Flexural behavior of bonded post-tensioned concrete beams with steel or GFRP bars

IF 3.9 2区工程技术 Q1 ENGINEERING, CIVIL

Structures Pub Date : 2024-10-24 DOI:10.1016/j.istruc.2024.107549

Mohamed Salah , Ahmed Farag , Hatem Mostafa , Ahmed Elansary

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引用次数: 0

Abstract

Post-tensioned concrete beams with GFRP reinforcement have gained attention in recent years due to their unique flexural behavior and potential cost benefits. Because of the absence of comprehensive guidelines in international codes and limited application in constructions, this hybrid system is adopted in the current paper as a pioneering solution for sustainable and eco-friendly construction practices. Particularly noteworthy is the corrosion resistance of GFRP bars, which significantly enhances the durability of structures. The influence of using GFRP with bonded post-tension concrete beam is experimentally investigated compared to concrete beams with prestressing and non-prestressing reinforcement. Eight concrete beams with different reinforcement types and ratios were cast and tested under three-point load. Flexural resistance, crack pattern, deflections, and strains of the beams were compared with a reference beam with prestressing and non-prestressing reinforcement. Experimental load capacities of the tested beams were compared to those obtained from various international codes. The experimental results revealed that the beams with GFRP bars had smaller failure load and larger deflection compared to those with non-prestressing steel by up to 25 % and 37 %, respectively. A 3D finite element model (FEM) was developed and validated by comparing the numerical results with those obtained from the experiments. A sensitivity analysis was performed, using the validated FEM, by changing the concrete strength, steel yield stress, and GFRP ultimate strength by ± 20 %. The sensitivity analysis included seventy-two beams which had the same dimensions, loading, and boundary conditions of the tested beams. Changing the concrete strength only led to varying the beam capacities by −7 % ∼ + 4 %. Changing the steel yield stress only led to changing of the beam capacities by −13 % ∼ + 11 %. No change was observed when the GFRP ultimate stress was varied by 20 %.

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带有钢筋或 GFRP 钢筋的粘结后张法混凝土梁的挠曲行为

采用玻璃纤维增强塑料加固的后张法混凝土梁因其独特的抗弯行为和潜在的成本效益，近年来备受关注。由于国际规范中缺乏全面的指导，且在建筑中的应用有限，本文采用了这种混合系统，作为可持续和生态友好型建筑实践的先驱解决方案。尤其值得注意的是，玻璃纤维增强塑料条的耐腐蚀性能大大提高了结构的耐久性。与使用预应力钢筋和非预应力钢筋的混凝土梁相比，实验研究了使用 GFRP 与粘结后张法混凝土梁的影响。在三点荷载作用下，浇注并测试了八种不同配筋类型和配筋率的混凝土梁。将这些梁的抗弯强度、裂缝形态、挠度和应变与带有预应力和非预应力钢筋的参考梁进行了比较。将测试梁的实验承载力与各种国际规范得出的承载力进行了比较。实验结果表明，与采用非预应力钢筋的梁相比，采用 GFRP 钢筋的梁的破坏荷载更小，挠度更大，分别高达 25% 和 37%。通过比较数值结果和实验结果，开发并验证了三维有限元模型（FEM）。利用经过验证的有限元模型，通过改变混凝土强度、钢屈服应力和 GFRP 极限强度 ± 20 %，进行了敏感性分析。灵敏度分析包括 72 根梁，这些梁的尺寸、载荷和边界条件与试验梁相同。改变混凝土强度只会导致梁的承载力变化 -7 % ∼ + 4 %。改变钢屈服应力仅导致梁的承载力变化-13 % ∼ + 11 %。当 GFRP 极限应力变化 20 % 时，未观察到任何变化。

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来源期刊

Structures Engineering-Architecture

CiteScore

5.70

自引率

17.10%

发文量

1187

期刊介绍： Structures aims to publish internationally-leading research across the full breadth of structural engineering. Papers for Structures are particularly welcome in which high-quality research will benefit from wide readership of academics and practitioners such that not only high citation rates but also tangible industrial-related pathways to impact are achieved.