Multi-component seismic response analysis of offshore platform by wavelet energy principle

A wavelet energy method is presented to search the critical incidence of earthquake excitation in a multi-dimensional seismic response of offshore platforms. The total effective energy and the instantaneous effective energy input rate of an earthquake can be obtained by wavelet transformation to predict the critical incidence of the earthquake and then the maximum dynamic response of the platform can be calculated. The critical incidence is determined using this method for an actual platform and a group of single degree-of-freedom systems. Numerical results show that the application of wavelet transform in a multi-dimensional seismic response of structures is convenient and reliable.