Constructing Environments Journal week 2

Analysis of the activityThe aim of todays task was to build a tower as tall as possible using 40 strips of bulsar wood that were approximately 400mm long. Given we had done some study on frames. We believed triangle structure would be the strongest, as it diverts the forces to a large base. If accompanied by lateral bracing the triangle structure would be very strong against vertical and horizontal forces. The constraint we faced was the length of the bulsar wood, which significantly affected the strength of our design.

Sequence of Construction

1- Upon deciding the triangle structure we assembled several isosceles triangles using glue. Our lack of planning in assembling the triangles lead to having full length (400mm) sides which caused problems later on.

2- When going up to the second level of the triangle we had planned to have a diagonal brace or a cross brace resulting in 2 or 4 triangles on each side. When it came time to brace we had realised that our bulsar wood couldn’t reach the diagonal distance, thus our design was quite weak laterally and could buckle.

Construction system employed:We built a frame structure and tried to create fixed joints using the glue for the majority of the frame. In the parts where gluing wasn’t appropriate we used wall pins which resembled a hinged frame where two rigid areas were connected

3- With the inability to brace our design we made a decision t go smaller to allow bracing. This involved making a smaller triangle which sat in the frame hoping the bigger triangle would be able to act as a footing and absorb the weight of the upper structure.

4- before going up we braced all sides continuing to create triangles. To gain more stability we braced the corners of the larger triangles using knee bracing with small bulsar pieces approximately 100mm long. As the glue became quite tedious in the upper layers we began to use sticky tape and wall pins.

5- The bulsar wood was becoming more brittle the higher we went, so we decided to test its weight holding capacity before continuing. The tower was able to hold a highlighter but succumbed to a mobile phone.

with a pin joint. The wooden frame structure diverts the loads down to the ground, which is why our larger base may have had some benefit for the tower.

Efficiency of Material:The bulsar wood was very brittle and light and was subjected to deflection and buckling when under strain. Where the bulsar wood was used in the frame setermined wether it was under tension or compression. Generally in triangle construction the tension is in the bottom chords which were the ones to break whilst giving way to the force. The glue was efficient in creating rigid joint in the lower parts of the tower where it was most stable but became difficult to hold frame members together when patience was required to hold the wood still. The pins were easy to attach and allowed for some movement which possibly helped the tower when it was under strain. The sticky tape was the least helpful material as it would not connect to all members equally and would result in uneven loads being passed through the frame.

The blue members represent what we believed provided stability for the structure, whilst the red members was where deformation was apparent.