The Damage Analysis Of Square High-strength Concrete-Filled Steel Tubular

The buildings will face all kinds of damage and destruction in service, and the earthquake is one of important natural factor in those problems. When an earthquake occurs, the building structure will be affected by low reversed cyclic loading. The structural components of the plastic hinge zone will bring unrecoverable shaping in deformation. When the seismic intensity is exceeding the structure limit, the structure will be damaged for the first time; to most of structures, it needs a process from minor damage to completely destruction, under the low reversed cyclic loading, the destruction process maybe need several times, some of them even need dozens of times. Therefore, after an earthquake, to determine a structure is able to continue use or need rebuild, it is necessary to evaluate the cumulative damage of the structure. It is truly a significant what calamities and casualties are greatly reduced during the earthquake.On the basis of former experimental results, this paper adopts ABAQUS software, it is a large finite element analysis and calculation software, to build the model of square high-strength concrete-filled steel tubular (CFST), finite element method is used for the calculation of square high-strength CFST under low reversed cyclic loading. Firstly, the hysteretic model is built, based on the result, the damage model is proposed. It is providing the theory basis for the damage model of square high-strength CFST, its contents involve primarily the following aspects:(1)Using the finite element analysis software--ABAQUS, the model of square high-strength CFST is built.The core of high strength concrete using the ABAQUS plastic damage model. The damage coefficient d and stiffness restitution coefficient w of high-strength concrete under cyclic loading are choosed.(2)Using the method of finite element, the hysteresis curve of square high-strength CFST under low reversed cyclic loading is done. Curve and the experimental curve are compared to verify the reliability of the model. Using hooping coefficientξ, the axial compression ratio n and slenderness ratioλas parameters, 128 square high-strength CFST have been calculated. Through the analysis of calculation results,the hysteretic model of square high-strength CFST is built .To verify the reliability of the hysteretic model , the experimental hysteresis curve and the curve which is obtained by hysteretic model are Compared.(3) In order to obtain the damage model of square high-strength CFST ,ultimate displacement and Cumulative hysteretic energy dissipation of 9 square high-strength CFST are obtianed by hysteretic model. Ordering the damage index D = 1,the two-parameter damage model is obtained through regression analysis.Using the damage model to calculate the damage index of the actual test specimen,the reliability of the model is verified.