Experimental Dynamic Characterization and Finite-Element Updating of a Footbridge Structure

Abstract

Nowadays, modern analysis of civil engineering structures implies the use of increasingly sophisticated computer models, designed not only to predict the response of actual structures to different loadings, but also to simulate the effects of eventual modifications in their structural configuration. Nevertheless, it is often discovered that when the numerical simulations are compared with experimental data, the degree of correlation is weak, thus preventing the use of the finite-element (FE) models with confidence in further analyses. In such cases, FE updating techniques are available to correct the FE models, based on dynamic response records of the real structures. These updating processes usually consist of four phases: preliminary FE modeling, experimental modal identification, manual sensitivity analysis and, finally, updating the FE model. The present paper presents all four phases of a successful updating process for the FE model of a footbridge structure. It is shown how the last phase of the process can be performed fully automatically by coupling an optimization routine with a commercial FE analysis program.