Basic Characteristics and Vibration-Serviceability-Related Properties of Recent Footbridges in China

Abstract

Purpose This study identifies basic characteristics and vibration-serviceability-related properties of recent footbridges in China. Also, it characterizes relations between vibration-serviceability-related properties and basic characteristics. Methods A database is constructed for recent footbridges in China based on systematic literature survey. For each footbridge, it collects basic information (name, function, province, location, service year), structural information (girder cross-section type, main span length, width, bridge type, girder material, deck material, first lateral and vertical natural frequencies, first lateral and vertical damping ratios), response information (crowd density, acceleration responses, mitigation measures), etc. Results Data analysis shows natural frequencies decrease with increasing bridge span. Estimation relations are proposed to quantitatively express fundamental natural frequencies and main spans in vertical and lateral directions. Damping ratios vary from 0.0015 to 0.0325, indicating the low damping capacity of the footbridges. Footbridges with non-solid cross-section are more vulnerable to human-induced excitations. Most footbridges apply mitigation measures, with mitigation efficiency from 18% to 70%. Conclusion This study provides designers with first judgements on feasibility of footbridges’ design scheme, for instance, a first estimation of natural frequency. Also, the reported information may guide them towards right directions of better design scheme, for example, by adjusting structural information.