How to reinforce cast-in-place slab by opening 1200mm*1200mm hole？

Let's see how we respond.

Person A:To open holes, first support, then reinforce, then cut holes.

Person B: Reinforced beams, externally covered with CFRP sheets

Person C:  After the large opening of the floor is weakened, the following measures should be taken to reinforce it.

1. The thickness of the residual slab at the entrance of the tunnel is thicker than that at both sides of the tunnel. Under the condition of increasing the reinforcement ratio of the floor, the double-deck bidirectional reinforcement is used. (the most effective is: when building or Party A's intention, increase the width of the remaining board and reduce the opening size).

Reason: after the big opening of the floor, the floor is partially discontinuous, and the seismic force can not be effectively transmitted. That is to say, the weakness of the floor slab in Article 3.5.2-4 of the Code for Seismic Design of Buildings is the most direct.

2. The following measures should be taken after the large holes in the floor slab of 3.4.8 of the Technical Specifications for Concrete Structures of High-rise Buildings are weakened:

1）. thickening the floor near the openings, improving the floor reinforcement ratio, and adopting two way two-way reinforcement.

2）. the edge beam and the hidden beam are set at the edge of the hole.

3）. the diagonal reinforcement is concentrated in the corner of the floor entrance.

Person D: Different reinforcement methods for opening holes are not the same.

Person E:  It's not so complicated, such a small hole, the surrounding steel beam is added, the top of the board paste steel plate.

Person F: Holes should be looked at in specific locations. Opening holes while reducing load can generally add steel beams / cast-in-place beams, or partially wrap carbon fiber fabric.