This paper reports on an investigation into the behavior of GFRP-reinforced precast concrete tunnel lining (PCTL) segments loaded on the concave side subjected to transportation, storage, and settlement loads induced by soil settlement underneath tunnels and/or internal vehicular accidents. Shear tests were conducted on four full-scale PCTL segments with a rhomboidal shape measuring 1500 x 250 mm in rectangular cross section and an arched length of 2100 mm. Three main parameters—namely, reinforcement type, concrete strength, and longitudinal reinforcement ratio—were studied under three-point loading until failure. The results reveal that all specimens experienced shear failure due to the diagonal tension mode, even if initiated by the yielding of flexural bars in the steel-reinforced segment. PCTLs reinforced with GFRP or steel bars at the same ratio demonstrated comparable shear strengths and satisfied serviceability limits. The use of both a high reinforcement ratio and high-strength concrete (HSC) increased the shear strength of the GFRP-reinforced PCTL segments. Experimental results were employed to review and verify North American code provisions and existing models with some amendments to meet the requirements of designing tunnel segments reinforced with GFRP bars in terms of deflection in the service state and checking shear strength in the ultimate limit state. Measured deflection was used to compare the experimental values of the effective moment of inertia to predictions with current models to evaluate their accuracy. Based on the analysis of the results, Bischoff’s equation for the effective moment of inertia of FRP-RC structures was modified, and an equation was developed to predict the deflection of GFRP-reinforced PCTL segments with 98 % accuracy. Based on a comparison of experimental and predicted shear capacities, the combination of concrete contributions (including the arch-shape effect of PCTLs and the tie resistance in the modified compression field theory (MCFT), plasticity theory (PT), and modified critical shear crack theory (CSCT)) provided better predictions.

中文翻译：

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GFRP筋预制混凝土隧道衬砌管片的凹性能评价

本文报告了对凹侧加载的 GFRP 增强预制混凝土隧道衬砌 (PCTL) 管片在运输、储存和隧道下方土壤沉降和/或内部车辆事故引起的沉降荷载作用下的行为的调查。剪切试验在四个全尺寸 PCTL 节段上进行，这些节段的菱形形状为矩形横截面，尺寸为 1500 x 250 毫米，拱形长度为 2100 毫米。在三点加载下研究了三个主要参数，即钢筋类型、混凝土强度和纵向钢筋比，直至失效。结果表明，即使是由钢筋段中的弯杆屈服引起的，所有样本都经历了由于对角拉伸模式而导致的剪切破坏。用相同比例的 GFRP 或钢筋加固的 PCTL 表现出相当的剪切强度和满足的使用极限。高配筋率和高强度混凝土 (HSC) 的使用提高了 GFRP 增强 PCTL 节段的抗剪强度。利用试验结果对北美规范规定和现有模型进行了审查和验证，并进行了一些修改，以满足GFRP筋加固隧道管片在使用状态下的挠度和极限状态下的抗剪强度校核的设计要求。测量的挠度用于将有效转动惯量的实验值与当前模型的预测值进行比较，以评估其准确性。基于对结果的分析，对 FRP-RC 结构有效转动惯量的 Bischoff 方程进行了修改，并建立了一个方程来预测 GFRP 增强 PCTL 节段的挠度，准确度为 98%。基于实验和预测抗剪承载力的比较，混凝土贡献的组合（包括 PCTL 的拱形效应和修正压缩场理论 (MCFT)、塑性理论 (PT) 和修正临界剪切裂缝中的拉力阻力）理论（CSCT））提供了更好的预测。