Prefabricated Panel Houses in the Wenchuan Earthquake
The prefabricated panel houses in the Wenchuan earthquake exposed issues of insufficient seismic resistance, which were closely related to the construction era, design standards, and construction quality.
Weak Seismic Resistance of Old Prefabricated Panel Houses: The prefabricated panel buildings constructed in the 1970s-1980s were mostly designed according to the 'Code for Seismic Design of Buildings' (TJ 11-78), with a seismic fortification intensity generally of 6-7 degrees, and some areas designed for 7 degrees. Due to technological limitations at the time, component connections were mostly made using simple steel bar overlaps or mortar joints, resulting in poor integrity and weak seismic resistance. In the Wenchuan earthquake (with an intensity of 8-11 degrees), these buildings suffered severe collapses, exposing their vulnerability under high-intensity earthquakes. For example, the prefabricated structural houses in the Hangkong Huayuan Community in Weizhou Town, Wenchuan County, were moderately damaged and classified as dangerous buildings in the May 12 earthquake. Although they were simply reinforced after the earthquake, cracks reappeared during subsequent earthquakes and aftershocks, indicating that the seismic performance of early prefabricated panel houses could not meet the requirements of high-intensity earthquakes.
Significant Improvement in Seismic Performance of Modern Prefabricated Buildings: Unlike old prefabricated panel houses, modern prefabricated buildings are designed according to the current 'Code for Seismic Design of Buildings' (GB 50011-2010), with a seismic intensity of up to 7-9 degrees depending on regional fortification requirements. By adopting advanced technologies such as high-strength concrete, prestressed technology, and steel bar sleeve connections, component connections are more secure, and overall integrity and seismic performance are significantly improved. For example, prefabricated shear wall structures can withstand earthquakes of magnitude 8 or above, effectively resisting damage from high-intensity earthquakes.
Comprehensive Assessment of Seismic Capacity of Prefabricated Panel Houses: The seismic capacity of prefabricated panel houses is not uniform but varies depending on the construction era, design standards, and construction quality. Old prefabricated panel houses generally have weak seismic resistance due to low design standards and inconsistent construction quality, while modern prefabricated buildings have achieved high levels of seismic performance through technological upgrades and improved standards. Therefore, for existing prefabricated panel houses, a comprehensive assessment should be conducted based on their construction era, design standards, and actual damage conditions, and reinforcement or renovation measures should be taken when necessary to enhance their seismic safety.
