Innovative Connection Systems for Sand-Coated and Helically Wrapped Glass Fiber–Reinforced Polymer Bars

Fiber-reinforced polymer (FRP) reinforced concret flexural members are typically designed as an overreinforced concrete section and to satisfy the design requirements, the overlap of bars is often ubiquitous. This paper presents innovative FRP bar connectors made of woven E-glass fiber cloth and vinyl-ester resin with various shapes and configurations. FRP bar coaxial and off-axis connections were investigated. Connector configurations, including the connection system number, length, and diameter as well as the bar type, were considered as the experiment’s variables. Connection system lengths of 25 and 50 mm, glass fiber tape lengths of 2 and 4 m (for wrapping the splice length), and glass fiber–reinforced polymer (GFRP) bar full and reduced cross sections (50% and 25% cross section reductions) were selected. To study the impact of bar type, sand-coated and helically wrapped GFRP bars were used. Based on the obtained results, increasing the connection system length, diameter, and number all have a significant effect on improving the GFRP bar’s developed tensile stress. Among all variables, using two connection systems with 50-mm connection length and 4-m tape length showed the most promising result in reaching the maximum developed tensile strength (bar rupture failure). The research contributes to reducing GFRP bar splicing length and efficiently achieving the required tensile stress.