The Stress-related Damping Ratio of Box Girder with Corrugated Steel Webs

In this paper, the stress-related damping ratio formula of box girder with corrugated steel webs is introduced. Using response spectrum method, an iterative algorithm is proposed to calculate the seismic response and the stressrelated damping ratio under different seismic intensities. Based on a simply supported composite box girder bridge with corrugated steel webs, the stress-related damping ratios are calculated under different seismic intensities through iteration. The analysis and comparison show that the stress-related damping ratio increased with the seismic intensity, which is smaller than 0.05 under the lower seismic fortification intensity, and larger than 0.05 under the higher seismic intensity. Different damping ratios should be considered under different seismic intensities for the seismic response analysis of the bridge.