Structural Diagram of Prefabricated Slab Houses in Shanghai
The structures of prefabricated slab houses in Shanghai are mainly brick-concrete structures, with prefabricated concrete slabs used for the floors. However, there are currently no publicly available standardized structural diagrams. The following is a detailed description of the specific structural features:
Overall Structural Type
Most of the existing old public housing in Shanghai (built from the late 1970s to the mid-1990s) is of the brick-concrete structure type. This means that brick walls serve as the main load-bearing structures, paired with concrete floors. This structural form was characterized by high construction efficiency and controllable costs at the time, meeting the demands of rapid urbanization. Prefabricated slab houses are a typical type within the brick-concrete structure category, with the core feature being the use of prefabricated concrete slabs for the floors instead of cast-in-place concrete.
Construction of Prefabricated Slab Floors
Prefabricated slab floors are concrete components pre-cast in factories, with standard dimensions typically ranging from 4 to 6 meters in length, 0.5 to 1.2 meters in width, and 12 to 15 centimeters in thickness. After being transported to the construction site, the prefabricated slabs are assembled onto the beams or ring beams supported by the brick walls using lifting equipment. The joints between the slabs are filled with mortar, and in some projects, steel mesh is added to enhance the connection strength. This construction method significantly shortens on-site work time, but the joints can easily become structural weak points and require regular inspection and maintenance.
Structural Features and Limitations
- Load-Bearing System: Brick walls bear the vertical loads, while the prefabricated slabs serve only as horizontal floor components and do not participate in the overall structural load-bearing. This design results in relatively weak earthquake resistance of the houses, especially in areas with high seismic intensity, where reinforcement measures such as structural columns and ring beams are required to compensate.
- Spatial Adaptability: With fixed slab dimensions, adjusting the interior layout is difficult, and any openings or renovations require careful assessment of structural safety.
- Durability: The mortar at the joints is prone to aging and detachment. If not properly maintained, it may lead to problems such as floor leakage and steel bar corrosion, affecting the structural lifespan.
Practical Considerations in Application
Due to the early construction period of prefabricated slab houses, some buildings are approaching their designed service lives. It is recommended to conduct regular structural safety inspections, focusing on the joints of the prefabricated slabs, cracks in the brick walls, and concrete carbonation. During renovations or decorations, avoid directly cutting or drilling holes in the prefabricated slabs. If walls need to be removed, confirm whether the wall is load-bearing and entrust a professional institution to design reinforcement measures.
