Prefabricated House Blocks in Wenchuan Earthquake

Prefabricated house blocks (prefabricated panel houses) performed poorly in the Wenchuan earthquake, being a significant factor contributing to severe casualties and building collapses.

Poor Structural Integrity Connection and Seismic Performance Prefabricated panel houses are typically constructed with load-bearing walls and walls made of red bricks, resulting in weak overall structural connectivity. Under the intense impact of seismic waves, the connection points between the prefabricated panels and the walls are prone to failure, leading to a loss of structural integrity. This type of structure lacks sufficient ductility and energy dissipation capacity during earthquakes, making it unable to effectively resist seismic energy and thus being the first to be flattened.

Limited Post-Earthquake Assessment and Reinforcement Effects After the Wenchuan earthquake, a large number of prefabricated panel houses were assessed as dangerous buildings. Even after simple reinforcement and continued use, their seismic performance did not fundamentally improve. In subsequent aftershocks or new seismic events, such houses may still develop cracks, experience partial collapses, or even collapse entirely, further threatening the safety of residents.

Service Life and Aging Issues The designed service life of prefabricated panel houses is generally 40 to 50 years. However, many prefabricated panel houses before the Wenchuan earthquake had been in use for decades, with widespread issues such as material aging and connector corrosion. Aging leads to a decrease in structural load-bearing capacity, making them more susceptible to damage during earthquakes and increasing the risk of collapse.

Summary and Implications The seismic deficiencies of prefabricated panel houses were fully exposed in the Wenchuan earthquake, with their structural forms, connection methods, and material aging issues collectively leading to severe consequences. Subsequently, China has further strengthened requirements for structural integrity, ductility, and energy dissipation capacity in building seismic design codes, and has gradually phased out or renovated old prefabricated panel houses to enhance the seismic safety of urban and rural buildings.