Experimental Research on the Flexural Performance of RC Rectangular Beams Strengthened by Reverse-Arch Method

Tao Yu,Chunwei Li,Yancheng Liu,Quansheng Sun

doi:10.3390/sym13091666

Abstract

Carbon fiber-reinforced polymer (CFRP) reinforcement technology has been widely used in the reinforcement of reinforced concrete (RC) beams. At this stage, high prestressed CFRP board reinforcement is often used in actual reinforcement. However, most reinforced bridges are designed for a long time, and the design value of the protective layer is low, and it is impossible to achieve a large prestressed tension. Therefore, this paper proposes the reverse-arch method to paste the CFRP board and apply low prestress to strengthen the symmetrical RC beam. Through the three-point forward loading test, the cracking load, ultimate load, crack width, mid-span deflection, strain and failure mode of a reverse-arch method-pasted CFRP board-reinforced beam, a directly pasted CFRP board-reinforced beam and an unreinforced beam are compared. The results show that the load-bearing capacity and stiffness of the test beam can be improved by pasting CFRP plates with anti-arch method, but the ductility of the test beam is reduced. Compared with the unreinforced beam, the maximum cracking load and ultimate load are increased by 56% and 63% respectively. The reverse-arch method can produce low prestress, improve the stiffness and bearing capacity of members, and has a good prospect of engineering application.

Highlights

The principle of Carbon fiber-reinforced polymer (CFRP) [1] board reinforcement of concrete members is to use structural adhesive to stick CFRP material on the surface of concrete to form a new structural bearing system, so that the CFRP board participates in the force, so as to achieve the purpose of strengthening the concrete
Through the analysis of the test data, it can be seen that the cracking load and ultimate load are improved compared with the reinforcement of the CFRP plate by the reversearch method and the reinforcement by the direct adhesion of the CFRP plate
Compared with the original beam, the inverse arch method-pasted CFRP plate reinforcement can increase the ultimate load-carrying capacity by 63%; The reverse-arch method-pasted CFRP plate reinforcement can effectively improve the rigidity of the beam

Summary

Introduction

The principle of CFRP [1] board reinforcement of concrete members is to use structural adhesive to stick CFRP material on the surface of concrete to form a new structural bearing system, so that the CFRP board participates in the force, so as to achieve the purpose of strengthening the concrete. There are three types of CFRP board reinforcement method [4]: direct external pasting reinforcement technology [5,6], surface embedding reinforcement technology [7,8], prestressed reinforcement technology [9,10]. The first method is to stretch the CFRP plate directly on the reinforced beam itself through the anchoring system, and maintaining the prestress through permanent anchors [11]. The second method is to use a separate tensioning system—first, a special tensioning system is used to apply tension to the CFRP board to generate prestress, and the lifting system is used to paste the tensioned CFRP board to the bottom surface of the beam, and the tensioning system is removed after the colloid is cured

Methods

Results

Conclusion