Free vibration analysis and shape optimization of box-girder bridges in straight and curved planform

This paper deals with the elastic free vibration analysis and structural shape optimization (SSO) of box-girder bridge with straight and curved planform. For this purpose, reliable and efficient computational tools are developed. The objective is either the maximization of the fundamental frequency or the minimization of the volume by changing the shape or thickness variation of the structureʹs cross-section with constraints on the volume or natural frequencies. Natural frequencies and mode shapes are determined using curved, variable-thickness Mindlin–Reissner finite strips (FSs). An automated analysis and optimization procedure is adopted that integrates FS analysis, parametric cubic spline geometry definition, automatic mesh generation, sensitivity analysis and mathematical programming methods. It is concluded that the FS method offers an accurate and inexpensive tool for the optimization of box-girder bridges having regular prismatic-type geometry with diaphragm ends.