纤维薄板与混凝土构件界面剥离断裂机理的研究

A large number of researches and applications in civil engineering have.been focused on fiber reinforced plastic (or fiber reinforced polymer, FRP), because of FRP’s excellent mechanical properties and their constructional convenience. This.project deals with a key mechanical problems of the strengthening structures with FRP sheet (or fiber sheet) plaited by ourselves in civil engineering, to study the “debonding fracture mechanism of the interface between a fiber sheet and reinforced.concrete members”. The main results obtained by theoretic and numerical and.experimental studies are: 1) A numerical analysis method based on a “over-stress area” theory is proposed to discuss the stress fields of the beams strengthened by fiber sheet and the interface. Using this numerical method and fracture mechanics theory synthetically, the cracked shape and.failure mode, and then the loading carrying capacity of the beam can be estimated. There are important scientific significance that the estimations are used to studying the failure mechanism of the beams and repairing and strengthening the RC structures (such as concrete bridges and buildings) with the fiber sheets;.2) A fracture criterion with a parameter of the maximum normalized circumferentialmixed mode crack. The criterion proposes a theoretic foundation for designing the strengthening method of the concrete structures with the fiber sheets, and choosing the fiber materials, and predicting the lives of the structures strengthened by the fiber sheets;.3) Based on the systemic studying results about the effects of the length of fiber sheet on the strength of the strengthening structures, a elementary strength criterion and an optimization design method for the strengthening structures are proposed, and applied.to the strengthening engineering of the damaged concrete bridges. 4) The strengthening engineering shows that the optimization design method is very.effective and the strengthening technique is crafty and economical, and the societal benefit and economical benefit are remarkable.

对纤维薄板增强混凝土构件的开裂性状以及纤维薄板与混凝土的界面的剥离断裂机理进行理论和实验研究，构筑界面剥离破坏的分析模型，提出复合材料的断裂力学新理论，建立纤维薄板增强混凝土构件的强度理论，对相关学科的发展，对桥梁、隧道、房屋等建筑物的抗震、防震、加固和维修，对新材料、新工艺、新结构的开发等意义重大，应用前景广阔。