Experimental Study On Suppression Of IC Debonding In FRP-plated RC Slabs With End FRP Strips

A large number of existing infrastructure suffer from structural deficiency due to degradation of constituent material properties as well as overloading,therefore need to be upgraded or retrofitted.Fiber Reinforced Polymer(FRP)composites are widely used for the strengthening of concrete structures due to their superior properties such as high strength-to-weight ratio,excellent corrosion resistance.Among these applications of FRPs for strengthening RC structures,externally bonding of an FRP plate to the soffit of RC beams/slabs is one of major applications to upgrade the flexural strength of the member.Existing studies indicate that FRP-plate RC beams commonly fail by debonding failure in a form of either IC debonding or concrete cover separation,which leads to a low utilization rate of the FRP strength.FRP-to-concrete bonded joints have been commonly used to investigate the bond behavior of the FRP-to-concrete interface.This paper presents an experimental study on the FRP-to-concrete bonded joints anchored with end FRP strips to validate the provision of end FRP strips for an effective improvement in the structural performance of FRP-plated RC slabs.The experimental study examines the major variables of end FRP strips,which for the fracture mechanism of the RC slab strengthened by the end FRP strips studies.This thesis mainly discusses the above research with two series of tests.The tests are as follows:(1)The series one of test was to study the effect of FRP-to-concrete bonded joints anchored with end FRP strips by the near-end support single shear test.There are 14 specimens with 3 kinds of variables include the inclination angle,bond length,width and thickness of the end FRP strips.(2)The series two of tests used the results of the series one of tests as reference,and selected the key variables for the four-point bending test of RC slabs: there are 8 slabs with a length of 2.7 meters and a width of 0.4 meters.The three variables of the width,inclination angle of the end FRP strips and width of the FRP plate are compared.Finally,the failure mode,load-displacement curves and FRP strain of the 8slabs were analyzed,and the effect of different end FRP strips in the actual structure was compared.The results shows that:(1)The end FRP strips can effectively improve the effect of the FRP-reinforced RC slabs;(2)The greater width of the end FRP strips have better effect of FRP-reinforced RC slabs in a certain range;(3)The inclination angle of the end FRP stripshas an effect on the effect of the FRP-reinforced RC slabs.The angle of the end FRP strips 30° is better than 90°.