CONSTRUCTING ENVIRONMENTS LOGBOOK WEEK 1 – WILL CARDWELL - 699152
INTRODUCTION TO MATERIALS There are a number of factors that are important when choosing the appropriate materials, these include: STRENGTH: The ability of a material to resist external forces – this can be from one or multiple directions. STIFFNESS: The rigidity of the material. For example, concrete is more stiff than timber. SHAPE: Whether the material is monodimensional (linear), bi-dimensional (sheet) or tridimensional (block). BEHAVIOUR: How a material responds under certain conditions; isotropic (similar characteristics no matter which way force is applied) or anisotropic (different characteristics depending on which way force applied). ECONOMY & SUSTAINABILITY: Cost, efficiency, ability to be transported, if readily available, durability, etc.
SITE ANALYSIS Process of studying forces that influence how a structure will be built. Involves significant amount of research into the site and surrounding area. Important factors include: topography, elevation of water table, soil quality and drainage, existing trees and wildlife, water features, climatic conditions, points of access, circulation paths, availability of utilities, position of favourable views, sources of congestion and noise, cultural and historical resources, scale and character of neighbourhood and position of site in relation to medical, public, commercial and recreational facilities.
CONSTRUCTION OVERVIEW Construction is the process of taking design ideas into the built form. It is a complicated process which can be understood by observing construction principles as well as experimenting and considering precedence for constructing environments. Constructing involves trades, engineers, architects, urban planners and many others who must collaborate and cooperate for a structure to be built successfully.
THE BUILDING The various types of loads which impact structures are static (dead, live, occupancy, kinetic and static loads) and dynamic (wind and earthquake loads) loads. These loads affect the construction of buildings as the design and building process must take into account these loads and be able to resist these forces. These loads can be represented by arrows in space with the head indicating direction and magnitude given by length of the arrow.
BASIC STRUCTURAL FORCES Force is any influence that causes change in shape or movement of a body, it is a vector quantity (magnitude and direction) and represented by an arrow in space. Tension forces involve particles moving apart when external load pull on material. Compression forces involve particles moving together when external load pushes on material.
MELBOURNES BLUESTONE Melbourne is famous for the use of bluestone as a construction material, which can be seen in many buildings throughout the CBD. The prominence of bluestone in buildings such as the State Library and the Melbourne Town Hall shows how the natural landscape impacts the constructed landscape as bluestone became available through volcanic activity of the past.
LOAD PATH DIAGRAMS Applied loads take most direct path along beams down through columns to the ground applying force downwards, where an equal and opposite force from the ground acts directly up. This connects with Newtons 3rd Law, where every action has an equal and opposite reaction.
SUMMARY OF TUTORIAL The tutorial involved an explanation into the properties of the three main construction materials; timber, steel and concrete.
Timber: hardwood (gumtree, eucalypts), (kiln dried to remove moisture to prevent warping), softwood (pine). Timber used predominantly in residential construction. Steel: composed of iron and carbon, strong material under compression and tension. Terminology: UB – Universal Beam, UC – Universal Column, PFC – Parallel Flange Channel, CHS/RHS/SHS – Circular/Rectangular/Square Hollow Section, UA – Unequal Angles, EA – Equal Angles. Concrete: made of cement, water, coarse aggregate (crushed rock) and fine aggregate (sand). Concrete in small scale is in the form of bricks while at large scale precast concrete panels (labour saving, shorten construction time) and poured concrete is used.
The activity during the tutorial was, in small groups, to construct a tower as tall as possible with at least one opening and using the least amount of materials. Initially, the group considered multiple options for constructing the tower; a square base with single bricked walls, a curved base with single bricked walls or a rectangular base with single bricked walls. After experimentation the circular base tower was chosen as a way to conserve materials and create a more balanced, strong tower.
Stacking the blocks in this manner creates an added bond, further improving the structural integrity of the building. In this manner, the weight force of the bricks as well as a greater frictional force is acting as opposed to when blocks are stacked directly on top of each other.
The heavier bricks and blocks above weighed down the underlying elements to create a strong section where the opening was formed. It was decided to construct with purely wooden blocks, until a point where cement bricks are used to create a bigger down force on the structure for added stability.
Due to the timed nature of the exercise, the group had to compromise build quality in order to gain as much height as possible and this resulted in collapses. The blocks were no longer being placed with evenly distributed load paths and even gaps between blocks, this results in a weaker structure as a higher proportion of the load is distributed to some blocks while poor placing of blocks results in weaker bonds, both caused collapses.
In order to create the opening, it was decided to remove blocks once it was under construction, so that blocks higher up in the tower will weigh down on blocks below, providing and preventing a collapse. This force is the weight force of the blocks and bricks acting down. If the group tried to create an opening from the initial construction, the blocks would have been unsupported and more likely to fail.
GLOSSARY
Load Path: The way that a load transfers down through a structure, through beams and columns to the earth. Masonry: Refers to building with units of various products, for example, brick, stone or concrete with mortar as a bond. Point Load: A load or force concentrated into a single, small area. Reaction Force: A force of equal magnitude and opposite direction to an initial force, which creates equilibrium and is related to Newtons 3rd Law. Beam: A rigid structural member that carries loads across spans. Compression: An external load pushes on a structural member, causing it’s particles to push together.
REFERENCE LIST
Ching, F. (2014). Building Construction Illustrated. (5th ed.). Hoboken, New Jersey: John Wiley & Sons. “Construction Overview” (2014, March) Retrieved from: http://www.youtube.com/watch?v=lHqr-PyAphw&feature=youtu.be “Introduction to Materials” - http://www.youtube.com/watch?v=s4CJ8o_lJbg&feature=youtu.be “Basic Structural Forces” (2014) Retrieved from: https://app.lms.unimelb.edu.au/bbcswebdav/courses/ENVS10003_2014_SM2/WEEK%2001/Basic%20Structural%20Forces%201.pdf Grose, M. (2014, March) “Melbourne’s Bluestone” Retrieved from: http://www.youtube.com/watch?v=CGMA71_3H6o&feature=youtu.be “Load Path Diagrams” (2014, March) Retrieved from: http://www.youtube.com/watch?v=y__V15j3IX4&feature=youtu.be