A proposed structural design method considering fluid viscous damper degradations

Abstract

Summary The purpose of this study is to perform a seismic assessment of the moment resistant steel structures enhanced with viscous dampers where the dampers are degraded due to possible leak of viscous fluid. This paper proposes a design procedure based on corrected response spectrums as a result of seismic assessments based on nonlinear time series analyses on three‐, five‐, and seven‐story steel frame structures denoted as “generic structures.” The proposed design procedure is a seismic displacement‐based design methodology for buildings with viscous dampers as passive energy dissipation systems. Prior literature on these types of structures often overlook the viscous dampers degradation due to the fluid leak. In this paper, in order to study these effects, a target displacement is specified at first and the lateral forces and required stiffness are obtained. The effectiveness of the proposed procedure is verified with the collapse fragility curves of the generic structures according to the ASCE 7‐10 and displacement‐based design methodology. The results show that the structures designed based on proposed procedure demonstrate acceptable performance with degrading dampers.

Seismic performance of the combined viscous-steel damping system suffering from oil leakage

“…In this stage, the leaked viscous damper would perform as an undamaged one. This finding is consistent with that of Ataei and Anaraki (2018).…”

“…Sinusoidal displacement loads with different characteristics were applied, of which the circular frequencies and amplitudes are listed in Table 1. The oil leakage level can be reflected by the Average Looseness of Viscous Damper (ALVD), which was suggested by Ataei and Anaraki (2018). The ALVD represents the gap length in the hysteretic curves of the leaked viscous damper, which can be determined aswhere η is the reduction factor reflecting the dissolution of the air; d leak is the volume percentage of the leaked oil; l c is the length of the cavity of the damper.…”

“…Once it happens, the viscous damper will no longer keep its favorable performance. Ataei and Anaraki (2018) found that a leaked viscous damper must overcome the so-called "gap" phenomenon before it can engage in vibration control, and the gap will significantly alter the damping force. Wang et al (2017) and Huang and Zeng (2018) revealed that the air inside the hydraulic damper will degrade its dynamic stiffness and damping.…”

Planar arrangement of permanent magnets in design of a magneto-solid damper by finite element method

“…There are a variety of different types of dampers for vibration control of structural and mechanical systems whose energy dissipation mechanisms can be categorized into two main groups: fluid based and solid based. Dampers with fluid-based energy dissipation mechanisms, although used most widely, are vulnerable to leakage of hydraulic fluid which limits their energy dissipation capability in the long term (Ataei and Kalbasi Anaraki, 2018; Constantinou et al, 1998; Sadek et al, 1996). For example, in a recent study carried out on Magnetorheological (MR) fluid dampers, it has been found that fluid leakage is the main cause of performance degradation in these dampers in long-term operation (Wang et al, 2019).…”

Effectiveness of In-Service Dampers over Long-Term Operation for Cable Vibration Suppression: A Study Based on Field Testing

“…With the viscous fluid leaking, the viscous dampers would restore the damping force through a delay that might dramatically decrease the control performance under seismic excitations. Furthermore, a design procedure based on corrected response spectrums was proposed, in which the possible fluid leak of viscous dampers was considered [15]. For the MR dampers, Caterino et al [16] assessed the effectiveness of a MR damper from 2008 to 2013 under a condition of absolute inactivity.…”