PHC pipe pile cracks

Reinforcement scheme

Based on the characteristics, crack location, characteristics and safety impact of comprehensive engineering, and combined with the existing domestic technical level, the treatment and reinforcement scheme of vertical crack of pile body is put forward.

1) crack treatment

For vertical cracks with relatively small crack width (delta <0.20mm), surface closure method is adopted.

2) sticking carbon fiber reinforced polymer(FRP) wrap outside the pile body.

The CFRP sheet is applied to the outside of the pile with vertical cracks to strengthen the restraint of the concrete. Three layers of CFRP sheet are attached to the cracks in the circumferential direction without interval. The length of the cracks is more than 500 mm and the overlap length is more than 200 mm.

Requirements for reinforcement materials

(1) carbon fiber cloth: high strength type I, 300g/m2;

(2) concrete repair adhesive and carbon fiber reinforced structural adhesive: Grade a glue.

(3) The reinforced concrete and concrete materials (cement, sand, stone, cement, admixture) used in the growth section of reinforced concrete pile core are the same as the crossbeam, and the concrete strength grade is not lower than the original design.

(4) Considering that the reinforced environment is in a humid environment, and some even in the water level change area, the concrete crack repair adhesive and the structural adhesive matching with carbon fiber should be able to adapt to the humid environment.

(5) Carbon fibers and patching adhesives are required to provide quality assurance certificates and certificates of conformity, and a report on aging resistance under hot and humid conditions.