Using Bridge Designer, group built a bridge with:
● Deck 12 meters above water
● Standard abutments
● No Pier
● No cable anchorages
● Medium strength concrete
● Standard two lanes
● Pratt Through Truss
● Carbon steel components
The goal for our bridge is to maintain the lowest possible cost while the compression force/strength ratio cannot exceed .40 (+/-.01), Tension force/strength ratio cannot exceed .45 (+/-.01), and 15% of bridge of members hollow tubes (+/- 1%).
Starting with an initial cost of ~350 thousand dollars, I was able to cut significant costs bringing the price to 300k. Our tension and compression/Strength do not go above .4 and .46 and three of our members are tubes. Through testing, I found tubes to be more effective than bars for compression, therefore, I put 3 wider vertical tubes for compression in the middle of the bridge.
The video above depicts a truck running over our bridge design, depicting that is does support the trucks weight.
1. Using the Bridge Designer, build a bridge with
● Deck 12 meters above water
● Standard abutments
● No Pier
● No cable anchorages
● Medium strength concrete
● Standard two lanes
● Pratt Through Truss
● Carbon steel components
Requirements
● Compression force/strength ratio cannot exceed .40 (+/-.01)
● Tension force/strength ratio cannot exceed .45 (+/-.01)
● 15% of bridge of members hollow tubes (+/- 1%)
● Lowest possible cost
● Calculate the net forces (compression and tension on each joint)
o Hint: use trigonometry to calculate angles
o Use vector addition to calculate net forces