Development of strength interaction diagrams for designing precast concrete tunnel lining segments reinforced with GFRP bars

Abstract

Replacing conventional steel reinforcement with noncorroding glass fiber-reinforced polymer (GFRP) reinforcement can be an effective solution to mitigate the corrosion problem in precast concrete tunnel lining (PCTL) segments. PCTL segments should be effectively designed to withstand the applied load during production, transportation, construction, and service stages. The literature, however, offers limited design recommendations or guidelines for designing GFRP-reinforced PCTL segments. In this study, an experimental program was conducted to investigate the effect of reinforcement ratio and tie configuration on the behavior of GFRP-reinforced PCTL segments at the service and ultimate stages. Novel procedures and equations were developed to obtain axial load–bending moment interaction diagrams at the ultimate and service stages. In addition, interaction diagrams were developed to consider the creep-rupture stress limits in GFRP bars. Furthermore, axial load–shear-strength interaction diagrams were developed for GFRP-reinforced PCTL segments, as well as a simplified procedure to control cracking. Afterward, a parametric study was performed to evaluate the effect of concrete compressive strength, reinforcement ratio, and cross-sectional thickness on the axial load–bending moment interaction diagrams of GFRP-reinforced PCTL segments. The analytical results were compared to the experimental results from the current study and the literature. The comparison revealed that the proposed analytical procedure was suitable for designing GFRP-reinforced PCTL segments.