Study Of The Severest Ground Motion For Large-and-long Structures And Their Seismic Response Analysis

The long-and-large structure was widely used in economic and cultural activitycenter or important transport hub structure. Therefore, the safety of this type of structurewas particularly important in China. The seismic input for long-and-large was oftensimulated as uniform input,which may be under estimation their seismic response. The2010Edition Code for seismic design of buildings had some basic requirements,but thecode did not give a specific method to the Excitations of Multi-dimensional and Multi-support[EMDMS].The EMDMS faced two key problems,one is if the popularcoherency function model [CFM] of strong ground motion could be used to simulate themotion in three direction in one model. The other was if the CFM could be appied tosimulate the real seismic excitation of the Long-and-Large structure with itssupportedtion span smaller than1000m,because the popular CFM was got based on thestrong ground motion stations with their distance larger than1000m.To solve the twoproblems, a new CFM was proposed in this thesis,based on the records from the LSSTand SMART-1array, and the seismic of response two typical Long-and-Largestructures were simulated by use of ANSYS,The main contents in this thesis werefollowed as:1. By use of the strong ground motun rescords from the LSST-SMART-1, acoherency function model by using the Matlab software’statistical regression wasconstructed, and the model parameters in different seismic conditions were discussed indetails. Adopting power spectrum model and the coherency function model,an aritificalseismic wave was Synthesised. A displacement curves aiming at the input of theSuspend-dome and the Suspension-bridge was also constructed.2. To compare with the seismic response of the large-span space structure underuniform seismic excitations and EMDMS, the seismic response of one Suspend-domestructure with90m span was simulated based on ANSYS. For the EMDMS, theincoherence effect, wave-prppagation effect, and their coupling effects was considered.The resluts shown that EMDMS is adverse relative to uniform input.3. In analyzing of one3-span Suspension-bridge with the342m length under theexcitations of multi-dimensional and multi-support, To estimate the effect of the pesduowave velocity on seismic reponse of this suspension bridge under multi-support seismicexcitations, sevel pesduo wave velocity, i.e.200m/s、300m/s、500m/s、1000m/s、1500m/s、2000m/s and3000m/s was input into this model, and the reslut wascompared to the results of the uniform excitations of two-dimensional. The resultsproved that wave-passage effect is adverse.