Finite Element Analysis Of Seismic Performance On High Toughness Cementitious Composites Reinforced Beam-Column Joints

Frame node includes node intersection area, beam ends and the column end, not only does it withstand the shear, hear forces and bending moments delivered by frame column and stand the shear bending moments transferred by beam, but also plays a role in the distribution of internal forces.Frame node is the power transmission hub and weak parts of framework structure. The frame joints which designed by seismic code are all according to the principle of "strong column weak beam", but this often leads to section size is too large or make the stirrup is too more. The dense steel in construction will create more trouble for concrete pouring, thereby affecting the quality of the project. Therefore, a better solution should be sought.Ultra High Toughness Cementitious Composite is based on the development of micro-mechanical fiber reinforced composites in recent years. The material transfer internal force by fiber bridging and stress 。In the fiber volume content does not exceed 2% of the cases,it showed a typical strain hardening and a steady cracking features with multiple microcracks under tensile. UHTCC has excellent toughness, good nonlinear deformation and significant crack control ability. This will make brittle failure mode of traditional cement-based materials change for ductile failure mode.Through the experiments on eight Ultra High Toughness Cementitious Composite beam-column joints and a comparison of the specimen under reversed cyclic loading,this dissertation study the feasibility of UHTCC replace stirrups in the framework joints. The main parameters of the test are node core area stirrup ratio and axial compression ratio.On the basis,this test was analyzed by Open Sees. Through simulating the UHTCC beam-column joints specimen under reversed cyclic loading,stress characteristics and failure mechanism of this kind of joints were analyzed. The influence of the core area of the node volume stirrup ratio and axial compression ratio of shear behavior of nodes was studied. Based on the Open Sees, finite element program was compiled to analysis the influence of the core area of the node volume stirrup ratio and axial compression ratio.Combined with experimental data and finite element analysis, calculation method for bearing capacity of UHTCC reinforced beam-column joints was putted. This provides a reference for practical engineering design and construction of such nodes...