Drift Spectrum: Measure of Demand for Earthquake Ground Motions

Iwan, W. D.

doi:10.1061/(asce)0733-9445(1997)123:4(397)

Cited by 168 publications

(87 citation statements)

References 1 publication

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“…Ivan [12] used the same elastic shear structure for obtaining "relative displacement spectrum" as measurement criteria for seismic need of multi-degrees of freedom structures exposed to near -field earthquakes pulse-like. They should that even for elastic structures, near -field effects cannot be calculated by multiplying the regulation basic shear coefficient by a coefficient as near -field effect factor.…”

Section: The Effect Of Near-field Earthquake On the One Degree Of Frementioning

confidence: 99%

Evaluating Main Parameters Effects of Near-Field Earthquakes on the Behavior of Concrete Structures with Moment Frame System

Jouneghani¹,

Hosseini²,

Rohanimanesh³

et al. 2017

Adv. Sci. Technol. Res. J.

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Amplitude and frequency content are two important features of earthquakes that are different for near and far-fault earthquakes and in most of the standards, the effects of near-field earthquakes in loading are not considered. Therefore, study and comparison of these effects on structures is necessary. In this paper, structural operation against near and far fault earthquakes for two near sites and two far sites is investigated. For this purpose and in order to achieve an operation point of a structural model with six staircases with a mean lateral bending frame resistant system seismic hazard information is analyzed with regards to special plan spectrums of 2 different sites using near and far faults. An evaluation of the effects due to near and far fault earthquakes based on the Iran's standard 2800 ranges on operation point and the comparison of operation effects of near and far fault spectrums with Iran's standard are results of this research work. After the presentation of results obtained from time history analyses, some suggestions are proposed for design correction based on the regulations in near -field earthquakes.

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Section: The Effect Of Near-field Earthquake On the One Degree Of Frementioning

confidence: 99%

Evaluating Main Parameters Effects of Near-Field Earthquakes on the Behavior of Concrete Structures with Moment Frame System

Jouneghani¹,

Hosseini²,

Rohanimanesh³

et al. 2017

Adv. Sci. Technol. Res. J.

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“…Kanai (1965) suggested that multiple reflections of waves in an elastic layer could be used to study seismic vibration of a structure, as well as to design a seismic resistant structure. Equation (1) shows the wave propagation solution of a continuous fixed-base shear beam model (e.g., Iwan, 1997;Sasani et al, 2006):…”

Section: Building Response During Earthquakesmentioning

confidence: 99%

“…The prediction solely based on modal decomposition using the first few modes does not adequately capture the initial upward traveling impulse from the ground, and it underestimates the peak floor response at the penthouse by a factor of more than 2 at t ≅ 1:5 s. However, this harmonic modal estimation matches the seismic records for subsequent times after the initial impulse has reached the top of the building. Iwan (1997) mentioned that pulses travel through the buildings as waves, and the conventional techniques using modal superposition method and response spectrum analysis may not capture the effect of these pulses. They indicated that maximum floor response might occur during the coherent impulsive ground motions before the resonant mode response dominates.…”

Section: Seismic Records From a 54-story Buildingmentioning

confidence: 99%

“…This can lead to an underestimation of floor displacement, especially if maximum floor response occurs during the coherent, impulsive ground motion before the resonant mode response dominates (Iwan, 1997). To address this issue, we decompose building motion due to earthquake excitation into the broadband traveling wave component and the low-frequency resonant mode component.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Prediction of Wave Propagation in Buildings Using Data from a Single Seismometer

Cheng¹,

Kohler²,

Heaton³

2014

Bulletin of the Seismological Society of America

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Crowd-sourced seismic networks in buildings collect important scientific data, in addition to allowing a diverse audience to visualize the vibrations of buildings. Visualization of a building's deformation requires spatiotemporal interpolation of motions from seismometers that are located wherever the crowd places them. In many cases, a crowd-sourced building network may actually be just a single seismometer. A method to rapidly estimate the total displacement response of a building based on limited observational data, in some cases from only a single seismometer, is presented. In general, the earliest part of the response is simulated by assuming a vertically propagating shear wave. Later motions are simulated using mode shapes derived from a beam model (a shear beam, or more generally a Timoshenko beam), the parameters of which are determined from the ratios of the modal frequencies and the building's exterior dimensions. The method is verified by (1) comparing predicted and actual records from a 54-story building in downtown Los Angeles, California, and (2) comparing finite-element simulations of the 17-story University of California, Los Angeles (UCLA) Factor building. The response of each of these buildings can be simulated with a simple shear beam. The importance of including the traveling wave part of the solution depends on the characteristics of the base ground shaking; the traveling wave becomes more apparent as the excitation becomes more impulsive. The method can be straightforwardly applied to multiple instrumented buildings, resulting in a tool to visualize linear elastic motions of those buildings.

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“…Then by imposing specific values of EDPs it is possible to move ranging from code requirements to superior performances such as fully operational level guaranteed under very rare earthquake. Inter-storey drifts proved to be a reliable parameter to quantify damages in framed structures [4].…”

Section: Introductionmentioning

confidence: 99%

Strong-Back System Coupled with Framed Structure to Control the Building Seismic Response

Laghi¹,

Palermo²,

Gasparini³

et al. 2017

J Civil Environ Eng

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In the present paper, the coupled behavior of structural systems obtained by connecting a moment resisting frame structure with a vertical elastic truss, known in the literature as strong-back, which acts as a mast by imposing to the structure a given lateral deformed shape, is investigated. The rigid behavior of the strong-back, which is designed in order to remain in the elastic field under strong seismic ground motion, imposes a uniform inter storey drift along the frame height, thus avoiding undesired effects such as soft storey and weak storey mechanisms.Consequently, the whole structural system may be, at first approximation, modelled as an equivalent Single Degree of Freedom system thus allowing for an analytical description of its response. In particular, in the work the attention is paid to the mutual actions exchanged by the strong-back and the frame by solving the static equilibrium equations, assuming a shear type behavior for the frame. Finally, some numerical simulations of frame systems with strong-back systems as subjected to earthquake ground motions are developed, encompassing both shear type frames and frames with flexible beams.

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Drift Spectrum: Measure of Demand for Earthquake Ground Motions

Cited by 168 publications

References 1 publication

Evaluating Main Parameters Effects of Near-Field Earthquakes on the Behavior of Concrete Structures with Moment Frame System

Evaluating Main Parameters Effects of Near-Field Earthquakes on the Behavior of Concrete Structures with Moment Frame System

Prediction of Wave Propagation in Buildings Using Data from a Single Seismometer

Strong-Back System Coupled with Framed Structure to Control the Building Seismic Response

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