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In this paper, according to domestic and foreign experimental researches, bond-slip behaviors of steel and concrete composite structure, the present status, research and development of bong-slip of SRC and CFST structures is introduced in general. The distribution mode of bond stress and slip along embedment length of steel or steel tubes and concrete interface are studied, the various factors influencing the bond strength are analyzed, as well as the bond-slip relationship between bond force and slip are also analyzed. At last, the SRC and CFST bond-slip constitutive equations are studied.In this paper, through push-out test, which are in the state of the uniaxial stress, the location of bond stress-related function F (x) and a function of position and slip the G (x) the establishment of the bond slip Constitutive equation are analyzed. SRC and CFST to make the following constitutive relationship of concrete:(1) Establish mathematical equation for SRC and CFST - anchoring conditions, establish curve according to test data, analyze the influence of anchorage conditions against bonding strength first by curve fitting, then establish the relationship between main factors and average bond strength according the developing stage of slip.(2) Design different sets of curves by using the data through constitutive relationship of SRC, Concrete Filled Square Steel Tube (CFSST) and Concrete Filled Round Steel Tube (CFTST), analyze different stage of the curve, set up a uniformed function, convert different curve functions into a Second polynomial function, establish the unified relationship between position function VS related parameters and Bond stress VS interface slip. (3) Establish curve by using the multiple values of parameters based on the set-up unified formula, analyze and compare the curve made of the test data.(4) Establish different constitutive relation of SRC, CFSST and CFTST by defining the scope of various unknown parameters, because the unified function is much more convenient for use as the basis of finite element simulation.
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