Seismic Resistance of Prefabricated Panel Houses

The seismic resistance of prefabricated panel houses varies significantly depending on their construction era and structural type. Overall, their seismic resistance is relatively weak, but modern prefabricated assembled buildings have significantly improved their seismic performance through technological advancements. Detailed analysis is as follows:

I. Seismic Defects of Old Prefabricated Panel Buildings (Constructed in the 1970s-1980s)

1. Outdated Design Standards
   These buildings were mostly designed according to the 1978 "Code for Seismic Design of Buildings" (TJ 11-78), with a seismic fortification intensity generally of 6-7 degrees (corresponding to seismic intensity levels 6-7). Some regions, such as Beijing, were designed for a 7-degree intensity. However, this standard did not fully consider the destructive potential of high-intensity earthquakes. For example, during the Wenchuan earthquake in 2008 (with an intensity of 8-11 degrees), a large number of old prefabricated panel buildings collapsed due to exceeding their designed load-bearing capacity.

2. Poor Structural Integrity
   Component connections were made using simple steel bar overlaps or mortar joints, lacking reliable seismic structural measures. For instance, prefabricated floor slabs were connected to walls only through the extended parts of steel bars, making them prone to detachment or overall collapse due to connection failure during earthquakes.

3. Limited Material Performance
   Early prefabricated components were mostly made of ordinary concrete with low strength and did not use prestressing technology, resulting in insufficient crack resistance and deformation capacity of the components, further weakening their seismic resistance.

II. Seismic Improvements in Modern Prefabricated Assembled Buildings

1. Enhanced Design Standards
   Designed according to the current "Code for Seismic Design of Buildings" (GB 50011-2010), the seismic fortification intensity can reach 7-9 degrees (corresponding to seismic intensity levels 7-9) depending on regional fortification requirements. For example, assembled shear wall structures can resist earthquakes above 8 degrees through optimized layout and reinforcement, with specific performance depending on design and construction quality.

2. Innovative Connection Technologies
   High-strength concrete, prestressing technology, and steel bar sleeve connections are used to significantly enhance the connection strength between components. For example, steel bar sleeve grouting connections can achieve equivalent force transfer performance to cast-in-place structures, preventing connection failure during earthquakes.

3. Optimized Structural Integrity
   By setting cast-in-place joints or post-pouring strips, prefabricated components are connected into a whole, forming multiple seismic defense lines. For example, in assembled frame structures, beam-column joints are cast with cast-in-place concrete to ensure coordinated structural behavior during earthquakes.

III. Summary and Recommendations

Old prefabricated panel buildings, due to their low design standards and weak connections, pose a risk of collapse during high-intensity earthquakes and offer little protection against earthquakes above 8 degrees. Modern prefabricated assembled buildings, through technological upgrades, have seismic performance close to or at the level of cast-in-place structures, meeting high-intensity fortification requirements. If residing in an old prefabricated panel building, it is recommended to conduct a seismic assessment and reinforcement; for new constructions, priority should be given to assembled structures that comply with current codes.