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I have a soil structure interaction problem.Details are as follows. An annular raft foundation is resting on soil. Elastic continuum is adopted for modelling the foundation and soil. Shell 63 element is used for foundation because i am interested on bending moments in raft and Solid 45 elements used...

I need help to find out source code of direct method of SSI system for seismic analysis in time domain. If anybody knows please share the information.