Damping Properties of Highway Bridges in China

Abstract

Full-scale data on the natural frequencies and the damping ratios of 114 highway bridges in China, and the dynamic characteristics monitoring data of four bridges under ambient excitation, have been collected and analyzed. The data indicate that the natural frequencies of the long-span bridges have power function relationships with the lengths of the main spans, whereas the damping ratios of the bridges scatter with the influence of the width of section, the piers, the material, the test environment, and the bridge type. Values of the damping ratios of different bridge types in China are proposed based on the collected data. With the increase in service ages, the natural frequencies of the bridges change little, whereas the damping ratios of the bridges decrease and tend toward stable after certain years. The forms of damage, the locations of damage, and the strengthening methods have a great influence on the changing of damping ratios.