Dynamic characterization, modelling and model updating of a lively footbridge

Abstract

This paper presents finite element analyses, experimental measurements and finite element model updating of a lively footbridge consisting on an arched main span 40m long and several shorter access spans. Firstly, a finite element model of the bridge is created in a commercial CAE software and static and modal response are numerically estimated. Then, experimental measurements using static loading test and ambient vibration tests are performed. Initial finite element model is adjusted to match with the static response by fitting some selected parameters. Modal parameters (natural frequencies, mode shapes and modal damping) are extracted and after that the current finite element model is updated. Among the selected parameters, semi-rigid connections in some joints, concrete Young’s modulus and mass density of the concrete deck (to account on pavement mass) are selected to minimize the differences between numerical and experimental structural response. Sensitivity of the modal response to these parameters is also shown. At the end of the study, good agreement between analytical and experimental results is achieved, revealing the suitability of the entire process.