Earthquake-Resistant Prefabricated Housing

Earthquake-resistant prefabricated housing is a building form that combines the characteristics of prefabricated assembly-type construction with seismic design requirements, and its seismic performance is influenced by the structural system, construction era, and reinforcement measures.

I. Characteristics of Prefabricated Assembly-Type Construction and Their Relationship with Seismic Resistance Prefabricated assembly-type construction involves the industrial production of building components (such as wall panels, floor slabs, and frame modules) and their on-site assembly. The main types include panel assembly, box assembly, and frame assembly. Among them, modular construction, as a more integrated model, breaks down the building into independent modules that are manufactured in a factory and then transported to the construction site for assembly. This industrial production method offers advantages such as short construction periods, controllable quality, and energy efficiency and environmental protection. However, the connection nodes between components are crucial for seismic performance. If the connection design is unreasonable, it may lead to insufficient structural integrity under earthquake action, affecting the seismic effect.

II. Selection of Seismic Structural Systems The seismic structural system is a core factor determining the seismic performance of prefabricated housing and must comply with the basic principles of seismic conceptual design. The main systems include:

1. Frame-Shear Wall Structure: By working in tandem with the frame and shear walls, this system significantly reduces inter-story displacements under earthquake action, improves structural stiffness and energy dissipation capacity, and is a commonly used seismic system in prefabricated housing.
2. Frame Structure: Suitable for low-rise or multi-story buildings, this system transfers earthquake forces through beam-column joints and requires ensuring joint connection strength to avoid brittle failure.
3. Multi-Story Masonry Buildings: Traditional masonry structures have weak seismic performance and require measures such as constructional columns and ring beams to enhance overall integrity. However, the introduction of prefabricated components may improve their seismic performance.

III. Quantification and Differences in Seismic Performance The seismic performance of prefabricated housing varies depending on construction standards and era:

• Newly Built Prefabricated Housing: The seismic standard can reach 7 degrees (according to China's seismic fortification intensity classification) and can withstand earthquakes of around magnitude 6. However, its overall integrity is still weaker than that of reinforced concrete cast-in-place housing.
• Old Prefabricated Housing: Prefabricated panel houses built before the 1980s have lower seismic standards and can now only withstand 6-degree earthquakes, posing significant safety hazards.

IV. Measures to Enhance Seismic Performance To enhance the seismic capacity of prefabricated housing, the following reinforcement measures can be taken:

1. Adding Reinforcement: Install additional reinforcement or steel frames at component connections to improve joint bearing capacity and ductility.
2. Installing Seismic Isolation Bearings: Set up a seismic isolation layer between the foundation and the superstructure to reduce earthquake energy transmission through flexible connections.
3. Using High-Ductility Cement: Replace traditional concrete with high-ductility cement to improve the deformation capacity and energy dissipation efficiency of components.

V. Summary The seismic performance of earthquake-resistant prefabricated housing must be achieved through the rational selection of structural systems, optimization of component connection design, and implementation of reinforcement measures. Newly built housing should prioritize the use of frame-shear wall structures and meet the 7-degree fortification standard, while old housing requires technical renovations such as adding reinforcement and seismic isolation bearings to enhance safety.