Brick-Concrete Prefabricated Panel Houses Are Not Earthquake-Resistant

Brick-concrete prefabricated panel houses indeed have issues of being non-earthquake-resistant or having poor earthquake resistance performance. The main reasons are as follows:

Poor Structural Integrity

In prefabricated panel brick-concrete structures, the prefabricated panels are usually simply placed on the walls like jigsaw pieces, lacking firm connections between each other, resulting in poor overall integrity. Under seismic action, these prefabricated panels are prone to falling off due to weak connections, and the staircase walls are also likely to collapse. For example, during earthquakes, the connection points between the prefabricated panels and the walls are often the most severely damaged parts, causing the overall structure of the house to fail rapidly.

Material and Design Factors

• Material Limitations: Brick-concrete structures mainly use bricks to build walls. Even when built to specifications, with reinforced concrete structures (such as structural columns and ring beams) used at wall connection points and on the upper parts, they can only increase overall stability to a certain extent. However, the performance of prefabricated floor slabs is relatively poor, and their connection methods with the walls determine their vulnerability during earthquakes.
• Low Design Standards: Brick-concrete structures have no strict seismic grade requirements and do not possess seismic grades. In some earthquake-prone areas, houses designed according to regulations generally do not use brick-concrete structures but instead choose frame structures or shear wall structures with better seismic performance.
• Step-by-Step Construction: The construction of brick-concrete structures is usually carried out step by step. First, the walls are built, then reinforced concrete structures are added, and finally, the floor slabs connect everything into one piece. This construction method results in an overall structure that is in a dispersed state and has almost no earthquake resistance during seismic events.

Quality Differences in Houses from Different Eras

• Houses built around 1978: They are basically unprotected, with no structural columns or ring beams, and have low-strength mortar and bricks, resulting in the poorest overall integrity and earthquake resistance performance.
• Houses built around 1984: They have low design standards and insufficient consideration for earthquake resistance. They still use prefabricated panel structures and have poor overall integrity.
• Houses built around 1995: They began to have preliminary seismic designs (with structural columns and ring beams set every other floor), but they are still essentially prefabricated panel brick-concrete structures with limited quality improvements.

Reflected in Actual Cases

Prefabricated panel buildings constructed from the 1970s to the 1990s have fatal weaknesses at the joints between panels. They leak air when the wind blows and let in water when it rains. They have low steel content and low concrete grades. After forty years, the steel has rusted, and the concrete has carbonized, seriously affecting the safety of the houses. For example, when evaluating a prefabricated panel building from the 1980s, a small piece was chiseled out of the wall, and the concrete was as crumbly as a biscuit, easily crumbling when pinched by hand.