The use of dynamic characteristics for the optimal design of arches

Abstract

The objective of this work was to develop a method enabling the optimal design of arch bridges based on their modal characteristics. The relationship between the resonant frequencies, a function of mass and stiffness, and the load carrying capacity of the arches was investigated. Natural frequency and dynamic direct implicit time integration analyses were performed to determine the resonant frequencies and analyse the responses to impact loading. Their collapse loads, under different loading regimes, were also investigated using elasto-plastic non-linear finite element analysis. The collapse loads were found to be related to the resonant frequencies and an optimal design could therefore be achieved. Under vertical loading, arches with span to rise ratios between 4 and 5 had both the highest resonant frequencies and collapse loads. The proposed method is simple and applicable to other structures as a design optimization tool.