Combined Topology, Sizing and Shape Optimizationin Bridge Structure Design

In the past, engineers make use of experience to design bridge structures. To be more economic, this research carries out an optimization procedure to find the design variables in the bridge structure. This research uses the optimization system developed by Li（2005）to carry out topology, sizing and shape optimization in bridge structure design.his research uses a two-step procedure, separate topology optimization and sizing, shape optimization. Topology optimization is used to find the roughly structure appearance. On the other hand, sizing and shape optimization is used to find the detail design of bridge structure. For the first step, we use topology optimization to decide where the material should be. According to different kinds of remove criterion, including energy, tension, and compression, evolutionary structural optimization (ESO) can find various kinds of bridge appearance. When combining topology and sizing, shape optimization, this research carries out a procedure to decide the connecting point and element for sizing and shape optimization. For the second step, we use sizing and shape optimization to find the design variables in the bridge structure design. Finally, we can find the section detail under suitable stress constraints and different loading cases by the iterative calculation.