Reliability analysis of footbridge sensitive structural system

Cable-stayed pedestrian bridges are usually very sensitive to small changes in the cable lengths. Several factors can produce a random variation of cable strains with respect to the design values: differences on design prestress, errors in manufacture or collocation, anchors slippage, non-uniform distribution of temperature and differential creep. In this paper is presented a method to systematically analyze the footbridge sensitivity to cable deformations that have not been explicitly considered in the original design. It is shown that using this method is possible to rationally define the cable strain tolerance in order do not affect the structural safety, to obtain the information needed to rationally strengthen the structure (if necessary) and to focus the quality control on the cables whose deformations are more critical for the structure.