Study On The Application Of Ground Motion Intensity Measures In The Seismic Analysis Of Hydropower House

In China,water energy resources are mostly concentrated in the western regions with frequent earthquakes,which pose a severe challenge to the construction of water conservancy and hydropower projects.As the main building structure of hydroelectric power generation,the hydropower house is usually divided into superstructure and substructure with the generator floor as the vertical boundary.The superstructure is composed of roof structure,walls,beams and columns,which is equivalent to the single story factory.The substructure is a large volume concrete structure arranged for the hydro generator,and the rigidity and mass of the substructure are obviously higher than the superstructure.Under the action of an earthquake,the superstructure is so easy to be damaged that staff safety and electricity supply are seriously threatened,so the seismic performance evaluation of hydropower house is very important to ensure the normal use function and reduce the structural damage,economic losses and casualties effectively.The application of ground motion intensity measures in the seismic performance analysis of hydropower house is mainly studied in this paper,in order to obtain the accurate seismic performance evaluation results.The main research contents and conclusions includes:(1)Referring to the simplified analysis method commonly used in the current seismic research of hydropower house,four calculation schemes are proposed to explore the influence of interaction between superstructure and substructure described by each simplified analysis method on seismic response of structures.The results show that the amplification effect of substructure and the coupling effect between superstructure and substructure should be considered in seismic analysis,but the constitutive model of substructure concrete can be considered as linear elasticity to save to save calculation cost.(2)According to the correlation analysis of 17 selected ground motion intensity measures and the maximum seismic response of hydropower house,it is found that the correlation between seismic response(EW,Dmax)and the 17 ground motion intensity measures is not high,while the correlation between seismic response(EP,?max)and each intensity measures is from high to low,which is velocity-type intensity measures and acceleration-type intensity measures and displacement-type intensity measures.The intensity measures with high correlation include CAV,Sa(T1),PGV,VSI,HI and PSV,among which Sa(T1),VSI,HI and PSV are all related to the characteristics of ground motion spectrum,so seismic response analysis of hydropower house,the type of intensity measures should be firstly determined according to the basic period of structure and the general applicability rule,and then the intensity measures related to the spectrum characteristics should be selected preferentially.(3)Accorrding to the results of incremental dynamic analysis,the rationality of PGA,PGD and six ground motion intensity measures with high correlation is discussed in probabilistic seismic demand analysis.The most reasonable combination of IM and EDP is VSI and ?max,and it can be applied to seismic fragility analysis to obtain the failure probability of four limit states(slight damage,medium damage,serious damage and collapse)and evaluate the seismic performance of hydropower house accurately.