Experimental And Numerical Investigation Of Square Tubed Steel Reinforced High-strength Concrete Short Columns

In this paper,the axial compressive behavior of square tubed steel reinforced high-strength concrete short columns is studied from both experimental and finite element aspects.Ten square tubed steel reinforced high-strength concrete short columns are designed and tested.The failure mode analysis and load-displacement curve analysis of the test members are carried out.Then through the verification of the effective finite element model for the expansion of the component,through the finite element analysis of the specimen stress and parameter analysis;By verifying the experimental data of others,the finite element model of square CFRP-steel tube composite constrained section steel high-strength concrete is established,and then the stress analysis and finite element parameter analysis are carried out on the members based on the model.Based on the finite element analysis,the axial bearing capacity formula of highstrength concrete short column with square steel tube constrained section was put forward,which was verified by the experimental data of myself and others.The specific research contents are as follows:（1）Taking concrete strength,steel tube strength,steel tube thickness and section steel form as test variables,the axial compression performance of 10 square tubed steel reinforced highstrength concrete short columns was studied.And the effects of various test factors on failure mode,load-longitudinal displacement curve and load-strain curve were systematically investigated.At the same time,the interaction mode of each component of the specimen was studied.The influence of various test variables on the ductility of the specimen is analyzed.（2）Using ABAQUS software,the finite element simulation of the axial compression performance of square tubed steel reinforced high-strength concrete short columns was carried out.Based on the experimental results,the validity of the finite element model used in this paper is confirmed.The correlation data and the stress nephogram in the model are used to analyze the stress variation of each component of the column during the whole loading process.Then the parameter classification under various working conditions is carried out.The influences of steel tube thickness,concrete strength,steel tube strength,section steel strength and steel matching type on the whole process curve and stress of members are discussed in detail.Based on the results of finite element analysis,a formula for calculating the axial bearing capacity of high-strength concrete short columns with square steel tube is proposed and validated（3）The mechanical properties of CFRP-steel tube composite confined steel reinforced concrete square short columns were investigated by using the validated numerical model above.The experimental data in previous papers are verified to prove the wide applicability of the model.The influences of the variables on the performance of the components are explored,such as whether the outer steel tube is through,the strength of concrete,the strength of steel tube and the number of CFRP layers.