Conversion of Wall to Beam in Prefabricated Panel Houses

Converting walls to beams in prefabricated panel houses is feasible, but it must be carried out strictly in accordance with specifications to ensure structural safety.

I. Pre-construction Preparations

1. Temporary Support: Set up reliable temporary support structures on both sides of the wall to ensure the stability of the floor slab and the overall structure when the wall is removed, preventing safety accidents caused by local instability.
2. Hole Positioning: Precisely chisel out holes at the beam positions on the wall according to design requirements. The hole sizes should meet the needs for steel bar arrangement and concrete pouring.

II. Selection of Construction Methods

1. Hole Drilling and Grouting Method
   • Steel Bar Reinforcement: First, tie the bottom steel bars of the beam and reinforce the supports, then fix them with formwork.
   • Floor Slab Treatment: If it is a prefabricated panel, it needs to be directly lifted away or knocked down; if it is a cast-in-place panel, holes need to be accurately made on the floor slab.
   • Concrete Pouring: Pour the mixed concrete through the holes. If the beam is relatively long, holes should be drilled in sections to avoid voids or exposed steel bars.
2. Side Formwork Grouting Method
   • Formwork Installation: Install one formwork vertically and the other diagonally to form a grouting channel.
   • Mechanical Assistance: Use a small concrete conveyor to pour concrete through the holes on the edge of the formwork using a conveying pipe, improving construction efficiency.

III. Requirements for Steel Bar Configuration

1. Beam Steel Bar Ratio: The length of the beam steel bars should be configured as 1/10 of the total length of the beam. For example, a 10-meter-long beam requires 1-meter-long beam steel bars.
2. Steel Bar Specifications: 25mm deformed steel bars are commonly used for the bottom steel bars, and auxiliary steel bars and waist steel bars are also configured to enhance the structural bearing capacity.
3. Stirrup Arrangement: The spacing between stirrups should be 5 - 7 per meter to ensure the shear resistance of the beam.
4. Waist Steel Bar Binding: The waist steel bars should be bound 15 - 20cm close to the bottom steel bars, rather than in the middle of the beam stirrups, to optimize the force distribution.

IV. Requirements for Curing and Formwork Removal

1. Side Formwork Removal: After the beam is poured, the side formwork can be removed after 24 hours, but collisions with the beam should be avoided.
2. Bottom Formwork and Support Removal: In summer, the bottom formwork and supports should be retained for at least 15 days, and in winter, the retention period should be extended to more than 20 days to ensure sufficient hardening of the concrete.
3. Curing Measures: Before formwork removal, water the concrete every day to keep its surface moist and prevent cracking.

Precautions: Wall-to-beam conversion involves structural safety. Before construction, a professional institution should evaluate the bearing capacity of the house and formulate a detailed construction plan. During construction, specifications should be strictly followed to avoid structural hazards caused by improper operations.