Random Field-Based Approach for Strength Evaluation of Suspension Bridge Cables

Abstract

A methodology is introduced to estimate the strength of suspension bridge cables using results of tensile strength tests performed on wire samples extracted from the bridge’s main cables. The innovation of the proposed methodology is to consider the spatial correlation of the wire strength over the wire’s length, a real and experimentally measured property of ductile steel wires that is disregarded in the current standard approach. The wire strength is modeled as a nonGaussian random field along its length. The number of parallel wires in the cable’s cross section is then considered to estimate the strength of the entire cable. The capabilities of the proposed methodology are demonstrated through an application involving an experimental data set of wire segments extracted from the Williamsburg Bridge. Results of the proposed methodology are compared to corresponding results of the current standard approach. It is explained why the former results are relatively more accurate than the latter. A procedure for estimating the tensile strength of a cable composed of parallel wires at different corrosion stages is also presented.