Experimental Study On Mechanical Behavior Of GFRP Confined Seawater Coral Concrete Reinforced With Epoxy Coated Steel Bars Columns Under Compression

The combination of GFRP tube,epoxy-coated steel bars(ECSB)and seawater coral concrete(SCC)to form a new kind of structure:GFRP confined SCC reinforced with ECSB(GSE).It is beneficial to the implementation of ocean development strategy and sustainable development of construction materials.In this paper,the axial compressive properties of GFRP confined SCC reinforced with ECSB are studied,the main research results are concluded as follows.(1)Under the influences of concrete type,GFRP tube thickness,longitudinal reinforcement ratio of ECSB and volume stirrup ratio,the failure characteristics and deformation behavior of GSE specimens under axial compression are studied and analyzed.The results show that the failure mode of GSE is similar to that of GFRP confined ordinary concrete specimens,which are all circumferential tearing of tubes and crushing of core concrete.But under the same condition,the bearing capacity of GFRP confined coral concrete is much lower than that of GFRP confined ordinary concrete.The thickness of GFRP tube,longitudinal reinforcement ratio and volume stirrup ratio can effectively improve the bearing capacity of the specimen,but their effects on ductility are small.The axial compression deformation curve of GFRP confined seawater coral concrete reinforced with epoxy coated steel bars is a double line curve.The transverse deformation coefficient of the specimen changes with the change of concrete type,stirrup ratio,tube strength and thickness.(2)Based on the theory of limit equilibrium,the influences of concrete type,GFRP tube thickness,longitudinal reinforcement ratio of ECSB and volume stirrup ratio on the axial compression properties of specimens are studied and analyzed.The calculation formula of GSE bearing capacity is proposed and verified.At the same time,according to the test data and relevant data,the model of GSE under axial compression is established,and the model curve is in good agreement with the test curve.(3)The finite element software ANSYS is used to simulate the axial compression performance of GSE.The peak stress increases with the increase of longitudinal reinforcement ratio,volume stirrup ratio and GFRP tube thickness.The stress-strain curves of concrete are different with different types of concrete.(4)Finally,the main research results of this study are summarized,and suggestions on the theoretical research of GFRP confined SCC reinforced with ECSB under axial compression are proposed.