Passive damping and seismic isolation steel devices with displacement-dependent hardening

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Dicleli M., Salem Milani A.

13th International Conference on Steel, Space and Composite Structures, Perth, Australia, 31 January - 02 February 2018, pp.100-110

  • Publication Type: Conference Paper / Full Text
  • City: Perth
  • Country: Australia
  • Page Numbers: pp.100-110


In this paper, a summary of analytical and experimental studies into the behaviour of a new hysteretic damper and a seismic isolator designed for seismic protection of structures is presented. The Multi-directional Torsional Hysteretic Damper (MRSD) and its isolator version MARTI (Multi-Directional Adaptive Torsional Isolator) are patented inventions in which a symmetrical arrangement of identical cylindrical steel cores is so configured as to yield in torsion while the structure experiences planar movements due to earthquake shakings. These new devices have certain desirable properties. Notably, their force-displacement response is characterized by a variable and controllable-via-design post-elastic stiffness. The mentioned property is a result of MRSD’s and MARTI’s kinematic configuration which produces this geometric hardening, rather than being a secondary large-displacement effect. Additionally, these new systems are capable of reaching high force and displacement capacities, show high levels of damping, and very stable cyclic response. The MRSD and MARTI have gone through many stages of design refinement, multiple prototype verification tests and development of design guidelines and computer codes to facilitate their implementation in practice. Practicality of the new devices, as offspring of an academic sphere, is assured through extensive collaboration with industry in their final design stages, prototyping and verification test programs.