Research on Response Spectrum CCQC Method Based on Viscous Damping Assumption

A pseudo-excitation method was used to deduce a new formula of original complex complete quadratic combination(OCCQC) method and its simplified form according to traditionally simplified complex complete quadratic combination(TCCQC).The results of TCCQC were compared with the results of stationary random vibration analysis based on complex damping assumption.The results show that the results of TCCQC of structures which have greater height to thickness ratio are much less,while the calculation results of OCCQC are in good agreement,which shows that OCCQC is more rational than TCCQC.Damping matrix based on viscous damping assumption interacts with results of complex modal analysis,so calculation results of response spectrum CCQC method are not unique and the rationality of results is difficult to be determined.If viscous damping matrix is properly constructed,calculation results of the response spectrum CCQC method based on viscous damping assumption will agree well with that of stationary random vibration analysis based on complex damping assumption,but constructing proper viscous damping matrix is a time-consuming and hard work.The response spectrum CCQC method based on viscous damping assumption is suggested only for structures where viscous damping type mechanical dampers are placed,otherwise the response spectrum CCQC method based on complex damping assumption is more convenient and efficient.