Structural Modification of Prefabricated Panel Houses

Structural modification of prefabricated panel houses requires careful operation, adherence to professional standards, and ensuring safety and stability.

Comprehensive structural safety assessment before modification:

1. Crack inspection: Focus on detecting the width of cracks at the production points of the prefabricated panels. If the width exceeds 0.3 millimeters, special treatment measures such as grouting repair or local reinforcement must be taken to prevent crack expansion from affecting structural safety.
2. Connection inspection: Check the connection status between the prefabricated panels and the ring beams, especially the corrosion of bolts. If the corrosion rate exceeds 30%, the bolts must be replaced to ensure the stability of the connection nodes and avoid structural instability due to connection failure.

Structural reinforcement measures during modification:

1. Temporary support system: Before construction, temporary supports must be erected. Steel pipe supports should be placed every 1.2 meters along the length of the prefabricated panels, and H-shaped steel beams should be used for underpinning at key nodes. The cross-section of the steel beams should be no less than 200*200 millimeters to disperse the load and prevent structural deformation during construction.
2. Panel joint treatment: For detected panel joint positions, remove the original filling materials, implant No. 6 deformed steel bars, and pour C30 fine aggregate concrete to enhance the shear resistance of the panel joints and reduce the risk of crack recurrence.
3. Addition of structural columns: Add structural columns at the four corners of the house, with a general cross-section of 240*240 millimeters. Use No. 6 and No. 8 steel bars for reinforcement and connect them reliably with the floor slab to improve overall seismic performance and structural stiffness.

Handling of special cases:

1. Reinforcement of Class C dilapidated houses: If a house is identified as a Class C dilapidated house but still has repair potential, it needs to undergo repair and reinforcement, including strengthening of walls, beams, columns, floor slabs, and foundations, as well as improving seismic capacity, to ensure the house meets safety standards for use.
2. Beam modification case: For two-story prefabricated panel houses, the beam-column structure can be upgraded and stabilized by modifying the beams, such as replacing the prefabricated panels with a cast-in-place beam-slab system to enhance overall structural integrity. However, strict load calculations must be carried out, and construction safety must be ensured.

During the modification process, it is essential to strictly follow design specifications and construction standards. If necessary, entrust a professional institution for design and supervision to ensure the structural safety and functional completeness of the modified house.