Parametric study on mass minimization of radial network arch pedestrian bridges

Abstract

This article deals with the optimization of radial network arch bridges for pedestrian traffic. This is a challenging optimization problem that involves determining certain topological parameters, as well as shape configurations and all sizing parameters of structural members, in order to seek minimum mass. An optimal bridge scheme was sought tuning a large set of design parameters of diverse character: the type of hanger arrangement, the number of hangers, their inclination and spread angles, the alteration of these angles, the arch rise, etc. Mathematically, the optimization of the bridge scheme is a mixed-integer constrained global optimization problem solved employing a stochastic evolutionary algorithm. Plane light-deck bridges of 60 m span were optimized using the proposed optimization technique. Decisive design parameters and their promising ranges were revealed. In addition, the influence of some simplified effects was shown: using constant spread and inclination angles, limiting the diameters of the hangers to a given value, etc. The results show that the available design recommendations for automotive and railway network arch bridges are not fully applicable to similarly designed pedestrian bridges.