Wave-Passage Effect of Earthquake Loadings on Long Structures

The wave-passage effect of earthquake loadings on long-span structures is studied through use of a multiply-supported single-degree-of-freedom (SDOF) system excited by traveling seismic ground motions. The absolute acceleration response of the SDOF system is represented in the analytical form in the time domain. The frequency-domain analysis results indicate that the wave-passage effect may reduce the absolute acceleration response and the earthquake loading acting on the multiply-supported SDOF system. Further, for different velocities of wave-passage, the response spectra are calculated to represent the reduction of the maximum earthquake loading on the long-span system caused by the wave-passage effect. The computation results of the response spectra indicate that the reduction of the maximum earthquake loading is fluctuant, but has a general tendency to decrease with the increase in the apparent wave velocity and the structural natural period.