Construction Journal Submission Report Week One: COMPRESSION Nicole Tan 641433 Analysis of activity: This week’s activity required us to build a tower as high as possible out of small wooden blocks whilst exploring the concept of compression. The light blocks used have fairly low compression strengths and hence cannot withstand heavy loads. Thus, we needed to determine a construction system of the tower that enabled the blocks at the base of the tower to withstand an increasing weight as the tower grew in height. Furthermore, we also needed to ensure the tower was balanced from the base to the top and that the compressive loads were maintained within the kern area (Ching 2008) of each block. This ensures that tensile stresses are not developed on the edges of the blocks which will in turn, cause the structure to tilt and fall.
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Photographic sequence and description of the construction process: This system was abandoned as the vertical columns were unstable. It was inefficient in transferring loads between the blocks whilst the concentrated load acting on each block increased the destabilising of the tower.
Figure 1. First attempt at tower construction (Tan 2013) NEW SYSTEM: STEP ONE: HONEYCOMB SQUARE BASE This system was much more stable. Each block was able to withstand the compression forces acting on them as the load was distributed more uniformly across the given surface areas.
Figure 2. Base of tower (Tan 2013) STEP TWO: ROUNDED HONEYCOMB The square base transitioned into a more circular system to eliminate the sharp corners. The honeycomb structure was still employed as it provided strength in tension and reduced the shear stress acting on each block. Furthermore, this system utilised minimal materials which allowed us to build the tower more quickly. Figure 3. Body of tower (Tan 2013) STEP THREE: USE OF COLUMNS Once a stable and sturdy base and body was constructed, the initial ‘column and beam’ system could be employed. This allowed the tower to reach greater heights by utilising the longer edge of the wooden blocks.
Figure 4. Constructing the peak of the tower (Tan 2013) Nicole Tan | Constructing Environments Journal
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Description and analysis of construction system employed: Our tower employed 3 different construction systems‘square honeycomb’, ‘rounded honeycomb’ and ‘columns and beams’. The honeycomb structures were efficient in both use of materials and withstanding compression forces as the load was distributed more evenly across each block. The ‘columns and beams’ system utilised at the tower’s peak was less stable however it was useful in providing added height for the tower. Our tower also tapered inwards and became narrower at the top as it increased in height which allowed the wider base to resist shear and also made the tower more material efficient by using fewer blocks at the top (which did not have to support such a heavy load). Figure 5. Scale of the tower (Tan 2013) Tower’s collapsing point: The tower’s collapsing point was right where the ‘column and beam’ system began indicating the system’s inefficiency at transferring loads compared to the honeycomb system. This is due to the concentrated loads acting on each beam and column rather than a uniformly distributed load in the honeycomb system.
Efficiency of material: The wooden blocks are fairly efficient in withstanding compression and a heavy load. During the deconstruction process, much of the blocks on the base could be removed before the tower collapsed (as seen in the Figure 6).
Figure 6. The deconstruction process (Tan 2013)
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Sketches of load paths:
CONSTRUCTION – COLUMN & BEAM The tall columns were more unstable as it was harder to maintain the loads within the kern area of the columns. Furthermore, the beams experienced both shear and axial forces which it had to withstand and transfer to the columns.
Figure 7. Sketch of load path at the peak of the tower (Tan 2013) CONSTRUCTION - HONEYCOMB The honeycomb structure was better equipped to handle the dead load as forces were distributed more uniformly throughout the structure leading to less concentrated stresses on each block.
Figure 8. Sketch of load path at the base of the tower (Tan 2013) DECONSTRUCTION - ARCHES
Figure 9. Sketch of load path at the during deconstruction (Tan 2013)
The deconstruction process demonstrated the strength of arches. Despite much of the base had been destroyed, the tower was still able to stand upright. This is because the arch was able to transform the vertical forces of the dead load into the inclined angles and transfer them into bricks on either side of the arch (Ching 2008).
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References: Ching, F. 2008, Building Construction Illustrated, John Wiley and Sons, Hoboken, New Jersey. Tan, N. 2013, Photographs from Constructing Studio Week 1, Melbourne.
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