Displacement Spectra for Long Periods

2004 ◽  
Vol 20 (2) ◽  
pp. 347-376 ◽  
Author(s):  
Ezio Faccioli ◽  
Roberto Paolucci ◽  
Julien Rey

Using selected sets of high-quality digital strong motion data from different regions (Taiwan, Japan, Italy, and Greece), the salient features of displacement response spectra in the long-period range are illustrated (up to 10 s period) as a function of magnitude, source distance, and site conditions. By means of simple analytical models of displacement waveforms, we have derived analytical expressions for the displacement spectra that provide satisfactory fits to the observations. These expressions also demonstrate that the moment magnitude and distance control the shape of the spectra consistent with the commonly accepted models of the seismic source. Furthermore, we derived from simple physical considerations an analytical expression of the variation of peak ground displacement with magnitude and distance that reasonably fits the observations. The findings of this study are believed to be particularly useful in the formulation of design elastic displacement spectra for seismic codes, and in zoning studies of seismic hazard for long-period structures.

Author(s):  
Reagan Chandramohan ◽  
Quincy Ma ◽  
Liam M. Wotherspoon ◽  
Brendon A. Bradley ◽  
Mostafa Nayyerloo ◽  
...  

Six buildings in the Wellington region and the upper South Island, instrumented as part of the GeoNet Building Instrumentation Programme, recorded strong motion data during the 2016 Kaikoura earthquake. The response of two of these buildings: the Bank of New Zealand (BNZ) Harbour Quays, and Ministry of Business, Innovation, and Employment (MBIE) buildings, are examined in detail. Their acceleration and displacement response was reconstructed from the recorded data, and their vibrational characteristics were examined by computing their frequency response functions. The location of the BNZ building in the CentrePort region on the Wellington waterfront, which experienced significant ground motion amplification in the 1–2 s period range due to site effects, resulted in the imposition of especially large demands on the building. The computed response of the two buildings are compared to the intensity of ground motions they experienced and the structural and nonstructural damage they suffered, in an effort to motivate the use of structural response data in the validation of performance objectives of building codes, structural modelling techniques, and fragility functions. Finally, the nature of challenges typically encountered in the interpretation of structural response data are highlighted.


1964 ◽  
Vol 54 (5A) ◽  
pp. 1257-1269
Author(s):  
John H. Wiggins

Abstract Empirical equations are derived which relate maximum acceleration, velocity, and displacement computed from strong motion earthquake records to magnitude and distance from source to site. Over fifty earthquakes recorded at three California sites were used in the study. The equations show that earthquake magnitude governs not only the character of response spectra but also the characteristic period content of the earthquake. As an added feature, the reported Modified Mercalli intensities are shown to correlate best with computed response spectra which include only the low period range.


2020 ◽  
Author(s):  
Maria D'Amico ◽  
Erika Schiappapietra ◽  
Giovanni Lanzano ◽  
Sara Sgobba ◽  
Francesca Pacor

<p>We present a processing scheme (eBASCO, extended BASeline COrrection) to remove the baseline of strong-motion records by means of a piece-wise linear de-trending of the velocity time history. Differently from standard processing schemes, eBASCO does not apply any filtering to remove the low-frequency content of the signal. This approach preserves both the long-period near-source ground-motion, featured by one-side pulse in the velocity trace, and the offset at the end of the displacement trace (fling-step). Hence, the software is suitable for the identification of fling-containing strong-motion waveforms. Here, we apply eBASCO to reconstruct the ground displacement of more than 400 three-component near-source waveforms recorded worldwide (NESS1, http://ness.mi.ingv.it/; Pacor et al., 2019) with the aim of: 1) extensively testing the eBasco capability to capture the long-period content of near-source records; 2) calibrating attenuation models for peak ground displacement (PGD), 5% damped displacement response spectra (DS), permanent displacement amplitude (PD) and period (Tp). The results could provide a more accurate estimate of ground motions, to be adopted for different engineering purposes such as performance-based seismic design of structures.</p><p>Pacor F., Felicetta C., Lanzano G., Sgobba S., Puglia R., D’Amico M., Russo E., Baltzopoulos G., Iervolino I. (2018). NESS v1.0: A worldwide collection of strong-motion data to investigate near source effects. Seismological Research Letters. https://doi.org/10.1785/0220180149</p>


1993 ◽  
Vol 9 (4) ◽  
pp. 739-754 ◽  
Author(s):  
Sudhir K. Jain ◽  
Satrajit Das

Strong motion records have been obtained at 13 stations during the Uttarkashi earthquake of October 20, 1991 (magnitude 6.6). A study has been conducted on these time histories to assess the codal provisions in India. Emphasis of the study is on evaluating relative consistency of design provisions for different seismic zones in India. The average response spectra from this earthquake show concentration of significantly more energy in low period range and less energy in high period range. The magnitude of seismic design force for zones I, II, and III is consistent while it is too low for zone IV; no records were obtained in area with shaking intensity corresponding to zone V. It is seen that for buildings in zones I, II, and III, the present design provisions may be lowered either by relaxing the requirement of special ductile detailing, or by reducing the design force. On the other hand, design provisions for zone IV need to be revised upwards.


1995 ◽  
Vol 22 (1) ◽  
pp. 190-196
Author(s):  
René Tinawi ◽  
André Filiatrault ◽  
Pierre Léger

An earthquake of magnitude ML = 4.3 occurred near Napierville, Quebec, on November 16, 1993. An accelerograph at the liquefaction, storage, and regasification plant of Gaz Metropolitain in Montreal, about 55 km from the epicentre, recorded the ground motion. Although the maximum accelerations and velocities from this event are small, the acceleration time histories do confirm the high energy content in the very short period range. The recorded ground motion and corresponding absolute acceleration response spectra are presented and various attenuation relationships, proposed for eastern North America, are utilized to compare the measured and predicted ground motion parameters. Key words: Napierville earthquake, attenuation relationships, acceleration spectra, strong motion records.


2012 ◽  
Vol 204-208 ◽  
pp. 2405-2409
Author(s):  
Heng Li ◽  
Chao Lian ◽  
Yu Yang Kong

The characteristics of near-fault ground motion displacements, with the obvious directivity, were analyzed. Along moving direction of the fault, displacements take on the feature of fling-step, and the large pulse is the main characteristic of displacements in the vertical moving direction of the fault. The models of near-fault ground motion with different detailed scales can be obtained by median filtering with different window length on the velocity series. Displacement spectra of the models were compared with observations from tremendous earthquakes. The results show that the highly simplified model can predict the response spectrum in very long periods, but there are distinct errors in the period range in which engineering is interested (Tp 5 sec). The refined model is necessary for very large magnitude earthquakes which include multiple rupture, and should be established according to characteristics of velocity.


2019 ◽  
Vol 35 (4) ◽  
pp. 1663-1688 ◽  
Author(s):  
Esengul Cavdar ◽  
Gokhan Ozdemir ◽  
Beyhan Bayhan

In this study, an ensemble of ground motions is selected and scaled in order to perform code-compliant bidirectional Nonlinear Response History Analysis for the design purpose of both short- and long-period structures. The followed scaling method provides both the requirements of the Turkish Earthquake Code regarding the scaling of ground motions and compatibility of response spectra of selected ground motion pairs with the target spectrum. The effects of four parameters, involved in the followed scaling method, on both the amplitude of scale factors and seismic response of structures are investigated. These parameters are the number of ground motion records, period range, number of periods used in the related period range, and distribution of weight factors at the selected periods. In the analyses, ground motion excitations were applied to both fixed-base and seismically isolated structure models representative of short- and long-period structures, respectively. Results revealed that both the amplitudes of scale factors and seismic response of short-period structures are more prone to variation of investigated parameters compared to those of long-period structures.


Author(s):  
Jim Cousins ◽  
Graeme H. McVerry

The Darfield earthquake of 3rd September 2010 UT and its aftershocks have yielded New Zealand’s richest set of strong-motion data since recording began in the early 1960s. Main-shock accelerograms were returned by 130 sites, ten of which had peak horizontal accelerations in the range 0.3 to 0.82g. One near-fault record, from Greendale, had a peak vertical acceleration of 1.26g. Eighteen records showed peak ground velocities exceeding 0.5 m/s, with three of them exceeding 1 m/s. The records included some with strong long-period directivity pulses, some with other long-period components that were related to a mixture of source and site effects, and some that exhibited the effects of liquefaction at their sites. There were marked differences between records on the deep alluvium of Christchurch City and the Canterbury Plains, and those on shallow stiff soil sites. The strong-motion records provide the opportunity to assess the effects of the earthquake in terms of the ground motions and their relationship to design motions. They also provide an invaluable set of near-source motions for seismological studies. Our report presents an overview of the records and some preliminary findings derived from them.


2009 ◽  
Vol 25 (3) ◽  
pp. 515-539 ◽  
Author(s):  
Ezio Faccioli ◽  
Manuela Villani

A new representation of seismic hazard is proposed for Italy based on displacement elastic response spectra in a vibration period range that extends from [Formula: see text]. This relies on an available seismotectonic zonation and earthquake catalogue, but makes use of a set of very recent, expressly developed attenuation relations. The long period picture of ground motion hazard is illustrated vis-à-vis the conventional one based on ground acceleration, and the feasibility of simple approximations of the displacement spectra, useful for design purposes, is shown. We give some foresight on the differences to be expected in hazard maps resulting from the use of a predominantly fault-based seismic source model, as opposed to the more conventional model that includes only spatially extended zones. Finally, we highlight the different hazard exposure of different regions depending on whether we represent hazard with a long or a short period parameter and we discuss the adequacy of recent code provisions regarding elastic displacement spectra.


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