Structural response of a cable-stayed bridge subjected to lateral seismic excitations

Cable-stayed bridges are structurally efficient and offer cost effective solutions in medium to large-span crossings. The study reported in this article aimed at determining the behavior of a typical cable-stayed bridge when subjected to lateral earthquake excitations. A hybrid analytical-experimental technique is introduced to experimentally simulate the earthquake excitations on the bridge. In this technique, displacement time history of the bridge mid-span was first obtained analytically by exciting the bridge using the earthquake acceleration records. To experimentally simulate the earthquake excitations, these displacements were applied on a scale model of a single plane cable-stayed bridge using a displacement controlled shaker. The efficiency of this technique was evaluated by comparing the experimental versus analytical response in terms of dynamic characteristics and displacement responses of the bridge. The analytical response of the bridge served as a verification tool for validation of key response parameters of the full-scale bridge. These parameters included forces in cables, strains and stresses in the deck, and moments and shear forces acting on pylons in the transverse direction.