Research On Compressive Behavior Of BFRP-confined Concrete Square Columns

Fiber reinforced composites(FRP)have the advantages of light weight and corrosion resistance,and FRP confinement has become an effective method of reinforcing and repairing concrete structures.The research on the behavior of FRP-confined concrete columns under axial compression plays an important role in the study of the application of reinforcement.The objective law of reinforcement effect can be obtained.The research results are the basis and basis for engineering design and application.There are few studies on the basalt fiber reinforced composites(BFRP),hybrid reinforcement and rectangular parallelepipeds,so this paper systematically studies the axial compressive properties of BFRP confined concrete square columns.First of all,15 concrete square columns strengthened with different kinds of basalt fiber reinforced plastic(BFRP)and three contrast columns were tested which were divided into five groups according to the parameters such as FRP layers,types and reinforcement methods.The damage process and failure characteristics were observed.Also,the effect of BFRP on the bearing capacity and ductility of concrete columns was evaluated by comparison between groups.The constitutive curves and the performance of FRP were analyzed.Then,finite element analysis using ABAQUS was performed to simulate the constitutive curve of each group of specimens and compare the results with the experimental results.Based on the simulation reliability,the stress contours of BFRP-constrained square columns was studied.Finally,the accuracy of the existing computational model for the bearing capacity and ultimate strain of FRP-confined concrete square columns is tested based on the experimental data.The results show that the compressive strength and ductility of BFRP-confined square columns increase with the number of layers,but the amplitude is reducing.The compressive strength and ultimate compressive stress of BFRP-confined square columns increase by 41%And 144%,respectively.The extent of FRP's utilization increased with the increase of the number of layers.The average ratio of lateral fracture strain of the square columns jacketed with one layer and two layers of FRP(300g/m~2)was about 0.21~0.22 and 0.4~0.445,respectively;When the number of layers of FRP is the same,the influence of weaving method and mixture on the degree of FRP's utilization is very small.The compression constitutive curves and characteristic points of FEM simulation are close to the experimental ones.The calculation model quoted in this paper agree well with the test data.