APPROXIMATE SPECTRAL MULTIPLE SUPPORT SEISMIC ANALYSIS: TRAVELLING WAVES APPROACH.

The seismic analysis of structures for travelling wave effects usually requires multiple support excitation procedures which are not well established for piping systems in nuclear power plants, arch dams, pipelines and tunnels, as well as for bridges. However, for the solution of these problems, time history analysis is required, and this is usually quite lengthy compared with spectral analysis. The purpose of the present Paper is to propose an approximate response spectrum technique for the multiple support excitation problem, with particular reference to the analysis of bridges. Whereas standard multiple support spectrum techniques ignore the time lag effects, which constitute the essence of the travelling wave approach and thus are quite conservative, the proposed approach is specifically designed to consider this effect, and should therefore lead to more realistic results. 17 Refs.