Laminated steel damper for seismic retrofitting of existing buildings

Multi-stage seismic steel damper with auxiliary dampers of varying lengths that sequentially convert into tension members based on displacement

This technology is a laminated steel damper for seismic retrofitting of existing buildings. It features a curved main damper installed between first and second base brackets, with multiple layered auxiliary dampers of varying curvatures placed inside. At low displacements, it works with the main damper to dissipate seismic energy through elastic deformation; at high displacements, it undergoes plastic deformation, straightening out to act as a linear tension member that restricts further displacement.

With less than 10% of domestic buildings meeting seismic standards, retrofitting is urgent. However, steel brace methods offer poor displacement control and aesthetics, while slit steel dampers show minimal energy absorption in earthquakes weaker than their design strength. Oil dampers are expensive and difficult to maintain due to temperature-dependent viscosity changes, and U-shaped steel dampers, while flexible, lack the strength and stiffness to control collapse loads during major earthquakes.

This technology features outer auxiliary dampers with longer extensions and higher maximum tensile loads than the inner ones, ensuring that as displacement increases, the dampers transition into tension members sequentially from the innermost one. The material and thickness of each damper can be customized, using steel or aluminum. Rigid rods hinged at both ends support vertical loads, and multiple damper assemblies can be arranged radially. Suitable for aging schools, public buildings, soft-story structures like pilotis, and low-to-mid-rise renovations, it manages energy dissipation and shear force support in stages, effectively delaying structural collapse.

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Key Features:

• A main damper installed between first and second base brackets, comprising a main damper curved section with a predetermined curvature and a pair of main damper extensions extending from both ends.
• A plurality of laminated auxiliary dampers installed inside the main damper that dissipate seismic energy through elastic deformation within a predetermined displacement and convert into linear tension members through plastic deformation beyond that point.
• A first laminated auxiliary damper featuring a first auxiliary damper curved section with a predetermined curvature and a pair of first auxiliary damper extensions extending from both ends at a second length.
• A second laminated auxiliary damper disposed outside the first laminated auxiliary damper, having a higher maximum tensile load and extensions of a third length, which is longer than the second length.

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This invention was developed with support from the Ministry of Education's LINC 3.0 project.

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