Translation of Previous House Structure: Prefabricated Panels
Prefabricated panels used in previous house structures were common flooring materials in early 20th-century construction. They are engineering modules or slabs produced in prefabrication yards and directly transported to the site for installation.
Definition and Manufacturing Process
Prefabricated panels are building components pre-formed in factories or on-site prefabrication yards. The manufacturing process involves first nailing wooden planks to create a hollow mold, placing steel reinforcement bars inside as a framework, and then pouring cement mortar. After drying and hardening, the external wooden planks are knocked off to form the prefabricated panel. This industrial production method enhances construction efficiency and reduces on-site work time.
Structural Types and Specifications
Prefabricated panels come in two types: solid panels and hollow panels. Hollow panels achieve lightweighting by reducing the amount of concrete in non-load-bearing parts, but their poor seismic performance has led to less frequent use in modern construction. Standard size specifications are as follows:
- Span: The longest prefabricated panels for residential use are 4.2 meters; custom fabrication is required for longer spans;
- Width: Primarily 500mm and 600mm, suitable for common wall spacing;
- Thickness: Common specifications are 120mm and 150mm, selected based on load requirements;
- Load Rating: Classified as Grade I (1kN/m²), Grade II (2kN/m²), with a minimum Grade IV (4kN/m²) specified in the southwest region to accommodate geological conditions.
Application Scenarios and Historical Significance
Prefabricated panels were widely used in residential flooring built before 1985 in China, as well as in non-load-bearing structures such as highway ditch covers and roof insulation layers. As a product of a specific historical period, prefabricated panel houses, with their short construction periods and low costs, became an important architectural form during the rapid urbanization phase, carrying the living memories of several generations.
Existing Issues and Policy Directions
Existing prefabricated panel houses generally suffer from weak seismic performance, poor sound and thermal insulation, and have a service life of approximately 30-50 years. Since 2022, China's renovation policies have focused on repair and reinforcement, with demolition only for prefabricated panel buildings that meet the criteria for dangerous structures, avoiding resource waste from large-scale reconstruction.
Technological Alternatives and Future Trends
With advancements in construction technology, cast-in-place concrete structures and prefabricated buildings (such as CMC composite modular buildings) are gradually replacing traditional prefabricated panels. Cast-in-place structures enhance overall building integrity through monolithic pouring, while prefabricated buildings use steel-concrete composite technology to improve seismic performance and reduce construction time by over 30%. Although prefabricated panels have exited the mainstream market, their industrial production concept still provides important references for modern building industrialization.
