DAN TRAN | LOGBOOK: WEEK 1
WEEK 1 – INTRODUCTION TO CONSTRUCTION This week’s activity was primarily focused on the force of compression. To experiment with this force, towers were to be made out of timber blocks with the following limitations/challenges:
The tower was to be built as high as possible without collapsing. The number of timber blocks used was to be kept to a minimum. The tower had to be able to house a small plastic dog inside. This plastic dog was to be placed inside AFTER the structure was finished. As part of the deconstruction process, timber blocks were to be removed from parts of the structure without allowing it to fall.
To address each of the limitations and challenges the tower had to have the following:
Sloping walls (To minimise usage of timber blocks) Gaps between block placement (To minimise usage of timber blocks and to allow blocks to be removed at the end of the construction process) Accurate spacing between blocks (To prevent collapse) A wide opening (To accommodate the plastic dog)
Since the room floor acted as the base of the structure, the construction of the wall commenced immediately using the block placement planned earlier. It was decided that a gap large enough to fit the plastic dog would be on the side of the tower rather than the top to avoid the risk of knocking the tower over when placing the plastic dog inside. At first, the tower walls were constructed without a slope to make the lower portion as sturdy as possible. When the tower reached an approximate height of 20-30cm, the structure was made to slope in a fraction; about 1mm each level. This was done in an effort to reduce the number of blocks used. Unfortunately it was later observed that the slope strategy in fact did not reduce the number of blocks used. Furthermore, whilst constructing the tower it was found that the gaps between blocks towards the ends of the wall had to be closer together otherwise it was not possible to continue building the tower. No slopes currently in structure in order to create a stable lower wall. Adequate spacing between the placement of blocks to minimise block usage. If the spacing was too big, the blocks would fall through and if the spacing was too small then more blocks would have to be used. Also if the spacing was too small it would be harder to remove blocks later on.
Sloping initially put in place to reduce blocks used but as shown, there is no comparable difference to if it had non-sloping walls.
As the building got higher and the walls became more slanted, it was acknowledged that if the walls were to continue to be built in the same manner, eventually the top of it would collapse due to the gravitational force acting on it. Thus, it was decided that the building would start to slant the other way to balance out the gravitational forces. Towards the end of the tutorial session, height became the primary objective and since the tower seemed stable at the time, a vertically straight column of blocks was added to address the challenge given at the beginning (Tower to be built as high as possible without collapsing). As with all the other timber blocks, this vertical column is classified as a live load (a load that is movable and typically acts downwards). In this structure, the vertical column acts as the point load (A concentrated weight on a structural member).
Unstable Live load: Forces are acting downwards and the load is able to be removed.
Walls form a wave-like pattern to balance out the gravitational forces and prevent the tower from collapsing.
Once the tower was completed the plastic dog was placed inside easily. As for removing the blocks, it sounded like a difficult task but in fact was simple. At first, the blocks were removed carefully one by one and the structure did not collapse. To take it further, a person suggested taking â€˜chunksâ€™ of blocks out at a time and to the amazement of the surrounding people, the tower was still standing. This is due to the compression forces throughout the tower holding all the blocks together as if it were the work of masonry (Units such as bricks bound together to form a building).
Compression forces between blocks above and below keep the structure sturdy.
The blocks hanging out work on the same principle as the blocks at the edge of the walls previously addressed.
Sources: FREE STANDING WALLS. Brick Development Association. (n.d.) Retrieved from http://www.brick.org.uk/resources/brick-industry/freestanding-walls/
Published on Mar 20, 2014