Evolutionary Structural Optimization in Form Finding of Bridges

Abstract:

The principle and the procedure of bi directional evolutionary structural optimization (BESO), which is the later version of evolutionary structural optimization (ESO), are stated in detail. A stream of ANSYS Parametric Design Language (APDL) commends based on BESO is programmed. An exploratory research is carried out by applying this program to solving 2D topology optimization problems whose boundary conditions are set according to real bridge structures. The topology optimizations for arch bridges with different rise to span ratios, main cable of suspension bridge and main tower of cable stayed bridge are achieved. The procedures provide several different topological forms and the results show rational structures with well distributed stress and smooth force transmission, which demonstrate the efficiency of the program. The program is then expanded from 2D plane to 3D space and the conceptual design of a canyon bridge is achieved on the basis of topology optimization result. The research indicates structural topology optimization is an effective tool which can be used to draw a reasonable and heuristic layout of a bridge structure in conceptual design phase.