Journal articles: 'Accelerogrammi'

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Mkrtychev, Oleg Vartanovich, and Andrey Aleksandrovich Reshetov. "REPRESENTATIVE SET OF EARTHQUAKE ACCELEROGRAMMS FOR STRUCTURAL ENGINEERING OF BUILDINGS AND STRUCTURES DURING EARTHQUAKE EFFECTS." Vestnik MGSU, no. 7 (July 2017): 754–60. http://dx.doi.org/10.22227/1997-0935.2017.7.754-760.

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In the process of structural engineering of buildings and structures with the use of direct dynamic methods the accelerogramms of earthquakes with the parameters corresponding to a specific construction site are required. Such accelerogramms could be obtained by various methods. For example, they could be produced by seismologists. However, for a structural engineer it could be required to get them processed (balancing, segregation of separate phase of impact, etc.), that is not always convenient to do. Moreover, an accelerogramm with slightly different spectral composition and lifespan, nevertheless applicable to a given construction site, could be required. Also an accelerogramm could be generated with the use of specially designed software. Although it’s not always convenient as it requires certain amount of time and could cause some difficulties during formation of original data for generation and also for obtaining correct results. In order to overcome the above-mentioned difficulties the authors proposed the representative set of synthesized earthquake accelerogramms which could be applied for various combinations of seismic properties of construction sites. The present article sets outs the principal approaches to formation of the set of earthquake accelerogramms, designated for design of buildings and structures in terms of earthquake effects. Purpose requirements to discrete accelerogramms and to the set as a whole have been disclosed, purpose characteristics of accelerogramms have been set out, clarifications and recommendations for application of the representative set of accelerogramms in practical calculations have been enclosed.

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Naumoski, Nove, Murat Saatcioglu, Lan Lin, and Kambiz Amiri-Hormozaki. "Evaluation of the effects of spectrum-compatible seismic excitations on the response of medium-height reinforced concrete frame buildings." Canadian Journal of Civil Engineering 33, no. 10 (October 1, 2006): 1304–19. http://dx.doi.org/10.1139/l06-085.

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Spectrum-compatible seismic excitations are required when dynamic time-history analysis is used for determining the response of a structure. This paper presents results from a study on the effects of different types of spectrum-compatible excitations on the response of medium-height reinforced concrete frame buildings. Two six-storey buildings designed for Vancouver and a five-storey building designed for Montréal were used in the study. Nonlinear time-history analyses were conducted by subjecting the buildings to selected ensembles of spectrum-compatible excitations (i.e., accelerograms). The ensembles used in the study included spectrum-compatible artificial accelerograms, simulated stochastic accelerograms, and recorded earthquake accelerograms (i.e., real accelerograms) scaled to the design spectrum ordinate at the fundamental building period and to the area under the design spectrum within the predominant period range of the building. The responses of the buildings resulting from spectrum-compatible artificial accelerograms and those from scaled real accelerograms were found to be quite similar. Based on the results of this study, the scaling of real accelerograms to spectral area is preferred for obtaining spectrum-compatible accelerograms.Key words: seismic, excitation, response, spectrum, accelerogram, building, drift, curvature, ductility.

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SIRCA, GENE F., and HOJJAT ADELI. "A NEURAL NETWORK-WAVELET MODEL FOR GENERATING ARTIFICIAL ACCELEROGRAMS." International Journal of Wavelets, Multiresolution and Information Processing 02, no. 03 (September 2004): 217–35. http://dx.doi.org/10.1142/s0219691304000524.

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In earthquake-resistant design of structures, for certain structural configurations and conditions, it is necessary to use accelerograms for dynamic analysis. Accelerograms are also needed to simulate the effects of earthquakes on a building structure in the laboratory. A new method of generating artificial earthquake accelerograms is presented through adroit integration of neural networks and wavelets. A counterpropagation (CPN) neural network model is developed for generating artificial accelerograms from any given design spectrum such as the International Building Code (IBC) design spectrum. Using the IBC design spectrum as network input means an accelerogram may be generated for any geographic location regardless of whether earthquake records exist for that particular location or not. In order to improve the efficiency of the model, the CPN network is modified with the addition of the wavelet transform as a data compression tool to create a new CPN-wavelet network. The proposed CPN-wavelet model is trained using 20 sets of accelerograms and tested with additional five sets of accelerograms available from the U.S. Geological Survey. Given the limited set of training data, the result is quite remarkable.

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Grigoriu, M., S. E. Ruiz, and E. Rosenblueth. "The Mexico Earthquake of September 19, 1985—Nonstationary Models of Seismic Ground Acceleration." Earthquake Spectra 4, no. 3 (August 1988): 551–68. http://dx.doi.org/10.1193/1.1585490.

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Characteristics of a nonstationary process obtained by modulating the amplitude and frequency of a stationary process differ from those of an oscillatory process. An accelerogram recorded in the soft soil of Mexico City during the 1985 earthquake serves to calibrate both nonstationary models. Responses of linear and nonlinear single-degree-of-freedom systems indicate that the process with modulated amplitude and frequency is preferable for reliability studies. Coefficients of variation of ductility demands of systems excited with accelerograms generated by the model with modulated amplitude and frequency are close to those corresponding to actual accelerograms.

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Inbal, Asaf, and Alon Ziv. "Automatic Extraction of Permanent Ground Offset from Near-Field Accelerograms: Algorithm, Validation, and Application to the 2004 Parkfield Earthquake." Bulletin of the Seismological Society of America 110, no. 6 (July 14, 2020): 2638–46. http://dx.doi.org/10.1785/0120200040.

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ABSTRACT Permanent ground offsets, constituting a prime dataset for constraining final fault-slip distributions, may not be recovered straightforwardly by double integration of near-field accelerograms due to tilt and other distorting effects. Clearly, if a way could be found to recover permanent ground offsets from acceleration records, then static datasets would be enlarged, and thus the resolution of fault-slip inversions would be enhanced. Here, we introduce a new approach for extracting permanent offsets from near-field strong-motion accelerograms. The main advantage of the new approach with respect to previous ones is that it corrects for source time functions of any level of complexity. Its main novelty is the addition of a constraint on the slope of the ground velocity spectra at long periods. We validated the new scheme using collocated accelerograms and Global Navigation Satellite Systems (GNSS) records of the 2011 Mw 9 Tohoku-Oki earthquake. We find a good agreement between accelerogram-based and GNSS-based ground offsets over a range of 0.1–5 m. To improve the spatial coverage of permanent ground offsets associated with the 2004 Parkfield earthquake, near-field accelerograms were baseline corrected using the new scheme. Static slip inversion of the combined GNSS-based and accelerogram-based ground displacements indicates appreciable seismic moment release south of the epicenter, about 5 km into the Cholame section of the San Andreas fault. We conclude that the strong shaking observed to the south of the epicenter is directly related to the slip in that area and is not the result of local amplification.

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Nguyen, Vo Thong, and Manh Hoang. "Establishment of Artificial Accelerogram for Structural Analysis according to the Earthquake Characteristics of Vietnam." Applied Mechanics and Materials 897 (April 2020): 211–20. http://dx.doi.org/10.4028/www.scientific.net/amm.897.211.

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This paper presents the method of establishing artificial accelerogram for analysis and calculation of structures in accordance with seismic characteristics and earthquake risk in one specific construction areas in Vietnam. The artificial accelerogram allow to analyze nonlinear or linear dynamic behavior of the structures in time series in accordance with Vietnam National Standards for Design of structures for earthquake resistances (TCVN 9386: 2012) and seismic parameters specified in Vietnam Building Code on Natural Physical and Climatic Data for Construction (QCVN 02:2009-BXD). The accelerograms are also used as input parameters for shaking table tests by Vietnam's most modern sharking table at the Vietnam Institute for Building Science and Technology.

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Anderson, John G., and James N. Brune. "The Victoria Accelerogram for the 1980 Mexicali Valley Earthquake." Earthquake Spectra 7, no. 1 (February 1991): 29–43. http://dx.doi.org/10.1193/1.1585611.

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Most of the remarkable digital strong motion accelerogram from the June 9, 1980 Mexicali Valley earthquake (Mw = 6.4) has been recovered by careful analysis. Peak horizontal accelerations (.98g, .87g) and duration were similar to the values for the recent Superstition Hills earthquake. The vertical accelerogram clipped the 1g instrument several times. The records provide an important example of near fault accelerations from a second earthquake in the deep sediments of the Imperial Mexicali Valley (the other being the records from the 1979 Imperial Valley earthquake). The 1980 accelerograms are important because they were not affected by foundation filtering, as were the records for the Imperial Valley 1940 earthquake, and because they illustrate the damaging near-source, intermediate frequency velocity pulse associated with passage of the rupture front.

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Zacchei, Enrico, and José Luis Molina. "Damage estimation on concrete gravity dams through artificial accelerograms." MATEC Web of Conferences 211 (2018): 14001. http://dx.doi.org/10.1051/matecconf/201821114001.

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The aim of this paper is to analyse the damage on gravity dams through artificial earthquakes from two methods. The first procedure defines the performance and the response curve of concrete gravity dams using a harmonic function which establishes linear displacements. The other procedure to obtain the artificial earthquake defines the power spectral density function consistent with the response spectrum. This artificial accelerogram is necessary to quantify the response curve of concrete gravity dams in the time domain. The seismic activity in Spain is not frequent, therefore it is often difficult to select real accelerograms to perform a complete seismic analysis, which makes artificial accelerograms extremely useful. Finally, combining these two procedures, a damage index is determined for assessing the crack’s magnitude. These both efficient and practical procedures are useful to develop further complicated analysis.

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Benin, Andrei, Olga Nesterova, Alexander Uzdin, Sergei Prokopovich, Yuri Rutman, and Youhai Guan. "On estimating the reduction factor of bridge piers." E3S Web of Conferences 157 (2020): 06012. http://dx.doi.org/10.1051/e3sconf/202015706012.

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Estimating the reduction factor for calculating massive reinforced concrete bridge piers was made. For this purpose a quasi-static “force-displacement” diagram was built up using the ANSYS software. This diagram has the form of a bilinear one, and the character of the bilinearity depends on the diameter of the reinforcing bars insignificantly. The percentage of reinforcement affects only the moment when all reinforcement bars begin to flow. The reinforcement flow takes place in the displacement interval from 3 to 5 cm. The collapse will occur when the reaction of the bearing part goes beyond the pier cross-section at pier displacements from 5 to 20 cm. Using “force-displacement” diagram, the behavior of the single-mass model with a bilinear deformation diagram and the limit displacement of 20 cm was analyzed. Then, it became possible to obtain for each accelerogram the limit elastic displacement and the limit position of the point corresponding to the maximum structure displacement during structure oscillations. It was done using real accelerograms of earthquakes with intensity 9 on the MSK scale without normalizing their amplitudes. In this case, long-period accelerograms had smaller peak accelerations, but resulted in greater plastic deformations. As a result, no evident dependence of plastic deformation on the input spectral composition was found and the value of reduction factor K1 turned out to be 0.25-0.27. However, it is shown that this reduction factor cannot be used to make transition from seismic loads obtained on the basis of time-history analysis by accelerograms to design loads.

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Lopes, Carla MV, Luís Silva, Pedro Sequeira, and Francisco Q. de Melo. "Assessing the thermal degradation of bonded joints in flat ceramic tiles of building facades by numerical and experimental dynamic analysis." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, no. 8 (June 2, 2020): 1129–41. http://dx.doi.org/10.1177/1464420720928569.

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Flat ceramic tiles are widely used as protective and aesthetic construction elements in urban building facades. Under the effect of extreme temperatures from the weather seasonality, bonded joints of these tiles undergo thermal cycle’s loads. In this work, a dynamic technique based on vibration metrology is implemented. This procedure consists in the analysis of accelerograms obtained in bonded ceramic tiles from low-intensity impact loads. A corresponding study carried out with finite element modelling allowed an accurate calibration of mechanical parameters of the tile/adhesive pair as well as the estimation of a vibration dissipation factor. Several test specimens subjected to a defined period of thermal cycles stressing were also analysed for the mentioned accelerogram and an expression for the ageing estimation of the mechanical properties of the bonded joints in the tiles was obtained.

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Soriano Camelo, Cristian, Samuel Felipe Mollepaza Tarazona, Maria Cascão Ferreira de Almeida, Márcio de Souza Soares de Almeida, and Ricardo Garske Borges. "Selection of earthquake ground motion accelerograms for the continental margin of Southeastern Brazil." DYNA 88, no. 217 (May 22, 2021): 228–36. http://dx.doi.org/10.15446/dyna.v88n217.93068.

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Brazil is in an intraplate area of low to moderate seismicity, this means that few or no records of strong ground motions are available. Part of the site response analysis and seismic design of structures require the use of acceleration time-histories compatible with a specified target response spectrum. This study aims to utilize methodologies based on the use of existing earthquake records from a well-known database and synthetic accelerograms to obtain ground motions representative of the Brazilian Southeast Region, particularly in the offshore Campos Basin. Information from a probabilistic seismic hazard assessment performed in the interest area was employed as input to the methodologies applied in terms of target response spectrum and the dominant earthquake scenarios. Besides, the acceleration time-histories of two relatively recent earthquakes that occurred in the Brazilian Southeast were used to apply one of the approaches to obtain a synthetic spectrum compatible accelerogram.

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Buzov, Ante, Jure Radnić, Nikola Grgić, and Goran Baloević. "Effect of the Drum Height on the Seismic Behaviour of a Free-Standing Multidrum Column." Advances in Materials Science and Engineering 2018 (June 19, 2018): 1–12. http://dx.doi.org/10.1155/2018/5729068.

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The results of a shake-table study on the effect of the drum height on the seismic behaviour and bearing capacity of small-scale free-standing multidrum columns are presented. Columns of equal height with one, three, and six drums through their height were considered for the case of their self-weight only and for the case with an additional weight on the top of the column. The columns were exposed to a horizontal base acceleration of three accelerograms by successively increasing the maximum acceleration to their failure. The characteristic displacements and accelerations of the column were measured. It was concluded that an increase in the number of blocks in the column can significantly increase or decrease its ultimate bearing capacity, depending on the type of the applied accelerogram. It is expected that the experimental database can be useful in the validation of nonlinear numerical models for the dynamic analysis of multidrum columns.

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Lee, Vincent W., and Mihailo D. Trifunac. "Torsional accelerograms." International Journal of Soil Dynamics and Earthquake Engineering 4, no. 3 (July 1985): 132–39. http://dx.doi.org/10.1016/0261-7277(85)90007-5.

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Azim, Raheleh, and Gholamreza Ghodrati Amiri. "The Effects of Near and Far Fault Accelerograms Modification on Seismic Behaviour of Concentrated Braced Steel Frames." Journal of Research in Science, Engineering and Technology 4, no. 01 (September 13, 2019): 16–25. http://dx.doi.org/10.24200/jrset.vol4iss01pp16-25.

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Steel braces hasve a growing application in building structural and industrial constructions. In the recent years there has been a lot of research done about performance and behavior of these types of structures in elastic and plastic states whos outcomes have been effective on improvement of design criteria and implementation quality of structures. On the other hand since near fault seisms have different properties from those of far fault seisms and issues related to effects of near and far fault have been recently separated in different regulations, seismic behavior of steel constructions designed on the basis of lateral load resisting concentrated bracing system and regulation of designing resisting constructions to seism (Standard No. 800-3rd edition) has been studied in this research. Frames studied are of 5, 10 and 15-floor structues from which one frame has been selected to be studied and time history non-linear dynamic analysis method and effects of two types of near and far fault accelerogram have been used. Values of displacement and floors reverse anchor and base shear in both modified (with scale) and unmodified (without scale) states of near and far fault accelerograms were calculated and the results were compared.

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Niazi, Mansour. "Accelerograms of the 1978 Tabas, Iran, Earthquake." Earthquake Spectra 2, no. 3 (May 1986): 635–51. http://dx.doi.org/10.1193/1.1585401.

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Three triaxial sets of accelerograms recorded in the near source region (within 50 km epicentral distance) of the September 16, 1978, Tabas earthquake (Ms 7.4 -7.7) are of great engineering importance. The distances of the recording sites from the nearest approach of the rupture surface are approximately 3, 17, and 28 km for Tabas, Dayhook and Boshrooyeh stations, respectively. The measured horizontal peak ground accelerations of 0.94 and 0.88 g at Tabas are higher than previously estimated. The peak vertical ground acceleration recorded at this station is 0.74 g. The normalized response spectra at these three stations are consistent with the Newmark-Hall elastic design spectra, suggesting that the latter adequately represent the spectral amplification factors at frequencies above 1 Hz. The main shock accelerogram at Dayhook exhibits at least three distinct events as indication of a complex source behavior. The widened spacing of these events on the Dayhook records further confirms that the rupture front moved northwestward away from this station and towards Tabas. The measured S minus trigger times at Tabas, Dayhook and Boshrooyeh stations are in conflict with the teleseismically determined epicenter, requiring it to move approximately 30 km to the southwest to about 33° 17′N, 57° 09′ E.

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Lin, Lan, Nove Naumoski, Murat Saatcioglu, Simon Foo, Edmund Booth, and Yuling Gao. "Selection of seismic excitations for nonlinear analysis of reinforced concrete frame buildings." Canadian Journal of Civil Engineering 40, no. 5 (May 2013): 411–26. http://dx.doi.org/10.1139/l2012-103.

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The selection of seismic motions is one of the most important issues for the time-history analysis of buildings. This paper discusses four different methods for obtaining spectrum-compatible acceleration time histories (i.e., accelerograms) of seismic motions. Based on these methods, four sets of accelerograms compatible with the design spectrum for Vancouver were selected for this study. These included (i) scaled real accelerograms, (ii) modified real accelerograms, (iii) simulated accelerograms, and (iv) artificial accelerograms. The selected sets were used as excitation motions in the nonlinear analysis of three reinforced concrete frame buildings designed for Vancouver. The buildings included a 4-storey, a 10-storey, and a 16-storey building, which can be considered representative of low-rise, medium-rise, and high-rise buildings, respectively. The storey shears, interstorey drifts, and curvature ductilities for beams and columns obtained from the analysis were used for the evaluation of the effects of the selected sets on the responses of the buildings. Based on the results from the analysis, scaled real accelerograms are recommended for use in time-history analysis of reinforced concrete frame buildings.

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Preumont, A. "An Automatic Procedure for the Generation of Accelerograms Enveloping Several Design Response Spectra." Journal of Pressure Vessel Technology 107, no. 1 (February 1, 1985): 88–90. http://dx.doi.org/10.1115/1.3264412.

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During various steps in the design of a nuclear power plant, it is a common practice to generate accelerograms matching a design spectrum for one particular value of the damping ratio. Such accelerograms, however, may be found unconservative for other values of the damping ratio. The present note describes a simple iterative procedure for generating accelerograms which envelop several design response spectra.

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Pineda, Paloma, Andrés Sáez, and Antonio Jesus Martín. "Seismic Hazard and Nonlinear Dynamic Analyses: Avoiding Collapse in Architectural Heritage." Advanced Materials Research 133-134 (October 2010): 591–96. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.591.

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Architectural heritage masonry buildings located in seismic areas are highly prone to suffer damage under seismic loading, due to their structural features. In this study, the Salares medieval tower, which is placed in the province of Malaga (Spain) - a zone with high seismic hazard in the Iberian Peninsula- is adopted as a case study. This is a precious heritage building which exhibits severe damages, such as depth cracks and inclination. Owing to those reasons detailed seismic and dynamic analyses are crucial for its preservation. The present work is arranged in three sections that deal with seismic hazard analysis, selection of real acceleration time-histories representative of the site, and dynamic response by means of numerical models. In order to obtain the design earthquake at the specific location, different parameters were analyzed, namely the region seismic activity, the geotechnical and geological conditions at the site and the acceptable risk level. Hazard analysis was performed following deterministic and probabilistic methods. As far as the seismic input is concerned, real accelerogram representative of the 1884 Andalusia earthquake were selected. It was a destructive earthquake that caused catastrophic damages near the analyzed structure. The accelerograms thus obtained were used as input for subsequent non-linear dynamic analyses on three-dimensional finite element models. Different cracking capable constitutive models were considered in order to predict local and global collapse mechanisms. Moreover, the suitability of each model was discussed when crushing, high plastic deformation or response under cyclic loading are concerned. The aforementioned studies yield significant results in order to perform a comprehensive safety assessment under ground motion effects. Thus, regarding the seismic input, the obtained accelerogram provides a relevant application aimed at revising the maximum acceleration and the response spectra of the Codes, as seismic code recommendations are limited in those issues. Furthermore, the dynamic structural response via numerical approach, allows determining damage propagation and collapse probability as a main step to select appropriate repair measures. The followed method could be used to assess and improve the structural strength of similar architectural heritage buildings located in active seismic areas.

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Yi, Jiang, Nelson Lam, Hing-Ho Tsang, and Francis TK Au. "Selection of earthquake ground motion accelerograms for structural design in Hong Kong." Advances in Structural Engineering 23, no. 10 (February 16, 2020): 2044–56. http://dx.doi.org/10.1177/1369433220906926.

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Hong Kong is situated in an intraplate area of low to moderate seismicity, where recorded strong-motion accelerograms are scarce. As part of the seismic design process, dynamic time-history analysis is sometimes required for assessing the seismic performance of structures. Hence, earthquake accelerograms representative of various local design hazard levels are needed. This study aims to develop a methodology for building up a database of earthquake accelerograms for the Hong Kong region which can be used for the analysis and design of a variety of structural and geotechnical systems. An outline of the previous probabilistic seismic hazard analysis studies conducted for Hong Kong is first presented and several design earthquake scenarios are determined, which contribute most to the local seismic hazard given a specific return period. The median response spectra and conditional mean spectra of the selected earthquake scenarios for reference rock sites are then derived based on the component attenuation model. The conditional mean spectra are then used as the target spectra for the selection and scaling of recorded accelerograms sourced from the available global database. Finally, a suite of conditional mean spectra–compatible accelerograms for rock sites is presented, from which event-specific and site-specific accelerograms are generated through dynamic site response analysis.

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Kharlanova, Svetlana V. ,., and Vladimir L. Kharlanov. "Application of the wavelet transform in filtering the noise of real earthquake accelerograms." Earthquake Engineering. Construction Safety, no. 3 (June 25, 2021): 19–27. http://dx.doi.org/10.37153/618-9283-2021-3-19-27.

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In the deterministic analysis of building structures, real accelerograms are used as input data. Very often, only instrumental recordings of accelerograms that are not cleared of noise are publicly available. Such accelerograms cannot be used directly in the analysis of building structures. Various broadband filters are used to adjust the instrumental recordings of accelerographs. This article discusses the possibility of applying filters based on the wavelet transform. The technique of the algorithm of filtering from the noise of the source data is considered. As an efficiency of this filtering algorithm, a comparative analysis of the dynamic coefficient and the energy criteria of the pulse and Arias for the corrected and instrumental accelerograms is carried out.

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Brune, James N., and Abdolrasool Anooshehpoor. "Foam Rubber Modeling of the El Centro Terminal Substation Building." Earthquake Spectra 7, no. 1 (February 1991): 45–79. http://dx.doi.org/10.1193/1.1585612.

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Results from a layered foam rubber model of soil and the structure (3-D) of the El Centro Terminal Substation building, site of the well known recording of the 1940 El Centro earthquake, indicate that the response of the foundation for frequencies above 4 Hz is as much as a factor of 3 lower than the free-field response amplitude. To validate the modeling technique with sample structure, we use the formulation for calculating theoretical responses of Wong and Luco (1977). Two-dimensional computer model results by Shannon and Wilson, Inc. and Agbabian Associates (1980), gave a response amplitude in the building about a factor of 2 lower than the response amplitude of the free-field for frequencies above 1.5 Hz. Foam rubber modeling shows that at higher frequencies most of the reduction in response is due to the energy being scattered by the shape of the rigid foundation rather than its inertial mass. Under the assumption that most of the energy was vertically incident SH, the free-field peak acceleration during the May 18, 1940 El Centro earthquake was about 50% higher than recorded on the 1940 accelerogram. The transfer function is very similar in shape to the weighting function used by Munguia and Brune (1984), to match synthetic accelerograms with the 1940 El Centro earthquake, suggesting that much of the relative deficit in high frequency energy was a result of soil-structure interaction rather than a source effect.

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Shekarbeigi, Mehdi, and Hasan Sharafi. "The Structural Dynamic Analysis of Embankment Dams Using Finite Difference and Finite Element Methods." Current World Environment 10, Special-Issue1 (June 28, 2015): 796–805. http://dx.doi.org/10.12944/cwe.10.special-issue1.96.

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This study is aimed to provide a structural dynamic analysis of embankment dams using numerical methods. The dynamic analyses are performed based on the time histories by applying accelerogram of several real earthquakes. For a dynamic analysis, it is initially performed a comprehensive study of the characteristics and coordinates of the earthquake accelerograms. The numerical analysis method is established on the comparison of the results of the numerical finite difference (FDM) and finite element (FEM) methods. This paper constitutes two-dimensional numerical plane-strain dynamic analyses in time domain. The focus of this research is to examine the amplified impacts of accelerations and the lateral (horizontal) and vertical (settlement) displacements due to earthquake loading. All the models are undergone the static analysis, followed by dynamic analysis, and after the initial static equilibrium, they are placed under dynamic loading. It is presented a case study on Jamishan Embankment Dam in Kermanshah Province, Iran. The analytical results indicate that there is a good agreement between both numerical methods; however, there are some rare cases with contradictory results, majorly due to the slight differences of fundamental calculations or the definitions of damping ratio and boundary conditions in both numerical methods. Nevertheless, the results illustrate that the free board height of the Jamishan Dam determined by the consultant engineer is responsive to the most critical conditions and prevents the water overflow from the dam in case of strong vibrations.

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Mancini, Francesca, Sebastiano D’Amico, and Giovanna Vessia. "Are Synthetic Accelerograms Suitable for Local Seismic Response Analyses at Near-Field Sites?" Bulletin of the Seismological Society of America 112, no. 2 (December 28, 2021): 992–1007. http://dx.doi.org/10.1785/0120210074.

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ABSTRACT Local seismic response (LSR) studies are considerably conditioned by the seismic input features due to the nonlinear soil behavior under dynamic loading and the subsurface site conditions (e.g., mechanical properties of soils and rocks and geological setting). The selection of the most suitable seismic input is a key point in LSR. Unfortunately, few recordings data are available at seismic stations in near-field areas. Then, synthetic accelerograms can be helpful in LSR analysis in urbanized near-field territories. Synthetic accelerograms are generated by simulation procedures that consider adequately supported hypotheses about the source mechanism at the seismotectonic region and the wave propagation path toward the surface. Hereafter, mainshocks recorded accelerograms at near-field seismic stations during the 2016–2017 Central Italy seismic sequence have been compared with synthetic accelerograms calculated by an extended finite-fault ground-motion simulation algorithm code. The outcomes show that synthetic seismograms can reproduce the high-frequency content of seismic waves at near-field areas. Then, in urbanized near-field areas, synthetic accelerograms can be fruitfully used in microzonation studies.

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Merjey, E. A. "GEODYNAMICS." GEODYNAMICS 2(11)2011, no. 2(11) (September 20, 2011): 205–7. http://dx.doi.org/10.23939/jgd2011.02.205.

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The dependence of the temporal parameters of the energy of the earthquake accelerograms and hypocentral distance. The conclusions about the need to consider the temporal characteristics of the original scaling accelerograms for the earthquake calculated energy level.

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Saikia, Chandan K. "Modeling of strong ground motions from the 16 September 1978 Tabas, Iran, earthquake." Bulletin of the Seismological Society of America 84, no. 1 (February 1, 1994): 31–46. http://dx.doi.org/10.1785/bssa0840010031.

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Abstract We have examined the adequacy of the published KS3 and L1 slip distribution models developed for the MS = 7.4 16 September 1978 Tabas earthquake (Hartzell and Mendoza, 1991) by modeling the high-frequency accelerograms recorded at Dayhook, Boshrooyeh, and Tabas stations. The agreement in peak ground acceleration (PGA) and duration between data and simulated accelerograms was chosen as the criterion for the model adequacy. The fault was specified with a seismogenic rupture area 95 km long and 45 km wide. We used a semi-empirical simulation method in which accelerograms from an aftershock from the 1979 Imperial Valley earthquake were used to represent the radiation pattern of P, SV, or SH waves for a source-receiver geometry. The fault surface is divided into many subfaults. The contributions from these subfaults, weighted by the slip amounts, were lagged and summed to simulate the accelerograms of the main event. We computed accelerograms assuming constant rake and variable rake on the fault plane. The former was simulated using the SUM slip model (i.e., the slip model representing the vector sum of the slip components at every point on the fault), and the latter was simulated by summing the accelerograms generated by the slip models of the dip-slip and strike-slip faults. The influence of the rise time of the main event was investigated. The KS3 asperity model produces results marginally better than the L1 asperity model. The duration is predicted, consistent with the data. The peak amplitudes of the simulated ground motions remain within a factor of 1.5 and 3 of the recorded data at Dayhook and Boshrooyeh, respectively, for the variable-rake and within a factor for 2.5 at both stations for the fixed-rake angle (KS3 model). The large PGA recorded on the Tabas accelerograms could not be reproduced, which warrants additional study. A notable agreement was obtained in the response spectra at Dayhook. This study demonstrates that accelerograms generated by an earthquake in one tectonic region can be transported to another tectonic region so that they can be used to represent the empirical radiation pattern of the subfaults in simulating ground motions for a large event.

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Douglas, Bruce M., Emmanuel A. Maragakis, and Bhabananda Nath. "Calculating static deformations from quick-release accelerograms." Bulletin of the New Zealand Society for Earthquake Engineering 23, no. 4 (December 31, 1990): 239–53. http://dx.doi.org/10.5459/bnzsee.23.4.239-253.

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This paper outlines a new method for performing base line corrections on accelerograms generated by the quick-release dynamic testing method. These accelerograms are produced when highway bridges are subjected to dynamic excitations by initially deforming the bridge structure and subsequently quick-releasing the loads causing the deformation. This base line correction method is developed in such a way that the step function character of the quick-release base line is preserved. It is this feature which allows the static deformations of the structure to be recovered by integrating the accelerograms. The reliability of the method is demonstrated by a series of laboratory measurements comparing the displacement time series obtained by double integration to independently measured displacement responses. These laboratory comparisons indicate that the offset displacements are accurate to within about 5% on the average. The method was applied on accelerograms obtained during a quick-release full-scale test of the Meloland Road Overcrossing, and some examples of this application are presented.

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Abrahamson, N. A., B. A. Bolt, R. B. Darragh, J. Penzien, and Y. B. Tsai. "The SMART I Accelerograph Array (1980-1987): A Review." Earthquake Spectra 3, no. 2 (May 1987): 263–87. http://dx.doi.org/10.1193/1.1585428.

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SMART 1 is the first large digital array of strong-motion seismographs specially designed for engineering and seismological studies of the generation and near-field properties of earthquakes. Since the array began operation in September 1980, it has recorded over 3000 accelerogram traces from 48 earthquakes ranging in local magnitude ( ML) from 3.6 to 7.0. Peak ground accelerations have been recorded up to 0.33g and 0.34g on the horizontal and vertical components, respectively. Epicentral distances have ranged from 3 km 200 km from the array center, and focal depths have ranged from shallow to 100 km. The recorded earthquakes had both reverse and strike-slip focal mechanisms associated with the subduction zone and transform faults. These high quality, digital, ground motions provide a varied resource for earthquake engineering research. Earthquake engineering studies of the SMART 1 ground motion data have led to advances in knowledge in several cases: for example, on frequency-dependent incoherency of free-surface ground motions over short distances, on response of linear systems to multiple support excitations, on attenuation of peak ground-motion parameters and response spectra, on site torsion and phasing effects, and on the identification of wave types. Accelerograms from individual strong-motion seismographs do not, in general, provide such information. This review describes the SMART 1 array and the recorded earthquakes with special engineering applications. Also, it tabulates the unfiltered peak array accelerations, displays some of the recorded ground motion time histories, and summarizes the main engineering research that has made use of SMART 1 data.

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Möller, Oscar, Juan Pablo Ascheri, and Leandro Emanuel Nardi. "Comparison of non-linear dynamic frame response under recorded and numerically generated accelerograms." Revista de la construcción 20, no. 3 (2021): 576–90. http://dx.doi.org/10.7764/rdlc.20.3.576.

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The time history analysis of the linear and non-linear response of earthquake resistant structures is a tool increasingly used in practice and required by codes. In this paper, a set of 12 accelerograms was generated numerically with the spectral representation methodology. Another set of 15 accelerograms were selected from a database of earthquake records and scaled with a uniform factor so that the mean spectrum fits the design one. The non-linear dynamic response of two frames of different stiffness and resistance was obtained under the action of the two sets of accelerograms. The global force - displacement results showed a higher coefficient of variation for the set of recorded accelerograms, especially for the structure of lower resistance that has a strong non-linear incursion. The same tendency was obtained for the moment - curvature relationships of beam and column sections, with higher dispersions compared to the global results. In addition, the influence of the vertical acceleration component was analyzed, resulting in a higher incidence in the interior columns of the frames.

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Poznyak, Elena V., Vladimir P. Radin, and Olga V. Novikova. "Time-frequency Analysis of Natural Accelerograms." Vestnik MEI 5 (2019): 135–41. http://dx.doi.org/10.24160/1993-6982-2019-5-135-141.

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Heaton, Thomas H., Fumiko Tajima, and Ann Wildenstein Mori. "Estimating ground motions using recorded accelerograms." Surveys in Geophysics 8, no. 1 (March 1986): 25–83. http://dx.doi.org/10.1007/bf01904051.

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31

Srivastav, Sanjeev, and James M. Nau. "Structural Response to Truncated Earthquake Accelerograms." Journal of Structural Engineering 114, no. 5 (May 1988): 1189–92. http://dx.doi.org/10.1061/(asce)0733-9445(1988)114:5(1189).

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Shrikhande, Manish, and Vinay K. Gupta. "Synthesizing Ensembles of Spatially Correlated Accelerograms." Journal of Engineering Mechanics 124, no. 11 (November 1998): 1185–92. http://dx.doi.org/10.1061/(asce)0733-9399(1998)124:11(1185).

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33

Naeim, Farzad, and Marshall Lew. "Deficiencies of design-spectrum compatible accelerograms." Structural Design of Tall Buildings 3, no. 4 (December 1994): 275–83. http://dx.doi.org/10.1002/tal.4320030406.

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RAGHUKANTH, S. T. G., and S. SANGEETHA. "EMPIRICAL MODE DECOMPOSITION OF EARTHQUAKE ACCELEROGRAMS." Advances in Adaptive Data Analysis 04, no. 04 (October 2012): 1250022. http://dx.doi.org/10.1142/s1793536912500227.

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This article analyzes the strong motion records of past earthquakes by empirical mode decomposition (EMD) technique. The recorded earthquake acceleration time histories are decomposed into a finite number of empirical modes of oscillation. The instantaneous frequency and amplitude of these modes and evolutionary power spectral density (PSD) is estimated from the Hilbert–Huang transform (HHT). Strong motion parameters such as spectral and temporal centroid, spectral and temporal standard deviation, Arias intensity, correlation coefficient of frequency and time are derived from the evolutionary PSD. The variation of these parameters with magnitude, distance and shear wave velocity of the recording station is reported. Empirical equations to estimate these six ground motion parameters are derived from the strong motion data by regression analysis. These equations can be used by engineers to estimate the design ground motion.

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Cecini, Domenico, and Alessandro Palmeri. "Spectrum-compatible accelerograms with harmonic wavelets." Computers & Structures 147 (January 2015): 26–35. http://dx.doi.org/10.1016/j.compstruc.2014.10.013.

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Elenas, A. "Seismic-Parameter-Based Statistical Procedures for the Approximate Assessment of Structural Damage." Mathematical Problems in Engineering 2014 (2014): 1–22. http://dx.doi.org/10.1155/2014/916820.

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This study describes two statistical methodologies to estimate the postseismic damage status of structures based on seismic parameters as novel combined procedures in earthquake engineering. Thus, a multilinear regression analysis and discriminant analysis are utilized considering twenty seismic parameters. Overall damage indices describe the postseismic damage status. Nonlinear dynamic analyses furnish the damage indices, which are considered as exact indices and references for the subsequent study. The aim is to approximate the postseismic damage indices or the damage grade of buildings using statistical methods, thus avoiding complex nonlinear dynamic analyses. The multilinear regression procedure evaluates the damage indices explicitly, and the discriminant analysis furnishes the damage grade of the structures. The proposed methods are applied to a frame structure. A set of 400 natural accelerograms is used for the training phase of the models. The quality of the models is tested initially by the same set of natural accelerograms and then by a blind prediction using a second set of synthetic accelerograms. The results of both proposed methods have shown a correct classification percentage ranging from 87.75% to 97.50% and from 70% to 90% for the sets of the natural and synthetic accelerograms, respectively.

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SEKINE, MASAKI. "Discrimination of walking form using accelerogram." Journal of Life Support Engineering 10, no. 2 (1998): 79–81. http://dx.doi.org/10.5136/lifesupport.10.79.

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Devaraj, Deepa, R. Ramkrishnan, T. Prabu, Sreevalsa Kolathayar, and T. G. Sitharam. "Synthesis of Linear JTFA-Based Response Spectra for Structural Response and Seismic Reduction Measures for North-East India." Journal of Earthquake and Tsunami 14, no. 06 (August 8, 2020): 2050023. http://dx.doi.org/10.1142/s1793431120500232.

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North-East India (NEI) has a long history of devastating earthquakes due to the complicated tectonic setting of the region. A shortage of sufficient recorded time-histories from the region calls for a synthesis of accelerograms for dynamic analyses. In this study, a novel Joint Time-Frequency Analysis (JTFA) technique is adopted for the synthesis of accelerograms, considering the non-stationary behavior of earthquake waves. JTFA is used for analyzing the signals in a joint time and frequency domain to better understand its characteristics and synthesize signals without compromising its inherent characteristics like frequency content and amplitude. Synthetic accelerograms are developed using JTFA techniques for different magnitude and distance ranges between 5 to 6.8 and 0–480[Formula: see text]km and response spectra are developed. Synthesized generalized accelerograms and their response spectra are compared with actual signals in the same magnitude-distance ranges and were found to match. A comparison of the frequency contents of actual and synthetic signals was also carried out using Fourier Transforms and spectrograms (SPs) and was found to be in good agreement. Further, a comparative study of various earthquake reduction measures for NEI is carried out for a scenario earthquake using the synthesized data, and the best suitable structural input for the region is recommended.

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Wang, Yu Shi, and Xiao Jun Li. "Analysis on the Mechanism for Baseline Drift of near-Fault Accelerograms." Applied Mechanics and Materials 166-169 (May 2012): 2078–82. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2078.

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Accelerograms recorded by accelerographs are of fundamental importance in seismic engineering, forming the basis of ground shaking employed for anti-seismic design. By analysis on the general solution of wave equation, this article demonstrated that the ground tilting is related with the ground velocity and displacement histories. For accelerograms with co-seismic permanent displacement, this ground tilting would be presented continuously with a tiny constant value after severe shock terminated. The co-seismic permanent displacement might be the reason of baseline drift, which caused that the real velocity and displacement histories could not be achieved by the direct integration of accelerograms. A baseline correction method was also proposed based on this finding, with which the ground velocity and displacement histories of several near-fault stations were given. But this proposed method still needed improvement because of the divergence in its iterative process.

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40

Mkrtychev, Oleg V., and Sergey V. Bulushev. "Probabilistic estimation seismic resistance of spatial steel frame under earthquake." Structural Mechanics of Engineering Constructions and Buildings 16, no. 2 (December 15, 2020): 87–94. http://dx.doi.org/10.22363/1815-5235-2020-16-2-87-94.

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Relevance. By its nature, seismic action is represented by the accelerogram a pronounced multidimensional random process, generally containing six components. The calculation in the deterministic formulation does not always allow to adequately assess the reaction of the system. While the calculation in the probabilistic formulation more adequately reflects the work of the system and makes it possible to evaluate its seismic resistance with a given security. The aim of the work is to assess the actual load-carrying capacity safety margin and the taken when designing coefficient K1, taking into account the permissible damage to buildings and structures for the steel spatial frame when calculating on the seismic action. Methods. In the article, the steel spatial frame was calculated for two sets of accelerograms, with dominant frequencies close to the main frequencies of the frame's natural vibrations. Each set was synthesized as a family of unsteady random seismic impact implementations. The calculation was carried out on two-component seismic action in nonlinear dynamic formulation in the software complex LS-DYNA. Previously, the frame was designed in accordance with national standard SP 14.13330.2014 “Construction in seismic areas on the seismic action” of the design earthquake level in the software complex PC LIRA 10.8. According to the developed probabilistic method for each set the actual load-carrying capacity safety margins were obtained and the coefficients K1 were estimated. Results . An analysis of the results shows that the steel frame under consideration has a sufficiently large margin of load-carrying capacity, and the coefficient K1 is taken in norms excessively conservatively. The developed technique allows to correct the value of the accepted coefficient K1 for buildings and structures of certain structural schemes. That in its turn will increase the economic efficiency of construction in seismic areas and ensure the reliability of the designed buildings and structures.

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41

Esteva, Luis. "Nonlinear Seismic Response of Soft-First-Story Buildings Subjected to Narrow-Band Accelerograms." Earthquake Spectra 8, no. 3 (August 1992): 373–89. http://dx.doi.org/10.1193/1.1585686.

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The nonlinear dynamic response of shear systems representative of buildings with excess stiffness and strength at all stories above the first one is studied. Variables covered were number of stories, fundamental period, along-height form of variation of story stiffness, ratio of post-yield to initial stiffness, in addition to the variable of primary interest: the factor r, expressing the ratio of the average value of the safety factor for lateral shear at the upper stories to that at the bottom story. The lateral strength at the latter was taken as equal to the nominal value of the corresponding story shear computed by conventional modal dynamic analysis for the design spectrum specified by Mexico City seismic design regulations of 1987 for a seismic behavior (ductility) reduction coefficient of 4.0. The excitation was in some cases the EW component of the accelerogram recorded at the parking lot of the Ministry of Communications and Transport in the same city during the destructive earthquake of September 19, 1985, and in some other cases an ensemble of artificial accelerograms with similar statistical properties. It is concluded that the nonlinear seismic response of shear buildings whose upper stories have lateral strengths and stiffnesses which correspond to safety factors larger than those applied to the first story is very sensitive to the relation between the average of the over-strength factors at the upper stories and that at the first one, as well as to the ratio of post-yield to initial stiffnesses. The nature and magnitude of the influence of r on the maximum ductility demands at the first story depend on the low-strain fundamental natural period of the system. The ductility demands computed for elastoplastic systems may in some cases be extremely large. Accounting for P-delta effects leads to an enhancement of the sensitivity of the response with respect to r.

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Anderson, J. G., and R. Quaas. "The Mexico Earthquake of September 19, 1985—Effect of Magnitude on the Character of Strong Ground Motion: An Example from the Guerrero, Mexico Strong Motion Network." Earthquake Spectra 4, no. 3 (August 1988): 635–46. http://dx.doi.org/10.1193/1.1585494.

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The Guerrero digital accelerograph network has been operating, since spring of 1985, on rock sites along the coast of Mexico, above an active subduction zone. The accelerograms collected through June 1987 include examples from events with magnitudes from 3 to 8, all recorded at nearly the same hypocentral distance. Spectra from these accelerograms scale in a manner that is qualitatively consistent with earthquake source theory. Based on four selected events, peak accelerations attenuate more rapidly for small events than for large events.

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Otarola, Cristian, and Sergio Ruiz. "Stochastic Generation of Accelerograms for Subduction Earthquakes." Bulletin of the Seismological Society of America 106, no. 6 (September 20, 2016): 2511–20. http://dx.doi.org/10.1785/0120150262.

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Menasri, A., M. Brahimi, R. Frank, and A. Bali. "ARMA Modeling of Artificial Accelerograms for Algeria." Applied Mechanics and Materials 105-107 (September 2011): 348–55. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.348.

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The main aim of this study is to examine on the real and simulated earthquakes effects. This paper deals with the use of ARMA models in earthquake engineering. The time-varying auto regressive moving average (ARMA) process is used as a simple yet efficient method for simulating earthquake ground motions. This model is capable of reproducing the nonstationary amplitude as well as the frequency content of the earthquake ground accelerations. The moving time-window technique is applied to synthesize the near field earthquakes, Chlef-1, Chlef-2, Chlef-3 and Attaf 1980 recorded on dense soils in Algeria. This model, is based on a low-order, time-invariant ARMA process excited by Gaussian white noise and amplitude modulated using a simple envelope function to account for the non-stationary characteristics. This simple model gives a reasonable fit to the observed ground motion. It is shown that the selected ARMA (2,1) model and the algorithm used for generating the accelerograms are able to preserve the features of the real earthquake records with different frequency content. In this evaluation, the linear and non linear responses of a given soil layer have been adopted. This study suggests the ability to characterize the earthquake by a minimum number of parameters.

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Sarkar, Kaushik, Vinay K. Gupta, and Riya C. George. "Wavelet-based generation of spatially correlated accelerograms." Soil Dynamics and Earthquake Engineering 87 (August 2016): 116–24. http://dx.doi.org/10.1016/j.soildyn.2016.05.005.

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Vrochidou, E., P. F. Alvanitopoulos, I. Andreadis, A. Elenas, and K. Mallousi. "Synthesis of artificial spectrum-compatible seismic accelerograms." Measurement Science and Technology 25, no. 8 (June 23, 2014): 085002. http://dx.doi.org/10.1088/0957-0233/25/8/085002.

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Vrochidou, Eleni, Petros Alvanitopoulos, Ioannis Andreadis, and Anaxagoras Elenas. "Artificial accelerograms composition based on the CEEMD." Transactions of the Institute of Measurement and Control 40, no. 1 (July 5, 2016): 239–50. http://dx.doi.org/10.1177/0142331216654533.

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In this work, a new methodology for generating spectrum-compatible accelerograms is presented. The proposed methodology considers the non-stationary and non-linear characteristics of seismic signals and utilizes the Hilbert–Huang transform (HHT) to analyse them. The two reported drawbacks of HHT, i.e. the mode mixing phenomenon and the end effects issue, are resolved through the proposed methodology. More specifically, the advantages of the recently introduced complementary ensemble empirical mode decomposition (CEEMD) are exploited in order to eliminate the mode mixing phenomenon. Moreover, the application of the proposed method only to the strong motion duration of the seismic signal assists to overcome the end effects issue. Thirty natural seismic records of different characteristics, such as frequency content, amplitude and duration, are employed as initial seed signals to demonstrate the proposed method. To illustrate the effectiveness of the proposed technique, comparisons with three established methods for generating spectrum-compatible seismic accelerograms are also provided.

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Seekins, L., A. Brady, N. Brown, and C. Carpenter. "Strong-motion accelerograms available on CD-ROM." Eos, Transactions American Geophysical Union 73, no. 41 (1992): 436. http://dx.doi.org/10.1029/91eo00327.

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Mkrtychev, O. V., and A. A. Reshetov. "Using wavelet analysisto obtain characteristics of accelerograms." Vestnik MGSU, no. 7 (July 2013): 59–67. http://dx.doi.org/10.22227/1997-0935.2013.7.59-67.

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Corigliano, Mirko, Carlo G. Lai, Maria Rota, and Claudio L. Strobbia. "ASCONA: Automated Selection of COmpatible Natural Accelerograms." Earthquake Spectra 28, no. 3 (August 2012): 965–87. http://dx.doi.org/10.1193/1.4000072.

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This paper describes an automated procedure for selecting and scaling real spectrum-compatible records. The methodology allows one to choose from a predefined database, assembled from accredited strong-motion accelerometric data banks, real records satisfying properly defined seismological constraints with the additional requirement of spectrum-compatibility with a reference spectrum in a specified period range. Among the different sets of records satisfying these constraints, the user can specify the desired one, based on additional requirements (e.g., limited scaling factors). The proposed algorithm allows one to select records compatible with either an acceleration or a displacement response spectrum.

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Journal articles on the topic 'Accelerogrammi'

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