One of the two bridge design projects, the pedestrian bridge project required us, a group of three, to design a steel truss bridge under certain geological condition, with our design philosophy justified. After problem analysis process, we sketched some drafts of design which satisfied the requirements. One of the original designs we had was an aesthetic design with complicated structure, but was omitted by us owing to the complexity in calculation. As engineering designers, one of the major design considerations was safety. We could design for safety when we confirm the bridge is safe and the priority of knowing safety is to know how to calculate.

Therefore, we refined the design and brainstormed again based on the criteria we set:

• Precise and clear calculation (more is preferred)

• Aesthetic design (more is preferred)

• Low cost of the entire bridge (less is preferred)

After iteration of ideas and optimization of the blueprints of the designs, we compared designs with slight differences of which heights and width of each span was carefully selected by our team. We scoped down to the final design by eliminating all possible tension-tension and zero force members in the truss, so that the final design solutions was confirmed based on iteration of calculation and engineering judgments.

From an engineering designer’s prospective, we were quite confident in its safety condition because we iterated 6 times of calculation in implementation process to make sure a high standard of safety was met.

In addition, a legitimate cost of $277,914 made the design economical in terms of cost-efficiency.