Seismic Resistance of Prefabricated Houses
The seismic resistance of prefabricated houses depends on specific circumstances and cannot be generalized.
From a design perspective: Prefabricated houses built before 1990 generally have weaker seismic performance. At that time, the old seismic code TJ11-78 was mostly followed, which had relatively low seismic standards. It did not clearly define the 'three-level seismic fortification' theory, and seismic structural measures were basically not required in areas with a seismic intensity of 6 degrees. Such houses often lack core seismic components such as structural columns and ring beams, and are prone to problems such as slab joint cracking and prefabricated slab detachment during earthquakes. After 1990, the implementation of the GBJ11-89 code and subsequent standards clearly required that prefabricated slabs must be connected with cast-in-place composite layers, prohibited pure bare laying, and mandated the installation of structural columns at the closed ring beams on each floor, at the four corners, and at the four corners of stairs, significantly improving seismic performance.
From a construction perspective: Construction quality has a significant impact on the seismic effect of prefabricated houses. Even if the design complies with seismic codes, if the construction擅自 (unauthorizedly) modifies the design or cuts corners, such as reducing the number of structural columns and ring beams, or using concrete with insufficient strength or shortening the curing time, the seismic performance of the house will be reduced. For example, an insufficient number of structural columns and ring beams will prevent the house from effectively transferring and dispersing seismic forces during an earthquake, leading to structural damage.
From the perspective of regulations and standards: Current regulations mandate seismic fortification. Article 38 of the Construction Law of the People's Republic of China requires that when construction enterprises prepare construction organization designs, they should formulate safety technical measures according to the characteristics of construction projects. For projects with strong professionalism, special safety construction organization designs should be prepared and safety technical measures should be taken. Article 19 of the Regulations on the Quality Management of Construction Projects clearly states that survey and design units must conduct surveys and designs in accordance with mandatory standards for engineering construction and be responsible for their quality to ensure that houses meet seismic requirements.
From the perspective of house types: Prefabricated panel houses can generally withstand earthquakes of around magnitude 6, but houses built before the 1980s can withstand an intensity of 6 degrees, while newly built ones can reach 7 degrees. However, even for new houses, their seismic resistance is not as good as that of reinforced cast-in-place houses because prefabricated panels are like building blocks, with poor integrity, and are prone to falling apart under seismic action.
