Performance-based Seismic Evaluation Methodology For An Intake Tower

As a kind of important hydraulic structure,intake tower can be used as a sluice structure for flood discharge and desilting.It also can be used as a diversion structure for irrigation,water supply and power generation.The structure seismic safety of intake tower is directly relate to the normal operation of the hydropower station,so it's very important to analyze the seismic response of intake tower structure under a certain site condition.In the previous study of the seismic performance of the intake tower structure,the elastic spectrum analysis or nonlinear time history analysis of the structure is mostly used by the standard response spectrum or the seismic waves generated by the standard response spectrum.This paper uses advanced performance-based seismic design concepts,combining the static elastoplastic method(Pushover)and the stochastic finite-fault method,a new and targeted earthquake stochastic Pushover analysis method is proposed,which can consider the effects of earthquake magnitude,epicentral distance,propagation path and site conditions on Pushover performance points.This method is applied to the intake tower structure,which provides a new idea for engineering evaluation.The main work of this paper includes:1.The capacity spectrum curve of the intake tower is obtained by the static elastoplastic analysis under three lateral force distribution modes,Transform them into double fold lines through the principle of energy equality.Find out that the results of the downward-pointing triangle model most close to the mode distribution mode,the shear is large when yielding under the uniform mode,and the seismic wave generated by standard response spectrum is used to analyze the structure.2.Then the stochastic finite-fault method,which can consider the effects of earthquake magnitude,epicentral distance,propagation path and site conditions,is used to get the earthquake waves that may be caused by a seismic fault zone,which are translated into demand spectrum curves.3.Finally,the displacement ductility coefficient is used as the analysis index of these performance points for statistical analysis.The results show that the mean square error of the spectral displacement is small and the distribution of the displacement ductility coefficient is reasonable.It can reflect the rationality of the proposed model.Thus,the proposed method realizes the organic combination of seismic hazard assessment and structural seismic performance evaluation.