Research On The Mechanical Behavior Of Steel Reinforced High Strength And High Performance Concrete Frame Joints

The steel reinforced high strength and high performance concrete(SRHSHPC) structure as a new type of structural form,can play fully excellent features of steel and high strength high performance concrete,so it gradually become one of the primary structures for the high-rise and supper high-rise buildings.In this paper,the mechanical behavior of SRHSHPC frame joints is studied,and the main research contents are as follows:Based on the test results of 5 SRHSHPC frame joints under low cyclic loading,the mechanical behaviors of frame joints is discussed,including crack development,the stress mechanism and the failure modes.The effect of the axial compression ratio,concrete strength on the carrying capacity,the skeleton curve,as well as the hysteresis curve of joints is respectively analyzed.ANSYS finite element program is used to perform the numerical simulation of loading process of the joint,and the load-displacement curve under monotonic axial load is obtained.Comparison of numerical analysis results with the experimental results indicates that the model is basically reasonable and can impersonally reflect the mechanical behavior of the joint.On the basis of the mentioned above,the effect of steel ratio on the mechanical performance of SRHSHPC frame joints is further discussed.The stress distribution of steel as well as the stress situation of longitudinal steel and hoop steel in the point area are analyzed.Based on the single,two-parameter damage model,the failure ratio and the cumulative plastic damage parameters are introduced,and the damage model for SRHSHPC frame joints is obtained,furthermore the damage parameters are ascertained by the regression of the experimental results.Finally,according to the change law of damage index,the effect of concrete strength and axial compression ratio on the damage performance of joint is studied.