Integrity of Precracked Reinforced Concrete Retrofitted withComposite Laminates

9634763 Buyukozturk本研究的目的是提供科学依据 断裂的潜在机制 和分层的预裂纹钢筋混凝土加固使用纤维增强塑料（FRP）复合材料层压板，并制定有效的应用和安全的工程设计这些系统的设计准则。 已经观察到层合梁通过几种机制失效，包括层合板的屈服、压碎 的 混凝土，并通过复合材料与混凝土的分层而发生脆性断裂。 现有的经验表明，在正常使用条件下，在低于材料极限的应力和载荷下，可发生分层断裂。 本研究的重点将是分层及其原因，特别是在存在组合的弯曲和剪切裂缝的加固混凝土梁。 基于断裂力学的试验和数值相结合的研究从混凝土粘结层的界面区域开始将在混凝土上进行 层合梁 与 纤维增强塑料。 参数研究 涉及 不同 材料 和建设 技术 将 确定 的 这些组合的最佳效果。 该项目将有 瑞士联邦 实验室 材料测试和研究（EMPA）在瑞士， 将进行规模试验， 与本研究中使用的参数一致。 这项研究预计 提供一个基本的知识， 的 FRP分层，并制定所需的设计准则，以有效，经济和安全的方式在改造领域的工程应用有直接的影响。 ***

9634763 Buyukozturk The objective of this research is to provide a scientific basis for the underlying mechanisms of fracture and delamination of precracked reinforced concrete retrofitted using fiber-reinforced plastic (FRP) composite laminates, and to develop design guidelines for efficient applications and safe engineering designs of these systems. Laminated beams have been observed to fail through several mechanisms, including yielding of the laminate, crushing of the concrete, and brittle fracture through delamination of the composite from the concrete. Available experience has shown that fracture through delamination can occur at stress below material limits and under loads within normal service. The emphasis of this study will be on delamination and its causes, specifically in the presence of combined flexural and shear cracks in the retrofitted concrete beam. Fracture mechanics based combined experimental and numerical studies of failure initiating from the concrete-adherent-laminate interface region will be performed on concrete beams laminated with fiber-reinforced plastics. Parametric investigations involving different materials and construction techniques will determine the optimum effectiveness of these combinations. The project will have the collaboration of Swiss Federal Laboratories for Materials Testing and Research (EMPA) in Switzerland where large scale tests will be conducted with consistent parameters as will be used in this study. This research is expected to provide a fundamental knowledge of FRP delamination, and be developing the needed design guidelines to have a direct impact on engineering application in the retrofitting field in an efficient, economical, and safe manner. ***