海洋湿热环境下FRP加固受损混凝土界面长期性能研究

The long-term performance of RC structures strengthened with FRP has attracted substantial research interest arround the world. In an FRP-strengthened RC member, The FRP-to-concrete interface is the most critical as well as weakest link for the load transition between FRP and concrete. As a result, the bond/debonding behavior of the interface usually governs the failure mode and strengthening effect of the strengthened structures, which needs carefull consideration in real-application. However, its long-term behavior has not yet been well understood mainly due to the lack of relative research worldwide. The proposed research project aims to clarify the long-term performance of the interface under environmental exposure, especially in the typical subtropical climate of southern China. In the first stage, two series of accelerated tests on bond behavior will be carried out to clarify the its deterioration under wet-dry cycle (using seawater) and natural environment exposure.The influence of crack pattern in concrete will also be investigated through the experiments. Based on the experimental results, a fracture energy-based bond-slip model taking into account the above effects will then be proposed. An extened finite element (i.e. XFEM based on discontinuous shape function) model will be developed adopting the proposed bond-slip model. The XFEM will be verified by experimental results and extensive parametric studies will be carried out to investigate the effects of significiant issues, such as existence and evolvement of micro-damage and/or imperfections in the interface, on the long-term performance of strengthened structures.Finally, a reliable but economic durability design method will be developed for FRP strengthened sttructures under typical tropical environment of southern China. The proposed design method will also provide valuable references for the design of FRP strengthened structures under similar environment in China and beyond. The accomplishment of this project is hopted to greatly promote the use of FRP in structural strengthening, and to generate great research significance and social value.

FRP加固结构的长期性能是国内外土木工程加固领域关注的热点，FRP-混凝土界面既是加固件的重要传力部位，也是薄弱环节，其在海洋湿热环境中的耐久性是亚热带地区亟待解决的关键问题。本项目拟探讨亚热带湿热气候对FRP加固受损混凝土界面长期性能的影响。基于亚热带湿热环境特征，制定FRP-混凝土受损界面在干湿循环作用下的加速老化实验系统和自然暴露实验系统；结合实验确定界面粘结滑移的时效退化规律，建立亚热带湿热气候下FRP-混凝土界面性能时变的损伤退化模型；提出FRP-混凝土界面含内嵌裂纹损伤断裂的耐久性仿真分析模型。本项目将为亚热带湿热气候下FRP加固受损混凝土结构制定一个安全、经济的耐久性设计方法，也为同类气候环境地区FRP加固受损混凝土结构长期性能提供重要的理论依据和实验数据。预期成果将能极大促进FRP这一高性能材料在结构维修加固领域的应用，对延缓基础设施老化和使用寿命具有重要的科学意义。

FRP加固结构的长期性能是国内外土木工程加固领域关注的热点，FRP-混凝土界面既是加固件的重要传力部位，也是薄弱环节，其在海洋湿热环境中的耐久性是亚热带地区亟待解决的关键问题。本项目探讨了亚热带湿热气候对FRP加固受损混凝土界面长期性能的影响。基于亚热带湿热环境特征，制定了FRP-混凝土受损界面在干湿循环作用下的加速老化实验系统和自然暴露实验系统；结合实验确定界面粘结滑移的时效退化规律，建立了亚热带湿热气候下FRP-混凝土界面性能时变的损伤退化模型；提出FRP-混凝土界面含内嵌裂纹损伤断裂的耐久性仿真分析模型。本项目为亚热带湿热气候下FRP加固受损混凝土结构制定一个安全、经济的耐久性设计方法，也为同类气候环境地区FRP加固受损混凝土结构长期性能提供重要的理论依据和实验数据。成果极大促进FRP这一高性能材料在结构维修加固领域的应用，对延缓基础设施老化和使用寿命具有重要的科学意义。