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Dr. Mohammad Alhassan
Department of Engineering
Indiana University – Purdue University Fort Wayne
Design of a Steel Bridge is a showcase opportunity for IPFW civil engineering students. The competition itself is to design a steel bridge that is between 17’-0” to 19’-0” long, must have a clearance of 1’-7” under the span of the bridge and be no higher than 2’-4” above the ground. Each component of the bridge is to be less than 3’-0” long. The bridge must be assembled in less than 30 minutes. It must be able to hold a total of 2500 pounds while only deflecting at most 3”. The bridge should also be visually appealing.
Conceptual Brainstorming ideas were generated by researching previous years and other schools bridges. Various designs were generated with different varieties of steel. Generated ideas are generally refined to make sure each conforms to the rules. Each is then drawn in SAP2000, an innovative structural analysis and design software, to determine its structural performance and weight. Each conceptual design is weighted and scored based on its deflection, weight, estimated construction time, ease of connections, and visual appeal. Accordingly, the final conceptual design is chosen and refined.
The final design for the steel bridge utilized high strength circular tube steel sections. The high strength steel allows for smaller amounts of steel to be used while still being able to be structurally viable. Circular tubes were chosen because of the aesthetic appeal. The connections for this bridge are small as to not increase the weight and are designed to be assembled quickly. Professional computer numerical control (CNC) machine operators and welders were used to do the actual fabrication of the bridge to ensure high quality construction of the individual members and to make sure it still looks visually appealing.
Finally, the bridge is tested as it would be at the competition. The loading resulted in a 1” vertical deflection, which is what it was designed to be. The weight of the bridge is 185 pounds, the lightest it has ever been for an IPFW bridge. With 6 people constructing the bridge, it is expected to take about 10 to 15 minutes to build, again the best in IPFW’s 5 year bridge history. The expected cost of the bridge, based on a scoring equations laid out in the rules, is around $7 million, which is expected to rank in the top 3 of 18 regional schools. 34
Hess, Ethan; Lambert, Dustin; and Timms, Calvin, "Design of a Steel Bridge to Compete in the 2014 ASCE Regional Conference" (2014). 2014 IPFW Student Research and Creative Endeavor Symposium. 41.