Reinforcement of Beams in Prefabricated Slab Houses

Several methods can be employed for reinforcing beams in prefabricated slab houses, and the appropriate approach should be selected based on the actual load of the house, the extent of structural damage, and reinforcement requirements:

1. Bonding carbon fiber or adding steel beams (suitable for cases with a slight increase in load) If the house experiences only a minor increase in local load due to adjustments in its usage function, carbon fiber sheets can be directly bonded to the bottom of the hollow slabs. Carbon fiber is characterized by high strength and light weight, effectively enhancing the flexural capacity of the beams with minimal interference to the original structure. If the load increase is more significant, steel beams can be added to the bottom of the slabs. By working in tandem with the prefabricated slabs, these steel beams alter the load-transfer path of the original structure and disperse local loads. The specifications of the newly added steel beams should be determined through calculations, typically using I-beams or H-beams. During installation, ensure tight contact between the steel beams and the prefabricated slabs, and secure them with chemical anchors or welding.

2. Constructing a beam system using I-beams For cases with large beam spans or severely inadequate load-bearing capacity of the original structure, I-beams can be used as the main beams. During operation, determine the layout density based on the profile specifications (e.g., No. 20 I-beams), typically arranging three beams in a group to cross the prefabricated slabs in an 'X' shape. I-beam columns should be installed at both ends of the beams as supports, with the column bases fixed to the walls using embedded steel plates or chemical anchors, and the tops welded or bolted to the beams. This method significantly enhances the overall structural integrity, but attention should be paid to the connection strength between the columns and the walls to avoid local stress concentrations that could cause wall cracking.

3. Adding a concrete layer and 'X' beams (suitable for scenarios requiring overall reinforcement) If the house has issues such as insufficient floor slab thickness or poor collaborative working capacity between the beams and the floor slab, a new layer of concrete can be poured on the prefabricated slabs to form a composite floor slab. During construction, remove some of the prefabricated slabs (typically at the mid-span positions), pour concrete beams, and add vertical beams on top of the horizontal beams to form an 'X' beam system. The newly poured concrete should be reinforced with a steel mesh and connected to the original prefabricated slabs using planted rebars or shear keys to ensure that the old and new structures work together under load. This method significantly increases structural stiffness, but the walls should also be reinforced simultaneously (e.g., by adding structural columns or ring beams) to prevent wall instability due to increased loads.

4. Adding angle steel supports at slab joints (for cases with insufficient bearing length) If the length of the prefabricated slabs bearing on the beams is insufficient (typically less than 50mm), cracking at the slab ends may occur due to excessive negative moments at the supports. In this case, L-shaped angle steel can be added as additional supports on both sides of the slab joints, with the angle steel specifications determined through calculations (e.g., ∠50×5). By drilling holes at intervals in the angle steel and installing through-bolts, the angle steel can be tightly connected to the prefabricated slabs and beams, forming an integrated load-bearing system. This method requires guidance from a professional structural engineer during construction to ensure that parameters such as bolt spacing and tensioning forces comply with specifications, avoiding structural damage due to improper construction.