Houses with Prefabricated Slab Floors
Houses with prefabricated slab floors, also known as prefabricated slab houses, are constructed using prefabricated slabs as the main components. They have characteristics such as low cost, short construction periods, but poor overall integrity and insufficient seismic performance. Currently, they are gradually being replaced, and the disposal follows the principle of 'adapting measures to local conditions and implementing differentiated strategies'.
Types and Production of Prefabricated Slabs
Prefabricated slabs are cement components produced in factories. During production, wooden models are nailed together, steel bars are arranged, and cement is poured to form the slabs. There are two types: solid and hollow. The hollow structure achieves lightweighting by reducing the non-load-bearing concrete. Since the hollow parts of the slabs do not bear loads, making them hollow can reduce weight and save costs.
Construction Characteristics
- Convenient Construction: Workers first produce the cement slabs in the factory and then transport them to the construction site for direct installation. The construction speed is extremely fast. For cast-in-place floors, it takes half a month for the cement to dry, while for prefabricated slab floors, one floor can be assembled in three days.
- Limited House Types: All rooms must be designed according to the dimensions of the cement slabs, resulting in relatively rigid house types.
House Characteristics
- Low Cost and Short Construction Period: These are significant advantages of prefabricated slab houses.
- Poor Overall Integrity and Insufficient Seismic Performance: Their seismic resistance is generally lower than that of cast-in-place structures, and their sound insulation and heat insulation effects are also relatively poor.
- Service Life: Generally, it is 30 to 40 years. However, the designed service life of regular civil residential buildings in China is 50 years. House safety depends on the construction quality and maintenance conditions.
Development History and Applications
Originating in the early 20th century, most residential buildings constructed in China before 1985 adopted this type of structure. During the 1970s and 1980s, a large number of them were built to address the housing shortage. With the progress of construction technology, cast-in-place concrete and prefabricated buildings are gradually replacing traditional prefabricated slab houses. In 2023, relevant departments stipulated that it is prohibited to newly build, renovate, or expand prefabricated slab houses and other buildings that do not comply with current regulations within the scope of urban construction land. Since 2022, the old community renovation policy has been implemented, focusing on the repair and renovation of prefabricated slab houses and only demolishing those that meet the criteria for dangerous buildings.
Existing Problems and Disposal
- Existing Problems: Prefabricated slab houses that have exceeded their service life are prone to structural aging, and the joints are likely to leak. Situations such as indiscriminately smashing load-bearing walls and long-term leakage without management can also affect house safety.
- Reinforcement Methods: These include the method of increasing the cross-sectional area and the method of bonding steel plates.
- Disposal Principles: Following the principle of 'adapting measures to local conditions and implementing differentiated strategies', it does not mean a comprehensive demolition. Prefabricated slab houses that are prioritized for demolition include those with damaged main structures, those unable to withstand natural disasters, those affecting municipal planning, and those located in prime urban areas. Demolition compensation and resettlement follow relevant regulations.
