Members: Egor Reznikov POE Engineering Stephen Decatur High School 1/18/15
Research Summary I tested the types of materials for my bridge by seeing which could withstand the weight of the truck. Quenched & Tempered Steel was the strongest, but cost the most. You could use solid or hollow bars and the hollow bars showed that they could work and be cheap. The parts that had the most compression or tension, I made them solid quenched & tempered steel. I also tested several designs to see which would be cheaper and worked the best.
Brainstorming Sketches/cad designs
There was not enough strength in this design.
Costs to much and not strong enough.
Final Bridge design
Dennis H. Mahan Memorial Bridge Project ID: 00001A- Iteration #7 (Tue, 2 Dec 2014, 22:51:07) Type of CostItemCost CalculationCost Material Cost (M)Carbon Steel Solid Bar(4680.8 kg) x ($3.78 per kg) x (2 Trusses) = $35,386.55 Carbon Steel Hollow Tube(3886.7 kg) x ($6.30 per kg) x (2 Trusses) = $48,972.92 Quenched & Tempered Steel Solid Bar(16625.4 kg) x ($5.70 per kg) x (2 Trusses) = $189,529.80
Connection Cost (C)(33 Joints) x (300.0 per joint) x (2 Trusses) = $19,800.00
Product Cost (P) 8 - 140x140 mm Carbon Steel Bar(%s per Product) =$1,000.00 36 - 140x140x7 mm Carbon Steel Tube(%s per Product) =$1,000.00 28 - 140x140 mm Quenched & Tempered Steel Bar(%s per Product) =$1,000.00
Site Cost (S)Deck Cost(11 4-meter panels) x ($4,850.00 per panel) = $53,350.00 Excavation Cost(0 cubic meters) x ($1.00 per cubic meter) = $0.00 Abutment Cost(2 standard abutments) x ($7,000.00 per abutment) = $14,000.00 Pier CostNo pier = $0.00 Cable Anchorage CostNo anchorages = $0.00
Total CostM + C + P + S$273,889.27 + $19,800.00 + $3,000.00 + $67,350.00 = $364,039.27
My material choices were based on strength and cost. The middle and end members needed to be stronger. The other members I made hollow carbon steel so I could be under the $400,00 limit.
References I used no references for this project.
1. The type and direction of stress applied affect the selection of the material type and the cross-sectional area because of the cost of the material and the strength. Hollow are cheaper but weaker and solid are strong and expensive. 2. Tension and compression work against each other to make the bridge stronger.