Finite Element Analysis And Study On Crack-retarding & Reinforcing Of FRP Composite RC Structure

The FRP composite RC structure is the basic realizing pattern of the crack-controlling idea of'Retarding', which is raised by the crack-controlling principle of the fracture mechanisms, and has broken through the traditional mentality of FRP reinforcing the old concrete structures.Based on the fracture mechanisms principle, this paper has analyzed two fracture mechanisms of the FRP Layer of Crack-retarding & Reinforcing(called the FRP layer): Forming central locking force and turning the side crack into internal eccentric crack; and has studied the effect factors of crack-retarding & reinforcing with the finite element method, such as the FRP layer thickness, the elastic modulus, the FRP layer's contact surface peeling length, the steel bars combining action and so on, and has confirmed the finite element analysis by experiments. The primary conclusions on this paper lays in: Firstly, through the FEM analysis on the pure concrete, the FRP composite pure concrete, the reinforced concrete and the FRP composite reinforced concrete structure with different crack heights, an important conclusion has been drawn out that the cracks would stop growing when their height develop to a certain height of the section (waved with the crack-retarding material elasticity coefficient, change of thickness, and contact surface whether to strip). Secondly, analyzed the effect of FRP composite concrete structures under the situations of the FRP layer's contact surface peeling, load change and so on, the conclusions have been obtained that the stress intensity factor of the vertical crack increases quickly after the FRP layer's contact surface peeling, and the vertical crack is easier to expand after the contact surface peeling. Finally, the effect of crack-retarding & reinforcing has been confirmed through the experiments on the FRP composite reinforced concrete structure with FRP layer of the different quality, thickness, and bonding style; and the experiment results are in concordance with the conclusions of the finite element analysis.