Failure Mode Optimization Of Reinforced Concrete Frames Under Earthquake Excitations Based On The Damage Performance

In the recent two decades, the construction industry has been rapidly developedin China, and at present, a large number of tall building structures have been built. Inaddition, China is located at the convergent boundaries of two worst seismic zones, sothe crustal movement is very active and the earthquake disaster is very serious. Sincetall buildings are characterized with large size, complex loading state and high densityof property and population, the earthquake disaster of such buildings is usually farmore serious than that of other buildings. Previous earthquake have demonstrated thatthe collapse of building structures is the primary cause for casualty and economic loss.Therefore, for the tall building structures under large earthquake, the study on damageprocess law and collapse mechanism and failure models of great theoreticalsignificance and engineering value in terms of increasing the structural seismic safety,reducing or preventing seismic disaster. In this dissertation, focusing on the reinforcedconcrete frames structure, the damage optimization method through failure mode isintensively studied.The specific research work included the following aspects:(1)The failure mode optimization method of the structure which is based on thedamage performance of the structure. Use the linear programming algorithm as thestructure failure mode optimization method, the constraint equation, the objectivefunction and the optimization variable of the method are the damage criterion of thestructure, the constructional element level damage criterion and the structuralparameters respectively. The final purpose is to make the damage index of each kindof column be equal through multiple iteration, and the basic steps of the optimizationare showed.(2)The single objective optimization of the12-story reinforced concrete frameBenchmark model. The failure mode optimization method which is based on thedamage properties is used and the ratio of longitudinal reinforcement, theconvergence speed, the dynamic response of the structure under the strong earthquakeand its damage development process are simulated.The research showed that: The mechanics model used in this dissertation caneffectively reduce the cost of the calculation. The definition of the structure and the element damage criterion can response the damage degree and the developmentprocess more clearly. The failure mode optimization method which is based on thestructural damage performance has the following advantages: The method caneffectively control and eliminate the weakness of the damage centralized phenomenonof the structure, the damage distribution of each story tends to be homogeneous, thedamage of the weak story is reduced and the seismic performance of the reinforcedconcrete frame structure has been remarkable increased.