New Type Prefabricated Panel for Buildings

The new type of prefabricated panel for buildings is centered around factory-prefabricated cement components, manufactured through standardized processes. It combines structural functionality with construction efficiency, but requires integrated renovation strategies to address existing issues.

I. Core Structure and Manufacturing Process of Prefabricated Panel Houses

Prefabricated panel houses use prefabricated panels as their primary load-bearing components, with a manufacturing process that reflects industrial characteristics:

1. Materials and Structure: Prefabricated panels are cement-based components reinforced with internal steel bars to enhance tensile strength, available in solid and hollow forms. The hollow structure achieves lightweighting through built-in large foam blocks, reducing concrete usage while improving sound insulation.
2. Manufacturing Process: The "pre-tensioning" prestressing technique is employed, where equipment first stretches steel bars to the designed strength. After concrete pouring, the retraction force of the steel bars compresses the concrete, creating ultra-high tensile strength. After pouring, vibrating rods are used to eliminate air bubbles, followed by high-temperature steam curing (in underground negative one floor, for 4 hours) or natural curing (covered with waterproof membranes, for 1 day). Finally, CNC electric saws cut the panels into standard sizes, with hollow sections usable for cable laying or drainage piping.

II. Historical Significance and Existing Issues of Prefabricated Panel Houses

1. Historical Application: This building form originated in the early 20th century, with most residential buildings constructed in China before 1985 adopting this structure, reflecting the demand for industrialized housing at the time.
2. Performance Limitations: Existing prefabricated panel houses generally suffer from weak earthquake resistance, poor sound and thermal insulation, with a designed service life of only 30-50 years, far shorter than the 80-100 years of modern reinforced concrete structures. A 2024 building safety inspection revealed that over 35% of prefabricated panel houses exhibit safety hazards such as wall cracks and loose floor slabs.

III. Policy Orientation and Renovation Strategies

1. Renovation Policies: Since 2022, China has implemented renovation policies focusing on repairing and upgrading prefabricated panel houses, with demolition only for buildings meeting hazardous house standards. The "Urban Renewal Action Implementation Guide" released at the end of 2024 emphasizes "preventing large-scale demolition and construction," advocating a combination of "preservation and renovation" with "demolition and reconstruction."
2. Differentiated Solutions:
   • Structurally sound but functionally outdated: Extend service life through reinforcement and functional upgrades;
   • Severe structural hazards: Implement demolition and reconstruction to ensure safety and compliance.

The transformation of prefabricated panel houses requires balancing historical value with modern demands, achieving sustainable renewal through technological upgrades and policy guidance.