Maison Bamboo - A Modular Exploration of Bamboo Construction

ARCH 7365 Assignment 3: Reinventing Maison Domino

Bundling/Modular/Triangular/Interweave Geometric and spatial explorations of bundling in bamboo construction

MAISON BAMBOO TAN, Regina Tania The University of Hong Kong

MAISON DOMINO

Forces Diagram

Assuming both staircase ends are joints.

Bending

Moment

Force diagram analysis using structural-analyser.com.

Assuming the cantilevering staircase is fixed only on the adjacent side All column & slab joints are pin joints, while column to ground is fixed joint.

The area that experience most bending, and moment subsequently, would be the center, away from the joint.

The area that experience most shear would be the joints, with the stress it is implicated upon.

Shear

From this, the general strategy is to : a. change the beam/slab profile according to the bending moment b. reinforce the slab, stiffening it to mitigate the bending c. allow larger area to receive the shear at the joints.

The following section will demonstrate a simple alterations to the Maison Domino, reacting to the force diagram.

MAISON ???

Prototype Exploration

Research: Bamboo Construction

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As our world is leaning towards sustainability, bamboo is becoming popular nowadays with its eco-friendly properties. It is part of grass species, hence the fast growth of bamboo. It is also strong, often mentioned to have tensile strength of steel and compressive strength of concrete. Although bamboo as construction material is gaining traction, it is more often used as partition or screen - making use of its slender and aesthetic properties - or as a curvilinear construct by making use of its flexibility. Of course, these different uses are according to the type of bamboo. However, when we look into the vernacular, often we would find bamboo is used similarly to timber, in bundles forming column-beam post system. Unlike timber, bamboo in such system are normally just get surface-treated, without alteration in its dimension as it is small. Thus, bamboo present a unique rawness to the architecture, with each element interacting through intricate joints or effective overlapping.

Bundling in bamboo is quite simple at glance, by using ties to hold multiple elements together, allowing the geometry to fit the poles in place. There is a lot of potential in bundling technique, as compared to the usual bending technique that actually require certain conditons (humidity of bamboo, weather, etc), expertise, and energy - heat is needed to bend the bamboo. WIth bundling, the aesthetic relies on the overlay, which could already be achieved through the ties and sometimes bolted steel. It has sustainable potential, as both joint system could be disassembled, making the bamboo reusable again. Another of my interest is using same-dimension short bamboo poles, to explore strictly in the geometry within the dimensional constraint, but also present an opportunity to work modularly. Having the same size would also generate a more general technique that may be applied more broadly.

A particular case study of interest would be the bamboo scaffolding in Hong Kong, with its linearity, modularity, and variety from the bundling technique.

Research: Bamboo Scaffolding around Hong Kong

Photos by TAN, Regina Tania

Bamboo scaffolding are ubiquotuous throughout Hong Kong, an example of structural variation that can be made almost anywhere. The construction method is one that factors in possibility of disassembly, mostly relying on ties. The strength of this construction come from the strong tensile and compressive strength of bamboo, and also the construction method. The individual elements are bundled and interweaved, creating a stronger collective. Sometimes, it forms a bigger element (e.g. column/beam), other times, it forms a sort of mesh from the interweaving. Another factor that is quite interesting is that through the language of bundling, the bamboo scaffolding structures are flexible in their material need, able to utilize a range of sizes.

System Prototype

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Initial exploration on possibilities

Planar

Diagonal

Bundle/interweave/longer span

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Column & Beam Prototype BUNDLING TYPES on plan

INTERSECT 1-way joint

LINEAR INTERWEAVE applied on Prototype 1.a

CIRCULAR - RECTILINEAR INTERWEAVE applied on Prototype 1.b

Linear

Chop

1-1

Column-post

Triangular bundle

Hold

1-2

Beams interweave

Semi-bundle

Clamp

1-2x2

Column-beam interweave

CIRCULAR - DIAGONAL INTERWEAVE applied on Prototype 2

Column height detail

Spacer

complex and not really working stiffening can be achieved from the diagonals

2-beams

Linear configuration

60°

Rectangular bundle

Insert - tight fit

1x3-2

Beam partitioned

3-beams

Triangular configuration

30°

Circular bundle

Insert - place

1x3-2x2

Beam diagonal

as an attempt to fit in to the grid, the result becomes the next iteration

4-beams

Diagonal configuration

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Prototype 1.a.: Linear Interweave

Semi-bundle column

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Prototype 1.b.: Circular-Rectilinear Interweave

Circular bundle column type present an inherent strength compared to other alternatives, as the entirety of the elements work together to form a larger circular form, given that the bamboo poles already has a circular profile. Based on the previous geometrical explorations, the minimum number for circular bundle is 7 same dimensioned bamboo poles. The next amount would be 19. The intermediary would be 13, achieved from direct radial expansion, and 14, achieved from closing the geometry.

This iteration works with the circular bundle column and beam, in the common rectilinear network. This is the common framework system to be found in vernacular bamboo architecture around Southeast Asia. Although seemingly simple, there is a lot of overlap needed to be make when changing directions. The rectilinear form means diagonal bracings would be needed. In principle, the construction follows the column-beam frame structural hierarchy. However, without an inherent geometrical hierarchy, overlaps may vary. Even though bamboo could account for variety with its flexibility, the overall structure may end up being messy aesthetically, or even tilted to certain sides.

Prototype 2: Circular - Diagonal Interweave: Column + Beam Explorations

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Prototype 2: Circular - Diagonal Interweave: Column + Beam Explorations

2 beams - Linear configuration

Limited potential as the column & beam overlap only allows in one direction.

4 beams - Diagonal configuration

Beams intersection also doubles as stiffener. The overlap of beam diameter and column gap creates a unique spatial quality, where the column in forced to bend. It is still stiff with the bundling nature that relies on the interlacing networks, yet it present an interesting hollow mesh-like form.

3 beams - Triangular configuration At the bottom, directly above the inner bundle.

3 beams - Triangular configuration In the middle of column.

Although the beam intersection functions properly as also a stiffener in the 4 beams prototype, here it does not go so well as there is not enough friction to hold. Thus, it just creates larger gap and not really effective in interlocking it. Thus, using the 3 beams configuration, it would be better for the beams to rest atop the inner bundle.

Prototype 2.a.: Diamond (Circular-Diagonal Interweave) SCREEN Natural division of rooms based on grid

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INNER BUNDLE as stiffener and connector to outer bundle

This iteration begins to explore the possibilities of diagonal beams. The form and fitting comes more naturaly, as the hexagon bundle has 60 degree shapes.

Working with it in opposite forms a 30 degree angled beams, which in collective form a diamond configuration.

Although there is endless possibilities with this iteration, it is a bit hard to carry forward a simple modular system, as the column and beam relation only creates 2 possible directions. This is not enough as the diamond shape is four-sided, therefore not inherently rigid. There is still a need to provide diagonal bracing across. We then encounter the same problem as in the linear system, where placement of bracings may seem awkward or forced, taking away the integrity of the structure. This shape does not generate an intuitive variety of joints, new directions must be accompanied with another element, taking away the integrity of the modular language possibility.

spacing in between columns to allow space for steel plate connecting to foundation & allow flexibility CONCRETE PLINTH as foundation, separating column from ground to avoid moisture.

DIAGONAL to provide lateral support and/or as screen SECONDARY BEAM

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Prototype 2.b.: Triangle (Circular-Diagonal Interweave)

The primary structural system of Maison Bamboo is the columns as vertical load-bearing structure, transferring the forces to the ground. Beams comes second functioning to connec the columns by overlapping technique, giving lateral stability to the overall network.

Flooring is non structural, but it is possible to join it together with the network of bamboo, strenghtening the whole structure in the process by adding more rigidity through the amount and interlocking.

Same as the previous iteration, the beam grid would naturally formed the spatial division. Bamboo screens could be used along the beam rail.

The strength of a triangular network is the rigidity inherent to the geometry, It would reduce the need of additional diagonal support.

Triangle also works really well with the hexagon, having possibility to go in three directions, therefore reducing the need of connectors and secondary beams Overall, less materials would be used due to the effectiviy of the triangular network - needing minimum elements compared to other alternatives.

Isometric

Bird’s eye view

Worm’s eye view

Plan

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A

1:50 0

0.5m

1m

2m

A’

Section

Bamboo is suitable for aboveground conditions, as it is susceptible to change in exposure to moisture. Thus, concrete plinth is used as footing connecting the column to the ground. Steel connection is chosen as opposed to embed the bamboo pole to the ground in consideration of mechanical fixing over chemical ones, to allow easier disassembly.

Section A-A’ highlights the different quality of spaces with the same module and construction method.

Bamboo diameter 75mm with thickness 10mm

ATTIC

ROOF the steep angle allows rainwater to directly fall down.

The roof form is created by following the triangular grid, allowing cohesiveness with the structure while introducing variety. A possibility to develop the roof as a feature of Maison Bamboo.

choice of private space (low ceiling height, enclosure) or as most public space (different spatial quality, as auditorium?

Possibility of grand spaces.

Threaded bar

Thin steel plate

FLOORS made of similar dimension bamboo. In practice, floors typically used lighter or smaller dimensioned bamboo.

SPLIT LEVEL

INNER BUNDLE as connector between 2 poles, allowing a continuous column.

Low ceiling space shifting the scale change of activity

Anchor

Concrete plinth

BEAMS stacked bamboo poles going through gaps between the columns. Although the gaps may be smaller than the diameter of the bamboo passing through, in real life this would be accounted from the irregularity of bamboo diameter, as well as its flexibility. The tight contact increase friction and provided extra stiffness for the column not to sway around.

High ceiling space connecting/emulating the outdoor

INNER BUNDLE as stiffener in the mid-length of the bamboo pole as it is the point that experiences the highest bending moment

ELEVATED GROUND

1:5 Foundation Section

FOUNDATION BUNDLE Extra support to provide rigidity near the foundation to prevent bamboo splintering due to the difference in stiffness.

CONCRETE PLINTH mitigating the ground, prevent moisture

Air space for ventilation

Section A-A’

1:50 in A2 0

0.5m

1m

2m

Module Expansion

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Growing from the basic triangular form, replication of its geometry forms other shapes, while still being in the same grid. In a sense, the expansion of modules in all directions follows the spirit of Maison Domino, using one system to expand all directions both horizontaly and vertically. Thus, there is a possibility to create either intimate or large space, as well as having multi-storey building.

TRIANGLE BASIC

PARALLELOGRAM HORIZONTAL AXIS EXPANSION

TRAPEZIUM VERTICAL AXIS EXPANSION

HEXAGON CLOSING THE LOOP

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Module Expansion

MULTI-STOREY UPWARD EXPANSION

INFINITE EXPANSION IN ALL DIRECTIONS

As a space: design opportunity of Maison Bamboo

The strength of Maison Bamboo lies on its module that can expand in two diagonal directions horizontally, and repeating the module vertically. Taking on the form of triangular plan, less materials for diagonal reinforcement would be needed with the stability of the triangle geometry. The triangle configuration also allows flexibility in floor slab/wall/roof variation as well. Being always planar, it is possible to develop a sort of folded structure, as seen in the roof of Maison Bamboo.

The planar and rigid quality also allows exploration and exploitation of bamboo as a lean and element based construction material.

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The room division would be unique to the structure, as walls would then follow the beam grid, creating a very unique spatial identity and experience.

The modularily and flexibility to put floors along the continous columns means a possibility of different height spaces. Different ceiling height at different datum accounts for different condition which can react to, with, or against the ground condition. Split levels, as seen in the image on the following page, is possible - creating intermediary spaces possibly functioning as atrium or auditorium.

The endless possibility of Maison Bamboo is first and foremost achieved through exploration of tubular same-dimensioned structural elements. Which means, this geomtery could be developed with another material as well such as steel - although they will work entirely different from the flexibility of bamboo.

Thus, Maison Bamboo provides a possible solution to the ever-changing needs of space utilization, meeting demands of the current sustainable market - sourced from eco-friendly material and constructed with vision of Design for Disassembly. A raw and vernacular material, it is a humble interjection to the contemporary advances in architecture.