Research on flexural performance of small-caliber CFRP-square section steel tube concrete
In order to study the flexrual performance of small-caliber CFRP-square section steel tube concrete,three different specimens with outer diameter of steel tube of 30,32,35 mm(named specimen A,B and C,respectively)were used and 12 sets of three-point bending tests were carried out.The failure morphology of the specimens was observed and the whole load-displacement curve was obtained.The finite element software ABAQUS was used to analyze the nonlinear finite element of the specimen,and to analyze the bonding ability between steel tube and cement,cement strength and CFRP thickness.By measuring strain change,the flexrual performance of specimens was analyzed.The results show that whether steel tube is filled with cement or wrapped out by CFRP,the maximum bearing capacity and bending stiffness of the specimen are improved.When the three materials of steel tube,cement and CFRP are combined,the lifting effect is the most obvious,and the maximum bearing capacity of specimen A,B and C increases by 81.6%,93.3%and 92.6%,respectively.Whether the steel pipe is filled with cement or not,it is obviously related to the final failure form of the specimen.The finite element analysis results of load-displacement curve and the failure mode are in agreement with the test results.The thickness of CFRP can significantly affect the maximum bearing capacity and bending stiffness of the beam.