Prefabricated Panel Houses in the Wenchuan Earthquake

Prefabricated panel houses performed extremely poorly in the Wenchuan earthquake, posing serious safety hazards.

I. Structural Defects Leading to Low Seismic Performance
The structural characteristics of prefabricated panel houses determine their weak seismic resistance. The prefabricated panels are directly placed on beams or load-bearing walls, with a lack of effective connection between the panels and beams, relying solely on gravity for stability. In brick-concrete structures, apart from the limited connections provided by structural columns and ring beams, other components are simply stacked, resulting in extremely poor integrity. This “assembled” structure is prone to disintegration under seismic waves, detaching like building blocks and causing the house to collapse instantly.

II. High Collapse Rate During Earthquakes, with Severe Consequences
During the Wenchuan earthquake, the collapse rate of prefabricated panel houses was significantly higher than that of cast-in-place houses. Numerous examples show that even prefabricated panel houses classified as Grade C (requiring reinforcement) may completely disintegrate in a magnitude-5 earthquake. During the collapse, the detachment of prefabricated panels creates lethal gaps, resulting in an extremely low survival rate for trapped individuals. According to statistics, the collapse of prefabricated panel houses was one of the main causes of casualties and property damage.

III. Multiple Practical Challenges in Reinforcement and Renovation
Although the safety issues of prefabricated panel houses have attracted widespread attention, comprehensive reinforcement still faces challenges:

1. Funding Shortage: Renovating old residential areas requires substantial funds, but homeowners are reluctant to share the costs, placing significant financial pressure on the government.
2. Coordination Difficulties: Involving multiple stakeholders such as homeowners, property management, and the government, achieving consensus is highly challenging.
3. Lack of Awareness: Some residents have insufficient awareness of earthquake risks and doubt the necessity of reinforcement.

IV. National Efforts to Promote “Old Community Renovation” to Enhance Seismic Capacity
To address this issue, the state has made seismic reinforcement a core component of old community renovation, prioritizing the reinforcement of public buildings such as schools and hospitals. By adding structural columns, ring beams, and tie bars, the overall structural integrity is enhanced; for severely damaged prefabricated panel houses, demolition and reconstruction or replacement plans are implemented. These measures aim to reduce earthquake risks and safeguard residents' lives.

Conclusion: The Wenchuan earthquake exposed the structural defects of prefabricated panel houses, and their inadequate seismic performance has become a consensus. Despite the challenges in reinforcement and renovation, the state is gradually promoting seismic upgrades of old buildings through policy guidance and financial support to reduce losses from future earthquakes.