Global Seismic Reliability Analysis Of Reinforced Concrete Frames Based On Subset Simulation

Structures will be subjected to a variety of random loads in the process of construction and use,such as wind load,snow load,seismic load and so on.The occurrence,strength and effect of these loads have a lot of uncertainty on the structure.There is also a lot of uncertainty in the construction process,such as the strength of the material,the size of the section and so on.The probability of evaluating the structure's ability to complete the predetermined function within the prescribed time and under the specified conditions belongs to the category of structural reliability.However,the global reliability of the structure can consider the real constitutive relation of the structure,and avoid the difficulty of searching the failure mode,which is to explore the performance of the structure on global structure system.This shows that it is very important to study the global reliability of the structure under ground motion while considering various uncertainties.There are a variety of methods for structural reliability analysis.In this main research,the subset simulation method is used to analyze the global reliability of the structure under ground motion,which is suitable for high dimensional small failure probability,the following study is carried out:(1)For the principles of the subset simulation method,learn by step and write programs with Matlab software.Several different examples were used to analyze the applicability,accuracy and efficiency of the method.And the subset simulation method can be verified by Monte Carlo simulation.(2)The actual structures were calculated using the subset simulation method to analysis the nonlinear static seismic global reliability.Open Sees software was used to build three reinforced concrete structural frames and make a performance analysis of the structures.Use the Pushover analysis to establish the relationship between the displacement of the structure vertex and the base shear.Then get the maximum base shear of the structure.Through the requirement spectrum and the capacity spectrum of the structure by capacity spectrum method,find the performance point of the structure.Next the performance functions were established based on the limit state of the load capacity and the deformation capacity of the structure.Finally,the seismic reliability and failure probability of the structures were calculated.Compare the results obtained by the subset simulation method with the Monte Carlo simulation method to estimate the accuracy.(3)The subset simulation method can be used to calculate the structural dynamic aseismic reliability.Using the specific ground motion as the excitation of the structure,the structural dynamic reliability index and failure probability can be calculated under the deformation capacity limit state and the damage limit state.Among them,the dynamic reliability of the structure is selected for the first transcendental breaking criterion.On the meanwhile,the structures were considered the various uncertainty,such as the uncertainty of the material strength and the uncertainty of the load.(4)Further consider the dynamic reliability of the structure under the stochastic of the ground motion.The random process model of the ground motion,considering the intensity nonstationary and the frequency nonstationary.Take the stochastic process of shock as the excitation of structure,and consider the randomness of ground motion and the randomness of structure.Then subset simulation method was used to calculate structural dynamic reliability.(5)Numerous structural finite element analysis lead to humous time spent on the stutctural reliability analysis.Therefore,this paper combine Kriging surrogate model and subset simulation.Though Kriging surrogate model,the real structural performance function could be substitute,which could improve the calculation efficiency.Using Latin Hypercube Sampling choice several samples to set Kriging surrogate model.Then,Kriging model work with subset simulation to calculate the structural reliability.Compare the results with three methods to estimate the accuracyThrough the above analysis,we can get the following results,such as the static reliability analysis of the structure based on the limit state of the loading capacity and the deformability,the dynamic reliability analysis based on the overall deformation capacity and the damage limit state.Use the subset simulation method and combining with Kriging method to select the appropriate initial sample point and the conditional probability to calculate the structural reliability based on the deformation capacity limit state.This main research will analyze the seismic global reliability of the structure in a variety of ways with accurate and efficient method.