Reasons for the Collapse of Prefabricated Concrete Houses
The reasons for the collapse of prefabricated concrete houses mainly include improper demolition sequence, inadequate implementation of the main responsibility for work safety by enterprises, and issues in construction management.
Improper demolition sequence is a direct operational factor leading to collapse. Taking the accident in Dongwenquan Town, Banan District, Chongqing as an example, when demolition workers were handling the second-floor cantilever beam structure, they did not follow the standard sequence of "demolishing the walls first and then cleaning the prefabricated slab floors." Before the brick railings on the outer side of the cantilever beams were completely demolished, they prematurely chiseled and cleaned the bedding layers and slab joints of the prefabricated slab floors, resulting in a reduction of the load (construction debris) pressing on the prefabricated slabs. This operation directly changed the structural force balance, causing the overturning moment outside the挑梁 (cantilever beam) room to exceed the anti-overturning moment inside the room, ultimately leading to collapse. Such operations violate the basic principles of structural mechanics and are typical cases of mechanical imbalance caused by incorrect construction sequence.
Inadequate implementation of the main responsibility for work safety by enterprises is a core issue at the management level. Taking Chongqing Songgang Construction Co., Ltd. as an example, it did not establish a clear work safety responsibility system, failed to provide pre-job safety education and training for demolition workers, resulting in a lack of risk awareness among the workers; it did not formulate a safety risk classification management system and a hidden danger investigation and treatment system, making it unable to promptly identify and eliminate accident hazards; and its supervision of the construction sequence was a mere formality, with the main responsible person failing to fulfill their work safety management responsibilities. These management deficiencies left the construction process in a disordered state, laying hidden dangers for accidents.
Issues in construction management involve multiple responsible parties. In the accident in Huayuan Village, Nanma Town, Dongyang City, the construction unit forced the construction to proceed in order to shorten the construction period. The construction unit did not stop work for rectification after receiving a notice of hidden safety hazards. Key positions were unstaffed, special operation personnel worked without certificates, and the supervision unit issued false rectification reports. This situation where the "construction-construction-supervision" parties all failed led to the systematic neglect of hidden safety hazards, ultimately causing the collapse. Such problems reflect the disregard for norms and standards in construction management and the regulatory failure among multiple responsible parties.
The collapse of prefabricated concrete houses is the result of multiple failures in operation, management, and supervision. Comprehensive prevention measures are required from the aspects of standardizing the construction sequence, strengthening the main responsibility of enterprises, and improving the construction management system.
