Horizontal Support - Week 1

Observations and Notes from the three bridges created in week 1

1. SATE STICK STRUCTURE

Construction process:

The first brainstorm included using triangular frames that would create a stable structure through compressive forces. We also wanted to build height in to the bridge as just a flat structure would not support as much weight, and would collapse inward faster. The final bridge was constructed by hot gluing three lots of sate sticks together to create a stronger frame. The joints were also hot glued together. After final assembly it was discovered that one side of the bridge was assembled upside down. The final bridge measured up to be approximately 10cm in height.

Observations:

Once the tray was laid on top it was obvious that structure was too narrow at the top, not supporting the tray itself. The structure on one side was assembled the wrong way so the forces didn't apply as we thought they would. On one side the triangular support compressed to hold up the tray on one side, however on the other there was very little support due to the triangle frame being upside down.

Weight of structure:

Approximately 65g

Weight at breaking point:

It held about 6 kg before sliding off, but not damaging the bridge itself.

Weight of supported load/weight of structure:

6000.00g / 65.00g = 92.30g

2. MONOFILAMENT ANCHOR BRIDGE

Construction Process:

The original idea was to create somewhat of a suspension bridge, however we discovered turning the main structure upside down would create in itself an anchor. The monofilament creates compressive forces on each side of the thick sate stick border, pushing the central joint up instead of down. Eight sate sticks were held together with rubber bands to create a strong border and column for the monofilament to span off. A triangular structure was formed on top, bridging between the two side anchors to form a base for the tray to sit on. 

Observations:

Anchors were created on both sides of the structure through tensile forces acting through the monofilament. This forced the joint of the sate sticks to stay together and not break inwards. The bridge failed when a joint holding a bunch of Sate Sticks together broke and so the whole system collapsed with it. 

Weight of structure:

Approximately 120g

Weight at breaking point:

The structure held about 12kg of weight before a human load was used to exert further force (as we ran out of paper weight). A “considerable amount of force” was required before one of the side joints gave way {approximately 30kg).

Weight of supported load/weight of structure:

42000.00g / 120.00g = 350.00g

3. PURELY PAPER

Construction Process:

In order to create a structure out of purely paper that could support weight, the structure needed to be dense to create a decent strength to hold up when compressed. An accordion like fold was made so that the paper would be able to stand up by itself without the aid of any other material. The height was made at the minimum weight of 5cm so that it would be less weak.

Observations:

 I believe the density of the accordion like fold is what made this structure surprisingly successful. Another factor is the height of the paper. The lower it is the more stable it is and likely to hold up a weight.

Weight of Structure:

Approximately 50g

Weight at breaking point:

The structure held up approximately 6 kg of weight before giving way. It seems as though after one accordion piece collapsed, the rest became unstable. 

Weight of supported load/weight of structure:

60.00g / 50.00g = 1.20g

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