Shenzhen Wahaha Rongtai Industrial Co., Ltd. is one of the subsidiaries of Hangzhou Wahaha Group. It was founded on August 15, 2001. It is located in the high-tech industrial park of Longgang Street, Longgang District, Shenzhen. The company covers an area of 50258 m2, of which the workshop area is 39573 m2.

Problem

The original design strength of concrete cantilever beam is C20, the end section is 200 mm x 250 mm, the root is 350 mm x 250 mm, and the main tension bar is 3 phi 22. According to this condition, the design is safe. The main reasons for the failure are as follows:

(1) The section size is insufficient to meet the design size requirements.

(2) The concrete strength is insufficient. The measured strength of cantilever beam concrete only reaches C15, which is lower than the design value C20.

(3) The position of reinforcing bar is inaccurate, and the position of main tension bar is generally lower by 40-60 mm, which greatly weakens the effective height of section. In this case, it is not suitable to use bonded steel plate reinforcement outside tension edge and other traditional reinforcement methods. The application of bonded steel enlarged section reinforcement method can solve these problems well and achieve good reinforcement effect. The principle of this method is that the bending resistance of cantilever beams can be improved by increasing the height and strength of beams.

Its advantages are that the connection between the steel beam and the original beam is simple, the integrity of the interface is strong after anchoring, and the construction is simple. When the section height of the cantilever beam is increased, the original reinforcement quantity has met the requirements of the tension zone, and the tension zone need not be strengthened. The compression zone of the reinforced cantilever beam is section steel, which fully meets the compression requirements. The reinforcement has no damage to the original structure.

After strengthening with bonded steel,

(1) After bonding steel, the bearing capacity and deformation resistance of cantilever beams have been significantly improved.

(2) The composite structure composed of steel and strengthened beams can effectively unite into a whole, jointly deform and bear forces.