Finite Element Analysis That Anchorage With U-Type Sheet Of Carbon Fiber Reinforced Low-Intensity Concrete Beams

The reinforcing with CFRP is a rising method in the field of constructional reinforcement. But the beams reinforced by this method often failure due to the early debonding of CFRP, the lower of concrete strength, the larger of possibility of failure due to debonding. Because this reinforcing method is restrained in the reinforcing of low-strength concrete construction, so we need to seek a additional anchorage method that can make this reinforcing method apply to low-strength concrete construction.This paper made 4 beams of low-strength concrete(C15), this paper mainly studied the style of debonding of a reinforcing beam of no additional anchorage, also the effectiveness of the additional anchorage of U-type steel sheet and the additional anchor bolt were experimental studied. Through the experiment result, in the FEM analysis the debonding rule of the interface of RC beam based on the first principal stress, was founded, and also the debonding criterion is founded. FEM model of flexural RC beams strengthened with CFRP are experimental verified, through FEM analysis of two RC beams and experiment result. It turns out that the calculation result by FEM model is more or less the same with the test result, which indicates the FEM model is reasonable.In order to carries on the deep step to the U-type steel sheet anchor analysis, there are 19 anchored with U-type steel sheet that analyzed. On these conditions that: the position, the width and height, the spacing of U-type steel sheet anchor, so to search the influence for beam characteristic. The results show that the carrying capacity of beams were increased with U-type steel sheet anchor, the deflection of beams were reduced and cracks in the U-type steel sheet position were obviously suppressed. The side plate of the U-type steel sheet pass the shear stress between the body of the concrete, control the crack growth rate, while the bottom of the concrete and vertical carbon fiber are bound by the U-type steel sheet, the local stress concentration problems of the interface is improved, reducing the role of the local concrete units main tensile stress to vertical carbon fiber play a role in preventing peeling. Different anchor forms will produce different result. The U-type steel sheet is suggested to apply along the shear-cross region with same pacing, should be applied to the position where has centralism load.