its own weight and that of freshly placed concrete as well as the construction live loads including materials, equipment and workmen. Formwork as a temporary structure is desired to safely support the concrete until it gains adequate strength to stand on its own. [9] It includes , the mold in contact with concrete and all the necessary supports, hardwares and bracings. Reinforced concrete construction primarily consists of three components: formwork, reinforcement, and concrete. Formwork represents a significant portion of any concrete construction project and accounts for 35-50% of the total concrete structure cost. In terms of time formwork operations consume maximum time varying between 50-75% of the total time period consumed. [9] Explanation of terms in formwork for concrete: a. Sheathing- that part of formwork, which is in contact with concrete. b. Form (Shutter)- that part of formwork, which consists of the sheathing and its immediate supporting members. c. False work- It is temporary structure erected to support work in process of construction. It is composed of shores, formwork for beams, slabs and lateral bracing. d. Centering- it is a temporary supporting structure of soffit. A specialized formwork used in the construction of arches and shell space structure where the entire false work is decentered as a unit, to avoid stress in any part of the structure. e. Mold A frame for casting precast units. f. Scaffold- A temporary structure for gaining access to higher levels of the permanent structure during construction. [9] Parts of Formwork: The parts of formwork and their function remain constant in any assembly. Only the material and quality of parts keep changing. Different company manufacture different types of parts with . Diagram shows different parts in a typical assembly of formwork for wall and beam and slab. Case studies will use these terms for explaining different assembly.

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Wood spreader Tie

Sheathing material

Wallers / Wall plate Studs

Sill/ Plate

2.2 Parts of typical wall formwork

Battens/ Joists, supports for sheathing

Sheathing material

Stringers for support for joists

Shores for support for stringers 2.3 Parts of typical slab formwork

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2.3 CONCRETE AND TEXTURE Looking at the history of concrete texture, formwork gives us clues as to how architects struggled while discovering new expressions of concrete. The texture is one of the most important things in visual acceptability of exposed concrete. Three factors namely formwork, mixture and finishes decide the texture of concrete. Formwork: The form material used to hold the liquid concrete, leaves a textured imprint on the final form. So, the imprints can actually be designed. Since history there has been experiments done to find true expressions of concrete. Earlier, the form material used was mainly timber, and the texture obtained was rough and with cracks. So, it was often covered by tiles and bricks, so that concrete could imitate stone masonry by providing grooves. Slowly the bare nature of concrete was accepted after many experiments by pioneers like Joseph Tall and Bombfield. Today the form materials used are plywood, metal, fiber glass and timber. It is very important to understand all these materials and its technical properties. For example, metal leaves its marks of rust if not cleaned properly. In using timber, it should be known that the it absorbs water and causes shrinkage of boards which will affect the texture on concrete and water seeps through joints, making cracks. Controlling humidity is critical in keeping boards from deforming. Some woods actually absorb air and prevents air bubbles on surface of concrete. Recently plywood has been used in concrete formwork. New processed plywood with thin layers have been developed to get smooth surfaces. [10]

[10]

Formwork as Design Tool by Shuji Suzumori, Master of Architecture at the Massachusetts Institute of Technology, February 2006. [11]

Marsh, Paul. Concrete as a visual material. London: Cement and Concrete Association, 1974. [12]

Bennett D., Exploring Concrete Architecture Tone Texture Form, Basel, Birkhauser, 2001, p. 8.

The different materials available for form are wood, plywood, fabric form, foam forms, plastic forms, paper forms, steel forms, concrete forms, metal mesh forms. They all are used with different technique of construction giving different imprint and texture to surface of concrete. Formwork of varying absorbency will produce concrete of different colour. It is essential for formwork to be clean, oiled before re use and covered until concrete is poured. Attention needs to be given to joints of the formwork to avoid loss of alignment between adjacent pours of concrete. Also the leakage of grout at joints must be guarded against. If joints are not sealed, leakage can discolor previously cast concrete. Honeycombing, crazing, plastic cracking, discoloration are all defects due to formwork errors.[11] Mixture: Concrete is a mixture of cement aggregate and water. These three components can be mixed in different combinations and different sizes to get the desired colour tone. The difficulty in specification for colour was explained by D.Bennett, “there is no definition by which quality and colour tone of the finish can be unequivocally described by specification alone. The same concrete mix poured into different formwork or placed in the same formwork 15


at different temperatures, or retained in the form for different lengths of time will result in colour variations. The longer the concrete is cured or left in the forms the darker will be the surface tone. The lower water cement ratio gave the darker tone�[12] Workability of mixture should be decided upon the machinery used and complexity of the form. Finish: Rendering is done to all the exposed concrete surfaces with the special tools developed. A thin protective layer is applied for long life and water resistance. The trick lies in choosing the right finish as it can change the colour of the concrete. It requires experience and knowledge. In some cases repairing of the concrete done by filling the cracks with same colour mortar. Basic repairing process is to fill in any faults with mortar, trying to match the existing color and tone.

[13]

Collins, Concrete, p. 148. ‘The nature of concrete is derived from the nature of the formwork, and it is in the making of the form-work that the craftsmanship must mainly reside. If the form-work is produced merely by pouring plaster of Paris on to a carefully prepared model in clay, then it becomes a mechanical system of reproduction, and not a creative process in itself. If, on the other hand, the form-work is made from plans, sections, and elevations, in the way that a carpenter constructs timber buildings, or a cabinet-maker creates furniture, then that formwork is a work of genuine art even if, like an engraving or an intaglio, it can only achieve fulfillment when transposed on to another medium in reverse’.

Thus, the three factors are interrelated to each other and requires a quality of craftsmanship which will be restricted by limitations. With such processes affecting nature of exposed concrete work, the designer must understand the thin line between decoration and underlying true expression of concrete. Collins makes a distinction between true and untrue use of concrete by focusing on the process of building the formwork. He says that the formwork must be made from architectural drawings just like a piece of furniture and cannot be a negative of some object already existing in other materials. [13] So also for repair and finish work of exposed concrete, the only repairs acceptable should be accidents which are unexpected. Repairs that are done to hide faults which have occurred due to ignorance and limitations of material properties of formwork are additional decoration, which would not be intentionally done by the designer.

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2.4 FORMWORK TYPOLOGY This section is cited from the book explaining formwork systems in Indian context *

*

Jha, Kumar Neeraj. Formwork for concrete structures. New Delhi: Mc Graw Hill Education (India) Private Limited, 2013.

Broadly, formwork systems can be divided into three groups: a. Conventional system of formwork: In this system timber and plywood are predominantly used, various formwork components are connected with nails. It is quite flexible. It can be fabricated, installed, and removed on site by skilled workmen like carpenters. b. Proprietary/patented system of formwork: This system makes use of standard factory-made components. There is very little making of formwork involved on site. It has features and accessories developed over many years of experience resulting into saving labour and giving higher productivity, as no labour is spent in making unlike the former system. This can be assembled and disassembled by unskilled labourers. Ready made materials are available for the general purpose and tailor made for special purpose. Climbing formwork, L&T formwork, PERI formwork, PERI climbing formwork, Doka climbing formwork etc are types of proprietary systems for both horizontal and vertical formwork. c. Modular systems of formwork. The formwork modules in this system are manufactured in a factory set-up. And delivered on site in a pre-fabricated form. They can be assembled very quickly at the project location, resulting in reduction of erection time. Other advancements of formwork systems have been introduced to economize the formwork and gain efficiency in time and accuracy. Newer solutions in formwork systems include systems like MIVAN technology. While increase in high rise buildings have led to the development of systems like flying formwork, where in large repetitions are possible for rapid cycle constructions. This saves material and labour costs. Slip form construction also known as sliding form construction another recent system, is similar to extrusion process in which wet concrete is extruded rather than retained in the forms until it is hardened. Concrete is shaped as desired during travel of the form. It is used in the construction of chimneys or high rise or towers.

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3. CONCRETE FORMWORK HISTORY

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3.1 CONCRETE IN HISTORY THROUGH FORMWORK 113–125 AD • One of the signatures of Roman construction, the arch, is not only a result of efficient masonry construction but also the result of innovation in concrete construction. Brick is used as formwork, in a form of an arch so it would withstand the weight of the concrete placed above. With this method, they were able to minimize the use of wood, limiting it to scaffolding used to initially place the brick, which was very precious at the time. The name coffer was derived from its timber forms and the resultant decorative effect due to logic of construction. Romans not only had great knowledge of concrete but understood its properties and applied them to the design of the formwork.* 1850 • Coingnet was the first to realize the true aesthetic of concrete. He said that concrete need no facing material. He said, mold in which concrete is poured should have the form to be given to masses. Thus all kind of reliefs and decorations can be done without covering exterior. He saw need to evolve concrete architecture within the nature of material, and perceived that limitations of formwork would necessarily bring about a great simplification in shapes. Method of construction defines the looks. He worked with pisé system of construction with concrete and brought mass concrete construction to the knowledge of modern world. In his house he concrete was used as monolith surface with different moldings.

3.1 Pantheon, Roman Empire

3.2 Coingnet house

1864 • Idea of RCC developed with the need of fireproof buildings and economy in building construction. Joseph Tall realized that expense of concrete work was due to timber formwork , so way to achieve economy and efficiency will be by standardization of formwork. His system was patented, it was very flexible in application, and could be hired for any building type. The idea of standardization was conceived. 1892 • Hennebique was another pioneer. In his early projects he replaced timber joists with precast beams and idea of bending reinforcement near the supports became his first patents. The system of integrating separate elements of construction, such as the column and the beam, into a single monolithic element was one of the first appearances of the modern reinforced-concrete method of construction. • Theorists began to regard rcc as only expressive when used in vast work of engineering. And could only discuss its work of ethos in factories, grain silos, airship hangers, bridges. It was inapplicable to domestic scale. Thus design of interesting rcc concrete structures tended to be regarded more of a domain for civil engineering. 19th century, however the introduction of steel construction suddenly divorced the technique of structural design from realities of structural execution, as engineers calculated the size of members by formula , and entrusted work to new class of operative for whom questions of 19


appearance were irrelevant. Constructional design was no longer matter of shape but of graphs and equations. When this same method was applied to concrete construction in the following decade it proved powerless to advance the evolution of concrete architecture, or make any vital contribution in search of appropriate forms. • 19th century there was a search for true appearance of concrete began. The resistance in acceptance of concrete was very few people considered bare concrete presentable intself, firstly because of the drab color of the cement and second because o the irregularity of the texture. Problem was ‘what kind of covering is consistent with honest expression of material beneath? There was no solution to how concrete should appear. • Imre bell understood quite well that fundamental problem of concrete was design of formwork. And he was more concerned with the surfaces of the mold then the shape of the molds. Concrete does not take shape until it is poured into formwork, and thus design of concrete structure lies in design of molds. But the tradition of patent apparatus and cheap labour obscured from the minds of both architects and contractors the real issue at stake. 1906 • Inventor Thomas Edison owned a cement manufacturing plant; in order to sell more cement, he developed casting methods for mass produced housing. The idea was to construct the formwork for the entire out of steel and cast as one piece. Although it proved to be too complicated, a few houses were made using this method. “The form-work consisted of 2,600 metal castings of a size and weight convenient for handling, and was held together by 10,000 nuts and bolts. It took 4 days to erect and 4 days to dismantle and pouring of concrete by compressed air was achieved in 6 hours.

3.3 Monolithic House by Thomas Edison

1916. • French builder Eugene Freyssinet was first to use sliding formwork for efficient construction of large concrete structures. Hangers of Orly was constructed in small sections using formwork that slides as the concrete sets. The undulation of the ribs are designed so the formwork can easily be removed.* 1930 • Swiss engineer, Robert Maillart, pushed the envelope of concrete structure with his designs of efficient bridges. He was commissioned many projects because it was the cheapest design, mostly due to efficiency in the use of concrete. Salginatobel Bridge is unique in the planning of its formwork. It was designed to only withstand the weight of the arch. Once the arch cured, it became the new working ground for the construction above, and the formwork was completely removed.*

3.4 Orlay Hangar by Eugene Freyssinet

3.5 Salginatobel Bridge by Robert Maillart

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1947 • Corbusier’s invention of beton-brut, where concrete surfaces bare the imprints of the molding process. At Unite d habitation, concrete was unable to bare the desired finishes, it was decided to keep concrete untreated after removing wooden formwork, which was called beton-brut. 1953-1957 • Hyperbolic Paraboloid (HP) shells are curved surfaces which can be generated only using straight members. Architect, structural engineer and contractor Felix Candela was a master of such shell structures made with concrete. Due to the nature of the form, the formwork for HP shells were made by stacking straight wood members. Excess water was able to seep out from the gaps between the formwork, resulting in a stronger surface.*

3.6 Unite d habitation by Corbuiser

3.7 Unite d habitation by Corbuiser

1953 • Louis kahn had already exploited all the possibilities of rough concrete in Yale art gallery. Forms were crafted from narrow floor boards, the use of raw materials was part of Kahn’s ideological critique to industrial materials of modernism. 1957. • Italian engineer Pier Luigi Nervi used ferro cement (thick concrete plastered over steel mesh) to build large complex structures with very little material. Individual ferro cement pieces are the formwork but become part of the structure once the concrete is poured. At a time when labor was cheap and material was precious, this process proved very successful and produced in complex concrete structures* 1958 • At Monastery of Sainte-de-la-tourette, sliding formwork which was mostly used in industries is used here for a public project. Concrete due to result of this production process was not rusty and did not bare traces of human hand techniques. The patterns of this exposed concrete were mostly the result of decisions made by the contractor and not designer. This challenged the architectural intention of concrete. 1960 • I.M.PEI- his most significant breakthrough was using a sophisticated technique of cast in place concrete construction making use of fiberglass molds. With this system he dealt with fundamental constraints of mold and workmanship related to making of exposed concrete. Technique explored the aesthetic potential of repeatable elements, where structure and envelope were molded into one and the same form, and build in a single operation. Concrete conceived in such a manner was smooth. This system was used in number of residential projects. In his further projects he made efforts to erase the traces of production by using a mechanical means like bushhammering for external texture.

3.8 Yale Art gallery, New Haven, US

3.9 Palazzeto Dello Sport, Rome

3.10 Sainte-de-la-tourette

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1960’s • During this time, precast technique was considered slick, flawless and machine made material but many architects were exploring rough character of concrete. There was no one definition to expression of concrete. 1961 • Marcel Breuer (1902-1981) showed interest in rough concrete by exploring the aesthetic quality of concrete at Begrisch Hall, where wooden formwork imprinted bold diagonal patterns and lines on the surface that challenged the horizontality of the cantilevered mass and disrupted the conventional reading of concrete pours. It was a means to express sculptural and heroic character of architecture. 1963 • Rudolph in his art and architecture building at Yale, which was RC building, enveloped with one foot thick concrete walls, with a textured finish achieved by pouring concrete into vertically ribbed forms. After mold were moved rigid surfaces were hand hammered to expose the aggregate, it was unexpected texture. This brought attention to artificial and highly crafted nature of the exposed material. 1965 • Kahn began to focus on the mold and molding process. At Salk Institute, he made sure that concrete was molded and patterned exactly as intended. The forms were made with three-quarter-inch plywood that were treated sophisticatedly before using. Rather then to try the joint between formwork panels, he chose to accentuate them, chamfering the panel so as to produce a V-shaped groove along the surface. Accepting the inevitable bleeding of the concrete at the junction of the forms, the V-joint allowed surplus to be molded into relief elements. The conical holes left by the ties holding the formwork together were treated with detail. The approach lay in the way concrete surface was crafted to register the traces of production. Here the concrete was left rough

3.11 Begrisch Hall

3.12 Architecture building at Yale

3.13 Salk Institute * Formwork as Design Tool by Shuji Suzumori, Master of Architecture at the Massachusetts Institute of Technology, February 2006.

• These were examples which changed concrete by using the production process of formwork. Concrete of various types certainly continued to be used after this, but major exploration was done till 1970s.

Bibliography for Time-line: Formwork as Design Tool by Shuji Suzumori, Master of Architecture at the Massachusetts Institute of Technology, February 2006. Jean-Louis Cohen, G. Martin Moeller. Liquid Stone: New Architecture in Concrete. Birkhäuser, 2006 Collins, Peter. Concrete The vision of a new architecture. London: Faber and Faber Limited, 1959. Rosellini, Anna. louis i.kahn towards the zero degree of concrete 1960-1974. switzerland: EPFL press, 2014.

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3.2 LIMITATIONS OF TOOLS AND TECHNIQUE Identification of parameters of framework for case study * Parameters are identified after reading the books mentioned in bibliography on page 21

Factors causing limitations : 1. Efficiency of tools in terms of time taken to perform the action and accuracy obtained using that tool on the outcome. 2. Material quality and availability of the parts and its effect on outcome. 3. Ease of assembly and efficiency in the technique used to assemble the formwork parts. 4. Workability of the construction joint of the output (in the building) using that technique. 5. Final finish of the output using the particular technique.

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4. CASE STUDY 1. Main building, L.D Indology 1960 2. Academic block, IIM-A 2000 3. Lilavti Library, CEPT 2017

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4.1 METHOD OF CASE STUDY *Typical building details and Formwork construction part is identified after doing a pilot study of a 4-story building in concrete construction in Ahmedabad.

Building Introduction • Construction planning • Structural system • Construction sequence

Formwork Construction • Parts Materials used for formwork Machines and tools used for formwork

Typical Building Details Reconstructing Data for Formwork

• Sequence Technique of erecting the formwork and concreting Construction detail of formwork

Effect of formwork construction on building language

Limitations • Workability of the construction joint of the building element • Efficiency of the tool/ technique of formwork in terms of time and accuracy and it material • Ease of assembly of formwork • Finish

• • • • • • • •

Horizontal Vertical Corners Tie holes Construction joints Openings Grooves Rendering

Final Outcome Correlation of various modules in the building

Studying identified parameters of framework Why is there difference in technique and tools of formwork in three case studies?

Conclusion

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STRUCTURE OF EACH CASE STUDY: • Introduction • Studying formwork for typical details of the building • Correlation of various modules in the building

4.3 CASE STUDY : 1 L.D Indology - 1960 Architect: B.V. Doshi, Vastu-Shilpa Construction: Gannon Dunkerley Company Limited PEOPLE INTERVIEWED: Mr. Kanjibhai Ramani- Centering contractor during Indology Mr. Ashwinbhai Ramani- Son of Mr. Kanji Ramani Mr. Purhottambhai Gajjar- Carpenter at Vastu-Shilpa Mr. Upendrabhai Desai- Architect at Vastu-Shilpa during making of Indology Mr. Hemal Shah- Son of Mr. Suresh Shah (Site engineer from Sangath during making of Indology) Mr. Suketu- Engineer at Vastu-Shilpa Mr. Bhalla bhai- Centering Contractor 26


2

1. indology main building 2. canteen 3. printing press 4. director bumgalow 5. upashriya building 6. staff quaters 7. car parking 8. peons quarters 9. electricians cabin

3

1 6

5

4

8 8

9

4.2.1 Site plan Not to scale

Introduction Institute of Indology houses ancient manuscripts which were donated by a Jain monk. Traditionally old texts were stored in the basements beneath temples. Doshi therefore placed the library half underground, letting indirect light in through angled windows, and reflecting it off a pond of water that was to help insulate. The main level was thus half story above the ground and was approached by a raised bridge above a moat. The upper floor was made to cantilever over the walkways beneath and to contain teaching rooms. It is supplied with a deep veranda to protect it from sun. There are deep cut ledges, overhangs and rows of pillars of concrete. [14] Texture of concrete was inspired from Kenzo Tange’s work where rough concrete texture is achieved with wooden forms.

[14]

William, Curtis. Balkrishna Doshi : an architecture for India. Mapin Pub. Pvt. Ltd. (Ahmedabad), 1988.

Structural System It is a concrete frame structure. Partition walls are brick walls. Overhang slabs are precast concrete slab. Columns are H shaped which can conceal drain pipes for rainwater on one side and electricity on other. There are large spans and grid of concrete beams. Constructional planning and concreting technology Exposed concrete building of such scale was one of the firsts buildings in the Ahmedabad. Before Indology, Corbusier had built ATMA (Mill owners Association) in exposed concrete where again wood was used for formwork. There was only one construction company Gannon Dunkerley which had a team to make exposed concrete building. Materials procurement was not easy as there was a cut on number of bags of cement by the government, so lime mortar was used for brick 27


masonry. The decision for using wooden formwork was taken mainly because steel shuttering was expensive therefore to economize the construction cost, wood carpentry was designed for formwork. It was also a design decision to have a rough texture in concrete like wood inspired from Corbusiers experiments. For concreting technology, vibrators were available, but they were not surface vibrators and the needle of vibrator was small. Mixer machine was used. There were no mechanical lifts, all the staging and ramps were made manually by workers. Sticks and rods were used for vibrating the concrete. Workers were skilled in carpentry and concreting. A well was made on site for using the water for construction. Construction sequence Construction sequence depends on the time taken for drying the concrete and curing. Sequence is shown in the diagram. All the columns of one floor are casted in two parts. Slabs are casted in one time depending on the availability of formwork material.

28


8

5 9

2

3

9

6

1. Entrance bridge 2. Main entrance hall & exhibition hall 3. Inquiry 4. Office 5. Meeting room 6. Curator 7. Directors office 8. Canteen 9. Toilet 10. Terrace garden 11. Water pool

7

4

10

11

1

4.2.2 Ground floor plan

Assembly hall

Office

Office

Office

Office

Verandah

4.2.3 First floor plan

5.6 inch DROP

Library

5.6 inch DROP

N 4.2.4 Basement floor plan

01

2

5m

29


4.2.10 Construction sequence of different elements

30


31

4.2.6 East elevation

4.2.5 North elevation


4.2.8 North Elevation

4.2.9 South Elevation

32


4.2.7 Section aa

4.2.9 South Elevation

33


FORMWORK FOR TYPICAL DETAILS OF THE BUILDING: A. Formwork for vertical elements : columns, walls B. Formwork for horizontal elements: slab, beams C. Grooves D. Tie holes E. Corners F. Construction joint G. Skylight openings, windows H. Rendering

34


*All the data collected for this case study is obtained from interviews and observations done on site. Building being constructed in 1960’s, made it difficult to obtain construction photographs. A visual dictionary of photographs of every detail is used to track back the formwork construction. Assumptions about formwork are done by analyzing the imprints and texture on the building.

A. Vertical elements: 1. Columns Columns are made with plywood sheets as form material. Various sizes of plywood were available, 4’x4’, 8’x4’, 6’x3 as per requirement. Plywood is used in various sizes instead of one standard size to create compositions, or maybe it was used in parts to avoid wastage and economize construction. 12mm nails are put around the edges so the surface remains straight and does not become wavy. Framing is done with deodar wood sections of 3”x1.5”. Wall pates of deodar wood section of 3”x5”. Tie rods are fixed with wooden clamps. These wooden sections of deodar are cut from full sizes of 10”x6” wood logs. They are cut according to required sizes in the saw mill. The length is cut as required by the carpenter. Tie rods are fixed next to wall plate so it tightens the assembly. If there is a gap between wall plate and tie rod, it is filled with wooden scrape[15].

[15]

refer 4.2.14, 4.2.16

[16]

refer 4.2.14, composition of plywood panel [17]

refer 4.2.15

pana*- tool used to bend hard metal ghodi*- tool set up to cut rods and plywood karvat*- hand saw

Nailing of plywood to wooden framing is done from inside, so we can see the imprints of nails on the cast. Nails used are 1.5” without heads, to avoid evident marks. Formwork is first prepared on ground, checked and corrected and then again dismantled before erecting it on site. For columns, it is done in 8 parts. The U is joined so that it can come out as one piece. It is tapered slightly on the inner side so it comes out easily[16]. If it is made exact fix to the cast at right angles, shuttering might not come out easily. Stronger the formwork, more compact the concrete and better output for exposed concrete. Columns are casted in two flights, first it is done till beam bottom, then the beam is casted and then rest of the column[17]. Starter is made with wooden boards. It takes one day to prepare shuttering for one column and one day for casting. If there are 10 columns then shuttering for two coulmns is prepared and for the rest its repetition. Shuttering is removed after 24 hours of casting. This can differ depending on the availability of material with the contract. Maximum height for casting one flight was 8’-9’. Vibrators were not advanced during that time, so a stick was used sometimes to vibrate concrete. Hence casting height of one flight has to be small, which will leave pour joints. Therefore in the shuttering pattern it is a composition of small plywood panels to hide pour joints. Machinery for carpentry for formwork was also limited. Tools like pana*, ghodi*, karvat* were developed locally by workers.

35


4.2.11 Typical H-column

4.2.12 H-column and intermediate beam

4.2.13 Nail imprints on each form panel of column

Assembly of formwork parts

deodar wooden strip framing 3"x1.5"

ladder

Composition of plywood sheet

plywood sheet 3"x5"wall plate

plywood sheet plywood panel

wooden clamps tie rod supporting shores nilgiri wood

deodar wooden strip framing 3"x1.5" starter

Section aa a

Elevation 1

tie rod beam line

plywood sheet

1

tapering in the U-assembl of plywood panel

b

b

plywood sheet 3"x5"wall plate

deodar wooden strip framing 3"x1.5"

Plan of H-column

a Plan of H-column

4.2.14 Formwork assembly for typical H-column

36


37

tie beam

beam lvl

Section bb

Assembly of formwork parts

wooden pannel

1100 1130

1

Elevation 1

Plan

Finished column

3320

4.2.15 Assembly of formwork parts for column

2

300

Elevation 2

356,31

1100 820 290


reinforcement rods 3”x5” wooden wall plate wooden clamps tie rods wood supporting shores

1.5”x3” wooden framing plywood sheet bamboo kahpeda

gachiya

4.2.16 Formwork assembly for H-column

38


FIRST FLIGHT - uptil tie beam Sending the required wooden logs to saw mill to cut required sizes transporting material on site cutting required sizes of wall plate and wooden boards and straightning their surfaces with hand tools

Storage of ms plates, and plywood sheets in safe area

PREPARATION OF PARTS OF THE FORMWORK FOR COLUMN Cutting of plywood sheet with hand saw on site as per measurements

Chamfering the corners to make the corners join each other

cutting wooden studs for framing

Mmaking the assembly of U in H, of plywood sheets on ground

PREPARING TIE ROD ASSEMBLY PARTS Checking the assembly by erecting it on ground and leveling it and dismantling the assembly

wooden sections as studs framed around plywood

Erecting the assembly of U plywood sheet and wooden framing

fixing wall plates

Erecting all plywood panels for column uptil beam bottom

Fixing wall plates on all sides

Cutting wooden clamps

Scaffolding erected for workers to go inside the hollow box made by shuttering

Fixing tie rods through wall plate

Tightning tie rod assembly to plywood with wooden clamps

PREPARING FORMWORK PARTS FOR TIE BEAM Cutting plywood sheet and wooden sections for support

Erecting bottoms and sides with wooden shores as support

Fixing supporting shores

Concreting

Tying reinforcement bars

Checking the angle of assembly with odimbo and plumb

Adjusting the assembly to become perpendicular by adjusting supporting shores

Centering and adjusting shores

Concreting

Dismantling CASTING SECOND FLIGHT FOR COLUMN- FULL HEIGHT Rendering

4.2.17 Construction sequence of formwork for H-columns

39


2. Walls Basement walls are brick walls, which are plastered and painted. Walls on ground floor which gives the shape for skylight are exposed concrete from outside.

[18]

refer 4.2.21

Plywood sheet is used as form sheet material. It is framed with wooden sections of 3”x1.5”. Wall pates of deodar wood section of 3”x5” are fixed. As the design didn’t have holes in composition, walls were casted without tie rods. Instead of tie rods, wires were used for binding. For grooves, a wooden groove strip is fixed to plywood sheet first [18].

4.2.18 Concrete wall from outside

4.2.19 Concrete wall from inside

4.2.20 Concrete wall from inside

40


41

plywood sheet

binding wire

vertical wooden groove strip deodar wooden strip framing 3"x1.5"

Elevation 1

groove form sheet imprint r residue b beam + slab x size of one panel y constant residue

Plan of wall

Elevation of wall from outside

a

a 1

1 Key Elevation 4.221 Assembly of formwork for wall

Section aa

brick masonry

groove

3"x5"wall plate binding wire wooden groove strip plywood sheet vertical wooden groove strip horizontal wooden groove strip

supporting shores

deodar wooden strip framing 3"x1.5"


B. Horizontal elements 1. Beams and Slab H- beams, cross beams and slab, are casted together, therefore all shuttering is to be erected first [19]. Bottom side of slab is plastered and painted so it is not possible to recognize method of construction and formwork patterns. Shuttering material used for beams is wooden boards, imprints of lines of boards and texture of wood is visible. It can be assumed that shuttering material for slab will be ms plates, because same is used in overhang on 4 sides. Color of the concrete in overhang is rusted slightly and there are no imprints of wood, the surface is plain and slight deformed, hence it is ms plates. In slab, we can see imprint of nails on edges of imprint of each plate, this means the ms sheet is nailed to wooden batons on all edges for support.

[19]

refer 4.2.22

[20]

refer 4.2.35

[21]

refer 4.2.34

[22]

refer 4.2.24

[23]

refer 4.2.30

[24]

refer 4.2.23

randho*MS plates*- mild steel plates

MS plates* are framed with metal sections as studs. Wall plate of 3”x5” is nailed to wooden batons. Niligiri wood shores are used for centering [24]. Wall plates are made from wooden logs of 10”12”, and then it is straightened and leveled with randho*. Scaffolding is done with nilgiri wood. khapeda were made with bamboo as concrete does not stick to bamboo. In overhang slab, bottom of slab is MS plates shuttering and groove and beam bottom is wood shuttering. At junction of two different shuttering material is fixed with wires and nails. The corners of this peripheral overhang slab are treated with different method as its a residue. A steel-wood formwork [20] is prepared where MS sheet of desired size is composed and nailed to wooden form. False staging is done to make get the slant angle in roof. Casting sequence is shown in diagram. [21] In beams, wooden boards is used as form material. It is important to detail the junction between two wooden boards as concrete slurry can come out if there is a gap in the junction while casting. In Indology, all the formwork with wooden boards is done by joining two boards with detail given in figure[22]. This makes two boards lock with each other avoiding any kind of gap, hence no slurry comes out. This is work of carpentry, like making a piece of furniture. Skilled workers are employed to make formwork of such kind. Each line and groove on beam is a result of its construction sequence. Wooden boards are used to create different texture to distinguish between two elements [23]. Beam of skylight has composition of wooden boards inclined at different angles, which continues to become straight on th adjacent side elevation.

4.2.22 Key plan showing H-beams and cross beams

42


junction od wooden boards and plate

supporting shore nilgiri wood

3"x5"wall plate gachiya

deodar wooden boards

ms plates deodar wood section as studs detail a

43

Section through typical H-beam and slab 4.2.23 Assembly of formwork for beam and slab


plywood patti wooden board ghisi

4.2.24 Detail between two wooden boards

4.2.25 Imprints on beam of ground floor

4.2.27 Imprints of wooden boards on beam on first floor

4.2.26 Grid of beams in basement. Ceiling is plastered

4.2.28 Grid due to imprint of ms plate on overhang.

4.2.29 Grid of shuttering pattern in overhang slab

44


Assembly during construction

Elevation of a finished beam

4.2.30 Formwork showing imprints on beam groove form sheet imprint r residue b beam + slab x size of one panel y constant residue

4.2.31 Imprint of texture of wood in skylight beam

4.2.32 Imprint of texture of wood in skylight beam

4.2.33 Pattern created with imprint of texture of wood in skylight beam

45


Section at A

In situ slab deodar wood form boards ms plate panel deodar wood form boards

beam bottom with wood boards

3"x5"wall plate gachiya supporting shore nilgiri wood

false staging

4.2.34 Construction joint at junction of beam and slab

Key Section

A

ms patru plywood wooden framing

4.2.35 wood-steel form

46


4.2.36 Shuttering pattern and groove towards the corner in overhang slab

4.2.37 Detail of shuttering pattern with ms plates towards the corner

4.2.39 Overhang slab

4.2.40 Precast slab on first floor

4.2.38 Shuttering pattern at beam bottom vs pattern in overhang slab

4.2.41 Groove in overhang

47


C. Tie holes [25]

There are no tie holes in the building as tie rods were not used to hold the shuttering in case of walls. In columns tie rods were passed, but not through the cast, they were fixed with the wallplate and frame to hold the assembly. In case of wall, wires are passed through wallplate and plywood and tied from the other side [25]. Wire is removed or cut after cast, and tiny holes made by wire in the cast are hidden while rendering, leaving no traces of holes, and giving plane surface.

refer 4.2.43

Section through wall showing formwork parts deodar wooden strip framing 3"x1.5"

binding wire

plywood sheet 3"x5"wall plate

4.2.43 Wire as tie rod

48


D. Grooves Every construction joint is marked by a groove making the joint evident as well as builds a language of the building. Groove in all cases is made with a wooden strip, which is slightly tapering from both side in section. If it is a rectangular strip, it will not come out after casting. This strip is properly oiled before casting, for smooth removal. The strip is nailed to plywood from inside, from the side of the cast, as nailing from outside is difficult. Grooves act as a relief to construction joint and makes an expression of continuity of concrete. It also hides the construction error of alignment between two pours.

[26]

refer 4.2.45

[27]

refer 4.2.44

[28]

refer 4.2.46, 4.2.47. 4.2.48

[29]

refer 4.2.49, 4.2.50

[30]

refer 4.2.51 to 4.2.56

[31]

refer 4.2.57

[32]

refer 4.2.58

[33]

refer 4.2.59

[34]

refer 4.2.60 to 4.2.62

Case 1: There is a groove between wall and beam, this signifies the change in element and material. In the construction above tie beam, it is concrete, still there is groove between them to demarcate the structure from inside. Walls are all painted, but the groove makes the expression of distinct elements [26]. In assembly, position of groove strip is at edge of every plywood panel. They are nailed from inside, from side of the cast [27]. On outside, the wall has grooves between the plywood panel used for formwork. These grooves are in harmony with groove lines of the marble clad walls above it. It builds up the image of the building as ship [28] . The grooves take care of the construction errors of non-alignments of form during casting. Case 2: Last groove in the wall in skylight is a construction joint. Wall is finished and an element of same dimension is added, because of the groove it seems as an extension of the wall giving a language to the building [29]. Case 3: Groove between concrete wall and beam of the skylight. It acts as a drip mold. This groove continues along with the beam, giving an expression of a distinct element.[30] It is casted along with beam with wooden strip. Case 4: Drip mold in cantilevered slab is made with similar technique. It is wooden strip with chamfered sides. This groove is bigger and becomes part of the element in expression of the building. [31] Case 5: groove between hand rail and vertical element on first floor makes a distinction between two precast elements. [32] Case 6: Groove in the bottom of beam of skylight acts as a drip mold. It is casted by making shuttering with wooden boards according to the shape. [33] Case 7: Groove under the opening in skylight is used to distinguish between two elements. [34]

49


50

Plan of wall on ground floor

Elevation at 1

groove form sheet imprint r residue b beam + slab x size of one panel y constant residue

4.2.44 Formwork assembly for grooves

a

a

horizontal wooden groove strip vertical wooden groove strip

Outside

30

Inside

horizontal wooden groove strip groove made in masonry

vertical wooden groove strip

3"x5"wall plate

deodar wooden strip framing 3"x1.5"

Detail of groove strip

Section aa

40

1

Key Elevation


Case1

4.2.45 Groove between wall and beam

4.2.46 Groove on wall

4.2.47 Groove on wall

4.2.48 Groove on wall

51


Case 2

4.2.49 Groove in skylight

4.2.50 Groove at construction joint smaller then groove on wall

Case 3

4.2.51 groove around window

4.2.52 Groove under beam, made with groove strip

4.2.53 Groove continues under beam

4.2.54 Groove corner

4.2.55

4.2.56

52


Case 4

Case 5

Case 6

4.2.57 Groove as drip mold

4.2.58 Groove in hand rail

4.2.59 Groove as drip mold

Case 7

4.2.62 Groove as drip mold

4.2.60 Groove at the bottom of opening

4.2.61 Groove at the bottom of opening

53


E. Corners Every corner is articulated in a different manner. Corners are distinguished by change in shuttering pattern. Right angle corners edges are sharp and clean, because while making the shuttering with wooden boards are tightly fixed. Corner at beam and slab show imprint of thickness of wooden board, as during assembly wood boards at junction do not meet at 45 degree (staircase landing slab). deodar wooden strip framing 3"x1.5" wooden boards junction of plywood imprint

4.2.63 Section through staircase landing beam

54


4.2.64 Imprint of wooden board edge for making the shuttering for landing slab seen on beams

4.2.65 Imprint of wooden board edge at corner of walls meeting at perpendicular junction on first floor.

4.2.66 Corner in precast vertical post on first floor.

4.2.67 Imprint of wooden board edge for making risers and tread is seen on the beam at corner

4.2.68 Corner in skylight beam with wooden boards as form material.

4.2.69 Corner in skylight beam

55


F. Construction Joint Case 1: Hand rail, balusters, and vertical elements for grill are all precast elements to avoid construction joint and as it were repeated in large numbers. It is difficult to get perfect sizes and detail, if in-situ concrete. Therefore, all the junctions are cold joints. They are fixed with each other with a tenon-mortise joint.[35]

[35]

refer 4.2.70

A

4.2.70 Construction joint at A

Key Section

Section showing construction joins

rcc in-situ channel wooden boards shuttering

4 rcc precast vertical elements

rcc precast handrail baluster fixed to hand rail with mortise-tenon joint

1

rcc precast baluster

2

3

precast vertical elmement fixed with precast slab, with mortar baluster fixed to slab with mortisetenon joint rcc precast slab

56


4.2.71 Junction at 4

4.2.72 Passage on 1st floor

4.2.74 Precast hand rail and baluster

4.2.76 Junction between handrail and vertical post

4.2.73 Shuttering pattern at 4

4.2.75 Shuttering pattern on handrail

4.2.78 Junction at 3

4.2.79 Junction at 2

57


Case 2: It is a joint between beams running perpendicular to each other. Cross beams do not end at the junction of two beams, but continue outside to create a language to building. N-S beam is casted with wooden boards as form material. There is a pattern made by wooden boards in each bay. This is framed by two bands, drip mold band below, and flooring ledge above, thus creating a symmetrical pattern. Formwork is used to distinguish between two elements by using different shuttering pattern in a construction joint [36].

[36]

refer 4.2.85, 4.2.86 * relate the numbers in images below with diagrams in the next page

3

1

4.2.80 Pattern in beam in elevation

4.2.81 Junction where two beams meet

6

5 4

7 2 4.2.83 Junction where two beams meet

4.2.82 Wooden shuttering pattern on beam

58


6 5

2

7

1

6

5

4

3

7

2 1

4.2.84 diagram showing assembly of different elements

59


60

wooden boards

Detail at A

4.2.85 Construction sequence for beam junction

Key Section

A


61

Section through wall showing detail at A groove form sheet imprint r residue b beam + slab x size of one panel y constant residue

4.2.86 Elevation at A


Case 4: construction joint between wall and beam of skylight is separated by groove and an extra element is added to vertical post of skylight [37].

4.2.87 Groove in skylight wall

4.2.88 Junction of vertical post and beam

4.2.89 Element after the groove

4.2.90 Groove in beam

[37]

refer 4.2.92. 4.2.93

4.2.91 Skylight in elevation

62


4 5

1 3

2

4.2.92 exploded 3d showing different elements

5 3 1

4

2

4.2.93 Junction at corner of building

63


64

4.2.95 Gutter spout

4.2.94 Junction at Gutter spout and beam

imprint of thickness of wooden form panel

4.2.96 Imprint of wooden board

4.2.97 Corner edge

cold joint between gutter spout and gutter

rebaring shuttering for bottom of spout

shuttering for sides of spout


Case 5 Gutter spout is caster after beam is finished. Imprint of thickness of the formwork for spout can be seen on beam. It is a cold joint. Reinforcement bars from beam are extended to cast the spout later. Surface of beam is made rough with before casting the spout to give strength to wet and dry concrete junction. [38]

[38]

refer 4.2.94

H. RENDERING AND FINISHING: Rendering after the cast was strictly avoided as the architect wanted to express nature of concrete to its true form. From the imprints of the on the building, it can be assumed that most of the surfaces are left untouched after casting as grains and imprints of the edges of form panel are visible. Some corner edges are repaired with cement slurry. Internal corner edges are left to expose the imprint of its form material. At many places it could be seen that the there is slurry between imprint of two form panel which are nor rendered after casting. This hints the sizes of panels used and sequence of construction. Only primary level of finishing was done with sand paper to finish the surface.

65


230 970 690 970

8260

DN

3500

UP

A

970 690 970

2240

4000

970 970 690 970

1770

2300 1400 160 1400 160 1400 160

UP

2650

2900

3500

970 690 970

3500

13180

970 690 970

230 1400

1150 1150 1150 1150 1150 1150 1150 1150 1500

1400 160 1770 160 2300

A

2300

1

66

0M

1M

3M

5M

4.4.98 Ground floor plan


67

1M

3M

5M

groove line

form material imprint line 4.2.99 Section AA

0M


4.2.100 Elevation 1

CORRELATION OF VARIOUS BUILDING ELEMENTS: *All the drawings are retraced and made again from the source drawing available.

The building is made up of different elements and not large surfaces. So formwork for each of them is different. No single technique is adapted for casting the whole building. It is a mix of precast, wooden forms, plywood forms and metal forms. All elevations are mirror image of the half. There is a play in surfaces of concrete by using imprints of different form materials. Formwork is used as a tool to express the bare nature of concrete. Different elements are distinguished by change in formwork pattern or with grooves. Wooden boards, used as formwork leaves the imprints of texture as well as the lines of its edges, this lined imprints divides the surface of element into parts. The stripped lines thus made by imprints then come in symphony with different elements of the building. Wooden strip imprints on beam, are lined with partitions of glass and wooden panels in elevation 1. In North elevation the cross strips of wood used in formwork of beam, highlights the skylight at the same time expressing the continuity of the beam. The building was visualized to be a like a boat in water*. In East elevation grooves in the wall make and beam are in sync to emphasize image of boat. Bridge too is stripped with plywood panels. Concrete of different elements flow into one other creating mysterious junctions and unable to perceive as different elements but as one single form. Grooves which are constructional requirement becomes part of language of the building.

*

“When the opening was there, there were people standing in the balcony, sadhus and others. The water was overflowing from the terrace tank, down in the pipe and came to that gargoyle which you see there on both sides and so it looked really like a boat in water and this is how this building was visualized and this was the time it looked like that. So it is not only the shading of the light etc., it is not cooling only but it also became part of the water and the floating area, so if you see the profile on the side you will see the shape - it goes like this, lifted up.” “In [Kenzo] Tange’s work I found concrete used as wood. I said that’s not a bad idea, you know. You should really do concrete like wood and the services can go into the columns, so the ‘H’ shaped column came, one side drain pipes for the rainwater, other side electricity and then large span and then this structural concrete structure, so that’s how this building happened. The first one, I don’t think there are many buildings like this where the upper balcony’s little pieces are all precast. In fact the detailing is very much like wood. It is one of the best detailed buildings that way. Very well done you know, in a sense, it has a quality which is very different. It stands apart.” (Transcript, DOSHI - a film by Premjit Ramachandran, Edited by Premjit Ramachandran. Bangalore: Hundredhands, 2008.) https:// architexturez.net/doc/az-cf-166184

68


69

3M

5M

groove line

form material imprint line

1M

4.2.101 North Elevation

0M


70

3M

5M

groove line

form material imprint line

1M

4.2.102 East Elevation

0M


4.3 Case study : 2 Academic block, IIM-A- 2000 Architect: HCP design, planning and managment Pvt. Ltd. Construction: J.M.C Projects Limited People interviewd: Mr. Jayant Gunjariya- architects office Mr. Mahendra bhai- civil engginer from architect’s office Mr. Kamlesh bhai- site enggnier of IIM-A Mr. Nikunj bhai- civil contractor Mr. Kireet padhyay- civil enggnier

71


4.3.1 Campus plan showing location for Academic block

Introduction

IIM-A is an institute of international repute devoted to management education, its 39-acre new campus houses an International Management Centre, as a center for innovation and incubation which accommodates additional teaching and residential facilities for an expanded postgraduate program in management. Other facilities include 9 dormitories which can house 340 students, an academic block with 5 classrooms and seminar rooms, administrative facilities, IMDC Hostels, 20 blocks for married students, 6 VIP suites, a sports complex, kitchen and dining facilities, a CIIE Block and 100 guest-rooms. The total built up becomes 55,000 sq.m.

[39]

http://www.hcp.co.in/project-details/61/67/2/indian-institute-of-management--2008 [40]

http://www.posts.architecturelive.in/newcampus-for-indian-institute-of-managementahmedabad-by-dr-bimal-patel/

The new campus is connected to the old through an underpass which houses an exhibition on Louis Kahn’s work. This pedestrian passage plays a pivotal role located in a way to not only connect, but also bind the two campuses together. The buildings of the new campus have been designed in exposed concrete and brick with fenestrations made from a combination of mild steel and wood.[39] Academic block is chosen as a case study. The architects’ of the building were conscious but did not want to imitate Kahn’s palette or grammar. Thus the buildings of the new campus were built in exposed concrete as the primary building material with fenestrations in a combination of mild steel and wood. To heighten the austerity of the crisp and smoothly shuttered concrete forms, with metal screens designed by Walter D’Souza, introduced into the fabric of the building.[40] 72


4.3.2 View of academic block from entrance to campus

4.3.3 View of one bay and courtyard in academic block

4.3.4 View inside typical classroom

4.3.5 View of double height passage between classrooms

4.3.6 View of backside of the academic block

4.3.7 View in the corridor on first floor

73


A

A

74

9

13

1. Entrance plaza 2. Entrance foyer 3. Book store 4. Room 5. Store 6. Electrical room 7. Exhibition space 8. Working space 9. Toilet 10. Courtyard 11. Faculty lounge

11

10

10

12. Corridor 13. Seminar room 14. Faculty room 15. A.H.U room 16. Lift well 17. Syndicate room 18. Meeting room 19. Research scholars 20. Pantry 21. veranda 22. Classroom

4.3.10 Ground floor Plan

9

15

4.3.9 First floor Plan

15

13

4.3.8 Section AA

5

12

14

22

C

C

C

C

4

10

B

B

B

4

3

5

17

5

B

D

D

D

D

1

1

6

20

21

01

7

5

5

5

5

9

10

9

19

N 20

A

A


1

1 2

7

3

2

2

3

10

3

8

6

3

4

4.3.11Section BB

4.3.13 Section CC

2

3

3

5

9

1. Upper terrace 2. Terrace 3. Corridor 4. Working space 5. Entrance foyer 6. Research scholars 7. Lower terrace 8. Seminar room 9. AHU room 10. Classroom 0 1

2

10

4.3.12 Section DD

Constructional Planning For the choice for material palette of the new campus, there was a demand from the client to use materials requiring low maintenance. The institution had been facing problems regarding the maintenance of old building, as huge amount of money had to be spent annually to keep the bricks intact. Hence exposed concrete was decided as a structural material for the new campus The building was a large-scale construction of exposed concrete. A number of things were installed on site before starting the project. As the concrete finish and color needed to be of a desired quality, ready mix cement was not used and it was all prepared on site with a small batching plant* and transit mixer*. Raw materials like grit and kapchi, were procured from one site throughout the project to avoid variations in concrete appearance and texture. Another important factor which affects the texture of concrete is water. Bore well water on the campus premise is with more salts, which results in efflorescence of concrete. Therefore, water purifier plant was installed and construction was done with purified water.

Batching plant*- A concrete plant, also known as a batch plant or batching plant or a concrete batching plant, is equipment that combines various ingredients to form concrete. (https:// en.wikipedia.org/wiki/Concrete_pla) Transit mixer*-Transit mixer is a piece of equipment that is used for transporting concrete/ mortar or ready mix material from a concrete batching plant directly to the site where it is to be utilized. Transit mixer is loaded with dry material and water. (https:// en.wikipedia.org/wiki/Concrete_mixer)

A material testing laboratory was set up on-site, to keep up the quality of the exposed work same throughout and set parameters by preparing samples. 4 to 5 sample walls of about 5 meters each were made to test the formwork system as well as the results of the concrete mix, these samples were later broken and not used as part of the building, but they provided a check in every stage of construction. 75


For concreting technology: Transit mixer transports the mix from batching plant to the working site. And then crane transports it vertically. But the slab was done manually using motor lifts and ramps. The crane being very slow it cannot be used for casting of large spanning slabs. Boom technology* is usually favorable for such a scale of construction, but it was not used because the quantum of concrete was less. Net volume of concrete was not enough and so it would choke up the tunnel. The shuttering work was more in quantity compared to the volume of concrete casted. Exposed concrete construction needed a constant check on site from the architect’s office, hence many decisions were taken as and when problems occurred during construction. It was a to-and-fro process of making samples, testing and building, involving architects, engineers, contractors and technicians from various fields to get the desired outputs.

Boom technology*- type of concrete pump is attached to a truck or longer units are on semi-trailers. It is known as a boom concrete pump because it uses a remote-controlled articulating robotic arm (called a boom) to place concrete accurately. Boom pumps are used on most of the larger construction projects as they are capable of pumping at very high volumes and because of the labour saving nature of the placing boom. (https://en.wikipedia.org/wiki/Concrete_ pump)

Structural System The academic block is a concrete shear wall structure. Inverted beams make the large spans of the building. The screens used as sun breakers also act as a truss. Brick walls are the partition walls. Slabs are prestressed. Construction sequence The entire building site of IIM-A was divided into two parts with a labor force of 80 people distributed in both the areas. The construction was carried out in increasing order of the plan starting from one side. If one classroom is built up to ground floor then the block adjacent is built till the first floor and so on, in increasing order. This was mainly to enable division of labor and material. Material was transported after every alternate block as it was very heavy to carry. Sequence of construction is decided on basis of curing time taken by the different element of the building. More time taken for curing of beams and slabs then compared to vertical elements, so distribution of formwork materials will be accordingly. Therefore the construction is done in ascending order. Atleast 7-8 repetitions were done for formwork material, before discarding. This suggests that technique of formwork was quite efficient in saving time and material.

76


Formwork for typical details of the building A. Formwork for vertical elements: walls B. Formwork for horizontal elements: beams, slabs C. Vertical and horizontal groove D. Tie holes E. Corners: walls inside and outside F. Construction joints: beam to slab, wall to beam G. Circular openings H. Rendering and finishing 77


The data collected below is from interviews with different people who were present during construction of the building and observations made on site.

A. Formwork for vertical elements Form material description and availability: Exposed concrete work is done with special laminated plywood sheets. Not many companies used to manufacture such sheets at that time, including a few in Delhi and Haryana. The sheets used were of standard size i.e. 1.22mx2.44m. The architectural demand of the shuttering pattern was a grid of 1.5mx1.5m. Construction of most of the blocks including the academic block was done with 1.22x2.44m size of plywood sheet. Later on some of the dormitory block used customized sheets of 1.5mx1.5m. But soon it was realized that the customized sheets were not feasible due to some practical reasons, and so the rest of the construction was done with standard sizes.

[42] refer [43]

4.3.15 refer 4.3.16

Description of the material and parts: The formwork is a special plywood with extremely thin metal wires as fibers to give strength. It is high density laminated ply and can take up to 30kg of load. • The panel is prepared on ground. First step is to prepare all the type of shuttering panels according to the elevations given. • The panel of 1.5x1.5m was made by joining two pieces from 1.2x2.4m sheet. This requires cutting of the sheet at exact perpendiculars to match the edges of two sheets. It is done with a hand cutter machine by skilled workers. • The panel of 1.5mx1.5m is framed with a ms angle section 50mmx60mm on all the four sides and then subdivided in one direction with t-sections.[42] • The nails used for joining the angle sections to the sheet were flat headed so that it leaves minimum imprint on the concrete.[43] • The panel size is the constant in all major elevations. Developing the formwork system: A customized system was developed for this project. Ease of construction, repetition, accuracy were main design concerns while developing the formwork system. In those times, there were no elaborate formwork systems developed in India. L&T was the only company to make sophisticated formwork, but expensive too. Hence a system was developed that would address the exact problems for this particular construction. Assembly comprises of plywood as sheathing material, MS angle sections as stud, and MS wallers and tie rods. MS angle brackets are fabricated on site for working platforms, from which supporting shores are fixed. Also, it provides the platform for workers to assemble formwork parts. The brackets are bolted on the tie rod holes in the previous cast, hence holes have to be drilled in the brackets beforehand according to drawings of the tie holes. Once the casting of one flight is finished, formwork assembly is dismantled and the brackets are shifted above for next flight. This bracket provides working platform only for formwork assembly.[44] Concreting is done with H-frame scaffolding. 78


4.3.15 Panel description Assembly of parts for one panel ms angle section as studs tie rods

Finished elevation of one panel 1500

288

517

572

1500

3mm laminated plywood sheet plywood sheet joint

550

wooden clamps ss wallers

Elevation ms studs 3mm plywood sheet ss wallers

eq

Plan

eq

eq

eq

Form sheet imprint

4.3.16 Imprint of flat headed nails.

4.3.17 Imprint of line where two plywood sheet are joined

Technique: For second flight of pouring concrete the junction where old cast ends and new sheet comes becomes very critical, as there are more chances of the concrete slurry to come out. To avoid this there is an overlap of sheet on the old cast from first flight. The overlap of the sheet is necessary to get support. 50mm packing helps to accurately place the sheet at right dimensions[44]. It is a very efficient system; erecting and dismantling of formwork becomes easy and also true to its fabrication process as the holes left by tie holes, which is a construction default becomes part of the construction sequence thus expressing its true nature.

4.3.18 Composition of panel in finished wall

[44]

refer 4.3.19, 4.3.21

79


80

4.3.19 Assembly of formwork parts for typical wall

cast from first flight

c-channel ms angle brackets

groove strip in already casted groove from first flight khapeda

vertical groove strip

vertical groove strip

ms studs

supporting shores

corks

tie rods

wooden clamps pvc pipes

horizontal groove strip reinforcement rods 50mm angle section frame

H-frame khapeda (working platforms)


4.3.20 Construction sequence for typical wall

FIRST FLIGHT Transporting of materials and tools to the work area of site

Line out on site

Cutting of reinforcement bars

Tying and placing reinforcement bars on marked position

Starter band casted for walls

PREPARATION OF PARTS OF THE FORMWORK cutting groove strips

Cutting of plywood sheet with hand saw on site as per measurements

Cutting metal studs that will frame plywood sheet

Drilling holes for tie rods in plywood sheet

Drilling holes through metal studs

Nailing groove srips to plywood as located in drawings

SEQUENCE OF ERECTION

Fabricating metal brackets for working platforms as per measurements Drilling holes in brackets according the distance between tie holes in drawings

PREPARING TIE ROD ASSEMBLY PARTS

Nailing studs to plywood with flat head nails using hammer.

Cutting tie rods

Erecting plywood sheet with support of starter band on one side

Cutting pvc pipes

Fixing supporting shores with plywood on one side

Making assembly of cork and pvc pipe for tie rods

Passing tie rods and assembly of pvc pipe and cork from one side

Erecting plywood sheet with support of starter band on second side and passing through tie rod assembly Fixing supporting shores with plywood on second side Fixing wallers on both sides Tightning tie rod assembly with plywood with wooden clamps

checking the angle of assembly with odimbo

Adjusting the assembly to become perpendicular by adjusting supporting shores

Erecting H-frame scaffolding Concreting Dismantling

SECOND FLIGHT

81


4.3.21 Assembly of formwork parts for typical wall

H-frame scaffolding

ms khapeda second flight first flight

Formwork assembly during cast

cast in pvc pipe for tie rod hole

groove from first flight

brackets nailed to casted walls at holes left by tie rods

ms bracket

50 mm packing

khapeda

pvc strip in already casted groove c- channel

plywood form sheet

ms waller ms tie rod

supporting shores

50mm angle section frame

pvc pipe wooden clamps

pvc groove strip

1500

Elevation of a typical wall

1500 1500 1500

Staging of H-frame scaffolding

82


4.3.22 Academic block showing assembly of brackets and H-frames

4.3.23 Academic block showing sequence of construction

83


4.3.24 Typical wall showing assembly of formwork and ascending H-frame scaffolding. casting 3rd flight.

4.3.25 Parts of H-frame and Plywood sheets

84


4.3.26 Typical wall and a worker trying to align the assembly with shores while casting first flight.

4.3.27Academic block showing construction sequence and formwork parts.

85


4.3.28 Formwork assembly and workers casting concrete of a typical wall in academic block.

4.3.29 Formwork assembly of 4th flight of a typical wall in dormitory building.

86


4.3.30 Formwork material on ground during construction

4.3.31 Starter done before casting wall.

87


B. Formwork for horizontal elements MS plates are used as form sheet for slabs. These sheets come in standard industrial sizes. After transport of plates on site, it is very important to store it in a proper space. There are very high chances of this plates to deform which will result into a deformed cast. These plates rust with more repetitions. It has to be cleaned thoroughly or it can leave marks and change the colour of the surface. The grid of plates on slabs is smaller compared to the plywood grid on vertical elements. Difference in form material, gives different surface finish and different grids highlighting the wall and slab.

[45]

refer 4.3.34 refer 4.3.35

[46]

Tube and clamp system*-

Plates have holes in them along the periphery to fix studs. Assembly is shown in figure. [45] Tube and clamp system of scaffolding was used for the supports of slabs. The vertical shores of this system are adjustable and available in different heights. Sheeting material for beams is plywood. Beams are casted along with slabs. Hence the junction at the corner edge between plywood and ms plate becomes critical. To avoid the imprint of thickness of plywood sheet in the corner edge, beam is casted first and then slab. Pour joint can be seen which is rendered later. [46]

4.3.32 Shores and batons of formwork for slab

4.3.33 Finished beam and slab. residue in middle

88


ms plate 50mm angle section frame plywood form sheet wooden batons supporting shores

adjustable shores

4.3.34 Showing partially showing formwork parts for slab.

4.3.35 Pour joint imprint on beam

89


4.3.36 Band of beam and slab

4.3.37 MS plate as form material

4.3.38 Composition of grid in slab in entrance plaza

4.3.39 Beam in the corridor on ground floor in corridor

4.3.40 Colour difference due to rusting of form sheet on ceiling in entrance foyer

4.3.41 Beam of corridor on first floor

90


C. Vertical and horizontal groove Blank facades of IIM-A are expressed with a grid of grooves. These groves eventually become a tool to create a language across all the buildings at IIM-A, but they primarily exist as a result of the construction sequence in exposed concrete. Casting long or high wall in one pour was impossible as the vibrators* available at that time were not advanced enough and so a particular panel size was decided which was a marker for one flight of casting. Groove is designed after each panel. If there are construction halts there will be a cold joint between old and new cast, which tends to develop cracks. Grooves allow for such construction halts. They are pour joints and if the crack develops it will be in the groove and not on the surface. Grooves takes care of the non alignment between cast from two panels. Also groove in between, will cast a shadow, making it difficult to realize construction errors with naked eye.

Concrete vibrator*- vibrators consolidate freshly poured concrete so that trapped air and excess water are released and the concrete settles firmly in place in the formwork. Improper consolidation of concrete can cause product defects, compromise the concrete strength, and produce surface blemishes such as bug holes and honeycombing. An internal concrete vibrator is a steel cylinder about the size of the handle of a baseball bat, with a hose or electrical cord attached to one end. The vibrator head is immersed in the wet concrete. (https://en.wikipedia.org/wiki/Vibrator_ (mechanical) [47]

refer 4.3.42, 4.3.43

Experiments on the technique of casting grooves were done on sample walls. The strip used for the grooves previously was metal, but concrete sticks to it while deshuttering . Therefore, a decision of using PVC strip was taken. The groove strip is slightly tapered at one end so that it becomes easy to remove it while deshuttering. PVC material gives clean grooves without concrete sticking to it. The PVC strip is fixed at the end of each panel in plan. Both horizontal and vertical groove strips are fixed to the plywood while preparing the panel. Groove strips are nailed to plywood from inside (side of casting). The first flight is cast till the horizontal groove strip at top. So incase a crack develops at the end, it will be in the groove and not on surface. For the second flight, plywood is overlapped by 100mm with the previous cast. A groove strip is fixed on the casted groove from first flight. This overlap and groove strip inside the groove, prevents slurry to ooze out and damage the groove (already casted) while construction[47]. Horizontal and vertical groove strip are fixed at perfectly perpendicular edges. This requires precise cutting of the groove strip, done by a skilled worker. Expression of the grooves: The groove lines define different elements of the building. It highlights the band of 210 all over the surface. Beams and floor slab are also indicated by the grooves. Grooves occur after every 1.5 meters horizontally and vertically, that is after one panel, which is a marker of finishing one flight of concreting during construction. Thus, grooves are an expression of pour joints. Due to the groove it is hard to perceive the colour difference or alignment difference between two pours with naked eye. It becomes an expression of the construction sequence, eventually forming an architectural language of building.

91


second flight

horizontal groove strip

50mm angle section frame vertical groove strip

100

plywood form sheet

pvc strip in already casted groove overlap

first flight

50 mm packing

foam sheet nailed to stop bleeding

Detail of groove strip section aa

4.3.42 Finished groove

1500

pvc groove strip

Position of groove strip in elevation

a

more support at junction

plywood form sheet horizontal groove strip vertical groove strip

1500

1500

a

1500

Plan of formwork for a typical wall

50mm angle section frame

4.3.43 Assembly of groove strip and panel

92


4.3.44 Non-alignment of the surface between two panels and groove.

4.3.45 Band of 210mm made by groove on the wall of store

4.3.46 Grid made by grooves on a typical wall and highlighting beam.

4.3.47 Groove as a drip mold

93


D. Tie holes: Holes left while inserting tie rods, is an inevitable detail in casting concrete. Tie rods resists the thrust exerted by wet concrete while casting. These holes can then become a tool to create a composition on blank concrete facades.

[48]

refer 4.3.50

Accessories for assembly of tie rod detail, can be both, available as ready-made fixtures or can be made on site. IIM-A uses both. Accessories for basement are ready made and for walls on ground floor and upper parts are assembled on site. Experiments were done in sample holes which helped to decide the size of pipes to be used and colour of cement to plug in. Tie holes on ground floor and above: Assembly of accessories for making tie hole consists of three parts. Two corks and PVC pipe (used for electrical work). PVC pipe is in between two corks as shown in the figure. The pipe has to be cut perfectly perpendicular at both the ends to fix with the cork edges[48]. A farma is made to cut perpendicular edges of pipe. A skilled worker cuts it with a hand saw. For sequence of assembly of tie rods refer image.[49] It is made sure while assembling that tie rod assembly flushes with the plywood, and then clamps are fixed. Grease is applied to the corks before casting, for easy removal after the cast. After cast, pvc pipe stays inside the cast, corks are removed with a pipe like tool. Holes are plugged with cement bonding agent and sand from both sides. Local methods are used for making the tool and for plugging cement in holes. The tool is made the negative of the hole and is tapered[49]. Cement is put inside and the tool is rotated to push cement in. There is an offset of 5mm from the surface. Holes in basement: For basement and water tank, the accessories used were conventional. It is a system with coils, in which the hole is not through the cast.This fixtures are ready avilable in market .In basement and water tank there are chances of water coming inside through holes, so this detail is used. The accessories for such technique is faster to use but expensive compared to ones which are made on site. Therefore, it is used only in the basement (of academic block) and water tank (not part of academic block). Corks removed while the shuttering can be used again for next cast. H-frame scaffolding is erected for rendering and finishing the holes. It is necessary to fill holes to avoid rusting and weather effects.

94


4.3.48 Finished hole, showing the color difference of grout Assembly of tie rods and pvc pipe during casting

4.3.49 Composition of holes in a typical panel

plywood form sheet Grout filed after cast ms waller

hollow pvc electric pipe

ms tie rod wooden clamps

cork

hollow pvc electric pipe grout tool to fill grout

4.3.50 Section through a typical wall showing assembly of tie rod and formwork

95


E. Corners [50]

Casting perfect corners is very difficult in large scale exposed concrete projects. Problems like corners getting chipped off or slurry coming out of the form while casting are very common. It was an architectural demand to avoid chamfered strips for any corners, so it was necessary to device a technique of casting perfect corners. The detail is experimented in sample walls first.

refer 4.3.56

There are two possibilities of casting corners: For the outer edge of the junction, assembly is made stronger by fixing two angle section studs vertically as shown in the figure. If assembly is strong and well fixed, slurry will not come out and a perfect edge will be obtained. For the inner edge two options are possible[50] Option 1: edge where two plywood form sheets meet, each of them are chamfered at 45 degrees and joined, to avoid imprint of thickness of plywood on any side. Option 2: one side of the wall is cast full and casting is done in 45 degrees, and then other side is cast, which leaves no marks of the thickness of plywood.

4.3.51 Output of option 1 at corner of the wall in courtyard

4.3.52 Corner where plywood sheets are not joint at chamfered angles at a junction in corridor. Imprint of thickness of plywood visible.

4.3.53 Corner where plywood sheets are not joint at chamfered angles at a junction in stairwell in basement. Imprint of thickness of plywood visible.

96


4.3.54 Wall casted according to option 2

4.3.55 Bleeding of slurry at a junction of beams, in corridor on ground floor. This junction is rendered.

Option 1: Plywood chamfered

plywood cut at 45 at the corner plywood sheet

wooden stopper put at 45 to cast in stages

angle section at corner to avoid bleeding

angle section at corner to avoid bleeding

Option 2: Casting in two parts

ood cut at t the corner wooden stopper put at 45 to cast in stages

angle section at corner to avoid bleeding

4.3.56 Plan of a typical wall at junction showing assembly of formwork for corners.

97


F. Construction joint

[51]

refer 4.3.60

[52]

refer 4.3.61

Two kinds of joints Joint 1: beam and slab junction Problem- Imprint of the thickness of plywood form sheet underneath beam and slab junction. Solution- beam is casted first till slab bottom level and then the slab. The usual practice is to cast beam and slab together to avoid cold joint at the critical junction. But in this case, it is cast in two parts, therefore extra reinforcement is designed at the junction after consulting the structural expert. Shuttering of slab is kept for a longer period to strengthen the joint.[51] Joint 2: slab and wall junction Problem- In junction between slab and wall (above ground floor), pour joint is visible. Solution- slab and wall is casted together. Formwork of slab and wall is erected at once. Concrete is poured for casting slab. While casting slab, at junction a stopper is placed at 45 degrees. Then after concrete is poured to cast vertical surface. This technique does not leave a mark of pour joint between slab and wall.[52]

4.3.57 Construction joint between beam and slab in the corridor on ground floor.

4.3.58 Junction of slab and wall at a toilet on first floor.

4.3.59 Junction of slab and wall from courtyard.

98


4.3.60 typical corner at beam and slab junction plywood sheet stopper at 45

concrete wall

Casting horizontal

Casting vertical

4.3.61 image showing section of beam and cold junction at corner

extra reinforcement plywood sheet

Situation to avoid

Casting beam

plywood sheet extra reinforcement

casting slab

4.3.62 Junction of slab and wall at a classroom on first floor.

4.3.63 Junction of slab and wall from corridor on first floor.

99


G. Circular opening

[53]

refer 4.3.65, 4.3.67

Circular opening is one of the landmark details of IIM-A. At the old campus it signifies the material properties of brick while the new campus it expresses the plasticity of concrete. It is important to understand the sequence of construction of the formwork, to know how the shape is derived. Sequence: • Draw the circular shape of the given dimension on ground. • To prepare the peripheral ring, bend two ms angle sections are bent according to the shape marked on the ground. This is done manually by skilled workers. • A metal sheet of 210 width is fixed between two angle sections making the form of a circular shape. • This process is done in two parts by dividing the circle into two. Two semi circular forms are prepared. • Now the circular opening is marked on the plywood sheet of the formwork prepared for walls. • The circular formwork is fixed to plywood from one side and erected. Reinforcement bars for wall are tied and then the second side of plywood for wall formwork is erected. • There is a gap between the form of two half circles, therefore two supporting members are kept at the center. This gap is due the technique of shuttering the form. After the cast is done. Both semicircular forms are removed by applying opposite pressure from the gap in the middle. This technique eases removing the form without breaking the cast. • Casting is done in two stages. Pour joint is in the middle of two half circles. • The technique of having gaps in between, leaves unequal division of groove line in the horizontal and vertical direction. Due to this gap, circular opening becomes oblong but this cannot be perceived at first glance.[53] Thus the form of opening is purely an expression of its construction sequence.

4.3.64 Imprint of form pattern on thickness of the wall of circular opening.

100


101

4.3.65 formwork assembly for circular opening

Section through wall with opening

UP

gap between two rings

ms supports

Elevation of formwork assembly

ring made by ms plate between two angle sections plywood form sheet

Formwork assembly of circular opening

DN

difference in size of plywood sheet

finshied elevation of facade with opening


4.3.66 Formwork of circular opening.

4.3.67 Finished circular opening in the corridor on ground floor.

102


H. Rendering and finishing • There are two types of finishes, one is rendering the grooves and holes and the other is applying a water proofing mix. • All grooves, tie holes and corners are rendered after casting to give it a clean elevation. • The mix is made up of white cement and grey cement to get the desired colour. • H-frame scaffolding was erected to do the finishing in all the cases. • Water repellent was applied all over the building and to all the concrete in order to make it safe from weathering. It also protects the colour of concrete. And it has to be reapplied every 5 years. • Building is maintenance free in terms of the concreting done.

103


A

A Key plan 1:2000 4.3.68 Plan at A. 1:300

r

9x

3x

First floor plan

n

8x

r

8x

r

n

3x n

12x

r n

Ground floor plan

104


B

B

Key plan 1:2000

r 210

4.3.69 Plan at B. 1:300

10x

k

210

3x

r

k r

m

x

4x

8x

m

r

210 2x x 210 x

r

210 2x

210 210 r x r r

k

r

210

First floor plan

3x

r

k m

r

14x

m

Ground floor plan

105


C

C

Key plan 1:2000

4.3.70 Plan at C. 1:300 a

r

a

10x

b

9x

r

6x

x

r

3x

2x

b 2x

i

2x

9x

r

r

9x

i

j

r

r

h

h

First floor plan

a

r

a

10x

b

9x

r

r

x

5x

r

3x

c

b

2x

g

e

9x

h

d

r

f

x

r

r

9x

r

h

Ground floor plan

106


x

x

x

x

x

b1

x

x

r

x

r/2

x

x

4.3.71 Elevation b

r

eq

4.3.74 Elevation a

x

x

x

x

x

x

x

x

x

x

x

r/2 x

r

x

x

3x

x

r 210

x

x x x x x

x

r

x

x

x

r

4.3.72 Elevation c

x

x

210

groove form sheet imprint r residue b beam + slab x size of one panel y constant residue

x x x

eq

eq

eq x

r/2

x

x

x

4.3.73 Elevation d

r

x

x

x

x

x

x

x

x

r/2 x

r

x x x x x

e

b

f

x

g

x

210

a

b

h j

a

c b

h d

107


x

x

x

x

x

x

r

x

x

r/2

x

x

4.3.80 Elevation h

x

x

x

opening

4.3.76 Elevation e

r

4.3.75 Elevation j

x

x

x

x

r

x

x

x

x

x

x

x

x

x

x

x

x

r/2 x

x

x

r

r/2

x

x

x r door r

x

x x x x

x

x

4.3.77 Elevation g

r

6x

eq

4.3.78 Elevation f

eq

groove form sheet imprint r residue b beam + slab x size of one panel y constant residue

x x

r/2

e

x

f

x

g

x

eq eq

x

a

b

h j

a

c b

h d

108


eq

y+210 x

x

x

x

x

x

x

eq

eq

4.3.81 Elevation m

r

4.3.80 Elevation k

x

x

x

r

eq

x

eq

y

eq

eq

y

eq

eq

r

x

y+210 eq x

x

210

r

x

x

x

eq eq

r

x

x

x

r

x

x

r

r

x

x

x

x

groove form sheet imprint r residue b beam + slab x size of one panel y constant residue

x

x

x

x

x

x

x

x

x

x

r

r

x

x

x x x x x x

210

k

m

k

m

109


x

eq

4.3.82 Elevation n

eq

x

eq

eq

x

eq

x

eq x

x

x

r

x

x

opening

x

x

x

x

r/2 x

x

x

x

x

x

x

x

x

x

x

x

x

r

r/2

x

x

x

x

x

x

x

x

x x x x x

groove form sheet imprint r residue b beam + slab x size of one panel y constant residue

n

n

110


4.3.83 Shuttering pattern for slab in entrance foyer

4.3.83 Shuttering pattern for slab in entrance foyer. It does not match with pattern on wall

111


Co-relation of various modules in building *All the drawings are retraced and made again from the source drawing available.

In IIM-A, the dimensions in plan and section are in multiples of x, which is the size of one panel being 1500 x 1500mm. There is no demarcation between different building elements, wall, beam, slab all become one with grooves running over. End of the walls is articulated with a band of 210. Railings, benches, tack boards, windows, light fixtures, metal clamps and other furniture are also in tune with the lines of grooves on exposed concrete. Expression of concrete is smooth, flawless and trying to erase the markings form its production process. The spaces in plan are divided according to a particular grid. N-S parallel walls are in multiple of module x. Last bay with staircase is the smallest bay is not in multiple of x. Partition walls are also not in multiple of x. Residue becomes the key here for composition to bring symmetry all across. Heights are in multiples of 1500, therefore there is no residue in the vertical direction. Band of slab and beam become one and runs all across the building. The strip of 210 is maintained in line with the wall thickness at end of each surface, and the residue is arranged near circular openings. Some elevations of the wall are explained below: • Elevation a, elevation n, elevation h elevation j are similar. • The residue is divided equally and arranged at both the ends to compose the wall. By putting the residue in the second last column it etches continuity and does not define an end. The size of openings is also in terms of x. • In elevation b, the residue is arranged after the end of circular openings in both direction. The band of 210mm which runs on both side, makes the construction joint neat. Slab and beam thickness expresses as one band which runs continuously all across the building. • In elevation d, the residue is at the end where the function of space is to accommodate the cleaning area. It demarcates the difference in function. • In elevation f, the width and height are equally divided as the wall is not in multiples of x. • In elevation h, below the beam band, residue is placed right after circular opening to match the last row with the composition above. More such examples are seen in photographs where the red marker highlights continuity with composition.

112


* Pictures show the modulation of surfaces using shuttering patterns in creating the expression for concrete. Highlighted band is the band of 210mm which runs all across as residue.

4.3.84

4.3.85

4.3.86

4.3.87

4.3.88

4.3.89

113


4.3.90

4.3.91

4.3.92

4.3.93

114


4.3.94

4.3.95

4.3.96

4.3.97

115


4.4 Case study : 3 CEPT Lilavati Library - 2016 Architect: Rahul Mehrotra Architects Construction: PSP Builders

People interviewed: P.S.P- MD of PSP builders Mr. Lalji bhai- civil enggineer from contractor’s office Mr. Hasmukh bhai- site enggineer Ms Ankita- manager at site office 116


1. Faculty of Architecture 2. Administration 3. Auditorium 4. Faculty of Planning 5. Lilavati Library 6. Hutheesing Visual Art Center 7. Office and Student council 8. Amphitheater 9. Kanoria Arts Center 10. Faculty of Technology

4.4.1 CEPT master plan

Introduction:

CEPT is an institute of international repute devoted to architecture, design, and engineering. Library building is a part of expansion project. It is strategically placed in the heart of the campus. It has three basements which are in exposed concrete that houses all the books and reading material. Spaces are designed to house various functional requirements like individual reading spaces, carrels for reading, computer lab, exhibition spaces etc. Two floors above ground are in steel structure. Construction planning: A material testing laboratory is set up on site. Experiments with colors of concrete and mixture are tried on sample walls. For construction, concrete pump* is installed to transport large quantity of concrete easily on work area. There is a workshop area on site where formwork is fabricated. Heavy machinery was brought on site to excavate land for making basements. Intermediate level is excavated in a way that it becomes platform around floor plate area. Water proofing in each level becomes very critical during construction.

Concrete line pump*-concrete pump is either mounted on a truck or placed on a trailer, and it is commonly referred to as a line pump or trailer-mounted concrete pump. This pump requires steel or flexible concrete placing hoses to be manually attached to the outlet of the machine. Those hoses are linked together and lead to wherever the concrete needs to be placed. Line pumps normally pump concrete at lower volumes than boom pumps and are used for smaller volume concrete placing applications. (https://en.wikipedia.org/wiki/ Concrete_pump)

117


4.4.2 N-E view of library.

4.4.3 Reading spaces on second floor

4.4.4 View of louvers on second floor

4.4.5 Entrance foyer

4.4.6 Book shelves in 1st basement

4.4.7 Passage in 1st basement

118


Structural system A stepped, exposed reinforced concrete retaining wall creates the sub-terrain base within which the lower half of the building rests, nestled in the center of this core are dense book racks, supported by an efficient exposed concrete column grid which continues until the floor of ground level. Moving above ground, programmatic variation is manifest through a response in structural system. Light weight structural steel frames the upper levels, maximizing natural light intake and minimizing additional loading on the lower levels. The building is capped with a thin extended roof. The edge of the roof is supported by minimal steel plus columns, within which rests a series of operable louvers.[54]

[54]

https://www.facebook.com/CEPTUniversity1/photos/ a.778303818948795.1073741875.3716 49769614204/ 778303905615453/?type=3&theater

Construction sequence Construction sequence is shown in the series of photographs during construction.

119


4.4.9 Section AA

8 6

6 7

9

4

5

A

1

1

A

3

2

1

1. Bridge 2. Entrance foyer 3. Exhibition space 4. Baggage 5. Reception 6. Toilet 7. Elevator 8. Electrical duct 9. Dumb water

0

1

2

N 5

4.4.10 Ground Floor plan

120


4.4.11 1st Basement Plan

4.4.12 2nd Basement Plan

4.4.13 3rd Basement Plan

121


4.4.14 Excavating site

4.4.15 PCC at bottom

4.4.16 Concreting using pump

4.4.17 Concrete pump

4.4.18 Plinth beam and column reinforcement

4.4.19 Casting concrete in the basement floor

4.4.20 Water proofing treatment

4.4.21 Water proofing treatment

122


4.4.22 Concreting finished in 3rd basement

4.4.23 Casting columns and wall simultaneously in 2nd basement

4.4.24 Casting columns and wall simultaneously in 2nd basement

4.4.25 Casting slab for 1st basement with pump

4.4.26 Slum test

4.4.27 Foundations for columns

4.4.28 Concrete pump

4.4.29 Concrete mixer

123


FORMWORK FOR TYPICAL DETAILS OF THE BUILDING A. Formwork for vertical elements B. Formwork for horizontal elements C. Vertical and horizontal groove D. Tie holes E. Corners F. Construction joints G. Skylight openings, windows H. Rendering and finishing 124


A. Formwork for vertical elements

[56]

refer 4.4.33

[57]

refer 4.4.32, 4.4.34

Criteria for choosing this system was based on availability of material and time taken to do construction. There are mainly four types of vertical element in this building: 1. Columns 2. Ground floor walls 3. Basement walls 4. First floor wall Formwork for each of them is done with a different technique.

shikanja*- ms member to hold wooden ties together in formwork for concrete.

Formwork material description Special laminated plywood with high density is used for shuttering of exposed concrete. Conventional system is chosen over proprietary system of formwork as it is easier cut the plywood on site according to patterns given by architect. Option of using ACRO system of formwork was ruled out as it was too old. Plywood sheet used is of standard size 1.2mx2.4m. Other parts of formwork are from PERI company. 1.Columns Concrete columns run from 3rd basement to ground floor. Typical column is 750mmx300mm. Height required for column is 3 meters, which is more than the standard size of form sheet (laminated plywood). Two sheets are joined to achieve the height. This joint leaves a mark on cast. Construction sequence is shown in diagram.[56] Formwork is removed after 24 hours of casting to get clean corner edges. Sometimes an extra runner is put at the corner edge. The vibrators of latest technology were available and so it was possible to cast the full height in one flight. In case if there is an overlap of plywood sheet to achieve height, it is very minimum of 50 to 60 mm. All columns have a starter which helps in alignment and gives support to form sheet. These starters are hidden in the flooring. Sometimes to achieve alignment with slab, columns are casted 10mm more and later cut with the cutter machine once aligned. H-frames are used for scaffolding. Assembly of formwork is shown in the diagram[57]. Wooden members are nailed to plywood sheet as studs on all four sides. Wallers and shikanja* are fixed on one opposite pair to make assembly tight.

4.4.30 Columns in 2nd basement

4.4.31 Columns during construction

125


126

concrete starter

reinforcement rods

wooden ties

ms wallers

tie rods

wooden studs

ms clamps

laminated plywood

shinkanja

wooden spacers

H-frame scaffolding

khapeda (working platform)

4.4.32 Formwork assembly for column


4.4.33 Construction sequence for formwork of columns

FIRST FLIGHT - FULL HEIGHT Transporting of materials and tools in work area of site Line out Tying reinforcement bars Casting starter

PREPARATION OF PARTS OF THE FORMWORK Cutting of plywood sheet with hand saw on site as per measurements

Joining two pieces of plywood sheet to make L

Preparing two such L of plywood panels

nailing wooden members as studs to each assembly of L

ERECTING SECONDARY SUPPORTS Erecting each assembly of L panel

Erecting H-frame scaffolding

Fixing wall plate on two opposite sides

Fixing sikanja with wall plate

Fixing ms wallers on the remaining two sides

Passing tie rods through ms waller at edges on both sides

Tightning assembly of tie rods with wooden clamps

Fixing supporting shores Checking the angle of assembly with odimbo and plumb

Adjusting the assembly to become perpendicular by adjusting supporting shores

END OF FORMWORK ASSEMBLY Fixing wooden packing inside hollow box prepared for concreting Concreting Dismantling

127


128

4.4.34 Formwork assembly for columns

Preparing panels in L-shape

Plan

Formwork assembly during cast

Section aa

Finished column


4.4.35 Column starter

4.4.36 Formwork assembly for column during construction

129


4.4.37 Sequence of casting columns in basement

4.4.38 Finished column showing mark of plywood sheet joint

130


4.4.39 Column starter in 3rd basement. concrete spacers in between

4.4.40 Starter for columns in 3rd basement

131


2.Ground floor walls: [58]

Ground floor walls are closed boxes in different shapes placed on plinth. It was most difficult part in making of the building. Challenge was to get the exact shapes, with sharp corners with existing formwork technique. Formwork parts used for ground floor walls is same as that is used for columns. The technique of using them is different. The walls are closed objects. All the walls were supposed to be casted hollow, but the technique of casting did not prove true for all kind of shapes. In three triangular walls, it was not possible to remove shuttering from inside once casting is finished, so they were casted solid[58], as the cost of concrete was less then shuttering cost. Drawings prepared didn’t take into consideration the thickness of the hollow walls. So, the position of tie holes was decided on site. Patterns thus created by tie holes are purely outcome of construction sequence. Construction till plinth level was finished before starting the walls. Casting starter was not preferred as it will leave a mark, therefore rcc packings were placed at the base. PERI beams are used as studs, wallers and tie rods holds the assembly. Casting is done in one fight till bottom of chajja. Formwork was removed after 24 hours of casting to get clean corner edges.

4.4.41 Ground floor wall after de-shuttering

refer 4.4.47

4.4.42 Ground floor walls

4.4.43 Ground floor walls after rendering

132


133

4.4.44 Assembly of formwork for ground floor walls

concrete spacers

reinforcement rods

plinth

tie rods

metal clamps

PERI beams

ms wallers

wooden studs on inside

ms supporting shores

wallers fixed vertically at corner


4.4.45 construction sequence of formwork for ground floor walls FIRST FLIGHT - FULL HEIGHT Transporting of materials and tools to the work area on site Casting till plinth level Marking the shape of walls on plinth

PREPARATION OF PARTS OF THE FORMWORK Cutting of plywood sheet with hand saw on site as per measurements

Chamfering the corners to make the corners join each other

Inner box to be erected corners checked on ground

Drilling holes for tie rods in plywood sheet

Fixing PERI beams as studs

PREPARING TIE ROD ASSEMBLY PARTS Cutting tie rods

Concrete packings of thickness of the wall, fixed to inner box of shuttering at base

Tying reinforcement bars

Fixing pvc pipes for tie rods with plywood sheet

Passing tie rods

Next set of formwork erected with concrete packing as support from base. This acts as a starter.

Fixing PERI beams as studs

Cutting pvc pipes

Scaffolding erected for workers to go inside the hollow box made by shuttering

Wallers fixed from both the sides

Tightning tie rod assembly to plywood with wooden clamps

Fixing supporting shores

Checking the angle of assembly with odimbo and plumb

Adjusting the assembly to become perpendicular by adjusting supporting shores

Concreting Dismantling Removing pvc pipes from tie holes Rendering

134


135

Assembly of formwork during cast

Section aa

Plan of ground floor wall

4.4.46 Assembly of formwork for ground floor walls


1

Key plan showing solid walls 1- Formwork parts shown for this wall

Line out

Erecting inner box of plywood

Nailing concrete spacers at the base Erecting outer plywood box 4.4.47 Sequence of erecting plywood panels for ground floor walls

4.4.48 Ground floor walls under construction

136


4.4.49 Ground floor walls under construction.

4.4.50 Ground floor walls under construction.

137


3. Basement walls Formwork parts used are same as that of ground floor walls. Starter is done to get the alignment and erecting the shuttering, which is then hidden in flooring. Drawings prepared by the architect’s office had three rows of holes in each panel in the elevation. But during construction, middle row was eliminated as it was not structural and it increased the time for construction. There is a color difference between the basement wall and ground floor wall. To differentiate between colors SS channel is casted between them. The size of the panels used for shuttering is 1.22 x 2.44 meters. Composition of each panel makes maximum use of full size of sheet to avoid wastage. Shuttering is prepared on site. Sheets are cut according to size and Peri beams are used as studs. Tie holes are skipped wherever it has to pass through wall thickness. In some walls in 3rd basement proprietary system of formwork is used, as it will not be exposed to users. Casting of full height is done in one flight.

4.4.51 walls in 2nd basement

4.4.52 walls in 2nd basement

4.4.53 walls in 1st basement

138


4.4.54 formwork assembly for basement walls

Section aa

Plan of basement wall at a typical junction

139


4.4.55 Basement wall under construction

4.4.56 Basement wall under construction

140


4.4.57 Proprietary formwork for basement wall

4.4.58 Proprietary formwork for basement wall

141


4. First floor wall 59]

Wall on first floor is made using wooden strips as form material. Wooden strip has its imprints on wall. The texture changes from smooth finish to wooden imprints. Difference in texture is used to emphasize change in structure on first floor which is all steel. The many striped divisions give a sense of a lighter material, unlike walls below which looks like a mass. Wooden strips are nailed to plywood sheet according to given sizes. The plywood is framed for primary support and wallers for secondary. Tie rods are passed in a way similar to other walls. [59]

4.4.59 Wall on first floor on South facade

refer 4.4.61

4.4.60 Wall on first floor on South facade during construction

142


4.4.61 formwork assembly for wall on first floor

Plan

Section aa

143


B. Formwork for horizontal elements: 1. Slab: Form material used for shuttering is laminated plywood sheets. Adjustable ms shores are mounted on tripod stands. On top of it, Peri girders are placed fixed with U-clamps. Plywood sheet is directly nailed to Peri girders.[60] Here the plywood does not need framing. Assembly is done in such a way that at every junction there is a support and girder runs across the grid of plywood sheet. Composition of sheets is done in a way that columns and skylights edge matches the grid made by sheets in slab [61]. Formwork for bridge is also done with similar technique.

[60]

refer 4.4.67

[61]

refer 4.4.66

Sketch of panels in slab.*not to scale 4.4.66 Position of columns are aligned with panel in one direction

4.4.62 Shuttering pattern of bridge

4.4.63 Bridge on East side

4.4.64 Shuttering pattern of slab

4.4.65 Skylight in slab

144


145

4.4.67 formwork assembly for slab

Section through slab during construction


4.4.68 Formwork for slab

4.4.69 Nailing plywood sheets on PERI girders for casting slab of 2nd basement

146


4.4.70 Temporary ramp made for transporting material to cast slab

4.4.71 Formwork assembly with cut outs in slab

147


2. Plinth Plinth becomes part of elevation of the wall inside the building. Formwork parts is similar to that of column. To avoid waste of material and dead shuttering, brick masonry is done up to 400mm, and then concrete is casted[62]. There are two rows of tie holes. In the lower row, tie rod is passed through brick masonry while laying bricks, this rod is not structural. In elevation outside it won’t be seen, but inside it is a part of composition of the holes in wall. As technique of casting, concrete spacers are put instead of making starter.

[62]

refer 4.4.80

4.4.72 Plinth during construction

4.4.73 Plinth during construction

148


4.4.74 Plinth on north facade

4.4.75 Plinth and wall

4.4.76 Pattern of plinth from inside

4.4.77 Plinth corner

4.4.78 Plinth on South facade

4.4.79 Plinth corner edge with wall

149


Plinth lvl

Ground lvl

Typical section through plinth showing formwork parts 4.4.80 formwork for plinth

150


3. Chajja

[63]

refer 4.4.86

[64]

refer 4.4.81

Texture on chajja is different on both sides, inside the building and outside. Inside form material used is plywood to match the elevation of wall. Outside it is wooden strips [63]. Shuttering sequence is shown in the diagram. Vertical is casted first and then horizontal, this leaves a line of pour joint beneath the chajja [64]. Scaffolding is similar to that of slab. Wherever chajja passes over closed hollow walls on ground floor, there is dead shuttering*. Dead shuttering is made up of angle sections nailed to wall inside, and on top of it waste plywood [65].

[65]

4.4.81 Chajja and wall

4.4.83 Chajja from inside becomes part of elevation of wall

4.4.82 Corner of chajja from inside

4.4.84 Shuttering pattern with wooden strips on chajja

refer 4.4.87 Dead shuttering*- Shuttering that cannot be removed after cast. It stays in tis place.

4.4.85 Shuttering pattern of wall and chajja match

151


Erecting scaffolding and shuttering

Casting vertical

Casting horizontal

Section through wall

Plan of ground floor wall showing position of plywood for chajja

4.4.86 Formwork assembly for chajja

4.4.87 Formwork for chajja above walls

152


C. Tie holes

[66]

refer 4.4.91

[67]

refer 4.4.89

Assembly of formwork for casting holes consists of pvc pipes (used for electrical work), tie rods, metal clamps. Samples were tried using corks along with pipes, but its assembly was time consuming, hence only pipes were used. Sequence of assembly of placing tie rods is given in the table. It is made sure during assembly that reinforcement rods do not touch the pipes [66]. After casting, tie rod is slides out. Pvc pipe is pushed out from one end with a specific tool. All holes are filled with grout, with a tool developed locally. Holes on ground floor are filled with epoxy grout and then finished with cement to match the color of the wall while rendering. An offset of 150mm is kept from the surface of wall, to mark the presence of holes [67]. Holes in basement are filled non-shrinkage grout and flushed with wall surface from outside as there could be chances of water leakage. Inside it is treated similar to holes on walls of ground floor. Tie rods are passed through formwork to hold concrete, but it can be placed wisely to make a composition on elevation. In typical elevation of the walls inside, holes are at distance of 400mm between two panels, and then divided equally in two parts between dimension of panel [68].

[68]

refer 4.4.93

4.4.88 Tie hole after rendering

4.4.90 Rendering

4.4.89 Tie hole during rendering

153


Section through typical wall showing formwork with tie rods

Tie hole after cast in wall on ground floor

Tie hole after cast in wall in basement

4.4.91 Formwork for tie holes

4.4.93 Tie holes on wall from outside

4.4.92 Composition of tie holes in a typical panel

4.4.94 Composition of tie holes in a panel on wall in basement

154


4.4.95 PVC pipes and tie rods passed through sheet from one side

4.4.96 Tie rods in place after cast

4.4.97 Tie rods before removing

4.4.98 Removing pvc pipe from cast with tool and hammer

4.4.100 Plugging epoxy grout in the hole

4.4.99 Tie hole after cast

4.4.101 Finishing with cement 4.4.103 Tie holes after filling the grout

155


D. Corners There are two types of corner edges. Inner corner edge and outer corner edge. Both are treated differently. Corner edges on inside at every perpendicular junction shows imprint of thickness. This is because when two plywood sheets joined at right angle, plywood is not chamfered at 45 degrees, exposing the thickness of plywood to cast[69]. While casting plinth perpendicular edge is difficult to cast. Sharp edge tends to chip off. To overcome this, a chamfer strip is nailed to shuttering as shown in the diagram[70]. Chamfer strip is laminated wooden strip. Plinth edge is not rendered after cast. In ground floor walls, Corners which are perpendicular are chamfered [69] . A similar groove strip is nailed at the corner while casting. It was difficult to get perfectly clean perpendicular edges as it used to chip off, due to wear and tear. Hence it was an on-site decision to chamfer the edges. Walls which are not perpendicular, their corner edges are not chamfered. Walls on the four corners were not supposed to be chamfered because it was not possible to match the angle of plinth which is perpendicular and angle of wall which is not. Perfect clean angle was obtained during casting, but due to ongoing construction on site, the edge eventually chipped off. Therefore, it was decided to chamfer it while rendering [71]. So, the junction where wall meets plinth is unresolved. Edges which don’t meet perpendicularly are not chamfered. The corner where the chamfered edge from wall and chamfered edge of plinth meet, is not detailed out. Therefore, the chamfer angles don’t meet as, formwork of strip is not erected together. Different conditions of corners are shown in the pictures.

[69]

refer 4.4.105

[70]

refer 4.4.104

[71]

refer 4.4.118, 4.4.119

156


4.4.104 Assembly of formwork for plinth with chamfer strip Plan of ground basement wall

Plan of ground floor wall

4.4.105 Formwork assembly showing junction at corners

157


4.4.106 Corner between non chamfered wall edge and chamfered plinth edge

4.4.107 Corner edge of the building. Chamfers don’t match

4.4.108 Corner between chamfered wall edge and chamfered plinth edge 4.4.109 Chamfer at ground floor wall and plinth

Corner junction between wall and plinth at corner of the building

Corner junction between typical wall on ground floor and plinth

158


4.4.110 Chamfered wall edge and chamfered plinth edge at corner of wall

4.4.112 Zoomed image at 4.4.110

4.4.113 Junction at chamfered wall edge and non chamfered plinth edge

4.4.114 Zoomed image at 4.4.113

4.4.115 Junction at chamfered plinth edge and non chamfered edge of non-orthogonal wall

4.4.116 Zoomed image at 4.4.115

4.4.117 Imprint of two chamfer strips nailed to make the required length

4.4.118 Rendered corner edge at the wall at corner of the building. Casted as perfect corner, chamfered later

4.4.119 Zoomed in at 4.4.118

159


4.4.120 Rendered corner edge

4.4.121 Non chamfered corner edge of the wall which is not orthogonal

4.4.121 Corner of building. Chamfered wall edge and chamfered plinth edge. Edge of chajja is not chamfered.

4.4.122 Outcome slurry coming out at chamfer strip while casting

4.4.123 Rendered corner edge at junction of wall and chajja

4.4.124 wall edge chamfered after casting. Junction between wall and chajja corner edge

4.4.125 Slurry coming at corner edge while casting

4.4.126 Zoomed in at 4.4.121

4.4.127 Corner edge inside with imprint of thickness of plywood form sheet

160


E. Construction Joint Skylight: There are cut outs and skylight in the slab. Once the formwork for slab is erected, shuttering for openings is done. For casting skylight and the drain, it is done in parts as shown in the drawing [72]. Bridge: The bridge slab is casted first and the shuttering is kept in place for longer time, reinforcement rods are kept out as dowels and then casted together with plinth. Shuttering of the slab is kept in place for longer time after plinth is casted. Extra reinforcement is required as it a cold joint. Problem is discussed with a structural engineer. Underneath the beam pour joint line is visible, which gives a hint of the construction sequence [73]. Mezzanine: When the column is casted on a mezzanine slab, a starter is done first to get the alignment. The imprint of the starter can be seen as there is no flooring [74].

4.4.128 Bridge

[72]

refer 4.4.136

[73]

refer 4.4.135

[74]

refer 4.4.147

4.4.129 Joint between bridge and wall

4.4.130 joint between parapet and slab of bridge

161


4.4.131 Junction at bridge and wall

4.4.132 Shuttering pattern for bridge

4.4.133 Construction joint edge between bridge and wall

4.4.134 Zoomed in at 4.4.133

Casting slab for bridge

4.4.135 Construction sequence for casting bridge and plinth

Casting plinth, whole slab shuttering still in place

162


4.4.136 Construction sequence for drain and skylight

Casting basement wall

Earth filling and pcc in the void

Casting slab and skylight

Casting drain and then wall

163


4.4.137 Shuttering pattern at skylight in corner

4.4.138 Joint between skylight and slab

4.4.139 Skylight - flooring -drain

4.4.140 Joint between skylight and slab

4.4.141 Band of beam from inside in basement

4.4.142 Construction joint between two flights demarcated with ss channel

4.4.142 Slurry coming out between two panels while casting. Pour joint

4.4.143 Slurry coming out between two panels while casting. Pour joint

164


4.4.144 Construction joint between beam and column

4.4.145 Imprint of starter

4.4.146 Zoomed at detail

4.4.147 Construction sequence for columns and beam at intermediate levels in basement

Starter

Imprint of starter

extra reinforcement at cold joint

Casting slab

Casting starter for next flight

Finished casting

165


F. Openings

[75]

refer 4.4.150

[76]

refer 4.4.149

Shuttering for opening is done along with walls. There is a plywood frame and then a wooden frame nailed to each other. Two frames are needed to resist thrust of concrete while vibrating [74]. These frames are taken out after casting and rendering is done to finish edges, that is why we see imprint of thickness of plywood sheet in elevation. All windows are designed in way that it comes on the edge of one panel, and matches the line in elevation [75]. Cut outs in slab are done while making its formwork [76].

[77]

refer 4.4.155

4.4.150 Formwork assembly for window in wall

Section through typical wall

4.5.148 Elevation of window after rendering

Elevation of wall and window

4.5.149 Composition of window in one panel

166


4.4.151 Window frame in place after cast

4.4.152 Window frame in place after cast

4.4.153 Fixing window frame with formwork of wall

4.4.154 Elevation of window after rendering

4.4.155 Preparing formwork for cut outs in slab

4.4.156 Formwork assembly for cut out in slab

4.4.157 Formwork for slab with cut-outs

4.4.159 Casting slab

167


G. Grooves

[78]

refer 4.4.161, 4.4.162

[79]

refer 4.4.160

There is a change in color of concrete between basement walls and ground floor walls. To mark this change a ss channel is casted between them instead of groove. It does not hold any constructional reason. It also marks the cold joint between two floors [78]. Drip mold is casted as groove in the chajja. A C-channel groove strip is fixed to shuttering which gives the imprint of groove [79]. H. Rendering and finishing Rendering and finishing is done after casting. A water-repellent coat is applied to all the surfaces of exposed concrete to protect it from any exterior damage. This coat has to applied every 5 years as a maintenance. The corners and chamfers are given touch up as they have not come out exact. Similar color slurry is prepared for touch up. Grooves and tie holes are rendered similarly. Pour joints are too carefully rendered to make is less visible.

4.4.160 Grooves for drip mold in chajja

4.4.161 Cast in SS-channel between two floors, marking color change

4.4.162 Cast in SS-channel

168


CORRELATION BETWEEN BUILDING ELEMENTS *All the drawings are retraced and made again from the source drawing available.

Sheet size is the module size. Composition is done by keeping 8’x4’ size modules fit in maximum number, and then equal divisions are done with concern of minimum wastage. Formwork pattern on each wall is the mirror of half. Divisions are not done in multiple of any number. IN vertical direction, it is in multiple of the height of one panel. Doors and window openings are not sized according to form panel size. In the elevation of walls on ground floor walls, position of tie holes was negotiated in comparison to drawings issued by the architect. Holes were not possible uniformly everywhere because the hollow walls have thickness. In the plinth near the both the ends there are no tie holes because the rods cannot pass through the thickness as it is continuous square. The holes near bridge are not possible because casting of bridge slab and plinth is done in parts. In some places, tie holes are missing because it was not possible to pass the rod, during construction.

169


A

1

A

Key plan

3.163 Elevation 1

4.4.163 Section AA Form material imprint line SS channel

170


B

B

2

Key plan

3.165 Elevation 2

4.4.164 Section BB Form material imprint line SS channel

171


C

3

C

Key plan

3.167 Elevation 3

4.4.165 Section CC Form material imprint line SS channel

172


3 D

D

Key plan

3.169 Elevation 4

4.4.166 Section DD Form material imprint line SS channel

173


5. INFERENCES AND CONCLUSION

174


CONCLUSION: Formwork for each of the typical detail of building is compared at a time in the analysis to draw parallels between them. Expression of forms have emerged alongside the technical developments. At Indology, concrete is used as a humanizing element, by using wooden boards for texture, the concrete is dripping and oozing at junctions, no additional treatment is done to the surface by letting concrete flow in its raw state. It is very much a reflection of its construction process. Texture is not of pristine quality as compared to in the later case studies. At IIM, there are conscious efforts to erase the traces of pours and joints and thus of construction process, a controlled, smooth textured surface is obtained. At library, a similar effort has been done to achieve the expression which tries to erase the construction process, but the efforts are in vain at many levels. Its evident that there has been a shift in tools and techniques, and the shift has occurred because there were limitations rising from that particular set at a given time period. The effects can be seen on number of tasks performed, number of parts for assembly and number of skills. Three buildings have different forms, but are binded by limitations rising from construction process and form is result of its response to them. Expression of each detail build the language for exposed concrete, therefore a discourse on construction techniques to its minutest details in exposed concrete buildings will lead to a product that possesses the capacity to be meaningful at both construction and design level. Tables and conclusion are discussed further.

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Table 5.1 BUILDING Indology

Typical H-column, Wall on ground

ASSEMBLY

MATERIAL Form material: plywood sheet 4’x8’ Primary supports: 3”x5” wall plate, 2”x3”wooden section framing, wooden shores

Column: shuttering is tapered in H-shape, erected in parts. Shuttering divided by plywood panels to get full height of casting in one flight. Starter hidden in flooring

Scaffolding: nilgiri wooden logs

IIM-A

Typical wall

Form material: laminated plywood sheet4’x8’ Primary supports: ms wallers, angle section framing Scaffolding: ms H-frames, angle brackets, ms shores, ms angle brackets

CEPT Library Typical column

TECHNIQUE Type: Conventional formwork system for column and wall

Form material: laminated plywood sheet4’x8’ Primary supports: peri wallers. Wooden section framing, ms wallers

Wall: grooves are provided vertically after every panel of shuttering to avoid pour joints. In horizontal direction height can be achieved in one flight of casting. No starter

Type: Shifting formwork System

Grooves provided horizontally and vertically after each panel to get full height for casting in one light avoiding pour joint. Starter in ground floor, hidden in flooring

Type: Conventional-PERI formwork system Two panels joined to make full length for casting in one flight. Imprint of panel at joint rendered later.

Scaffolding: ms H-frames, adjustable supporting shores

CEPT Library Wall on first floor

Form material: Wooden strips

Primary supports: Plywood panel, wooden section framing, ms wallers Scaffolding: ms H-frames, adjustable supporting shores

CEPT Library

Ground floor wall

Form material: laminated plywood sheet4’x8’ Primary supports: peri beams framing, ms wallers Scaffolding: ms H-frames, adjustable supporting shores

Type: Conventional-PERI formwork system

Wooden strips nailed to plywood panel instead of using wooden strip as panel. Panel is erected as conventional method. Chajja beam becomes the starter

Concrete packing used as starter to avoid full starter band as it will give imprint on wall. Some walls filled up fully as hollow shuttering not possible. Wall divided in two panels for shuttering to achieve full height in one flight of casting.

176


VERTICAL ELEMENTS • In Indology, time taken to prepare shuttering was more as it had to be made from materials which are not industrially processed and machinery was not power operated. Studs and wall plates have to be cut and from wooden sections. So less number of repetitions were possible from one set which led to making of more formwork panels and hence more time consuming. But assembly was more responsive to particular to problems as each assembly was made by skilled carpenters just as piece of furniture. Factors of time and accuracy have led to development of tools and their material quality. At IIM, framing material becomes ms sections, which are lighter in weight and easy to handle on site. They are industrially manufactured and therefore are precise and only needs assembly on site. This saves time and gives more accuracy in the assembly of formwork. Similarly, in library, parts of formwork have become more efficient in terms of its density and durability as they are industrially manufactured. For all this reasons, no of parts of formwork in library have decreased compared to Indology and IIM; making assembly faster. • Material quality and finish of form material has changed. This is because the acceptability of texture of exposed concrete has changed its preferences over time. At Indology, the plywood was not much in use for shuttering, and therefore its material quality was not advanced enough to give good results in texture of the exposed concrete surface. Texture of wooden boards was very raw, as the wood was not processed before using. While at IIM and library laminated plywood specially designed for exposed concrete work with high density, use of wooden boards has decreased as smooth texture is more acceptable in exposed concrete work. • Aviliblity of form material effect the assembly of formwork which in turn effects the outcome. There has been a transition in expression, with form material as a constant. In Indology there are no modules of panel size on surface, instead the elements itself are modules which makes the building, where as in IIM and Library, there is modulation of surfaces with panel size. • At Indology, plywood available in 1960s used to come in different sizes and not the industrial size of 4’x8’. Column surfaces are composition of different sizes of plywood panel to avoid wastage of the sheet or to hide the pour joints. The imprints of nail heads on the periphery of each panel in column are more in number. This is result of fixing wooden studs to form sheet, it will require more nails to keep the form panel straight as it is not perfectly sized and straight. In IIM, plywood sheet used as form material comes in industrial sizes of 1.2x2.4m, sheet of 1.5m x 1.5m is cut from full size to make one panel, leaving the residue which is then used for formwork of 210 band. This size repeats in vertical and horizontal direction to make a grid. At 177


some places in the building, in the smallest space, surfaces are not in multiple of x, leaving residue. This means it is not resolved or module size if big enough. There has been a deliberate choice made in not using standard size of sheet but using it in 1.5x 1.5m module. The determinant factor for the size of module are availability of material, maximum use and less wastage, available concreting technology, available tools (will be discussed ahead). Along with the technical factors it is also a design decision to decide the size of smallest module. In library full panels of 1.2x2.4m are used for minimum wastage of sheet, and fast assembly. Surface is not in multiple of one standard dimension which makes residues of unequal dimensions. The size is big to be repeated as modules. • Tools available for concreting technology effect the choice sequence of casting and therefore the output. During Indology, concrete technology was not advanced enough, vibrators needles were not long to vibrate more volume of concrete. Large and big surfaces were practically impossible to cast without pour joints or making grooves which hide the pour joints. This could be one of the reasons of grooves on wall, and many divisions of plywood panel on surface of column. More number of shuttering assemblies will have to be made, giving less repetitions, as it takes time in concreting and drying. During IIM, vibrators available were still not advanced enough to cast high walls without a construction joint. Therefore, grooves are designed around each panel. Grooves hide mark of construction joint and allows for halts in construction. Grooves which are a technical requirement, become language of the building. In library, advanced machinery in concrete technology is available, making it possible to cast large volumes of concrete without halts in one flight. The column therefore has no imprints of construction joint or pour joint on its surface. As height of casting one flight is equal to height of one floor, there are no construction joints and hence no grooves necessary. As there are no grooves, there is non alignment between two pours. As the technology gets more sophisticated, tasks in assembly of formwork decreases but it also reduces attention to particular details. • The technique of making formwork has its effect on outcome and construction sequence. In Indology, formwork was first assembled on ground; tried; dismantled and then erected again. This increased a step in sequence of construction. The technique of constructing formwork for column lied in designing how easily it would be dismantled and therefore the shuttering is slightly tapered which make the final form tapered too, which means this system of formwork does not prove true for highly accurate output. Erecting wooden supporting shores took less time compared to adjustable shores, as it was done with nails but less accurate. 178


A technique of formwork that is easy to dismantle and could be repeated was needed at IIM as the walls were high and long. The shifting formwork for casting walls makes the assembly more accurate and faster to erect. Angle brackets as supports that can be fixed in the holes left by tie rods shows how interconnected the construction process and form is. This led to standardize the position of holes and size of panels across the building. The step of checking whether assembly is correct or not is eliminated because it is designed in way that it checks for itself. In Library, the assembly of the secondary supports of the shores is more accurate as it is done with adjustable shores, but takes more time compared to system in Indology. For the walls on ground floor, the technique of dismantling the formwork from inside was not feasible due to which some of walls were casted solid. Tie rods could not be passed through few junctions and so holes are not symmetrically composed in some cases. Walls are casted by using PERI formwork system, this requires less of nailing as there are no studs for support and only PERI girders. This effect the construction sequence of the whole building, as it is faster to build formwork.

HORIZONTAL ELEMENTS • Indology and IIM both use ms plates as form material for slab, this dramatically changes texture of the surface compared to wood and plywood. Color is little orangish as metal gets rust and the edges of panel are not smooth. Library uses standard plywood sheet to maintain same texture in horizontal and vertical elements. • In Indology, wooden boards are used for formwork of beams. It is material property of wood to absorb water and shrink, so the junctions can leak. Shrinking helps in deshuttering the form panels, without damaging cast. It has to be oiled and cleaned to be reused increasing a task. Limitations imposed by type of form material, can be used as a tool to design the surfaces of exposed concrete. Length of wooden boards used for formwork of beams came in limited sizes. Form panel for beams are composed out of wooden boards in a way that it can hide the imprint of its size by merging it into a pattern. Availability of metal forms in certain size leaves the imprint of its industrial manufacturing on the surface. As the plates are not available in any other sizes, residues are dealt with wood-metal formwork technique which gives the designer freedom to design the residue to continue the expression of 179


the concrete. Beam bottoms are done with wood, this gives difference in texture differentiating two elements of the building. At IIM, industrially manufactured ms plates are used for formwork of slab, this divides the celling into a pattern made by the standard sizes. Beams uses plywood. It has been conscious effort to match the lines of size of the form panel in beam and slab, but not in walls. At Library, plywood sheet of 8’x4’ are used. To avoid wastage, maximum use of full sheets is done. Corners are not dealt differently because there was no limitation on availability of size and plywood. It was easily possible to cut the residue in required dimension with power tools. • Technique of making formwork: In Indology, form panels are made with hand tools, which gives the maker the responsibility to make the piece that addresses all the problems at that given point. The technique used in beams is tenant mortise joint between two panels; takes more time but gives clean junction as the slurry does not leak. The distance between two shores that support the slab is 2-3’ which is less compared for assembly in IIM and library. This is because of limited length available in wall plates that support slab. More number of parts, more time taken for assembly. At IIM, as a solution to problem of imprint of the thickness of plywood at corner junction, construction sequence is changed. Casting in two parts effects workability of the joint, as it becomes a cold joint between slab and beam requiring more reinforcement material. For residue metal sheet is cut according to size and its panel is made differently. This technique gives freedom to explore composition. In Library, PERI beams are highly durable and so plywood does not need framing support due to which there are no imprints of nail heads on periphery of each panel. Technique of erecting takes less time, as number of parts in assembly decreases compared to at IIM and Indology.

180


Table 5.2 BUILDING Indology

Beam and Slab

ASSEMBLY

MATERIAL Form material: Beam: deodar wooden board. 10’-12’ length. Slab: ms plate Primary supports: 3”x5” wall plate, wooden section framing for beam form, angle section framing for slab form. Scaffolding: nilgiri wooden shores, working charpai with wooden shores

Indology

Overhang slab

Form material: Beam bottoms and side: deodar wooden boards Slab: ms plate Primary supports: 3”x5” wall plate, wooden section framing for beam form, angle section framing for slab form.

TECHNIQUE Wooden boards used for beams to get longer lengths. Boards joined with groove detail, to avoid leakage of slurry. Shuttering of beam is slightly tapered for easy removal. For slab, ms plate used in slabs, but they are plastered later. At junction of ms plate and wooden board, two different types of shuttering is either tied with each other or overlapped to avoid leakage

Beam bottom and side are wooden form. Slab bottom is ms plates. Near corner of overhang slab, for residue, pattern is created using steelwood farma as form panel, to maintain the texture.

Scaffolding: nilgiri wooden shores, working charpai with wooden shores

IIM-A

Beam and slab

Form material: Beam: Laminated plywood Slab: ms plate Primary supports: ms angle section framing to slab, wooden sections framing to beams Scaffolding: H-frames and ms shores, wooden shores

CEPT Library Slab

Form material: Laminated plywood sheet4’x8’

ms plates used for slab and plywood used for beams. Imprint of line at joining of two form panels continues from slab to beam. Both form panels are of same dimension. At junction inside, where two form materials meet; imprint of thickness of edge of either one is avoided. Casting is done in two parts, metal form overlaps plywood form. Pour joint of casting done in two parts can be seen outside, which is rendered later. Use of maximum size of panel to avoid wastage. Pattern of form sheet changes near cut outs in slab.

Primary supports: PERI girders

Scaffolding: Adjustable cup lock system

181


Table 5.3 BUILDING Indology

Beam and Slab at staircase landing

IIM-A

Plan of typical wall showing corner detail

ASSEMBLY

MATERIAL Material for corner: No special material used.

TECHNIQUE Shuttering panel of beam and slab are not overlapped. This gives imprint of thickness of the wooden board on either side while casting. Outer corners are neat, no rendering done after casting. This kind of imprint of thickness of edge of form sheet can be seen at many corners.

For casting clean corner edge Material for corner: Plywood stopper in case of on outer side, assembly is made strong by fixing two option 2. angle sections, which are bigger compared to studs on panel. This studs hold the angels from both sides at the corner. Slurry does not come out giving clean corner. For casting inner edge of the corner, two options. 1. Cut the plywood sheet at 45 degrees, to avoid the imprint of plywood thickness. 2. Cast in two parts, by keeping a stopper at an angle. Some of the outer corners are rendered later

CEPT Library

Material for corner: Wooden chamfer strip

Ground floor wall: Perpendicular corner edges, difficult to cast. Chamfer strip is fixed at corner with plywood panel. It is nailed from inside (side of casting). Corners, which are not 90 degrees are made, by chamfering plywood panel at junction at required angle. Basement wall: Plywood sheet is not chamfered at corner. Cast shows imprint of thickness of plywood sheet on one side of the corner. Corners which are not chamfered are chamfered later with plastering and rendering tools once the construction of building is finished.

CEPT Library

Material for corner: Wooden chamfer strip

Corner at plinth is chamfered. Chamfer strip nailed to vertical plywood sheet at the end from inside.

Plan of basement wall and ground floor wall showing corner detail

Section through plinth showing corner detail

182


CORNERS: There is a shift across three case studies in the material quality and type of formwork parts with a concern to overcome the problems of time taken for assembly and the durability and quality of material. Analyzing the corner junctions, same detail of corner edge is addressed differently in all three, responding to the limitations during their respective time period. At Indology, it has an imprint of thickness of form sheet at its corner edge. This is a limitation of formwork assembly. To cut the wooden boards at an angle with hand tools will take more time, provided they are not all the same size. Because of material property of wood is to shrink and absorption of water, the junctions of corner edges of the formwork assembly are not accurate and they leak slurry making it an uneven cast at corner. This could also be a design decision to leave the concrete rough with joints leaking and oozing. At IIM the industrially manufactured parts of formwork make the assembly faster and more accurate giving clean corner edges, though the problem for avoiding the imprint of thickness of plywood was solved by casting technique; casting the wall in two parts. At Library, materials for formwork assembly become less, that means it takes less time to assembly the formwork parts, still the technique of assembling the formwork was not designed in a way to avoid the imprint. In the hollow walls and plinth chamfer strip is used as a solution to failure of casting perfectly sharp corners. Wooden chamfer strip does not come in enough length, mark at the junction of joining two strips can be seen with an imprint of nail on it. One of the reasons of failure could be curing time and mix of concrete. Corners built up the expression of the building. In Indology the uneven corners justified the raw character of wood, at IIM, it was necessary to get clean corner edges to create the uninterrupted expression of concrete, and at library corners are just an expression of failure of technique of formwork to cast corners.

183


Table 5.4 BUILDING Indology

ASSEMBLY

MATERIAL

TECHNIQUE

Section through wall showing tie hole detail

Material of tie rod assembly: No tie rods, binding wires used for tying

Binding wire is passed through plywood panel and fixed with nails on wall plate on both sides. This technique leaves no holes. Tiny holes by wire are rendered later.

IIM-A

Material of tie rod assembly: pvc pipes, corks

Assembly for tie rod to pass through is made up of pvc pipe and two corks. Corks removed after casting. pvc pipe stays inside. Holes filled from both side with special grout. Because of corks, holes are slightly tapered

CEPT Library

Material of tie rod assembly: pvc pipes

Tie rod is passed through pvc pipe. Pipe is oiled while casting for easy removal. Pipe is slided out after casting is finished and hardened. Hole is filled with special grout.

Section through wall showing tie hole detail

Section through wall showing tie hole detail

184


TIE HOLES: Two shutter panels have to be tied across to make the assembly strong and resist from the force of concrete while vibrating and stop it from falling apart. During Indology it was fixed by passing a binding wire and nailing it to wall plate. This wire is cut later, and leaves almost no mark on the cast. Technique of wire is easier for assembly and less time consuming, but not feasible where more volumes of concrete is to be cast. Less number of tasks. At IIM, issue was addressed by using assembly of corks and pvc pipes. Technique is time consuming as it requires to cut pvc pipe exactly perpendicular to match the edge of cork and wooden clamps. This increases a task construction sequence and also requires skilled workers. The technique is adopted because it is cheaper compared to ready made snap ties. Due to cork, the hole casted is tapered slightly, this allows water to drain off the holes which is again the result of the kind of part used for assembly. Grouting is done to fill holes to protect against weather which adds one more task in construction sequence as compared to Indology. This hole become anchors for supporting the formwork of wall, where the angle brackets are fixed in these holes. Here, limitation rising from the inevitable need of construction process of passing tie rod, becomes an essential part for constructing formwork and defines the language of building by composition of this holes on its facade. At library, technique of assembly and parts for tie holes were purely a result to limitation of time. Pvc pipes and industrially manufactured metal clamps used for passing tie rod. This technique requires less time for assembly. Pvc pipes are removed after cast, for more repetitions, this may have caused damage to periphery of the holes on wall. These holes are not tapered as no corks are used as in IIM. So, it required to fill the holes and also waterproofing.

185


Table 5.5 BUILDING Indology

ASSEMBLY

MATERIAL Material of groove strip: Deodar wood strip

Section through wall showing groove detail

30

40

IIM-A

Section through wall showing groove detail

100

Material of groove strip: pvc strip, foam strip

1500

1500

TECHNIQUE Wood strip prepared on site, with hand tools. Tapered at one end for easy removal. Oiled before casting. Placed at the end of each panel supported by extra stud to prevent the leakage of slurry from junction. Groove strip nailed to plywood panel from the side of casting.

Pvc strip backed by thin foam strip to avoid bleeding. Nailed from inside(side of casting) to plywood panel. Vertical groove strip fixed at the end of every panel, with support of extra stud. For horizontal groove strip, there is an overlap of 100mm in of panel to get perfect alignment. Groove strip is placed in the already casted horizontal groove to avoid damage while casting.

1500

CEPT Library

186


Grooves: In Indology, groove strip is made from wooden sections with hand tools which increases the time in assembly. The tapered shape of strip is considered for easy removal after cast which in turn makes the groove on the surface tapered helping in water to run off. Material property of wood is to absorb water and shrink this helps in easy removal of strip after the cast has dried, but wood is also responsible for uneven texture in the groove. Concrete tends to stick to wood while casting, because of which oiling is done to strip. This increases the time of assembly of formwork furthermore. Limitations in terms of time taken for assembly and texture of the groove are addressed by changing the material of grove strip. At IIM, PVC strip which is factory made saves times in assembly and does not allow concrete stick to its surface. Tapering shape of the strip helps in runoff water in the groove and easy removal of groove strip. Groove is designed as a result of constraint of inefficiency of vibrators to cast large volume of concrete. In the process of construction, it works as a marker for halts. Groove is designed around each panel which eventually forms the language of the building regulating its dimensions. In library, there are no grooves on the surface of wall, which could be to save time during construction or because there was no technical need as it was possible to cast concrete for given heights with advanced concreting technology. The result of not having grooves, leaves marks of panel on surface. Non alignment of concrete on surface between two panel can be observed which could have been taken care of it there was groove between them.

187


Table 5.6

BUILDING Indology

Junction at meeting of two beams and slab

ASSEMBLY

TECHNIQUE At the junction of beams, it is the sequence of construction that is important. Concrete is casted in a manner that it seems like cast of one mold. Beams are casted first. The technique of making formwork pattern different for both sides of beam is different. One side wooden boards are paced horizontally along its length and on other side that are placed vertically making patterns in various directions. After that stubbed columns are casted, to support the slab that is extended above it.

IIM-A

At the junction of slab and starter of the wall, it the technique of casting concrete that is important. To avoid the imprint of pour joint, casting is done in two parts. A stopper is placed at an angle after first step as shown

CEPT Library

At the junction of beam and slab, to avoid the limitation in technique of making of formwork, that is to avoid imprint of thickness of plywood sheet on Corner edge, casting is done in two parts, with cold joint junction.

Plan of typical wall showing corner detail

Plan of basement wall and ground floor wall showing corner detail

CEPT Library Section through plinth showing corner detail

At the junction of bridge and plinth beam, sequence of casting is important. Re baring is done to avoid the cold joint. Shuttering is kept in place for longer time to give strength to cast.

188


CONSTRUCTION JOINT: Construction joints are mainly result of limitations rising from either the construction sequence of formwork or sequence of casting concrete effecting workability of the joint Indology Formwork is used as a tool to create different textures the junction of two beams. Groove, stubbed column and extension of floor, the three different elements are expressive of character of building and in rhythm with the divisions created by other elements. Sequence of formwork and casting is designed according to design decision. IIM At the junction of slab and wall, it is technique of casting that is important. The joint expresses the flawless nature of concrete which is not hindered by any lines or imprints. Casting is done in two parts, to avoid the pour joint line on surface. This technique costs more time. At junction of beam and slab again, it is casting sequence that solves the problem of imprint lines of plywood edge. As casting is done in parts, joint becomes weak and more reinforcement bars are designed for the junction. This is a limitation rising from the workability Library Junction of bridge slab and plinth beam is also casted in parts. This leaves a mark of pour joint on the surface where two elements meet. Form pattern changes at the junction highlighting different element. Similar to IIM more reinforcement is designed as it is a cold joint. Shuttering is kept in place for longer time after casting as a technique to give strength to junction.

189


Table 5.7 BUILDING IIM-A

ASSEMBLY

Section of wall showing circular opening detail

CEPT, library Section of wall showing opening

Indology

MATERIAL

TECHNIQUE

Material for formwork of opening: ms angle sections and plate.

Circular ring of formwork is supported by vertical trusses. There is gap in between semi circular rings of formwork. This allows to apply force in opposite direction to remove formwork.

Material for formwork of opening: Wooden framing, plywood framing

Double framing, of plywood and wooden strips is done to keep the shape intact. Framing of plywood around wood, avoids the leakage of concrete slurry while casting. Plywood framing leaves imprint of its thickness on th wall surface.

No openings in wall

190


OPENINGS Indology There are no openings or cut outs on the surface of wall. All openings are full height openings. IIM Circular formwork for openings is customized technique developed for this particular project. Technique for erecting of formwork is designed with a concern of deshuttering the assembly after cast. Circular metal form is divided in two parts with a gap in between. The gap gives space to provide force in opposite direction to deshuuter without damaging the cast. This effects the circular shape. The quadrant is not divided equally as the gap makes the shape oblong. This is a limitation rising from the technique, perfectly circular shape is not achieved. Library Two layers of framing is done, one with plywood and other with wooden bar. This may be because of the material property of this frames. Plywood framing alone will not take the thrust of concrete and fall apart, therefore wooden framing inside it gives a packing as compared to IIM where only one layer which is metal faming can do. This double framing in opening at library leaves the imprint of marks of plywood thickness on the surface of wall. This is purely a result of limitation rising from technique of making formwork

191


6. BIBLIOGRAPHY Banham, Reyner. The New brutalism : ethic or aesthetic. London: London : Architectural Press, 1966. Collins, Peter. Concrete The vision of a new architecture. London: Faber and Faber Limited, 1959. Gage, Michael. Guide to exposed concrete finishes. London,England etc: Architectural Press , 1974. Hale, William Braham and Jonthan. Rethinking Technology. great Britan: Routledge, 2007. Jean-Louis Cohen, G. Martin Moeller. Liquid Stone: New Architecture in Concrete. Birkhäuser, 2006. Makakli, Elif Suyuk. Technology in Architecture. The role and impact of technology on Architeture. Germany: LAP LAMBERT, 2010. Marsh, Paul. Concrete as a visual material. London: Cement and Concrete Association, 1974. “Notes for theory of making in a time of Necessity.” Zambonini, Giuseppe. Notes for theory of making in a time of Necessity. The MIT Press on behalf of Perspecta, volume 24, 1988. 2-23. Rosellini, Anna. louis i.kahn towards the zero degree of concrete 1960-1974. switzerland: EPFL press, 2014. Thornton, Charles H. Exposed structure in building design. Berkley,P.A,New York,Tokyo etc: McGraw Hill Pub., 1993. Zambonini, Giuseppe. “Notes for theory of making in a time of Necessity.” Perspecta (1998): 2-23. Jha, Kumar Neeraj. Formwork for concrete structures. New Delhi: Mc Graw Hill Education (India) Private Limited, 2013. lika. Re-inventing construction. Ruby press Berlin, 2010. UNPUBLISHED THESIS Rastogi, Parth. Role played by materials and building techniques in the development of elemental forms. Ahmedabad: CEPT UNiversity, 1983. Formwork as Design Tool by Shuji Suzumori, Master of Architecture at the Massachusetts Institute of Technology, February 2006. Shah, Rahil. Concrete expressions : study of architectural expressions in four exposed reinforced cement concrete buildings in Ahmedabad. CEPT University, Ahmedabad, 2014.

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7. ILLUSTRATION CREDITS 2.1 Rastogi, Parth. Role played by materials and building techniques in the develop ment of elemental forms. Ahmedabad: CEPT UNiversity, 1983. 2.2, 2.3 Jha, Kumar Neeraj. Formwork for concrete structures. New Delhi: Mc Graw Hill Education (India) Private Limited, 2013. 3.1 https://www.google.co.in/search?rlz=1C1DIEZ_enIN752IN752&biw=1280&bih=615&tbm=isch&sa=1&ei=AXcKWqDIKoPrvgSwyoWABQ&q=panthenon+architecture&oq=panthenon+architecture&gs_l=psy-ab.3..0i13k1l2j0i13i5i30k1j0i8i13i30k 1l4.5291.5291.0.5851.1.1.0.0.0.0.210.210.2-1.1.0....0...1.1.64.psy-ab..0.1.210....0.DHnmyyPUQ80#imgrc=76wovGFlqWoOHM 3.2 https://www.google.co.in/search?q=Fran%C3%A7ois+Coignet+house+in+concrete&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj00O-oyr3XAhUBK48KHVMgB-EQ_AUICigB&biw=1280&bih=566#imgrc=Gnzz9cPIEY06zM: 3.3 https://www.google.co.in/search?q=thomas+edison+concrete+formwork&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiHodyWq73XAhWLNo8KHZ8fBq8Q_AUICigB&biw=1280&bih=566#imgdii=xoWhBIBfczaV6M:&imgrc=HZQyrIWrJEKP0M: 3.4 https://www.google.co.in/search?q=ORLY+HANGAR+1916.+Limousin+and+Company+(Freyssinet+Technique.)&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiem8TUp73XAhWFpo8KHSlECh4Q_AUIDCgD&biw=1280&bih=566#imgrc=AdTEzO_I1Q_-3M: 3.5 https://www.google.co.in/search?q=SALGINATOBEL+BRIDGE+Robert+Maillart&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi78oHIo73XAhWDuI8KHd_NDqcQ_AUICygC&biw=1280&bih=566#imgdii=DZ7fXqNkE15j-M:&imgrc=0yhW5gcIgOwDKM: 3.6 https://www.google.co.in/search?q=unite+d%27habitation&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwie0rPa1b3XAhVKwI8KHQsdAskQ_AUICigB&biw=1280&bih=566#imgrc=cSWWNm6dAiOKrM 3.7 https://www.google.co.in/search?q=FElix+candela+concrete+formwork&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjouMyVpL3XAhUYTY8KHZ2UBBEQ_AUICigB&biw=1280&bih=566&dpr=1.5#imgrc=fYgAXWI6FrsIVM: 3.8 https://www.google.co.in/search?q=Yale+art+gallery+Louis+Kahn&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjo34LP9r3XAhUGPo8KHZetA9EQ_AUICigB&biw=1280&bih=566#imgrc=reC5RoaBr6M8hM 3.9 https://www.google.co.in/search?q=luigi+nervi+concrete+formwork&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjjyZb7qr3XAhXBPI8KHT3fDEcQ_AUICigB&biw=1280&bih=566#imgrc=S6JIXRaw-f7tsM: 3.10 https://www.google.co.in/search?q=luigi+nervi+concrete+formwork&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjjyZb7qr3XAhXBPI8KHT3fDEcQ_AUICigB&biw=1280&bih=566#imgrc=S6JIXRaw-f7tsM: 3.11 Jean-Louis Cohen, G. Martin Moeller. Liquid Stone: New Architecture in Concrete. Birkhäuser, 2006. 3.12 https://www.google.co.in/search?rlz=1C1DIEZ_enIN752IN752&biw=1280&bih=566&tbm=isch&sa=1&ei=SuIKWpvBJozyvgSFsoPwDg&q=Paul+Rudolph++concrete+architecture+building&oq=Paul+Rudolph++concrete+architecture+building&gs_l=psyab.3...39667.49143.0.49650.14.14.0.0.0.0.426.2503.0j7j2j1j1.11.0....0...1.1.64.psy-ab..3.4.723...0i7i30k1j0i8i13i30k1.0.0lLZjqpbVQ8#imgrc=8pZ8-q_BaNRIeM: 3.13 https://www.google.co.in/search?rlz=1C1DIEZ_enIN752IN752&biw=1280&bih=566&tbm=isch&sa=1&ei=jOIKWrmgOo2UvQTC1LX4Cg&q=salk+institute+concrete&oq=Salk+Institu&gs_l=psy-ab.1.2.0j0i67k1l2j0l2j0i67k1j0j0i67k1j0l2.1235515.1 238650.0.1242072.12.12.0.0.0.0.785.1917.2-3j0j1j0j1.5.0....0...1.1.64.psy-ab..7.5.1913....0.z0Y9tYACpYg#imgdii=y7n1OtZkSrKjVM:&imgrc=fStKrJLPFymzYM: 4.2.1 -4.2.9

Rahil Shah

4.3.1 https://www.google.co.in/search?q=IIM-A+map&rlz=1C1DIEZ_enIN752IN752&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjwu8Pys8TXAhUIQo8KHfiVDQEQ_AUICygC&biw=1280&bih=615 4.3.2, 4.3.4, 4.3.5 http://www.posts.architecturelive.in/new-campus-for-indian-institute-of-management-ahmedabad-by-dr-bimal-patel/ 4.3.8 to 4.3.13 HCP Design, Planning and Manangement Pvt. Ltd 4.3.22 to 4.3.32, 4.3.66 Nikunj Bhavsar 4.4.1 https://www.facebook.com/search/top/?q=cept%20library 4.4.2 to 4.4.7 https://www.facebook.com/search/top/?q=cept%20library 4.4.9 to 4.4.13 CEPT University, Campus office 4.4.14 to 4.4.29, 4.4.30, 4.4.31, 4.4.35 to 4.4.41, 4.4.49. 4.4.50, 4.4.55 to 4.4.58, 4.4.60, 4.4.68 to 4.4.73, 44.95 to 4.4.103, 4.4.151 to 4.4.159 PSP Projects Limited 4.4.48 Instagram- Cept University * All other photographs are taken by the author * All the technical drawings are drawn by the author * Drawings in 4.2.98 to 4.2.102, 4.3.68 to 4.3.82, 4.4.163 to 4.4.166 are retraced, measured on site and drawn by the author from the base drawings from source

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Symphony in Concrete  

Studying impact of evolution of tools and techniques of formwork in exposed concrete

Symphony in Concrete  

Studying impact of evolution of tools and techniques of formwork in exposed concrete

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