Evaluation of optimal FVDs for inter-storey isolation systems based on surrogate performance models

Abstract

Inter-storey seismic isolation is increasingly gaining attention. One of the main related issues is the need to limit the relative displacement between substructure and superstructure, while maintaining a good seismic performance of the superstructure. As shown in some studies, fluid viscous dampers (FVDs) mounted in isolation systems are effective in reducing isolator deflection but can be harmful by amplifying inter-storey drifts and floor accelerations. Additionally, the effectiveness of FVDs for inter-storey applications was investigated only recently, and specific approaches for their optimisation and performance evaluation are missing. Therefore, this paper proposes a method for the optimal multi-objective design of FVDs, based on the definition of appropriate surrogate response models, which allows for rationally comparing the FVD effects for a wide range of dampers and structures. In particular, the optimal FVD parameters are provided in a dimensionless form, so that they can be predicted by design equations of general validity within the range of the structures analysed. This method is applied to a stock of regular structures with various vibration periods of superstructure, isolation and substructure, examining a linear and a non-linear isolation system and a set of natural records, in order to comprehensively assess the effects of FVDs and their non-linearity on the seismic performance of these structures. Finally, prediction models of optimal FVD parameters are provided based on the results obtained and are applied to three case studies as an example.

Performance evaluation of multiple tuned inerter‐based dampers for seismic induced structural vibration control

“…There are many methods to deal with the multi-objective optimization problem, for example, the multi-objective genetic algorithm. 55 However, if the number of design variables is large, the computation cost of this algorithm is very expensive, particularly for multi-objective optimization problem. The weighted sum method 56 is employed in this study.…”

Intermediate Isolation System with Nonlinear Lower Structure and Isolation System

“…An experimental campaign on a multi-story frame structure equipped with nonconventional TMD has also been reported in [27], with white noise, sine sweep, and natural earthquakes as input motion conditions. Donà et al [28,29] have considered IIS made by fluid viscous dampers and have derived the optimal parameters for minimizing the isolation drift and simultaneously controlling the superstructure performance. Bernardi et al [30] have proposed a multi-objective optimization approach applied to a 2DOF model, representing an IIS working as a TMD.…”

Evaluation of the Inter-Story Isolation System Applied to an Existing Rc School Building

“…Inter-story isolation system (IIS) is a technique that consist in inserting a seismic isolation system between two stories of the structure. Applied to high rise buildings, the technique allows a great architectural freedom, as the structural parts can have different architectural and structural characteristics (e.g., different geometries, materials, etc) [1,2,3,4,5].…”

“…In general, the dynamic behaviour of the IIS combines the function of seismic isolation and mass damping [10,11], and different approaches need to be considered according to the specific case. Studies evaluating the technique acting as a seismic isolation system generally use models with three or more degrees of freedom (e.g., [3,4,5,10,12,13,14,15]); on the other hand, when the IIS acts as a TMD system for the substructure, two-degree-of-freedom (2-DOF) systems have been used ([6, 7, 16, 17, 18, 19, 20]).…”