The Analysis Of Influence Factors On Seismic Behavior Of Specially Shaped Columns Members And Preliminary Research On Failure Mechanism Of Structures

Beam-hinge-yield mechanism with'strong column and weak beam'is expected in the seismic design for reinforced concrete frame structure. However, in the earthquake in Wenchuan on May 12, structures of such type rarely performanced damages in beam-hinge,and buildings more generally be damaged because of the break of plastic-hinge in the ends of columns. While many engineering and researchers have worked on finding the reasons and the solutions,we must be aware that, special shaped column structures were built seldomly in the seismic regions,its mechanical performance and failure mode have not been checked in the earthquake.Therefore, there were still interrogatives for engineering designers and researchers which yield mechanism will be performanced and whether the Beam-hinge-yield mechanism could be achieved.In this paper, taking the specially shaped columns members and frame structures as the study object, it aims to investigate the influence factors on seismic behavior of specially shaped columns members and failure mechanism of structures. The main research work finished in this thesis is as followings:â‘ By the beam-column element of fiber model based on nonlinear finite element flexibility method, the specially shaped columns members under different different characteristic value of transverse reinforcement and different longitudinal reinforcement ratio have been analyzed.Throughout the process,the analysis results of ultimate strength,ductility and hysteretic energy dissipation have been compared .â‘¡According to'Chinese Technical Specification for Concrete Structures with Specially Shaped Columns'(JGJ149-2006), the following frame structures were designed: A building of 3 x 2-span and 6-storey typical regular frame structures with specially shaped columns in intensity region 7(0.15g),A building of 3 x 2-span and 4-storey typical regular frame structures with specially shaped columns intensity region 8(0.20g).Meanwhile, according to the way mentioned above, the specially shaped columns frame structures taken into account slab effect are designed in intensity region 7(0.15g) and intensity region 8(0.20g).â‘¢Using the program of fiber beam-column element based on flexibility method of finite element, nonlinear dynamic analysis is taken to analyze these structures. The response differences of structures taken into account slab effect with structures not taken into account slab effect is obtained under the rare grand motion, which lie in structural seismic behavior and yield mechanism. Their nonlinear seismic behavior evolution pattern are compared.â‘£Using the program of fiber beam-column element based on flexibility method of finite element, pushover analysis is taken to analyze these typification frameworks which are extracted from these structures taken into account slab effect and structures not taken into account slab effect. The influence of slab effect on specially shaped columns frame structures are verified.