Earthquake Resistance of Prefabricated Panel Houses

Prefabricated panel houses can generally withstand earthquakes of around magnitude 6, with newly built ones capable of reaching magnitude 7. However, their overall earthquake resistance is lower than that of reinforced cast-in-place houses, but their performance can be enhanced through reinforcement. Here is a detailed introduction:

General Earthquake Resistance

There are differences in the earthquake resistance of prefabricated panel houses. Old houses built before the 1980s, limited by the building standards of the time, can generally only withstand magnitude 6 earthquakes. The earthquake resistance of newly built prefabricated panel houses has improved, reaching magnitude 7. Nevertheless, compared to reinforced cast-in-place houses, prefabricated panel houses have relatively poor overall earthquake resistance. This is because during construction, prefabricated panels are assembled like building blocks, resulting in poor integrity between the panels. In the event of an earthquake, relative displacement between the panels is likely to occur, causing the house structure to become loose and potentially collapse.

Factors Affecting Earthquake Resistance

• Age: The earthquake resistance of prefabricated panel houses varies depending on when they were built. Houses built before the 1980s have limited earthquake resistance due to the relatively low building technology and standards at the time, and can now withstand at most magnitude 6 earthquakes. As time goes on, the aging problems of these houses will gradually become more prominent, further affecting their earthquake resistance.
• Structure: The house structure has a significant impact on the earthquake resistance of prefabricated panel houses. Prefabricated panel houses with brick-concrete walls have poor earthquake resistance and are prone to damage during earthquakes. In contrast, those with frame structures perform relatively better, as frame structures can better withstand earthquake forces and reduce house deformation and damage. Additionally, the stability of the foundation is also crucial. Houses with deep foundations or piles are less likely to collapse during earthquake shaking.
• Floor Height: Floor height is also a factor affecting earthquake resistance. Generally, prefabricated panel houses with fewer than six floors are safer than high-rise buildings. Beijing explicitly stipulates that prefabricated panel houses cannot exceed 12 floors. This is because high-rise buildings are subject to greater earthquake forces during earthquakes and have higher structural requirements, while the structural characteristics of prefabricated panel houses make it difficult to meet the earthquake resistance needs of high-rise buildings.

Reinforcement to Improve Earthquake Resistance

To enhance the earthquake resistance of prefabricated panel houses, appropriate reinforcement measures can be taken. For example, adding steel reinforcement, improving structural connections, installing steel frames or pouring concrete into walls, laying steel mesh at joints, installing seismic isolation bearings, and plastering walls with high-ductility cement. These measures can strengthen the overall integrity and stability of the house, enabling it to have better collapse resistance during earthquakes. However, reinforcement measures must comply with relevant seismic fortification requirements and pass safety appraisals by professional institutions to ensure that the reinforced houses meet seismic safety standards.