Experimental Study on FRP-to-Concrete Bonded Joints with FRP Sheet Anchor System

Weiwen Li,Wei Liu,Feng Xing,Xu Yang

doi:10.1155/2020/2514313

Weiwen Li, Wei Liu + Show 2 more

Open Access

https://doi.org/10.1155/2020/2514313

Copy DOI

Abstract

Fiber-reinforced polymer (FRP) has been widely used for retrofitting and strengthening concrete structures over the past two decades. Because concrete members retrofitted by externally bonded FRP sheets can fail prematurely in debonding because of the fracture between FRP and concrete, FRP tensile strength cannot be fully utilized in engineering practices. Numerous useful investigations have been conducted to develop effective anchor systems to restrict FRP debonding. Thus, an FRP sheet-anchor system was developed and observed to be one of the most effective and convenient anchor systems. The FRP sheet-anchor system is applied to reinforced concrete beams strengthened with U-wrapping and side-bonded FRP configurations in few design guidelines. However, only a few investigations have focused on the failure mechanism of the FRP sheet-anchor system in the existing literature. Therefore, the main objective of this study is analyzing the effect of the carbon FRP (CFRP) sheet-anchor system on the bonding behavior of the CFRP-concrete interface, particularly the effect of the width and stiffness of the CFRP sheet-anchor system. In addition, the anchor-strengthened stage is defined by the load-slip response, which is different from that of specimens without the CFRP sheet-anchor system. Based on the experimental results, three linear stage models of the bond-slip constitutive relationship are proposed in this study.

Highlights

In reinforced concrete (RC) members, shear-strengthened with externally bonded fiber-reinforced polymer (FRP) sheets, the premature debonding failure mode often occurs in the side-bonding or U-wrapping FRP schemes
One anchorage system is the FRP spike anchor, which is made of a tow of unidirectional fibers to be inserted into the predrilled holes in concrete, which can be pushed through to the other end of the tow where this relatively new FRP spike anchor spreads on top of the FRP to form a fan [6,7,8,9,10]. ese investigations have shown that this anchor system can improve the ultimate capacity [6] and can be used to prevent premature debonding of FRP sheets from concrete surfaces [7]
In few design guidelines, such as GB50608-2010 [35], the FRP sheet anchor system is recommended for RC members shear-strengthened with U-wrapping and sidebonded FRP schemes

Summary

Introduction

In reinforced concrete (RC) members, shear-strengthened with externally bonded fiber-reinforced polymer (FRP) sheets, the premature debonding failure mode often occurs in the side-bonding or U-wrapping FRP schemes. [8] presented an analytical model to predict the anchoring behavior of the FRP spike anchor system; Breña and Mcguirk [9]and Teng et al [10] showed that the FRP spike anchor system can enhance both the capacity and ductility of FRP reinforced concrete members to some extent Some metallic elements such as bolts and plates have been used to anchor systems and have good applicability in improving capacity [11,12,13,14,15,16]. It is a convenient and effective anchoring method used to delay and inhibit the premature

Objectives

Results

Conclusion