Experimental Study And Theoretical Analysis Of Reinforced Concrete Frame Structure Considering Cast-in-situ Slabs

Frame structure which can gain greater use of space has the characteristics of flexible layout.it is widely used in the form of resisting lateral force structure at present in China.Existing research indicates that cast-in-situ slab have great effect on the capacity, stiffness and deformation behavior of reinforced concrete frames.It is dangerous to ignore the effect of the cast-in-situ slab.In Wenchuan earthquake, Reinforced concrete frame structures appeared a large presence of "column hinge" mechanism rather than "beam hinge "mechanism.which not only threaten the safety of personnel, but also brought about great loss of property. In the earthquake, the influence of cast-in-situ slab has caused people enough attention.China's "Code for concrete structure design"(GB50010-2002) gives the values of flange width in compression zone,but effective flange width in tension zone in beam end is not put forward. Although existing trail researches have provided suggestion formula of effective flange width in tension zone of beam end, each difference is larger. So studying effective flange width in tension zone of beam end is better for completing frame structure seismic design and improving structural measures to provide important theoretical and practical significance.In order to study the seismic behavior of frames with cast-in-situ slab,the comparison test of 1 RC frame,2 RC frames with cast-in-situ slab are tested under low-cycle reversed load;researched from seismic behavior including bearing capacity and deformation ability,ductility and deformation and failure mechanism.Results showed that cast-in-situ slab have certain effect of bearing capacity and ductility of frame.appropriately considering the influence of bearing section of slab upper reinforcement parallel with beam end reinforcement and reducing upper tensile rebars in beam end to improve the ductility performance in frame for better to achieve the aseismic design principles of"Strong column and weak beam".Non-linear finite element analysis models of frames with cast-in-situ slab are set up by making use of solid element C3D8R,truss element T3D2 in ABAQUS.Behaviors of 3 specimens are analyzed by using the method of nonlinear finite element analysis,besides the calculative results were compared with the experimental results. The analysis showed that the calculative values are in general good agreement with experimental values; behavior of reinforced concrete frame with cast-in-situ slab can be simulated by using finite element analysis model proposed in this paper.Then the finite element method is used to analyze cast-in-situ slab thickness ,cast-in-situ slab width, beam span, beam high, upper reinforcement change in beam end for studying the influence of effective flange width.and the decision of effective flange width is put forward.On the basis of experimental study and theoretical analysis,coming up with suggestions of reinforcement in beam end while considering the decision of effective flange width ,which provide the basis to improve the existing method of seismic design.