常幅循环载荷下纤维薄板增强钢筋砼梁的损伤行为研究

以碳纤维薄板增强钢筋混凝土梁为研究对象,通过对常幅循环载荷作用下增强梁的弯曲试验研究,揭示其疲劳破坏机理,建立描述构件损伤、断裂过程的结构损伤累积模型.试验得到增强梁的疲劳寿命曲线以及跨中挠度、抗弯刚度的演化规律.提出的由构件抗弯刚度表达的非线性结构疲劳损伤演化方程,描述包括混凝土开裂、碳纤维薄板与混凝土界面剥离等破坏模式在内的损伤、破坏过程,并能够对构件疲劳寿命进行预测.

FATIGUE DAMAGE EVOLVEMENT OF REINFORCED CONCRETE BEAM STRENGTHENED WITH FIBER LAMINATE UNDER CONSTANT AMPLITUDE LOAD

The fatigue properties of reinforced concrete (RC) beam strengthened with Carbon fiber laminate (CFL) under constant amplitude load were probed by three bending experiments. The fatigue failure mechanism of strengthened RC beam was studied and the structural damage cumulative model was proposed to describe the damage and fracture process of strengthened beam. The fatigue lives, histories of midspan flexibility and bending rigidity of RC beams strengthened with CFL were recorded in experiments. Then the evolvement equation of nonlinear structural fatigue damage expressed by member's bending rigidity was proposed. The structural fatigue damage model describes the damage and failure process of strengthened RC beam well, including concrete cracking, CFL debonding from concrete, and can predict the fatigue lives of strengthened RC beams.