The Effective Flange Width Analysis Of Cast-in-situ Concrete Frame Beam End Section

Widely used as the the frame structure is,though has prominent advantages such as good seismic behavior,stable structural performance,long life and so on.But in recent years the earthquake disasters show: According to the current standard design of reinforced concrete frame structure,because of without considering the cast-in-situ slab of negative bending moment on the beam end resistance to strengthen effect, often appear in the earthquake damage characteristics of "column hinge" mechanism.In order to study the seismic behavior of frames with cast-in-situ slab, the large finite element software ABAQUS is utilized. With C3D8 R element to simulate concrete solid, T3D2 element to simulate stirrups and longitudinal reinforcement and plastic damage models is adopted to analyse concrete, analysis model of considering the influence of the cast-in-situ slab to the nodes and a single story and single span frame structure are established.Finite element analysis simulation is performed to the tests of considering the influence of the cast-in-situ slab to the nodes and a single story and single span frame.Analysis is focused on the comparision of load-displacement skeleton curve and patterns for the strain and stress distribution in the section of the end of the beam to test the feasibility of the existing finite element models.Then the nonlinear finite element method is used to analyze factors such as beam hight,longitudinal beam span, cast-in-situ slab thickness,cast-in-situ slab width,inter-story displacement angle,joint form for exterior joints and middle joints stiffness of orthogonal beams and Reinforcement ratio,which effects effective flange width.Emphasis is put on the study of strain distrubution patterns for the beam top during the elastic-plastic stage when the inter-story displacement angle is θ=1/50 and longitudinal reinforcement which is parrallel to the girder rib in the cast-in-situ slab.So, effective flange width values is put to that the beam top during the elastic-plastic stage when the inter-story displacement angle is θ=1/50 and the suggestions of design, Improving the earthquake resistance ability of reinforced concrete frame structure.