Steel pipes play a multifaceted role in seismic-resistant structures, leveraging their unique properties to enhance resilience during earthquakes. Here's a structured overview of their contributions:

1. ​Structural Framework Components

​Braced Frames: Steel pipes are used as diagonal braces in concentrically or eccentrically braced frames. Their hollow sections provide an optimal strength-to-weight ratio, efficiently transferring seismic forces while allowing controlled deformation.

​Moment-Resisting Frames: In beam-column connections, steel pipes contribute to flexibility and energy absorption, resisting bending moments caused by seismic activity.

2. ​Energy Dissipation Systems

​Dampers and Buckling-Restrained Braces (BRBs): Steel pipes are integral in devices like viscous dampers and BRBs, where they dissipate energy through yielding or friction, reducing seismic impact on the structure.

3. ​Composite Construction

​Concrete-Filled Steel Tubes (CFST): Combining steel pipes with concrete infill enhances both materials: the concrete prevents local buckling of the steel, while the steel confines the concrete, improving compressive strength and ductility. This synergy is critical in columns and piers subjected to cyclic loads.

4. ​Foundation and Substructure

​Pile Foundations: Steel pipe piles, often filled with concrete, provide deep foundation support, transferring loads to stable soil strata and resisting lateral forces during ground movement.

5. ​Retrofitting Solutions

​Reinforcement of Existing Structures: Steel pipes are added to older buildings as braces or external frames to improve seismic performance without major structural changes.

6. ​Advantages of Steel Pipes

​Ductility: Allows significant deformation without failure, absorbing seismic energy.

​Strength-to-Weight Ratio: Efficient for vertical and lateral load resistance.

​Versatility: Adaptable to various shapes and connection methods (welded/bolted), accommodating dynamic loads.

7. ​Design Considerations and Standards

​Codes Compliance: AISC and international codes (e.g., ISO, Eurocode) provide guidelines for seismic design, including slenderness limits and connection details to ensure performance under cyclic loading.

​Corrosion Protection: Coatings or stainless steel variants mitigate corrosion risks, ensuring longevity.

8. ​Case Studies and Research

​Applications: High-rise buildings in seismically active regions (e.g., Japan, California) and bridges employ steel pipes for their dynamic load resilience.

​Testing: Cyclic load tests validate steel pipe performance, informing innovations in seismic design.

Conclusion

Steel pipes are indispensable in modern seismic design due to their ductility, strength, and adaptability. They enhance structural integrity across frameworks, energy dissipation systems, and foundations, ensuring buildings withstand earthquakes while minimizing damage. Ongoing research and adherence to seismic codes continue to optimize their use in earthquake-prone areas.