Shanghai Prefabricated Slab House Reinforcement

The reinforcement of prefabricated slab houses in Shanghai should be based on the actual safety appraisal results of the houses. Not all situations are suitable for perimeter reinforcement, and classification and precise strategies are required.

Reinforcement Should Be Based on Safety Appraisal

The reinforcement of prefabricated slab houses in Shanghai should be combined with the safety inspection reports issued by third-party testing companies to clarify key issues such as the degree of structural damage and bearing capacity defects. For example, in the reinforcement project of the house at No. 1255 Changle Road, Shanghai Real Estate Trading Center (originally designed as a mixed structure of prefabricated slabs and wooden slabs in the 1930s), the winning supplier formulated plans for wall problems on different floors based on the inspection report: restoring some demolished walls on the first floor, reinforcing walls with insufficient bearing capacity on the first and second floors, and dealing with walls with an excessive height-to-thickness ratio on the third floor. This case shows that reinforcement should be targeted at specific types of damage rather than uniformly adopting a perimeter reinforcement model.

Reinforcement Techniques for Local Insufficient Bearing Capacity

If there are only local bearing capacity problems in the prefabricated slab floor, mature techniques can be used for targeted treatment:

• Section Steel Reinforcement Method: Set section steel along the four corners under the prefabricated slab to transform the original four-sided support into an eight-sided support, significantly improving the floor's bearing capacity. This method is suitable for areas with large spans and concentrated local loads.
• Carbon Fiber Bonding Method: By bonding high-strength carbon fiber cloth to the tension zone of the floor, its tensile properties are utilized to enhance the overall structural integrity. A 1982 prefabricated slab office building in Shanghai was transformed into a high-end hotel using this technology, verifying its feasibility.
• Plywood Reinforcement Method: Add a reinforced concrete夹层 (sandwich layer) on the surface of the prefabricated slab to form a composite structure, suitable for scenarios where a significant increase in bearing capacity is required.

Policy Orientation: Classification and Avoidance of a One-Size-Fits-All Approach

The 15th Five-Year Plan for Urban Renewal issued by the State Council in 2026 clearly proposes to "steadily promote the governance and renovation of prefabricated slab houses" and emphasizes classification and precise strategies. For houses with structural safety but outdated functions, priority should be given to improving performance through reinforcement; for houses with serious safety hazards, demolition and reconstruction are required. This policy avoids the waste of resources from demolition and reconstruction while ensuring the safety of residents.

Summary: The reinforcement of prefabricated slab houses in Shanghai should be based on safety appraisal, select techniques (such as section steel, carbon fiber, and plywood reinforcement) according to the type of damage, and follow policy guidance for classification to ensure that the renovation is scientific, economical, and safe.