Seismic-Resistant Precast Concrete House

The seismic performance of seismic-resistant precast concrete houses varies significantly depending on their type and technology. Modern precast buildings generally have better seismic resistance than traditional structures and can withstand earthquakes up to magnitude 9. Detailed analysis is as follows:

1. Basic Concepts of Seismic Capacity

The seismic capacity of buildings is measured by the seismic fortification intensity, which ranges from 6 to 12 degrees and has no direct correlation with earthquake magnitude. Intensity reflects the degree of damage an earthquake can cause to buildings. The higher the fortification intensity, the stronger the seismic performance a building must possess. For example, a building with a fortification intensity of 8 degrees should be able to withstand moderate to strong earthquakes, while 9 degrees corresponds to rare and intense earthquakes.

2. Seismic Performance Differences in Precast Panel Buildings

1. Old Precast Panel Buildings
   Old precast panel buildings constructed in the 1970s and 1980s were mostly designed with a seismic fortification intensity of 6-7 degrees, with some areas adopting 7 degrees. Limited by the technology of the time, component connections often used steel bar overlaps or mortar joints, resulting in poor overall integrity. Such buildings can maintain their basic structure under earthquakes of magnitude 6-7 (corresponding to intensity 6-7 degrees) but offer no guarantee against earthquakes above magnitude 8, making them prone to component detachment or partial collapse.

2. Modern Prefabricated Assembly Buildings
   Designed according to the current Code for Seismic Design of Buildings (GB 50011-2010), these buildings can achieve a seismic fortification intensity of 7-9 degrees based on regional requirements. By adopting high-strength concrete, prestressed technology, and steel bar sleeve connections, their overall integrity is significantly enhanced. For example, prefabricated shear wall structures with rigid node connections can withstand earthquakes above magnitude 8, meeting the seismic objectives of "no damage in minor earthquakes, repairable in moderate earthquakes, and no collapse in major earthquakes."

3. Technological Breakthroughs in Seismic Resistance for Concrete Houses

1. Structural Reinforcement
   These houses are constructed using C35 concrete with embedded Φ12-18 threaded steel bars, with each column containing up to 8 steel bars, forming a "steel cage" load-bearing system. Measurements show that their lateral stiffness is 6.8 times that of brick-and-concrete structures, effectively resisting horizontal seismic forces.

2. Flexible Connections and Energy Absorption Design
   Modules are welded using E55 welding rods, with each connection point capable of withstanding 20 tons of tensile force. In earthquake simulation tests conducted in Yunnan, when subjected to a rare magnitude 9 earthquake, the maximum displacement between modules was only 15 cm, and the overall structure remained intact. The steel bar mesh absorbs energy through elastic deformation, withstanding up to 15 cm of deformation without breaking, a 7.5-fold increase over the 2 cm safety threshold of brick-and-concrete structures.

3. Comprehensive Seismic Data
   The seismic capacity of concrete houses is 8 times that of traditional brick-and-concrete structures. Under the same intensity, when brick walls crack, the strain in the walls of concrete houses is only one-eighth of that, truly achieving "no collapse in major earthquakes and repairability in minor earthquakes."