How Earthquake-Resistant Are Prefabricated Houses?

The earthquake resistance of prefabricated houses depends on specific circumstances and cannot be generalized. The overall earthquake resistance is influenced by factors such as the era of construction, building standards, structural characteristics, as well as design and construction practices.

From the perspective of era and building standards, prefabricated houses built in the early days (e.g., before the 1980s) generally have weaker earthquake resistance, typically able to withstand earthquakes of magnitude 6. Newly built prefabricated houses have improved earthquake resistance, with some capable of withstanding magnitude 7 earthquakes, and new buildings using prestressed technology can even withstand earthquakes of magnitude 7 - 9. However, the specific earthquake resistance also depends on whether the construction team cuts corners. If there are quality issues in construction, even with high design standards, the actual earthquake resistance will be significantly compromised.

In terms of structural characteristics, prefabricated houses are assembled from prefabricated panels, resulting in poor overall integrity, similar to assembling building blocks. During an earthquake, the panels and columns shake independently and are prone to collapse. Early prefabricated houses often lacked core earthquake-resistant components such as structural columns and ring beams. The prefabricated panels were directly placed on brick walls without overall connection, leading to issues such as panel joint cracking and panel detachment during earthquakes, seriously affecting the structural safety of the houses.

From the perspective of design and construction, prefabricated houses built before 1990 mostly followed the old seismic code TJ11 - 78, with relatively low seismic standards. The GBJ11 - 89 code implemented after 1990 and subsequent standards clearly require that prefabricated panels must be reinforced with cast-in-place composite layers, and pure bare laying is prohibited. They also mandate the installation of structural columns at the corners of each floor, the four corners of the building, and the four corners of the stairs, significantly improving earthquake resistance. However, even if the design complies with seismic codes, if the construction擅自 modifies the design or cuts corners, such as reducing the number of structural columns and ring beams, or using insufficient concrete strength and shortening curing times, the earthquake resistance of the house will be reduced.