Renovation of Concrete Prefabricated Panel Houses

The renovation of concrete prefabricated panel houses should be carried out based on the actual conditions of the houses, following the principle of 'adapting measures to local conditions and implementing different strategies for different cases,' which can be divided into two methods: repair and renovation, and demolition and reconstruction.

For prefabricated panel houses with undamaged main structures, repair and renovation can be carried out. Structural safety assessment is the first step, focusing on inspecting the crack width at the production points of the prefabricated panels. Special treatment is required if the crack width exceeds 0.3 millimeters. At the same time, the connection status between the prefabricated panels and the ring beams should be checked, and bolts with a rust rate exceeding 30% should be replaced. In terms of exterior wall treatment, the original exterior wall tiles should be removed, repainted, and reinforced with steel bars and grouting to enhance the load-bearing capacity and tensile properties of the walls. During the construction preparation phase, a temporary support system should be erected, with steel pipe supports placed every 1.2 meters along the length of the prefabricated panels. Key nodes should be supported with H-shaped steel beams, with a beam section of no less than 200200 millimeters. When treating panel joints, the original filling materials should be removed, No. 6 threaded steel bars should be implanted, and C30 fine aggregate concrete should be poured. Regarding the addition of structural columns, structural columns should be added at the four corners of the house, generally with a section of 240240 millimeters, tied with No. 6 and No. 8 steel bars, and connected to the floor slabs. In terms of construction sequence, the principle of 'from the middle to the sides' should be adopted, with segmental demolition and cutting, maintaining symmetrical demolition. The daily demolition volume should not exceed 30% of the total floor slab area. At the same time, the stress changes in the support system should be monitored in real-time, and the use of heavy hammers for impact demolition is prohibited to avoid shock and damage to the foundation structure.

For prefabricated panel houses with safety hazards, demolition and reconstruction are mandatory. Three types of prefabricated panel houses that should be prioritized for demolition include: first, those with damaged main structures that cannot be repaired even through old house renovation; second, those with undamaged main structures but unable to withstand natural disasters such as earthquakes and floods; and third, those located on municipal planning land. These houses, due to serious safety hazards or impacts on urban planning, need to be demolished and rebuilt in a timely manner to ensure the safety of residents' lives and property and the sustainable development of the city.