Linear Spectral Seismic Analysis of High-rise Building

Authors:  
Rubric:     Theoretical and experimental studies   
Key words: seismic response, linear spectral method of analysis, combined asymptotic method, high-rise building
Annotation:
Summary: Linear Spectral Method (LSM) by origin is accurate only for single-degree- of-freedom systems. For more complicated systems (and real systems are always more complicated) LSM uses certain double summation rules to combine single-mode responses to one-component excitations. These rules are not precise, they are rather statistical; in different codes they are different. In fact, these rules are based on experience with structures of certain type. That is why the author thinks special check is necessary when one deals with structures having certain peculiarities (like high-rise buildings). This is essentially a check for the applicability of the summation rules. Algorithm for such a check – to compare the results obtained in the time domain for excitation timehistories with LSM results provided input spectra for LSM are obtained from the same time-histories and damping in oscillators is equal to the structural damping. In the present paper seismic responses are compared in the format of the integral response forces under the base mat. The main result is that conventional summation rules in LSM lead to the considerable deviation in the results including underestimation of the response forces.