Abstract:
A simplified method for the simulation of ergodic spatially correlated seismic ground motions was proposed,based on the commonly used original spectral representation method.Firstly,the phase angles,to represent the correlation among ground motions,were given by explicit items with a clear physical.By using these explicit items,computational efficiency can be increased by changing the decomposition of complex cross-spectral matrix into the decom-position of real incoherence coefficient matrix.Double-indexing frequencies were introduced to simulate ergodic seismic ground motions,and the ergodic feature of the improved method was demonstrated theoretically.Subsequently,an explicit solution of the elements of the lower triangular matrix under Cholesky decomposition was given.By using this explicit solution,the improved method had been simplified,and the computational efficiency can be increased greatly,by avoiding repetitive Cholesky decomposition of cross-spectral matrix in every frequency step.At last,a numerical example was employed to illustrate the good character of the improved method.
