Is the Prefabricated Panel Structure House Earthquake-Resistant?
The prefabricated panel structure house has insufficient earthquake resistance, and its overall seismic capacity cannot be compared with that of modern buildings. Here is a detailed analysis:
I. Structural Characteristics Lead to Inherent Seismic Deficiencies
Prefabricated panel structure houses are assembled from prefabricated concrete panels, with the panels and columns connected by steel bars in a somewhat makeshift manner, forming a “building-block-like” construction. This structure lacks integrity, and during earthquakes, individual components are prone to shaking independently, making it difficult to form a coordinated load-bearing system. The strength of its connection nodes is far lower than that of cast-in-place concrete structures, resulting in poor seismic resilience and difficulty in dissipating seismic energy through deformation.
II. Age Differences Significantly Affect Seismic Capacity
- Old Prefabricated Panel Buildings: Houses built in the 1970s and 1980s were mostly designed to withstand magnitude-6 earthquakes, but their actual seismic performance is weaker. Most of the prefabricated panel buildings that collapsed during the Wenchuan earthquake were built during this period, with problems such as steel bar corrosion and loose connections exacerbating structural vulnerability.
- Modern Prefabricated Panel Buildings: After being reinforced with prestressed technology, they can theoretically withstand magnitude-7 to magnitude-9 earthquakes. However, the actual effect highly depends on construction quality. If the steel bar joints are not firmly welded or the concrete strength is insufficient, the seismic capacity will significantly decrease.
III. Building Damage Further Weakens Seismic Resistance
If cracks appear in prefabricated panel buildings, their seismic capacity will significantly decrease. Old prefabricated buildings with cracks exceeding 3 millimeters should be purchased with caution even if they are inexpensive, as cracks may indicate structural damage or connection failure, making them prone to partial or complete collapse during earthquakes.
IV. Actual Seismic Performance Falls Short of Theoretical Values
Although modern codes require prefabricated panel buildings to withstand magnitude-7 earthquakes, a large number of them collapsed during the Wenchuan earthquake under earthquakes of lower magnitudes, exposing the gap between theoretical values and actual performance. This is mainly related to construction defects, material aging, and outdated design standards.
Summary: The seismic performance of prefabricated panel structure houses is influenced by structural type, construction age, construction quality, and damage status. Old buildings have high seismic risks, and modern buildings require strict control over construction quality. When purchasing or renovating a house, structural safety should be prioritized to avoid secondary disasters caused by insufficient seismic resistance.
