Optimization Of Input Ground Motions And Base-isolation Design Of Main Plant Of A Conventional Island

This paper consists of two parts: the first part is about the selection of real groundmotions compatible with the code spectrum, the second part is the seismic isolationand reduction design of main plant of a conventional island plant. First part is to selectsome real ground motions for time-history analysis according to the responsespectrum curve given in the seismic code, based on the ground motion recordsavailable. Second part mainly includes the seismic isolation and reduction design of aconventional island plant, which is steel-concrete hybrid structure, and the dynamicresponse comparisons of two structures are made, the results show that the seismicperformance of the structure is greatly improved with the isolation system.1. Nowadays, more and more attention is being paid to structure time-historyanalysis method, which is widely used in the performance analysis and safetyassessment of structure. For a given structure, how to select input ground motions andwhat kind of records should be chosen are great issues. This paper carries on someresearch based on what have mentioned above. Based on the real records databaseavailable, related Matlab programs are written to select some records compatible withthe code spectrum curve in certain period ranges. The selected records are also begrouped in terms of characteristic period Tg. The selected records and some records incommon use are input to a frame structure model for the time-history analysis toinspect structural response parameters, including base shear force, vertexdisplacement and maximum interstory drift and so on. The results show that, the baseshear force simulated by single record is bigger than the65%of the result fromresponse spectrum method; the average values of multiple records are above the80%of the result from response spectrum method. Those results can live up to the coderequirements and show small disperse compared with the records in common use,which verify the rationality of the selected records.2. Seismic isolation technology, the applications is growing at home and abroad,which can significantly reduce the structural responses and help people to restore thesignificant loss of lives and property at a lower cost in the earthquake. However, casesof isolation technology applied in the conventional island plant structure are still rare.Base isolation is designed for a conventional island plant located in Shandongprovince, which is a steel-concrete framed bent structure with complex loading casesand irregular layout. Proper rubber bearings are chosen after making severalcomparisons and some viscous dampers are assigned in the isolation layer to limit thelevel of lateral displacement. Analyses under frequently-occurred and rarely-occurredearthquakes are taken with SAP2000, the results show the responses of the structureare effectively controlled and the upper-structure is almost elastic.