Research On Bond Mechanism Of GFRP Bolt

Bolt is widely used in civil engineering. The traditional steel bolt is easy to get rust, especially in corrosive environment, which will affect the safety and durability of structures. Recently, fiber reinforced polymer (FRP) bars have been introduced in market as tendons for grouted anchors and as reinforcement for concrete structure, which is lighter, stronger, anticorrosive and nonconductive. However there is little research being done on FRP bolts, especially the mechanism of bolt anchorage.Glass Fiber Reinforced Polymer (GFRP) bar is one kind of FRP bars, which has a high performance to price ratio. In this dissertation, modified pullout tests were conducted on selected samples to study the bond behavior between GFRP bolt and high strength mortar. Based on the test results, a program named ARCTRACE was developed using axisymmetric finite element method and modified arc length method to simulate pullout behavior. The research being done will contribute a lot to the design method, construction techniques and quality control standard of GFRP bolt.The main achievements are as follows.(1) Investigation on the bonding test method of bolts was presented;a modifiedpull out test model was erected according to the mechanics of bolt.(2) Based on the results of modified pullout tests, the bond behavior of GFRP bolts, including failure mode, critical bond length, bearing capacity, average bond stress, axial force distribution along the bar and load-slip curve were evaluated.(3) A constitutive curve was proposed by summarizing the literatures on bond -slip constitutive and the modified pullout tests results.(4) The axisymmetric finite element method was adopted to analyze the pullout behavior of GFRP bolt and a finite element model was also developed.(5) A program named as ARCTRACE was developed to simulate the whole curve of load-slip, which was used the modified arc length iteration algorithm. Duringprogramming, the object oriented program technology was employed. The comparison of numerical tests results and modified pullout tests results validated the program.