Prefabricated Panels for Building Construction
Prefabricated panels for building construction are built mainly using prefabricated panels, which have specific characteristics, application scenarios, dimensions, and are gradually being replaced with the development of building technology. Currently, there are clear handling methods for them in the old housing renovation policies.
Characteristics and Types: Prefabricated panels are cement components prefabricated in factories. During production, wooden models are nailed, steel bars are arranged, and cement is poured. They are divided into solid and hollow types. The hollow structure achieves lightweighting by reducing the non-load-bearing concrete. Their advantages include low cost, fast construction speed, and the ability to be quickly assembled, allowing a building to be completed in just a few days. However, their disadvantages are weak earthquake resistance, poor sound and heat insulation, and a service life of about 30 - 50 years.
Application Scenarios: They were widely used in early 20th-century buildings, mainly for floor slabs and roof insulation layers. Residential buildings constructed in China before 1985 mostly adopted this type of structure.
Dimensions: For residential spans, the maximum length is 4.2 meters without considering modular dimensions; lengths beyond this require customization. The most common widths are 500mm and 600mm, and common thicknesses are 120mm and 150mm. Regarding live load ratings, Grade I panels (capable of bearing a live load of 1kN/m²) and Grade II panels (capable of bearing a live load of 2kN/m²) are generally used for residential buildings. In the southwest region, the minimum requirement is Grade IV panels (capable of bearing a live load of 4kN/m²). The length is generally based on a 300mm module, such as 3000, 3300, 3600, etc. The maximum length of ordinary panels is 4200, and there are also special lengths like 3800 and 4000. The width is usually four-hole 400mm or five-hole 500mm.
Development and Replacement: With the development of building technology, cast-in-place concrete and prefabricated buildings are gradually replacing traditional prefabricated panel houses. The construction period of prefabricated buildings is 30% shorter than that of traditional methods. The purpose of making prefabricated hollow panels is to reduce weight and save costs, but their use is no longer advocated. Building structures now mostly adopt cast-in-place structures, which offer better integrity.
Old Housing Renovation Policies: Since 2022, China has been implementing old housing renovation policies, focusing on the repair and renovation of prefabricated panel houses. Only buildings that meet the criteria for dilapidated houses are demolished, and some regions have already started demolition work.
