Inerter-added transmissibility to control base displacement in isolated structures

• Published in: Engineering structures Vol. 251; p. 113564
• Main Author: Morales, Cesar A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.01.2022; Elsevier BV
• Subjects: Active control; Base displacement; Base isolation; Displacement; Earthquake loads; Far fields; Ground motion; Inerter; Isolator displacement; Isolators; Passive control; Structural models; Base isolation; Isolator displacement; Passive control; Base displacement; Inerter
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2021.113564

•An original expression for inerter-isolation relative transmissibility is derived and presented.•This transmissibility is applied to the solution of the large base displacement problem.•The Method can be the basis of a design procedure for isolation systems that include an inerter.•Moreover, another novelty is the application of new seismic ground displacement narrowbandness.•These passive-control results are quite favorable even when comparisons are made with active-control solutions. A solution to the large base displacement problem in isolated structures under seismic loads is proposed; it is based on a displacement transmissibility formulation that includes the inerter device. The solution is also based on a novel spectral characterization of ground displacement; it should be clear that if the problem is displacement, the focus must be on displacements, both, as the excitation: ground displacement (rather than acceleration which is the norm) and as isolator displacement, through a transmissibility that relates both input and output displacements, all of which is a new approach. The proposal can serve as a passive-control design procedure, either under near-field or far-field conditions, when an inerter at the base level is chosen to solve the large isolator displacement problem. An isolated structural model commonly used in the subject literature is employed to show that the base displacement level can be reduced to under the ground displacement level, which implies a positive comparison with previous passive and active control solutions, including inerter solutions; in fact, the design aim is a competitive 0.95 ratio for both displacements.