Shear Tower

The primary concept behind the structural design revolves around the forces demonstrated in the moment diagram. To reduce the amount of tensile force, we tapered the tower as the distance from the base increased. Because there are fewer forces acting on the end of the structure, it gave the shear system the affordance to become tapered towards the end of the tower, conserving material and reducing weight. In addition, we reinforced the lower half of the structure by increasing the span of the concrete board, implementing additional material, and installing a foam board in the base. To distribute the stresses and prevent fractures in one direction, we designed the shear walls in the shape of an "X" around our core. The connection of the planes was done through dovetail joints, adhered with liquid nails, and stabilized with evenly distributed floor plates.

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RESULTS:
MAX LOAD: 185 lbs
WEIGHT: 26 lbs
STRENGTH/WEIGHT RATIO: 7.12

The torsion during testing and the resulting separation at the base was not what we predicted in our initial hypothesis - we instead thought that the failure would occur at the joints/overlap of the panels vertically attached to reach the full tower height. The shear wall system and its overlap were actually very strong, and the point of failure ended up being caused by the twisting of the tower and the stress it caused on the base.

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Tower requirements: [1] The tower will stand 70" tall--including 10" base, [2] Shear wall teams will receive one sheet (3' x 5' x 1/4") of cement board, [3] Base of the tower must have solid walls and measure 10" x 10" x 10" deep, [4] Towers should have multiple floors and window openings--should be considered a 7 story  building.