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Structural Vibration Control Using Passive Devices
Published in Suhasini Madhekar, Vasant Matsagar, Passive Vibration Control of Structures, 2022
Suhasini Madhekar, Vasant Matsagar
Passive control strategies typically include base isolation and supplemental dampers. The different types of base isolation systems include elastomeric bearings, lead rubber bearings (LRB), and high damping rubber bearings (HDRBs). Friction pendulum system (FPS), variable friction pendulum system (VFPS), variable curvature friction pendulum system (VCFPS), and variable frequency pendulum isolator (VFPI) are the examples of sliding friction isolators. Dampers inherently have a few advantages over the base isolation technique as they are easy to install and maintain. In a multistory structure, a multilevel control strategy controls the response of the structure more efficiently. This objective can be achieved with the help of dampers. The different types of dampers used for energy dissipation are metallic yield dampers, friction dampers, viscous fluid dampers, viscoelastic dampers, tuned mass dampers, and tuned liquid dampers. The following sections deal with different types of major passive control systems used globally.
Value protection of existing built environment: New frontiers on risk assessment and management
Published in Airong Chen, Xin Ruan, Dan M. Frangopol, Life-Cycle Civil Engineering: Innovation, Theory and Practice, 2021
Base isolation is known to be an effective tool in providing uninterrupted functionality for structures and infrastructures hit by a severe earthquake maintaining the structure within its elastic limit state and fully protecting its overall value and the value of the contents. The possibility to provide also existing structures and infrastructures (and specifically buildings originally built with a fix base) with base isolation, has become in recent years a reality. After the earthquake that hit the city if L’Aquila in central Italy in 2009, several cases of the application of this technique have took place in Italy, mainly boosted by economic incentives introduced by the Italian Government for the re-construction, in order to promote an increased and diffuse seismic resilience of the National built environment. One technique consists in applying a cut at a certain level of the existing structure and to insert the anti-seismic devices one by one (Figure 17).
Dynamic analysis for structures supported on slide-limited friction base isolation system
Published in B.F. Spencer, Y.X. Hu, Earthquake Engineering Frontiers in the New Millennium, 2017
Base isolation is regarded as a practical and economical way to protect structures from damages subject to earthquake motion. Isolators implemented between the base raft of the structure and foundation can dissipate and absorb earthquake energy, and reduce the transmission of ground motion to structure obviously. In a short, the principle of base isolation includes two factors. i) The natural period of structures with fixed base is usually 0.2 ˜ 1.2 s, close to the natural period of foundation which is 0.2 ˜ 0.8 s. By using base isolator, the natural period of structures increases and is apart from the resonance area of ground excitations. ii) Normal structures absorb the earthquake energy at the expense of large plastic deformation of structural and non-structural elements, but base isolation structures dissipate earthquake energy through continuous motions of isolator with high damping to do work. In the past, numerous schemes for base isolators have been suggested. Among these schemes, frictional base isolators are the most popular. This kind of base isolation system includes Pure-friction base isolation system (P-F), Resilient-friction base isolation system (R-FBI), Electricite de France base isolation system (FDF), Friction pendulum system (FPS), and so on. In recently years, the rolling frictional base isolators have been also developed such as Free circular rolling rods for base isolation, Elliptical rods for base isolation, and Ball system with restoring property. Among these frictional base isolation systems, P-F and R-FBI have been developed widely both in theory and practice.
Seismic Performance of Building with Novel Steel Roller Isolation Bearing: Experimental and Numerical Studies
Published in Journal of Earthquake Engineering, 2023
Yanhui Liu, Jiajun Zhang, Xiangyun Huang, Songtao Xue
Strong earthquakes cause severe structural damage to buildings and endanger human safety. Because earthquakes are unpredictable, it is crucial to prevent earthquake disasters through scientific and technological means. Base isolation is a well-known technology that is widely used in buildings and bridges to mitigate the effects of earthquakes. Compared with non-isolated structures (fixed foundation), the use of base isolation technology has shown a significant reduction in the seismic vibration of isolated structures. The isolation design of ground structures primarily reduces the force and deformation caused by earthquakes in the superstructure by setting isolation layers in the structure to prevent injury to occupants and damage to the contents of the structure (Ibrahim 2008). Many isolation devices with different working mechanisms to resist earthquakes have been reported in the literature (Buckle and Mayes 1990; Foti and Mongelli 2011; Jangid and Datta 1995; Naeim and Kelly 1999; Ordonez, Foti, and Bozzo 2003).
Adaptive Control of a Parallel Base-Isolated System
Published in Structural Engineering International, 2019
Most of the past research in the field of base isolation has focused on the use of rubber bearings and sliding bearings. The simplest sliding isolation system is a pure-friction sliding isolation system without any restoring force. Compared with the rubber isolation system, the advantages of a friction sliding isolation system are: (a) the friction force is proportional to the weight supported by the sliding bearings, implying that there is no eccentricity between the mass centre and stiffness centre of the superstructure; (b) the friction sliding bearing has no natural frequency, so it can dissipate the seismic energy over a wide frequency range without the risk of resonance with the earthquake ground motion; and (c) the friction sliding bearing is simple in construction and inexpensive. However, the larger sliding displacement and residual displacement in the pure-friction sliding system hinder the independent application of sliding bearing in practical engineering. In the present study, the parallel base-isolated system is composed of conventional rubber isolation bearings and pure-friction sliding isolation bearings, in which the majority of bearings adopt rubber isolation bearings providing the restoring force, and the minority of bearings adopt sliding isolation bearings supporting light parts of the structure without unnecessarily stiffening the isolation system. Parallel base-isolation strategies can usually achieve better economic and technical results.
Innovative technologies in manufacturing, mechanics and smart civil infrastructure
Published in International Journal of Smart and Nano Materials, 2018
Passive structural control commonly adopts energy dissipation strategy through various damping devices, such as friction dampers, metallic-yield dampers, buckling-restrained braces, viscous fluid dampers, visco-elastic dampers, tuned-mass dampers, shape memory alloy dampers, eddy-current dampers, and so on. Another strategy is to reduce the seismic input energy using base isolation systems. Base isolation or seismic isolation works by shifting a short fundamental period that is located in the dynamic excitation frequency range to a long fundamental period. Base isolation is usually used in low- to medium-rise buildings and nuclear power plants for seismic resistant design. However, base isolation systems are ineffective for wind-induced vibration mitigation [50]. The passive structural control systems do not require any external energy supply.