FRP-混凝土中部裂缝剥离分析与设计研究
| 基于有限元模型，提出了FRP-混凝土中部裂缝剥离模型的设计公式，通过与大量试验对比，表明该实际公式优于现有各分析或设计公式。 指导老师：香港理工大学滕锦光教授，清华大学叶列平、江见鲸教授 论文下载 FRP片材加固混凝土梁剥离承载力的计算及设计方法 摘 要：粘贴FRP片材加固混凝土结构的界面剥离问题是FRP片材加固混凝土结构技术的关键基础问题。本文根据近年来对FRP片材加固混凝土的界面粘结性能、FRP片材加固混凝土梁的受弯和受剪剥离性能的试验和理论研究，介绍了FRP片材加固混凝土梁的抗弯和抗剪剥离承载力的计算和设计方法，及其有关保证剥离承载力的构造要求。
Intermediate
crack debonding in FRP-strengthened RC beams: FE analysis and
strength model Abstract: Reinforced concrete (RC) beams strengthened in flexure with a bonded fiber-reinforced polymer (FRP) plate may fail by intermediate crack (IC) debonding, in which debonding initiates at a critical section in the high moment region and propagates to a plate end. This paper first presents a finite-element (FE) model based on the smeared crack approach for concrete for the numerical simulation of the IC debonding process. This finite-element model includes two novel features: (1) the interfacial behavior within the major flexural crack zone is differentiated from that outside this zone and (2) the effect of local slip concentrations near a flexural crack is captured using a dual local debonding criterion. The FE model is shown to be accurate through comparisons with the results of 42 beam tests. The paper also presents an accurate and simple strength model based on interfacial shear stress distributions from finite-element analyses. The new strength model is shown to be accurate through comparisons with the test results of 77 beams, including the 42 beams used in verifying the FE model, and is suitable for direct use in design. Design proposals for the debonding strengths of FRP strengthened RC beams in the Chinese design code ABSTRACT: Debonding failures are very common in FRP strengthened RC structures so they must be carefully considered in design. In the last few years, significant new understandings of the debonding behaviour of both flexurally and shear strengthened RC beams have been achieved based on recent research on the behaviour of FRP-to-concrete interface. These new understandings are reflected in the national design standard of China, Standard for FRP in Civil Engineering, which is being drafted. This paper summarises relevant specifications adopted for such debonding failures in the new Chinese standard. Recent research on intermediate crack Debonding in FRP-strengthened RC beams ABSTRACT: An important failure mode for an RC beam strengthened with an externally bonded FRP plate is debonding of the FRP plate from the soffit of the beam due to major flexural cracks. In this failure mode which is commonly referred to as intermediate crack (IC) debonding, debonding initiates at a critical section in the high moment region and then propagates to one of the plate ends. Despite many experimental and theoretical studies, accurate predictive models for IC debonding failures have not been developed. This paper presents a new smeared crack approach for the finite element simulation of the IC debonding process, in which a new model for the FRP-to-concrete interface capable of capturing the effect of local slip concentration near a flexural crack is proposed. The finite element model is shown to be accurate through comparisons with the results of 45 beam tests. The paper also presents an accurate and simple design model based on interfacial shear stress distributions from finite element analysis. The new design model is shown to be accurate through comparisons with the test results of 73 beams, including the 45 beams used in verifying the FE model. |
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