Design and Evaluation of a New Resin-Filled GFRP Pipe Connection System for Butt Splicing of FRP Bars.

Hui Huang,Zhizhong Wu,Jie Lian,Dong Meng,Jiaxing Li,Bin Jia

doi:10.3390/ma14010161

Abstract

Fiber-reinforced polymer (FRP) bars are one of the promising alternatives for steel bars used in concrete structures under corrosion or non-magnetic environments due to the unique physical properties of FRP materials. When compared with steel bars, FRP bars are difficult to be spliced in field application due to their anisotropy and low shear and compressive strengths. In view of this, the paper presents a new non-metallic connection system (i.e., resin-filled glass fiber-reinforced polymer (GFRP) pipe connection system) for the butt splicing of FRP bars. With the proposed connection system and a simplified trilinear interfacial bond-slip model, a set of design formulas were derived based on the requirement that the proposed connection system should provide a load transfer capacity beyond the tensile capacity of the spliced FRP bars (i.e., to fulfill the high tensile strength of FRP materials). Besides, considering the fabrication error-induced load transfer capacity reduction of the connection system in field application, a correction factor was introduced in the paper to compensate for the reduced load transfer capacity by increasing the FRP bar anchorage length. At last, to estimate the effectiveness of the proposed connection system and the derived design formulas, nine specimens were fabricated with a kind of commercially available basalt fiber-reinforced polymer (BFRP) bars and the designed connection system and tested under unidirectional tension to study their tensile performance. With the comparison between the tested and theoretical results, the effectiveness of the proposed connection system and the derived design formulas are verified.

Highlights

Fiber-reinforced polymer (FRP) bars have been gradually used extensively in civil engineering due to the unique merits of light weight [1], high strength [2,3], fatigue and corrosion resistance [4,5,6,7], non-magnetic [8,9,10,11], reversibility [12] and the easy incorporation with fiber sensors [13,14]
3, the observed failure caused by the premature failure mode of basalt fiber-reinforced polymer (BFRP) bar pullout
It should be values under a given load. These behaviors are caused by the fabrication er mentioned that the tested relative slips presented in Table 3 were all recorded on LVDTs duced mechanical reduction of the BFRP bar-bonding layer interface, which reduc near the failure end

Summary

Introduction

Fiber-reinforced polymer (FRP) bars have been gradually used extensively in civil engineering due to the unique merits of light weight [1], high strength [2,3], fatigue and corrosion resistance [4,5,6,7], non-magnetic [8,9,10,11], reversibility [12] and the easy incorporation with fiber sensors [13,14]. According to the literature research conducted by the authors, relatively few studies [17,18] are focused on the development of a connection system for the butt splicing of FRP bars. In these studies, Huang et al [18] proposed the resin-filled round steel pipe connectors for the butt splicing basalt fiber-reinforced polymer (BFRP) bars and conducted a set of tensile tests to verify the effectiveness of the connection system with four variables. The test results showed that adhesive-type couplers can be applied to GFRP bar connection and mechanical-type couplers should not be adopted. Since the latter causes damage to the surface of the GFRP bars, and induces premature failure

Objectives

Methods

Results

Conclusion