Reinforcement of Houses with Prefabricated Floor Slabs

There are various methods for reinforcing houses with prefabricated floor slabs, and the appropriate approach should be selected based on actual needs and conditions. Here are some commonly used methods:

1. Section Enlargement Reinforcement Method
By adding a post-cast layer of reinforced concrete with a thickness of no less than 40mm on the surface or bottom of the prefabricated slab, a rigid floor or roof cover is formed. If surface pouring is chosen, the construction is relatively simple; if a composite layer is poured at the bottom of the slab, the bottom of the slab needs to be roughened and the喷射法 (jetting method) should be used for construction to enhance the bond between the new and old concrete. This method can significantly improve the overall stiffness and load-bearing capacity of the structure and is suitable for scenarios requiring a substantial increase in load-bearing capacity.

2. Carbon Fiber Sheet Bonding Reinforcement Method
Structural adhesive is used to bond carbon fiber sheets along the span direction to the tensioned bottom part of the slab. Carbon fiber sheets are lightweight, high-strength, and corrosion-resistant, effectively improving the structural load-bearing capacity and stiffness while adding minimal weight to the original component and not affecting the building's appearance. When the load increase is relatively small, carbon fiber sheets can be directly bonded to the bottom of hollow slabs, making this method suitable for renovation projects with high space requirements.

3. Structural Load Path Modification Reinforcement Method
By adding beams, columns, or steel beams at the bottom of the prefabricated slab, the original load-bearing system is altered, reducing the slab's bending moment and improving its load-bearing capacity. For example, adding steel beams can transform the load distribution of hollow slabs into a more reasonable pattern, making this method suitable for scenarios with insufficient local load-bearing capacity or the need to adjust the structural load path.

4. Prefabricated Slab Replacement
High-strength, high-performance prefabricated slab materials are selected to replace the original components, while strengthening weak connection points (such as joints and reinforcing bars) to significantly enhance the overall strength and stability of the house. This method is suitable for houses with severely aged prefabricated slabs or those designed to outdated standards.

5. Reinforcement After Opening Holes
Opening holes in prefabricated slabs cuts off the original load path and reinforcement, necessitating the determination of a reinforcement plan through internal force analysis and load-bearing capacity verification. Common measures include bonding carbon fiber sheets around the hole, adding reinforcing bars, or installing steel supports to restore structural safety.

6. Steel Section Reinforcement Method and Clamping Plate Reinforcement Method
Steel sections (such as angle steel) are installed along the four corners at the bottom of the prefabricated slab, forming an octagonal support system that effectively improves the floor's load-bearing capacity; the clamping plate reinforcement method involves adding steel plates at the bottom of the slab and securing them with bolts to enhance local bending resistance.

It is important to note: Reinforcing the surrounding areas of prefabricated slab floors is not a one-size-fits-all solution. If a house has suffered from fires that have compromised the strength of prestressed reinforcing bars or structural cracking due to foundation settlement, reinforcement becomes difficult, costly, and may even approach the cost of reconstruction, in which case demolition and reconstruction are recommended. All reinforcement measures should be implemented based on the results of a house safety appraisal to ensure a scientific and reasonable plan.