A numerical investigation into the behaviour of cable-stayed bridges under deck explosions

This paper explores the behaviour of cable-stayed bridges (CSBs) when subjected to intentional explosion events. An example CSB was proposed and analysed using a three-dimensional (3D) finite-element (FE) model; a nonlinear time-history analysis taking into account the geometric and material nonlinearities was conducted. Six blast scenarios were considered; the explosion took place on the bridge deck. Response quantities, such as forces in cables, movements of deck and pylons, states of stress in main girders, and reactions on bearings and pylon foundations were examined. The critical blast scenario for each of these quantities was identified. Some design measures for mitigating cable failure were proposed and examined. The results of analyses showed that considering several blast scenarios for the design and evaluation of CSBs is mandatory. Non-symmetric (relative to the bridge longitudinal axis) blast loading scenarios are generally more critical than symmetric ones. Increasing the area of some long cables in the main span, and increasing spacing of the cables nearby the pylon together with strengthening the main girder nearby the pylon could be useful measures to reduce failure potential. This study may help better understand the response of CSBs to extreme events.