Slab crack strengthening

A brief introduction to the scheme of structural repair and reinforcement

1. Floor slots are filled with modified epoxy resin for reinforcement and waterproofing.

2. the bottom of the slab is bonded with 2 layers of fiber reinforced polymer(FRP) wrap, and 1 layers of epoxy mortar are used to protect, and the thickness is 30mm.

3. 1 layers of U - shaped FRP wrap are attached to the beam for shear reinforcement. The U shaped hoop is perpendicular to the beam axis and is pasted on the beam side. The whole beam is long pasted, the width of the beam is 200mm, and the distance is 200mm. 2 layers of CFRP sheets were bonded at the bottom of the beam for bending reinforcement, width 300mm, parallel to the beam axial paste. 1 layers of carbon fiber cloth (upwards) are attached to the middle of the column for seismic reinforcement, and the direction of the paste is perpendicular to the axial direction of the column, so the bearing capacity and the seismic capacity of the structure are improved.

4. After carbon fiber reinforcement is finished, surface protection treatment is carried out. The epoxy resin mortar is used to protect the carbon fiber cloth and the thickness of the protective layer is 20mm.

Construction plan

1, crack repair and waterproof treatment of floor slab

Concrete crack is the most common engineering disease, but most cracks can be repaired to restore the original function of concrete structure. Usually, pressure grouting, slotting and coating sealing methods are usually used. There are not many cracks in this project. The width of the crack 0.5~3mm can be repaired by slotting to fill the modified epoxy crack injection resin (including matching primer and repair adhesive). Waterproof and structural repair is completed once.

2,Strengthening of carbon fiber fabric at the bottom of the slab

After the floor cracks were treated, 2 layers of carbon fiber cloth and 2 layers of carbon fiber reinforcement were applied at the bottom of the floor.

The fiber direction of the carbon fiber cloth is the same as the force direction of the plate. The carbon fiber cloth extends to the side of the beam and uses a multi strip scheme. The width is 200mm, the distance is 200mm, and the unit mass is 300g/m2.

The carbon fiber layering, which is perpendicular to the direction of carbon fiber cloth, is stretched in the range of carbon fiber cloth. The width is 200mm, the spacing is 200mm, and the unit mass is 300g/m2.

3, reinforcement of epoxy mortar layer with steel wire mesh on slab bottom

Laying steel wire netting on the bottom of the board, reinforcing epoxy mortar, and thickness of epoxy mortar layer 30mm.

4, The beam side is bonded with 1 layers of U type CFRP sheets, and the bottom of the beam is bonded with 2 layers of CFRP sheets.

The beams were strengthened with carbon fiber, and 1 layers of U shaped carbon fiber hoops were bonded on the side of the beams to reinforce the beams. 2 layers of CFRP sheets were bonded to the bottom of the beams for flexural strengthening. The carbon fiber cloth is made of imported Japanese Dongli silk, which is made of first grade cloth, with a unit mass of 300g/m2 and a tensile strength of 3400Mpa.