Experimental Study Of Anchoring Methods On Negative Moment Area Of RC Beam Strengthened By Gluing Steel Plates

In the project of reinforced concrete structure of the reinforcement, we often meet the problem that the Bearing capacity of frame beams in the negative moment region is not enough, the reasons include building function change, new functional requirements live load increases; The concrete strength of the original structure is insufficient; There are some flaws exist in the design of original structure. In order to deal with the above mentioned problems we can use the method paste steel plate in the processing of the beam in the tension zone to reinforced the frame beams.The design specification of concrete structure reinforcement GB50367-2006gives the anchorage method that to sticky steel reinforcement in the negative moment the girder ends of the framework, this method is to paste L steel plate in beams, with U hoop board L model steel plate is fixed to the beams, meanwhile,it gives the paste length and the anchor bolts level and quantity of L steel beam and column, but it does not give distance of U hoop board from beam-column joints and the stiffness of the corner influence situation.When giving stress toL steel plate, deformation in a node location, the sticky steel plate can’t play its role. In order to find the anchoring of effective method, we use four different anchor methods to do the research of pasting steel reinforcement in the negative moment region of the girder ends to deal with the problem shortage of flexural strength in this paper, and on the basis of experiments, we proceed with the three-dimensional finite element analysis, in this paper we discuss the influence of bearing capacity of the negative moment region in the beam with different anchor methods, the main research contents are as follows:(1) Three single span reinforced concrete H framework models with scale1/2are Designed and produced, three single span frame beams reinforced beam are designed to fitness, and no damage. In the experiment, a framework of reinforcement for comparison specimens, we use four different anchoring methods respectively to paste steel plates on the four girder ends nodes in the negative moment region of the rest two frames, and do static loading test on three frame beams. (2) Based on the results of the Static loading test on the two RC Beams Strengthened by Gluing Steel Plates and the one RC Beam without being Strengthened by Gluing Steel Plates, the strain of the tensile steel and the strain of steel plates in the negative moment region of the girder ends and the deflection of midspan with four different kinds of anchoring methods under the action of the static load are analyzed, The results show that the corner stiffness of the steel plate and beams and the strength of the Hoop board in the corner of columns is the main factor of different anchor effections in the test, increasing the corner stiffness of the steel plate can play to the ability of the steel plate better, the actual reinforcement effect also can more close to the requirement of design reinforcement effect.