Mianzhu Prefabricated Panel Houses
Mianzhu's prefabricated panel houses pose serious structural risks and urgently require systematic renovation.
Mianzhu City has a large number of prefabricated panel houses built in the 1990s, whose design lifespans and earthquake resistance capabilities fail to meet modern safety standards. These houses have suffered from over three decades of natural erosion and the severe impact of the May 12th earthquake, resulting in prominent structural aging issues. Cracked walls, loose floor slabs, and rusted steel bars are common phenomena, with some houses even exhibiting C-level hazardous features such as peeling protective layers and exposed steel bars, and in severe cases, reaching D-level standards with insufficient support length at the ends of prefabricated panels, posing a risk of falling.
The earthquake resistance deficiencies of prefabricated panel houses were fully exposed during the May 12th earthquake. Their structural characteristics include weak connections between floor slabs and walls, making them prone to complete collapse or partial collapse due to horizontal forces during earthquakes. In the Mianzhu earthquake, the domino-like collapse of prefabricated panel buildings shattered 2,689 families, directly demonstrating the lethal risks of such houses under strong earthquakes. Despite some houses having been in service for over 35 years with defects, current urban renovations mostly focus on exterior wall painting and decorative beautification, failing to address the core issue of structural reinforcement, resulting in improved appearances but unresolved internal hazards.
From a technical perspective, the renovation of prefabricated panel houses requires systematically addressing two major issues:
- Structural reinforcement: For C- and D-level hazardous components, measures such as carbon fiber cloth reinforcement, adding structural columns, and replacing rusted steel bars should be taken to enhance load-bearing capacity; for prefabricated panels with insufficient support length, chemical anchoring or adding supports should be used to prevent falling.
- Earthquake resistance upgrading: Improve overall earthquake resistance by adding shear walls and installing dampers to prevent chain collapses due to connection failures during earthquakes.
The current renovation model in Mianzhu is merely a cosmetic effort, failing to address the fundamental needs of safety and durability, leaving residents continuously exposed to the risks of dangerous houses. It is recommended that the government prioritize structural safety in renovations, formulate special policies to promote systematic reinforcement of prefabricated panel houses, and effectively safeguard residents' lives and property.
Reports on the current renovation status of prefabricated panel houses in Mianzhu
Classification standards for hazardous levels of concrete components in buildings
Current status of over-aged service of some prefabricated panel houses in Mianzhu
Disaster records of the May 12th earthquake in Mianzhu
