Dynamic Characterization of a Stress Ribbon and Butterfly Arch Pedestrian Bridge Using Wireless Measurements

Abstract

For their aesthetic values, both arches and stress-ribbon decks are widely used in design of pedestrian bridges. The combination of the two systems provides the solution of a self-anchored structure. In the current paper, the dynamic characteristics of a short-span stress ribbon and butterfly arch bridge are investigated by means of operational modal analysis. Ambient vibration of the bridge is recorded by using several highly-synchronous three-axial wireless accelerometers deployed on the bridge deck. Modal parameters, including natural frequencies, mode shapes and damping ratios are extracted from the measurements. By comparing the experimental modal results to their numerical counterparts obtained from a preliminary finite element model, interesting results are found both related to the flexibility of the whole system and the stiffness contribution of the non-structural elements. The findings also serve as the basis of the serviceability assessment of the pedestrian bridge.