A review of base isolation systems with adaptive characteristics

Sheikh, Hediyeh; Engelen, Niel C. Van; Ruparathna, Rajeev

doi:10.1016/j.istruc.2022.02.067

Cited by 30 publications

(14 citation statements)

References 121 publications

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“…This is achieved by elongating the fundamental period of the structure and increasing its energy dissipation capacity, thereby enhancing the seismic performance and safety 2 . However, the behavior of seismic isolation bearings is highly nonlinear and intricate 4 . Thus, it is crucial to develop accurate numerical models of the isolation bearings for assessing the overall dynamic behavior of isolated buildings.…”

Section: Introductionmentioning

confidence: 99%

“…2 However, the behavior of seismic isolation bearings is highly nonlinear and intricate. 4 Thus, it is crucial to develop accurate numerical models of the isolation bearings for assessing the overall dynamic behavior of isolated buildings. Elastomeric isolators are widely utilized devices that take advantage of the flexible characteristics of an elastomer, making them ideal for base isolation due to the low shear modulus and capacity to accommodate large recoverable strains.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of seismic fragility curves of unbonded FREIs: Adaptive characteristics and modeling sensitivity

Sheikh,

Ruparathna,

Van Engelen

2024

Earthq Engng Struct Dyn

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Fiber‐reinforced elastomeric isolators (FREIs) are composed of layers of elastomer reinforced with either steel or fibers, and can be placed in a bonded or unbonded configuration between the upper and lower supports. The use of fiber reinforcement in FREIs was intended to reduce the production and installation costs compared to common steel‐reinforced elastomeric isolators (SREIs) and to develop an isolator suitable for widespread application, particularly in developing countries. The unique rollover deformation exhibited by unbonded FREIs (UFREIs), due to their flexible fiber reinforcement, enables them to adapt to multiple performance objectives at different hazard levels. In this study, the impact of different numerical models of UFREIs on the seismic response and failure probability of structures is investigated. The research employs incremental dynamic analysis and the development of fragility curves for different limit states, considering three sets of ground motions (including far‐field and pulse‐like). Moreover, the effect of full rollover was investigated by comparing the fragility curves of UFREIs when supported on modified support geometries, which involved three types of support: unmodified, accelerated, and delayed full rollover. The effectiveness of the adaptive characteristics to behave as a displacement restrain is demonstrated. The results emphasize the importance of employing an accurate model to simulate the behavior of UFREIs as an adaptive device for effectively utilizing their potential capacity, particularly at larger displacements where there is more dissipated energy due to full rollover.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of seismic fragility curves of unbonded FREIs: Adaptive characteristics and modeling sensitivity

Sheikh,

Ruparathna,

Van Engelen

2024

Earthq Engng Struct Dyn

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“…Seismic isolation has been identified as one of the most effective and practical seismic protection strategies for civil engineering structures [1][2][3][4][5][6]. Several studies have investigated the seismic performance of different types of isolation bearings, e.g., lead rubber bearing (LRB) [7,8], pure-friction sliding isolator [9][10][11], and friction pendulum [12][13][14][15][16][17][18], which can effectively shift the fundamental period of the structures away from the predominant period of the seismic excitations, hence minimizing the seismically induced structural damage.…”

Section: Introductionmentioning

confidence: 99%

Superelastic Conical Friction Pendulum Isolator for Seismic Isolation of Bridges under Near-Fault Ground Motions

Zheng

Tan

et al. 2023

Structural Control and Health Monitoring

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To improve the seismic performance of bridges, this study develops a novel superelastic conical friction pendulum isolator (SCFPI) by incorporating an improved conical friction pendulum isolator (CFPI) with shape memory alloy (SMA). The flat sliding function designed for the improved conical friction pendulum isolator is to enhance the adaptability under service loadings. The analytical model of the novel SCFPI is derived and the numerical model is developed within the OpenSees platform to investigate the hysteretic behavior under cyclic loadings. A cost-effective design method is proposed to design the SCFPI system for example bridges. The response mitigation efficacy of the novel SCFPI system is investigated using the optimum design parameters under near-fault ground motions. Several case studies are conducted to demonstrate the effectiveness of the novel SCFPI system and cost-effective design method. Results indicate that the cost-effective design method is particularly effective for parameter optimization of the novel SCFPI, which achieves effective mitigation for the displacement responses of the isolator and superstructure and also effectively controls the seismic force increment in piers. Case studies indicate the reliable re-centering capacity and mitigation efficacy of the SCFPI system for bridges under near-fault ground motions. The findings of this study contribute to upgrading structural resilience and promoting seismic applications as a reliable technical guidance.

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“…When seismic isolation is applied to a structure, the design is based on dynamic analysis. On the other hand, excessive ductility of the isolator in the face of an unexpected earthquake with great intensity puts the safety of the design at risk [2,3]. To verify the safety of the isolation system, it has been proposed to use random earthquake excitations.…”

Section: Introductionmentioning

confidence: 99%

“…To verify the safety of the isolation system, it has been proposed to use random earthquake excitations. The high ductile isolator prevents its movement under the lower levels of the earthquakes, thus preventing the transmission of earthquake forces to the structure [2,4]. For both types of earthquakes, the aim should be to determine the optimum parameters for the isolators, to design a structure.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Seismic Base Isolation System Using Adaptive Harmony Search Algorithm

et al. 2022

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In this study, a seismic isolator placed on the base of a structure was optimized under various earthquake records using an adaptive harmony search algorithm (AHS). As known, the base-isolation systems with very low stiffness provide a rigid response of superstructure, so it was assumed that the structure is rigid and the base-isolated structure can be considered as a single-degree of freedom structure. By using this assumption, an optimization method that is independent of structural properties but specific to the chosen earthquake excitation set is proposed. By taking three different damping ratio limits and isolator displacement limits, the isolator period and damping ratio were optimized so that the acceleration of the structure was minimized for nine cases. In the critical seismic analysis performed with optimum isolator parameters, the results obtained for different damping ratios and isolator periods were compared. From the results, it is determined that isolators with low damping ratios require more ductility, and as the damping ratio increases, further restriction of the movement of the isolator increases the control efficiency. Thus, it is revealed that increasing the ductility of the isolator is effective in reducing the total acceleration in the structure.

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A review of base isolation systems with adaptive characteristics

Cited by 30 publications

References 121 publications

Investigation of seismic fragility curves of unbonded FREIs: Adaptive characteristics and modeling sensitivity

Investigation of seismic fragility curves of unbonded FREIs: Adaptive characteristics and modeling sensitivity

Superelastic Conical Friction Pendulum Isolator for Seismic Isolation of Bridges under Near-Fault Ground Motions

Optimization of Seismic Base Isolation System Using Adaptive Harmony Search Algorithm

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