Nonlinear Response of RC Framed Buildings with Isolation and Supplemental Damping at the Base Subjected to Near-Fault Earthquakes

Mazza, Fabio; Vulcano, Alfonso

doi:10.1080/13632460802632302

Cited by 81 publications

(32 citation statements)

References 18 publications

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“…The energy dissipation provided by the yielding of the lead core allows to achieve an equivalent viscous damping coefficient up to about 30%, thereby reducing the horizontal isolator displacement effectively [1, 2,24]. However, the supplemental damping at the base isolation system does not guarantee a better performance of the superstructure, which can reduce inter-story drifts in all cases, especially for the low-rise building structures with relatively short periods [25]. In addition to damping, high vertical stiffness is obtained by thin layers of rubber reinforced with steel shim plates.…”

Section: Modeling Of Base Isolation Systemsmentioning

confidence: 99%

Seismic Response and Performance Evaluation of Self-Centering LRB Isolators Installed on the CBF Building under NF Ground Motions

Seo

2016

Sustainability

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This paper mainly treats the seismic behavior of lead-rubber bearing (LRB) isolation systems with superealstic shape memory alloy (SMA) bending bars functioning as damper and self-centering devices. The conventional LRB isolators that are usually installed at the column bases supply extra flexibility to the centrically braced frame (CBF) building with a view to elongate its vibration period, and thus make a contribution to mitigating seismic acceleration transferred from ground to structure. However, these base isolation systems are somehow susceptible to shear failure due to the lack of lateral resistance. In the construction site, they have been used to be integrated with displacement control dampers additionally withstanding lateral seismic forces. For this motivation, LRB isolation systems equipped with superelastic SMA bending bars, which possess not only excellent energy dissipation but also outstanding recentering capability, are proposed in this study. These reinforced and recentering LRB base isolators are modeled as nonlinear component springs, and then assigned into the bases of 2D frame models used for numerical simulation. Their seismic performance and capacity in the base-isolated frame building can be evaluated through nonlinear dynamic analyses conducted with historic ground motion data. After comparative study with analyses results, it is clearly shown that 2D frame models with proposed LRB isolators generally have smaller maximum displacements than those with conventional LRB isolators. Furthermore, the LRB isolation systems with superelastic SMA bending bars effectively reduce residual displacement as compared to those with steel bending bars because they provide more flexibility and recentering force to the entire building structure.

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Section: Modeling Of Base Isolation Systemsmentioning

confidence: 99%

Seismic Response and Performance Evaluation of Self-Centering LRB Isolators Installed on the CBF Building under NF Ground Motions

Seo

2016

Sustainability

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“…The performance of base-isolated structures against near-fault earthquakes characterized by long-duration pulses with peak velocities has been investigated by several researchers [1,2]. Recent research results have shown that near-fault earthquakes characterized by long-duration pulses with peak velocities will result in significant base displacements and inter-story drifts of a seismically isolated structure [3]. Kalkan and Kunnath [4] showed that the fling-step effect would mainly excite the first order modal response of the structures with middle and long natural vibration period, and cause the maximum deformation of the structure at the bottom, which would result in the failure mode of the structure.…”

Section: Introductionmentioning

confidence: 99%

Self-Tuning Fuzzy Control for Seismic Protection of Smart Base-Isolated Buildings Subjected to Pulse-Type Near-Fault Earthquakes

Zhao

Liu

2017

Applied Sciences

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Pulse-type near-fault earthquakes have obvious long-duration pulses, so they can cause large deformation in a base-isolated system in contrast to non-pulse-type near-fault and far-field earthquakes. This paper proposes a novel self-tuning fuzzy logic control strategy for seismic protection of a base-isolated system, which can operate the control force of the piezoelectric friction damper against different types of earthquakes. This control strategy employs a hierarchic control algorithm, in which a higher-level supervisory fuzzy controller is implemented to adjust the input normalization factors and output scaling factor, while a sub-level fuzzy controller effectively determines the command voltage of the piezoelectric friction damper according to current level of earthquakes. The efficiency of the proposed control strategy is also compared with uncontrolled and maximum passive cases. Numerical results reveal that the novel fuzzy logic control strategy can effectively reduce the isolation system deformations without the loss of potential advantages of base-isolated system.

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“…Moreover, the vertical to horizontal response spectral ratios are dependent on the structural vibration period and site-to-fault distance (MacRae et al 2001;Bozorgnia and Campbell 2004;Elnashai and Papazoglou 1997). Different techniques aimed at enhancing the seismic performance of a structure through base isolation (Mazza 2015a;Mazza et al 2012;Mazza and Vulcano 2009;Ponzo et al 2012) or energy dissipation (Baratta et al 2012;Sorace and Terenzi 2014;Mazza 2015b;Mazza et al 2015;Mazza and Vulcano 2011, 2013, 2014a systems are available in literature to mitigate near-fault effects.…”

Section: Introductionmentioning

confidence: 99%

“…Besides, increasing of the acceleration ratio can notably change the axial load in reinforced concrete (r.c.) columns, producing undesirable variations in these elements (Mazza and Vulcano 2009;): e.g., reduction in the shear force, buckling of the longitudinal bars, brittle failure under compression, bond deterioration or failure under tension. Plastic hinges are needed along the span of the girders, especially if the span is rather long (Perea and Esteva 2004) and at the upper storeys where the effects of gravity loads generally are more than those of the horizontal seismic loads and an amplification of the vertical motion can be found.…”

Section: Introductionmentioning

confidence: 99%

Effects of near-fault ground motions on the nonlinear behaviour of reinforced concrete framed buildings

Mazza

2015

Earthq Sci

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The design provisions of current seismic codes are generally not very accurate for assessing effects of near-fault ground motions on reinforced concrete (r.c.) spatial frames, because only far-fault ground motions are considered in the seismic codes. Strong near-fault earthquakes are characterized by long-duration (horizontal) pulses and high values of the ratio a PGA of the peak value of the vertical acceleration, PGA V , to the analogous value of the horizontal acceleration, PGA H , which can become critical for girders and columns. In this work, six-and twelve-storey r.c. spatial frames are designed according to the provisions of the Italian seismic code, considering the horizontal seismic loads acting (besides the gravity loads) alone or in combination with the vertical ones. The nonlinear seismic analysis of the test structures is performed using a step-by-step procedure based on a two-parameter implicit integration scheme and an initial stress-like iterative procedure. A lumped plasticity model based on the Haar-Kàrmàn principle is adopted to model the inelastic behaviour of the frame members. For the numerical investigation, five near-fault ground motions with high values of the acceleration ratio a PGA are considered. Moreover, following recent seismological studies, which allow the extraction of the largest (horizontal) pulse from a near-fault ground motion, five pulse-type (horizontal) ground motions are selected by comparing the original ground motion with the residual motion after the pulse has been extracted. The results of the nonlinear dynamic analysis carried out on the test structures highlighted that horizontal and vertical components of near-fault ground motions may require additional consideration in the seismic codes.

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Nonlinear Response of RC Framed Buildings with Isolation and Supplemental Damping at the Base Subjected to Near-Fault Earthquakes

Cited by 81 publications

References 18 publications

Seismic Response and Performance Evaluation of Self-Centering LRB Isolators Installed on the CBF Building under NF Ground Motions

Seismic Response and Performance Evaluation of Self-Centering LRB Isolators Installed on the CBF Building under NF Ground Motions

Self-Tuning Fuzzy Control for Seismic Protection of Smart Base-Isolated Buildings Subjected to Pulse-Type Near-Fault Earthquakes

Effects of near-fault ground motions on the nonlinear behaviour of reinforced concrete framed buildings

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