Prefabricated Brick-Concrete Structure House

A prefabricated brick-concrete structure house is a hybrid structural system where brick walls and prefabricated reinforced concrete components (such as prefabricated hollow floor slabs) jointly bear the load. It is commonly found in old residential areas built in the 1970s and 1980s, featuring specific structural characteristics and historical limitations.

Structural Characteristics and Historical Background

This structure uses brick or block masonry walls as vertical load-bearing components, with prefabricated hollow floor slabs (such as the commonly used 120mm thick prestressed hollow slabs in the early days) used horizontally. Wall layout methods include transverse wall bearing (suitable for small-bay residential buildings), longitudinal wall bearing, or a combination of both. Its construction is simple and cost-effective, and brick walls offer good durability and fire resistance. It was once the mainstream solution for addressing housing shortages in China. However, due to technological limitations at the time, this structure had inherent weaknesses: poor overall integrity and weak seismic performance. In particular, during the 1976 Tangshan earthquake, a large number of prefabricated brick-concrete houses suffered severe damage due to weak joint connections and insufficient coordination between walls and floor slabs. After 2008, the country gradually phased out prefabricated slabs and promoted cast-in-place floor slabs to enhance seismic performance.

Renovation Challenges and Reinforcement Needs

Existing prefabricated brick-concrete structure houses often face two major issues:

1. Difficulty in installing elevators: It requires chiseling out stairwell walls or removing prefabricated slabs, which damages the original structural integrity. Additionally, connections between new and old structures (such as anchoring elevator shafts to original walls) can easily lead to stress concentration, causing wall collapses or fire hazards.
2. Seismic reinforcement needs: According to the Standard for Seismic Appraisal of Buildings, multi-story brick-concrete residential buildings need to enhance their seismic performance by installing structural columns and ring beams (to strengthen wall constraints) or adopting prestressed low-intervention techniques (such as external prestressed reinforcement). For example, during the renovation of the Great Hall of the People, prestressed carbon fiber plates were used for reinforcement, which reduced damage to the original structure while significantly improving load-bearing capacity.

Summary of Advantages and Disadvantages

Advantages: Short construction period, low material costs, and brick walls offer better durability and fire resistance compared to pure frame structures.
Disadvantages: Heavy self-weight increases the foundation load; poor seismic performance (especially when transverse wall spacing is too large); more wet operations (masonry, plastering, etc.); and prefabricated slab joints are prone to cracking, affecting overall integrity.

During renovation, it is essential to strictly follow the General Specification for Appraisal and Reinforcement of Existing Buildings, conduct professional inspections to assess structural safety, and avoid blind construction that could trigger secondary disasters.