scholarly journals Evaluation of the Floor Acceleration Amplification Demand of Instrumented Buildings

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Baofeng Huang ◽  
Wensheng Lu
Keyword(s):  
Strong Motion ◽  
Critical Parameters ◽  
Acceleration Response ◽  
Distribution Profile ◽  
Parabolic Distribution ◽  
Acceleration Amplification ◽  
Seismic Force ◽  
Importance Factor ◽  
Instrumented Buildings ◽  
Floor Acceleration

The floor acceleration amplification (FAA) factor is one of the most critical parameters in computing the equivalent seismic force of nonstructural component (NC). To evaluate the heightwise FAA distribution profile, the recorded acceleration response of the instrumented buildings was analyzed using the California Strong Motion Instrumentation Program (CSMIP) database. The FAA demands for three groups of buildings consisting of reinforced concrete, steel, and masonry buildings were analyzed. In each group, the buildings were classified into four subgroups according to their heights. Parabolic distribution profiles were suggested that could envelop most of the FAA data, as demonstrated by the processed results. An earthquake experience-based importance factor was suggested in terms of the percentage of the enveloped records. The obtained FAAs at the roof were generally larger than those in other levels. The percentile distributions of the roof acceleration amplification (RAA) were computed. The results showed that the roof FAA was underestimated in ASCE 7-16. The magnitudes of the FAA and the RAA correlated to the fundamental period of the building, which was considered by classifying the buildings according to the period ranges. The RAA profile against the period was obtained from a regression analysis. The developed FAA profile is expected to be useful in the seismic design of NCs, and it is expected to be adopted in future code provisions.

scholarly journals A practice-oriented method for estimating elastic floor response spectra

2020 ◽  
Vol 53 (3) ◽  
pp. 116-136 ◽  
Author(s):  
Kieran Haymes ◽  
Timothy Sullivan ◽  
Reagan Chandramohan
Keyword(s):  
Response Spectra ◽  
Superposition Method ◽  
Acceleration Response ◽  
Nonstructural Components ◽  
Floor Response Spectra ◽  
Acceleration Response Spectra ◽  
Modal Superposition Method ◽  
Displacement Response Spectra ◽  
Instrumented Buildings ◽  
Floor Acceleration

A practice-oriented modal superposition method for setting elastic floor acceleration response spectra is proposed in this paper. The approach builds on previous contributions in the literature, making specific recommendations to explicitly consider floor displacement response spectra and accounts for uncertainty in modal characteristics. The method aims to provide reliable predictions which improve on existing code methods but maintain simplicity to enable adoption in practical design. This work is motivated by recent seismic events which have illustrated the significant costs that can be incurred following damage to secondary and nonstructural components within buildings, even where the structural system has performed well. This has prompted increased attention to the seismic performance of nonstructural components with questions being raised about the accuracy of design floor acceleration response spectra used in practice. By comparing floor acceleration response spectra predicted by the proposed method with those recorded from instrumented buildings in New Zealand, it is shown that the proposed approach performs well, particularly if a good estimate of the building’s fundamental period of vibration is available.

Evaluation of floor acceleration demands from the 2017 Mexico City code seismic provisions using a continuous elastic model and records of instrumented buildings

2020 ◽  
Vol 36 (2_suppl) ◽  
pp. 213-237
Author(s):  
Miguel A Jaimes ◽  
Adrián D García-Soto
Keyword(s):  
Mexico City ◽  
Seismic Design ◽  
Soft Soil ◽  
Response Spectra ◽  
Elastic Model ◽  
Ground Acceleration ◽  
Nonstructural Components ◽  
Floor Response Spectra ◽  
Instrumented Buildings ◽  
Floor Acceleration

This study presents an evaluation of floor acceleration demands for the design of rigid and flexible acceleration-sensitive nonstructural components in buildings, calculated using the most recent Mexico City seismic design provisions, released in 2017. This evaluation includes two approaches: (1) a simplified continuous elastic model and (2) using recordings from 10 instrumented buildings located in Mexico City. The study found that peak floor elastic acceleration demands imposed on rigid nonstructural components into buildings situated in Mexico City might reach values of 4.8 and 6.4 times the peak ground acceleration at rock and soft sites, respectively. The peak elastic acceleration demands imposed on flexible nonstructural components in all floors, estimated using floor response spectra, might be four times larger than the maximum acceleration of the floor at the point of support of the component for buildings located in rock and soft soil. Comparison of results from the two approaches with the current seismic design provisions revealed that the peak acceleration demands and floor response spectra computed with the current 2017 Mexico City seismic design provisions are, in general, adequate.

scholarly journals Strong motion earthquake records

1974 ◽  
Vol 7 (2) ◽  
pp. 53-61
Author(s):  
P. W. Taylor
Keyword(s):  
Strong Motion ◽  
Response Spectra ◽  
Elementary Level ◽  
Acceleration Response ◽  
Earthquake Intensity ◽  
Earthquake Records ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
San Fernando ◽  
Initial Concept

This article reviews, at an elementary level, the ways in which information from strong-motion earthquake records may be presented. The various methods of presentation are illustrated with reference to the strong-motion records obtained at Pacoima Dam, in the San Fernando earthquake of 1971. As acceleration response spectra from the basis of most codes for the design of earthquake resistant structures, the historical development of response spectra is traced from the initial concept. Simplification of presentation by the use of 'pseudo' response spectra, and the use of spectra to define earthquake intensity are outlined.

Passive Seismic Control Using Shape Memory Alloy Springs

2006 ◽  
Author(s):  
Yoshitaka Yamashita ◽  
Arata Masuda ◽  
Akira Sone
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shaking Table ◽  
Scale Model ◽  
Response Analysis ◽  
Acceleration Response ◽  
Restoring Force ◽  
Seismic Control ◽  
Seismic Force ◽  
Sma Spring

In this paper, seismic response analysis is made both experimentally and numerically for a passive isolation device with pseudoelastic shape memory alloy (SMA) spring as a restoring force component. Thanks to the material nonliniarity and the geometrical nonliniarity, the SMA spring used in the device has well-defined softening, or “force limiting”, property that can suppress the acceleration response of the superstructure by limiting the seismic force transmitted from the ground. To illustrate how the presented device can suppress the acceleration response under the prescribed level, shaking table tests of a reduced-scale model of uniaxial isolator are carried out with seismic inputs appropriately scaled both in time and in amplitude. Then, a Preisach model of the SMA spring is constructed for the purpose of design study, and verified by comparing the simulated seismic responses with the experimental ones.

Study on the Comparison of Ground Response Analysis for Class І Site

2014 ◽  
Vol 919-921 ◽  
pp. 1031-1034
Author(s):  
Xiao Fei Li ◽  
Rui Sun
Keyword(s):  
Strong Motion ◽  
Response Spectra ◽  
Response Analysis ◽  
Acceleration Response ◽  
Seismic Response Analysis ◽  
Ground Response ◽  
Real Situation ◽  
Ground Response Analysis ◽  
Ground Acceleration ◽  
Maximum Shear Strain

In order to test the applicable of the two equivalent linear seismic response analysis procedures SHAKE2000 and LSSRLI-1 for class І site, 21 underground strong motion records were selected from 11 stations of KiK-net as input earthquake motions. By using these two programs to calculate the peak ground acceleration, soil maximum shear strain and acceleration response spectra. By comparing the results of the two procedures and the measured results to evaluate the proximity of these two methods and then judge which program is closer to the real situation. Studies have shown that in class І site, the results of SHAKE2000 and LSSRLI-1 differ little; but according to the measured records, there are some differences between the two programs results and the measured records. While no matter comparing from which side, SHAKE2000 is closer to the earthquake records.

Bi-Directional Pseudo-Acceleration Response Spectra

2016 ◽  
Vol 10 (04) ◽  
pp. 1650007
Author(s):  
Anat Ruangrassamee ◽  
Chitti Palasri ◽  
Panitan Lukkunaprasit
Keyword(s):  
Seismic Design ◽  
Response Spectrum ◽  
Ground Motions ◽  
Strong Motion ◽  
Response Spectra ◽  
Acceleration Response ◽  
Acceleration Response Spectra ◽  
Acceleration Response Spectrum ◽  
Two Degree Of Freedom ◽  
Ratio Response

In seismic design, excitations are usually considered separately in two perpendicular directions of structures. In fact, the two components of ground motions occur simultaneously. This paper clarifies the effects of bi-directional excitations on structures and proposes the response spectra called “bi-directional pseudo-acceleration response spectra”. A simplified analytical model of a two-degree-of-freedom system was employed. The effect of directivity of ground motions was taken into account by applying strong motion records in all directions. The analytical results were presented in the form of the acceleration ratio response spectrum defined as the bi-directional pseudo-acceleration response spectrum normalized by a pseudo-acceleration response spectrum.

scholarly journals New Zealand acceleration response spectrum attenuation relations for crustal and subduction zone earthquakes

2006 ◽  
Vol 39 (1) ◽  
pp. 1-58 ◽  
Author(s):  
Graeme H. McVerry ◽  
John X. Zhao ◽  
Norman A. Abrahamson ◽  
Paul G. Somerville
Keyword(s):  
New Zealand ◽  
Subduction Zone ◽  
Strong Motion ◽  
Response Spectra ◽  
Regression Analyses ◽  
Acceleration Response ◽  
Attenuation Relations ◽  
Volcanic Region ◽  
Crustal Earthquakes ◽  
Subduction Zone Earthquakes

Attenuation relations are presented for peak ground accelerations (pga) and 5% damped acceleration response spectra in New Zealand earthquakes. Expressions are given for both the larger and the geometric mean of two randomly-oriented but orthogonal horizontal components of motion. The relations take account of the different tectonic types of earthquakes in New Zealand, i.e., crustal, subduction interface and dipping slab, and of the different source mechanisms for crustal earthquakes. They also model the faster attenuation of high-frequency earthquake ground motions in the volcanic region than elsewhere. Both the crustal and subduction zone attenuation expressions have been obtained by modifying overseas models for each of these tectonic environments to better match New Zealand data, and to cover site classes that relate directly to those used for seismic design in New Zealand codes. The study used all available data from the New Zealand strong-motion earthquake accelerograph network up to the end of 1995 that satisfied various selection criteria, supplemented by selected data from digital seismographs. The seismographs provided additional records from rock sites, and of motions involving propagation paths through the volcanic region, classes of data that are sparse in records produced by the accelerograph network. The New Zealand strong-motion dataset lacks records in the nearsource region, with only one record from a distance of less than 10 km from the source, and at magnitudes greater than Mw 7.23. The New Zealand data used in the regression analyses ranged in source distance from 6 km to 400 km (the selected cutoff) and in moment magnitude from 5.08 to 7.23 for pga, with the maximum magnitude reducing to 7.09 for response spectra data. The required near-source constraint has been obtained by supplementing the New Zealand dataset with overseas peak ground acceleration data (but not response spectra) recorded at distances less than 10 km from the source. Further near-source constraints were obtained from the overseas attenuation models, in terms of relationships that had to be maintained between various coefficients that control the estimated motions at short distances. Other coefficients were fitted from regression analyses to better match the New Zealand data. The need for different treatment of crustal and subduction zone earthquakes is most apparent when the effects or source mechanism are taken into account. For crustal earthquakes, reverse mechanism events produce the strongest motions, followed by strike-slip and normal events. For subduction zone events, the reverse mechanism interface events have the lowest motions, at least in the period range up to about ls, while the slab events, usually with normal mechanisms, are generally strongest. The attenuation relations presented in this paper have been used in many hazard studies in New Zealand over the last five years. In particular, they have been used in the derivation of the elastic site spectra in the new Standard for earthquake loads in New Zealand, NZS 1170.5:2004.

The Comparative Numerical Experiments of Frequency Features for Earthquake Responds in Liquefiable Field and Elastic Field

2011 ◽  
Vol 90-93 ◽  
pp. 1531-1538
Author(s):  
Jian Ping He ◽  
Wei Zhong Chen
Keyword(s):  
High Frequency ◽  
Essential Feature ◽  
Underground Structure ◽  
Free Field ◽  
Soil Layer ◽  
Low Frequency ◽  
Elastic Field ◽  
Acceleration Response ◽  
Acceleration Amplification ◽  
Frequency Features

The natural frequency characteristics of field has the remarkable influence to the field acceleration response. This paper realized the free field liquefaction numerical simulation experiment based on the Finn model, simultaneously performed the elastic field acceleration response comparative experiment, and has studied the acceleration response frequency features question of liquefiable field. The results indicated that, the acceleration response essential feature of liquefaction field is low-frequency amplification, high frequency reduction. The low-frequency amplification effect is higher than the high frequency reduction effect obviously. The acceleration is amplified in early time and is weakened in later period during the liquefaction process. The acceleration amplification in liquefiable field is remarkable for inputting low frequency waves, the acceleration response is 13 times to input value. Elastic fields also have “low-frequency amplification, high-frequency deflation features”, However, this feature of elastic field is not significant as liquefiable field. At the lower position of liquefiable field acceleration amplification is the largest, at the surface of elastic field acceleration amplification is maximum. The underground structure seismic design in liquefiable field was carried on as in the conventional elastic field, then caused the underground structure to be at the dangerous condition. Researching results will provide a theoretical and experimental basis for the dynamic analysis of underground structures passing through liquefaction soil layer.

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