Response Analysis Of Reinforced Concrete Frame Structure Under Random Seismic Excitation

ABSTRACT:It is a significant development of structural seismic design theory that regarding the seismic excitation as a stochastic processes, and using random vibration theory to study structural response and probability characteristic. As the constraints of current economic level, the frame structure is still one of the largest select of building structures in our country. However, its damage under earthquakes is serious due to many problems of seismic design. This paper aims to study the structural response of reinforced concrete frame under random seismic excitation. The pseudo excitation method which can to simplify the principle of calculation and program operations is introduced. The structural response of a damaged building is comparative analysis by the current structure design method and the random vibration method.The primary work is listed as follows:(1) In this paper, nearly 10 types of stationary and non-stationary random ground motion model are respectively analyzed for their models'physical meaning and the application scopes. Combined with Code for seismic design of buildings, the parameters of the Kanai-Tajimi spectrum and Do-Chen spectrum which are as the ground motion input in the following examples are extracted.(2) The pseudo excitation method, a highly efficient algorithm for random vibration analysis proposed by Professor J.H.Lin, is further developed in the present study, so that it can be used to analyze the random seismic responses of reinforced concrete structures. Based on the pseudo excitation method, a calculating program has been proposed for the one-dimensional random vibration analysis of the reinforced concrete frame structural buildings. The calculation results agree well with ANSYS finite analysis results, verifying the correctness of this calculating program.(3) A damaged building under wenchuan earthquake which is an eight-story and eight-span reinforced concrete frame structure is used as an instance.According to the current structural design method, elastic lateral displacement and inter-story elastic displacement angle of the building are computed in seismic fortification intensity with 6 grade and 7 grade and 8 grade.With the random vibration method, the response spectrum of structure under the earthquake action of level axis directions are obtained. Comparison of the results of two algorithms, suggestions accordingly to structural design method is presented.