Are Prefab Houses Durable? The Earthquake Truth

Beyond Prejudices: Is Prefab Really Safe?

Many people in Turkey are skeptical when it comes to prefab structures: the question "What happens if there's an earthquake?" comes to mind. In this article, we answer this question from a scientific and engineering perspective; we let the data speak, not prejudices.

Factors Determining Earthquake Behavior

There are three fundamental elements that determine the earthquake performance of a structure:

1. Structural system and material selection
2. Conformity of the design with earthquake regulations
3. Construction quality

When these three conditions are met, prefab structures can demonstrate comparable, and in some criteria even superior, seismic performance to reinforced concrete structures.

Steel-Structured Prefab: Seismic Advantages

Steel is a ductile material; meaning it can significantly deform before fracturing. This property is of critical importance in earthquake engineering: the structure "absorbs" the energy, sustaining damage rather than easily collapsing but maintaining its integrity. The Turkish Building Earthquake Code (TBDY-2018) recognizes this ductility property and specifies special design criteria for steel structures.

• Weight advantage: Steel structures are much lighter than reinforced concrete. Since earthquake force is directly proportional to the weight of the structure, lighter structures attract less seismic force.
• Energy dissipation capacity: Well-designed steel connections dissipate earthquake energy through plastic deformation.
• Predictable damage: In steel structures, damage typically develops at connection points and under control; the risk of sudden collapse is lower than in reinforced concrete.

Light Steel Frame Systems

These systems, which use thin galvanized steel profiles in a dense grid arrangement, distribute their load-bearing capacity across numerous elements. Light steel systems, widely used in North America and Japan, have gone through numerous large earthquakes and demonstrated superior performance. In Turkey, these systems can be evaluated within the scope of TBDY-2018.

Sandwich Panel Systems: Points to Note

Sandwich-paneled structures need a frame system (usually steel or concrete) to carry earthquake loads; the panels are not load-bearing on their own. Therefore, in a sandwich-paneled prefab villa:

• The load-bearing steel or reinforced concrete frame must comply with the earthquake code.
• Panel connections must be made according to standards.
• The foundation system must be sized according to soil survey results.

When these conditions are met, sandwich-paneled prefab structures can also demonstrate a safe earthquake performance.

What Have the Earthquakes in Turkey Shown?

The 2023 Kahramanmaraş earthquakes once again revealed how determinative construction quality is. When the collapsed structures were examined, the vast majority were found to be poorly executed reinforced concrete; in contrast, steel-structured and qualified prefab structures generally remained standing. On the other hand, prefab structures built with poor-quality materials or faulty application can also be damaged. The result is clear: what matters is not the system, but the application.

Checklist for the Right Choice

• ✅ Can the company provide a structural project compliant with TBDY-2018?
• ✅ Are the steel profiles used TSE/CE certified?
• ✅ Will a soil survey be conducted?
• ✅ Will connection details be supervised by an approved engineer?
• ✅ Will a building inspection firm be included in the process?

A prefab structure purchased from a company that answers "yes" to all of these questions is as safe as a reinforced concrete structure built in compliance with regulations.

Conclusion

Prefab houses are not earthquake-resistant; on the contrary, properly designed and applied steel-structured prefab structures offer various seismic advantages compared to reinforced concrete. As Tunahanyeniçeri, we commit to delivering a safe structure in every prefab project with TBDY-2018 compliant structural design, certified materials, and supervised application.