Al-Negheimish Abdulaziz I, El-Sayed Ahmed K, Al-Saawani Mohammed A, Alhozaimy Abdulrahman M
Center of Excellence for Concrete Research and Testing, Department of Civil Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia.
Polymers (Basel). 2021 Sep 28;13(19):3322. doi: 10.3390/polym13193322.
Plate end (PE) debonding is one of the critical debonding failure modes that may occur in reinforced concrete (RC) beams strengthened with externally bonded fiber reinforced polymers (FRPs). This study investigated the effect of internal steel stirrups on the PE debonding failure load of FRP-strengthened RC beams. The dimensions of the beams were 3400 × 400 × 200 mm. The beams were strengthened with carbon FRP (CFRP) sheets bonded to the soffit of the beams. The beams were divided into two series based on the distance of the cutoff point of the CFRP sheets from the nearest support. This distance was 50 mm or 300 mm, and the amount of steel stirrups was varied in terms of varying the stirrup diameter and spacing. The beams were simply supported and tested under four-point bending. The test results indicate that the effect of stirrups on the load carrying capacity of the beams was more pronounced for the beams with CFRP sheets extended close to the supports. It was also indicated that beams with larger amounts of stirrups failed in PE debonding by concrete cover separation while beams with lower amounts of stirrups failed in PE by either PE interfacial debonding or critical diagonal crack-induced debonding. The beams were analyzed using several analytical models from design guidelines and the literature. The result of analysis indicates that most of the available models failed to reflect the effect of stirrups in predicting PE debonding failure load of the beams. On the other hand, the models of El-Sayed et al. and Teng and Yao were able to capture such an effect with the best predictions provided by El-Sayed et al. model.
板端（PE）脱粘是用外部粘结纤维增强聚合物（FRP）加固的钢筋混凝土（RC）梁可能出现的关键脱粘破坏模式之一。本研究调查了内部钢箍筋对FRP加固RC梁的PE脱粘破坏荷载的影响。梁的尺寸为3400×400×200mm。梁采用粘结在梁底部的碳纤维增强塑料（CFRP）板进行加固。根据CFRP板切断点到最近支座的距离，将梁分为两个系列。该距离为50mm或300mm，通过改变箍筋直径和间距来改变钢箍筋的用量。梁为简支梁，并在四点弯曲下进行试验。试验结果表明，对于CFRP板延伸至靠近支座的梁，箍筋对梁承载能力的影响更为显著。研究还表明，箍筋用量较多的梁因混凝土保护层分离而发生PE脱粘破坏，而箍筋用量较少的梁则因PE界面脱粘或临界斜裂缝引起的脱粘而发生PE破坏。使用设计指南和文献中的几种分析模型对梁进行了分析。分析结果表明，大多数现有模型在预测梁的PE脱粘破坏荷载时未能反映箍筋的影响。另一方面，El-Sayed等人的模型以及Teng和Yao的模型能够捕捉到这种影响，其中El-Sayed等人的模型预测效果最佳。
Zotero 插件
