Vuk Milacic 640020
Week 4 Timber Activity In this activity, we were given several pieces of timber and made to design and construct a spanning structure able to hold a point load. Figure 1. Final product
Our group thought that the load test would be a compression one, by which only the centre of the structure would be subject to the force, we were wrong. The machine suspends each end of the structure, then applies a downwards force in the centre. This being the case, our structure was not very strong, as it was prone to failure at both ends of the span between the middle and outer supports. Our final product is at right and below. With construction, we had to be wary of knots and wood grain in the timber as they create structural flaws. If the timber had knots, we had to ensure that it was on the bottom side (under compression) rather than tensile as tensile forces would separate the wood and cause the knot to fall out, slandering the integrity of the material as a structural component
As you can see, we had though there would be a clamp-like compressive force being applied on both the top and bottom of the structure so we reinforced this are with multilayered timber which creates a strong compressive resistance.
Major point of failure - Not adequately supported bending moments within span from support to support causes failure
Figure 2. Left-hand supports Below is how the tension/compression affects knots.
We basically cut one section of timber into smaller parts, than stack these parts on top of each other, nailing each one to the next, to create supports. We then nailed the thin sheet of timber onto the side for additional support but we ran out of time and were unable to nail it to the other side.
Vuk Milacic 640020
Our structure failed fairly quickly, but this was expected as we had some misunderstandings with how the test was to occur as mentioned previously, and this ultimately lead to a poor design for the particular test. Our structure lasted to the 99th click, and was the worst of the class. As shown in FIgure. 3, our product failed between supports just as we predicted. Figures 3 (top). and 4. (bottom), show the end result.
Introduction to working drawings We were also put into groups of 3-4, in our case 4, and given a site on campus as a case study. We were then given the working drawings for the site and a set of questions to complete using these drawings. Our answers were in both written and drawing forms. An example is shown below.
Figure 5. (at right) is an example of a question we had to answer using the working drawings, involving both a written aspect and a diagram.