Double rolling isolation systems: A mathematical model and experimental validation

Harvey, P. Scott; Gavin, Henri P.

doi:10.1016/j.ijnonlinmec.2014.01.011

Cited by 45 publications

(31 citation statements)

References 21 publications

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“…By using granulated or stripped tire‐soil mixtures as an isolation layer, this GSI system exhibited good seismic isolation in both the horizontal and vertical directions, as demonstrated in subsequent numerical studies and experimental surveys . Another system with circular cone‐type surface, called the ball‐in‐cone isolator, was introduced by Kasalanti et al and subsequently studied by Chang and Spencer and Harvey et al . The ball‐in‐cone isolator is particularly suitable for light structures because it has a point contact to support the structure.…”

Section: Introductionmentioning

confidence: 89%

Introduction of the convex friction system (CFS) for seismic isolation

Xiong

Zhang

Jiang³

et al. 2016

Struct. Control Health Monit.

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SUMMARYThis work introduces an innovative seismic isolation system named the convex friction system (CFS). This newly introduced isolation system has a sliding concavity with a circular cone-type surface, and exhibits some distinct features compared to conventional isolation techniques, such as increased uplift stability, improved self-centring capacity, and resonance dodge when subjected to near-fault earthquakes. A series of comprehensive analytical and numerical investigations are performed to verify these features of the CFS. First, the force-displacement relation of the CFS is established to describe the underlying philosophy of the system. The analytical model is then incorporated into numerical simulations to evaluate the seismic isolation performance of the CFS. Various ground accelerations, such as near-fault shakings, are included in these numerical calculations. Furthermore, the numerical results are rigorously investigated to illustrate the feasibility of the CFS. Finally, the limitations of the CFS study are discussed, and conclusions are drawn. The analytical and numerical results show that the CFS performs well in seismic isolation applications. The structural response can be reduced by approximately 30% with the CFS when compared to that with the Curved Surface Slider (CSS) with a spherical-surface concavity for some near-fault earthquakes, which verifies the aforementioned advantages of the CFS.

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Section: Introductionmentioning

confidence: 89%

Introduction of the convex friction system (CFS) for seismic isolation

Xiong

Zhang

Jiang³

et al. 2016

Struct. Control Health Monit.

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“…Different isolation techniques have been proposed, developed, and employed in structures and equipment, such as friction pendula, rolling and sliding isolators, and bearings. The principle of operation is basically the same: The horizontal components of the ground (or floor) movement are mechanically separated from the isolated structure (or equipment) through compatible, sliding, rotating, or rolling interfaces . In rolling isolation systems proposed by Harvey and Gavin, Harvey et al and Harvey and Gavin, the limited rolling of steel spheres encapsulated between convex surfaces is employed in order to confine the displacement of the ball by means of a lip located at the border of every rolling surface.…”

Section: Introductionmentioning

confidence: 99%

“…The principle of operation is basically the same: The horizontal components of the ground (or floor) movement are mechanically separated from the isolated structure (or equipment) through compatible, sliding, rotating, or rolling interfaces . In rolling isolation systems proposed by Harvey and Gavin, Harvey et al and Harvey and Gavin, the limited rolling of steel spheres encapsulated between convex surfaces is employed in order to confine the displacement of the ball by means of a lip located at the border of every rolling surface. The roll‐n‐cage isolators limit the peak isolator displacements and prevent PADJS under strong seismic excitation by using a self‐braking mechanism, which contains the pounding inside the roll‐n‐cage isolator's frame.…”

Section: Introductionmentioning

confidence: 99%

Influence of the characteristics of isolation and mitigation devices on the response of single‐degree‐of‐freedom vibro‐impact systems with two‐sided bumpers and gaps via shaking table tests

Andreaus

Angelis

2020

Struct Control Health Monit

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Summary During strong earthquakes, structural pounding may occur between structures (buildings, bridges, strategic facilities, critical equipment, etc.) and the surrounding moat wall because of the limited separation distance and the deformations of the isolator. An arrangement that favors the solution of this problem is the interposition of shock absorbers. Thus, the influence of geometrical and mechanical characteristics of isolation and mitigation devices on nonlinear, nonsmooth response of vibro‐impact systems is experimentally investigated in this paper on the basis of a laboratory campaign of experimental tests. Shaking table tests were carried out under a harmonic excitation in order to investigate two different configurations: the absence and the presence of bumpers. Three different values of the table acceleration peak were applied, four different amplitude values of the total gap between mass and bumpers were considered, and also four different types of bumpers were employed; moreover, two problems were addressed, namely, control of excessive displacements and control of excessive accelerations, and hence, two types of normalization were adopted in order to better interpret experimental results. Suitable choices of pairs of bumpers and gaps were suggested as a trade‐off between conflicting objectives. Furthermore, a numerical model was proposed, and its governing parameters identified in order to simulate the experimental results.

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“…() Exceeding the displacement capacity results in the pounding between adjacent structures or the impact in system's components. () Pounding/impact produces harmful undesired transmitted acceleration to the system,() which is detrimental for acceleration sensitive components.…”

Section: Introductionmentioning

confidence: 99%

Enhanced passive control of dual‐mode systems under extreme seismic loading: An optimal control approach

Tehrani

Harvey

2019

Struct Control Health Monit

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Devastating economic losses can arise from damage to mission-critical facilities, structures, and systems supporting vital equipment (systems in general). One of the sources of damages to such systems is displacements in excess of the displacement capacity. The increase in displacement demand is more pronounced in systems located on soft soils 1-3 or when they are exposed to long-period seismic loadings or near-fault excitations with large pulse duration. 4,5 Exceeding the displacement capacity results in the pounding between adjacent structures or the impact in system's components. [6][7][8] Pounding/impact produces harmful undesired transmitted acceleration to the system, [9][10][11][12] which is detrimental for acceleration sensitive components.The most straightforward solution to mitigate impact is to increase the displacement capacity. However, it is not always possible to increase the displacement capacity because of environmental limitations or cost prohibitions, in both new construction and retrofit of an existing structure. 8,9 In the literature, different solutions for pounding mitigation have been proposed and assessed. One method is to connect adjacent structures at some specific locations. These connections enforce the adjacent structures to have in-phase motions with one another. [13][14][15] For instance, the use of hard rubber bumpers or stiff linking between the segments of a bridge can improve the bridge behavior during severe earthquakes 13 or inserting a shock-absorbing material such as rubber for pounding mitigation in buildings. 8 Alternatively, a pair of pressurized fluid-viscous dissipaters was used for pounding mitigation between a church structure and its bell tower. 7 Applying a similar concept, a share tuned mass damper between two adjacent tall buildings can reduce both structural responses and the probability of pounding. 14 Others have shown that using links such as springs, dashpots, or viscoelastic elements between two adjacent three-story buildings can significantly reduce the gap size and prevent pounding. 15 Another solution to this problem is to reduce the displacement demand via some energy dissipative mechanisms, which has been studied extensively. For instance, increasing the damping in an isolation system reduces the isolator displacement and base shear. [16][17][18] Approaches based on semi-active control have also been developed to decrease structural displacement. 19 Recently, inerters have been shown to be effective for response reduction as well. 20,21 Although the above-mentioned solutions have shown to be effective, there are some drawbacks with these approaches, and several studies showed that devastating damage to systems has been observed under high-amplitude seismic loadings, even with the presence of some energy dissipative mechanisms. 4,7,17 One of the disadvantages of connecting adjacent structures is the impairing of the dynamics of each individual structures. In addition, reducing the displacement demand comes at the expense of increasing the total transfer...

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Double rolling isolation systems: A mathematical model and experimental validation

Cited by 45 publications

References 21 publications

Introduction of the convex friction system (CFS) for seismic isolation

Introduction of the convex friction system (CFS) for seismic isolation

Influence of the characteristics of isolation and mitigation devices on the response of single‐degree‐of‐freedom vibro‐impact systems with two‐sided bumpers and gaps via shaking table tests

Enhanced passive control of dual‐mode systems under extreme seismic loading: An optimal control approach

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