Research On Seismic Response And Design Of Multi-Story Buildings Based On Wavelet Method

There are many uncertainties in the seismic design of structures, the inputinguncertainty of ground motion is one of them. In this paper, ground motion is dividedinto the wavelet components, which is inputted different frame structures’ stiffness ratio(ρ) between column and beam of the five-story frame structure. The calculation ofstructural seismic response and input energy distribution in frequency domain, in orderto analyze the relative size and input energy of seismic response of different bands, toprovide corresponding theoretical support for seismic research.The main work and achievements are as follows:1. A variety of methods will require the various forms of input ground motionswhen analyzing seismic responses of structures. In this paper, Wenchuan Wolong wavesand Baoji waves be decomposed by using the B-spline wavelet, broken down into thedifferent nine band wavelet components, and which be used as entering seismic wavesto time history analysis energy analysis of multi-degree of freedom system (MDOF).2. According to the mode decomposition method, research on modal contributionfactor depends on the reaction (base shearVb, the top-level shearV5, base overturningmomentsM b, the top displacementu5), the results showed that, the fundamental modemaximum contribution amount for each reaction in the fixedρvalue, the second andhigher modal for the contribution of theVb is more significant than the contributionM boru5; the contribution of higher modes in any one of the base shear, the top shearand base overturning moment of total reaction increases withρdecreasing.3. Inputting energy of MDOF is transformed into modal relating single degree of freedom system(SDOF)inputting energy. Calculation of the action of the modalinput energy in the original wave and its wavelet components. The results indicated thatthe different values ofρcorresponding to different values of inputting energy.4. The differentρof the MDOF structural system is inputted two seismic wavesand the corresponding wavelet components, calculation the energy of each modal of thetop-level displacement, base shear and each modal input energy. On this basis, the topdisplacement, base shear and inputting energy of each modal about wavelet of theoriginal wave and the band be researched inρthe same circumstances. the differentvalues ofρcorresponding to different values of seismic response.The research results express that, regardless ofρchanging, low frequencycomponent and low order modes play a leading role in the top displacement, the baseshear and input energy. High frequency component is almost not working. Thefundamental frequency of the structure is large, the band of excellent frequency gives agreat contribution to the response of the structure as well as the input energy. In a word,the low-frequency band and predominant frequency band of ground motion have asignificant impact on structure after the multistory structure is inputted into level groundmotion.