Multi-Story Buildings Using Prefabricated Panels

The use of prefabricated panels in multi-story buildings is primarily reflected in the prefabricated panel buildings constructed from the 1970s to the 1990s. These buildings, mainly featuring brick-concrete structures, are characterized by fast construction and low costs, but they suffer from weak earthquake resistance and difficulties in renovation. In the 2026 urban renewal plan, D-grade dangerous buildings will be demolished and rebuilt.

Structural Form and Construction Background
Prefabricated panel buildings are centered around brick-concrete structures, with floors made of prefabricated concrete panels and walls mostly consisting of load-bearing brick walls or prefabricated concrete wall panels. This structural form was widely used in the construction of urban affordable housing and economic housing from the 1970s to the 1990s due to its short construction period and low material costs, which could quickly meet the housing demands of the time. For example, some six-story residential buildings in older neighborhoods adopt this structure, with floors directly connected to walls through prefabricated panels, resulting in low overall stiffness and reliance on wall load-bearing.

Architectural Features and Limitations

1. Restricted Floor Plan Layout: Affected by the standard sizes of prefabricated panels (such as 3.3 meters and 3.6 meters), the apartment design is fixed, with room spans generally ranging from 3 to 4 meters, making it difficult to achieve large open layouts and resulting in poor north-south ventilation.
2. Compact Space: The floor height is usually 2.6 to 2.8 meters, lower than modern residential standards, leading to a strong sense of oppression indoors and limited space utilization.
3. Difficult Renovation: Walls are mostly load-bearing structures, and their removal or modification may undermine overall stability, making it difficult to adjust the apartment layout during renovation and resulting in low flexibility.
4. Performance Defects: Cracks are prone to occur at the joints of prefabricated panels, leading to poor sound insulation and thermal insulation effects; the brick-concrete structure has weak earthquake resistance and is prone to wall collapse during earthquakes; the service life is approximately 30 to 50 years, and some early buildings are approaching their design lifespan.

Governance and Renewal Directions
According to the 2026 urban renewal plan, the governance of prefabricated panel buildings focuses on safety:

• For prefabricated panel buildings identified as D-grade dangerous housing (overall danger requiring immediate demolition), the principle is to adopt demolition and reconstruction methods, addressing residents' needs through diversified resettlement options such as housing vouchers and monetary compensation.
• For buildings that do not meet the criteria for dangerous housing but have hidden dangers, structural safety may be improved through reinforcement and renovation, such as adding seismic components and improving joint waterproofing.
• During the renewal process, it is necessary to balance historical preservation with functional upgrades, such as retaining some architectural appearance features while optimizing internal space layout and facility配套 (facility配套 should be translated as 'facility配套' is not a standard term, here it means 'facility arrangements' or 'facility upgrades', but for simplicity, we can just say 'facility improvements').