A Semi-Automated Procedure for Selecting and Scaling Recorded Earthquake Motions for Dynamic Analysis

2008 ◽  
Vol 24 (4) ◽  
pp. 911-932 ◽  
Author(s):  
Albert Kottke ◽  
Ellen M. Rathje
Keyword(s):  
Seismic Design ◽  
Response Spectrum ◽  
Ground Motions ◽  
Acceleration Response ◽  
Analysis Process ◽  
Target Spectrum ◽  
Acceleration Response Spectrum ◽  
Individual Scale ◽  
The Individual ◽  
Selection Of

Suites of earthquake ground motions play an important role in the seismic design and analysis process. A semi-automated procedure is described that selects and scales ground motions to fit a target acceleration response spectrum, while at the same time the procedure controls the variability within the ground motion suite. The basic methodology selects motions based on matching the target spectral shape, and then fits the amplitude and standard deviation of the target by adjusting the individual scale factors for the motions. The selection of motions from a larger catalog of motions is performed through either a rigorous method that tries each possible suite of motions or an iterative approach that considers a smaller set of potential suites in an effort to find suites that provide an acceptable fit to the target spectrum. Guidelines are provided regarding the application of the developed procedures, and example applications are described.

Smooth Acceleration Spectra for Pulse-Like Ground Motions

2020 ◽  
Vol 110 (6) ◽  
pp. 2755-2765
Author(s):  
Cuihua Li ◽  
Guofeng Xue ◽  
Zhanxuan Zuo
Keyword(s):  
Seismic Design ◽  
Amplification Factor ◽  
Response Spectrum ◽  
Ground Motions ◽  
Response Spectra ◽  
Acceleration Response ◽  
Constant Acceleration ◽  
Step Procedure ◽  
Acceleration Response Spectrum ◽  
Smooth Acceleration

ABSTRACT Idealization of acceleration response spectra is the basis for construction of target spectra for seismic design and assessment of structures. The adequacy of current methods to reasonably idealize (or smooth) the acceleration spectra of pulse-like and nonpulse-like ground motions is examined in this study. The influence of separated pulses on different regions of acceleration response spectrum is first investigated using wavelet transform. One representative method is selected as the benchmark to examine the effectiveness of the Newmark–Hall-based methods to smooth the acceleration spectra of pulse-like and nonpulse-like ground motions. Presented are some important insights into why the plateau (or amplification factor) associated with the constant-acceleration branch may be underestimated and the ending cutoff period Tg be overestimated by Newmark–Hall-based methods. This study highlights the intrinsic characteristics and the importance of the constant-acceleration branch, based on which a two-step procedure is proposed to idealize the acceleration spectra. The results show that the proposed methodology can accurately identify the constant-acceleration branch regardless of the influence of pulses on the descending branch of acceleration spectra.

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.

A Metric to Screen Acceptable Velocity and Displacement Time Histories of Modified Ground Motions

2017 ◽  
Vol 33 (4) ◽  
pp. 1495-1512
Author(s):  
Clinton P. Carlson ◽  
Dimitrios Zekkos
Keyword(s):  
Goodness Of Fit ◽  
Response Spectrum ◽  
Ground Motions ◽  
Time History ◽  
Visual Assessment ◽  
Acceleration Response ◽  
Earthquake Scenarios ◽  
Target Spectrum ◽  
Time Histories ◽  
Acceleration Response Spectrum

Ground motion modification is extensively used in practice to modify a seed acceleration time history in intensity and frequency content until its acceleration response spectrum matches a target spectrum. However, the decision to accept or reject a modified motion commonly relies on a subjective process where the time histories of the modified motion are visually compared to those of the seed motion. Various metrics were used to quantify the similarity between the modified time histories and their scaled counterparts for hundreds of modified ground motions from three different earthquake scenarios. Of the metrics considered, the inverse modified RMSE metric for time histories ( imRMSE t) was found most appropriate as it resulted in the least amount of dispersion in the goodness-of-fit values with respect to spectral mismatch. The imRMSE t was then found to be correlated to qualitative rankings assigned to the modified time histories through a visual assessment. The correlation between the quantitative imRMSE t values and qualitative rankings is used to establish threshold values to screen modified velocity and displacement time histories that are likely acceptable or likely unacceptable.

Seismic Response Characteristics of Deep Soft Site with Depth under Far-Field Ground Motion of Great Earthquake

2011 ◽  
Vol 378-379 ◽  
pp. 477-483
Author(s):  
Ji Yan Zhan ◽  
Guo Xing Chen ◽  
Dan Dan Jin
Keyword(s):  
Peak Ground Acceleration ◽  
Response Spectrum ◽  
Ground Motions ◽  
Great Earthquake ◽  
Far Field ◽  
Acceleration Response ◽  
Ground Acceleration ◽  
Long Period ◽  
Reduction Coefficient ◽  
Acceleration Response Spectrum

Considering the dynamic nonlinear characteristics of soil by equivalent linear method, one-dimensional wave models were established to study the seismic effects along depth of deep soft sites under far-field ground motions of great earthquake. The results show that the magnified effect of acceleration response spectrum of each layer present more outstanding under far-field ground motions than under Suzhou artificial waves, with the increasing of bedrock peak ground acceleration, there is probability that the peak of long-period component of acceleration response spectrum appears higher than that of the short-period within 15m depth, which may adversely affect the long-period building structures. However, the reduction coefficient of peak ground acceleration (PGA) along depth according to the three levels of earthquake fortification standard was relatively higher when inputting far-field ground motions of great earthquake. As the curve fitted by Longjun Xu et al. based on records collected California Strong Motion Instrumentation Program geotechnical arrays of the United States and Hosokura Mine arrays of Japan, is not suitable for Suzhou area, suited quantitative formula about reduction coefficient curve of PGA with depth in deep soft site is given. Besides, maximum shear strain at the depth of approximately 15m and 40m present to be greatly changed when inputting far-field ground motions of great earthquake, with the growth of inputting bedrock peak ground acceleration, the layer in the depth of about 15m comes to be the most unfavorable position of shear deformation.

scholarly journals Some limitations of modal analysis in seismic design

1969 ◽  
Vol 2 (3) ◽  
pp. 284-288
Author(s):  
R. Shepherd
Keyword(s):  
Seismic Design ◽  
Response Spectrum ◽  
Individual Member ◽  
Square Root ◽  
High Rise ◽  
Earthquake Resistant Design ◽  
Recent Computer ◽  
Computer Analyses ◽  
Design Loads ◽  
The Individual

In the normal-mode, response-spectrum approach to earthquake resistant design of multistorey buildings the extended elastic seismic design loads are frequently calculated as the square root of the sum of the squares of the modal responses. The individual member forces are then determined using these seismic design loads. Previous research workers have examined the limitations of this technique and it is accepted as being generally applicable in practical design procedures. Recent computer analyses of projected New Zealand high-rise buildings have illustrated two conditions in which the “square root of the sum of the modal responses squared” rule is inapplicable. In this note these situations are described and suggestions are made of an alternative approach which may be adopted when deriving design loads in such cases.

The Comparative Analysis on Calculation Methods of Vertical Seismic Response to Suspended-Dome Structure

2013 ◽  
Vol 351-352 ◽  
pp. 849-853
Author(s):  
Lan Chen ◽  
De Long Lu ◽  
Xiao Gang Yin
Keyword(s):  
Response Spectrum ◽  
Time History ◽  
Seismic Effect ◽  
Time History Analysis ◽  
Vertical Acceleration ◽  
Analysis Method ◽  
Calculation Methods ◽  
Acceleration Response ◽  
History Analysis ◽  
Acceleration Response Spectrum

Based on the vertical seismic information, the vertical seismic response spectrum was calculated by Matlab Lsim function. The seismic effect of Kiewitt-Lamella suspended-dome was measured by dynamic to static ratio. According to the EL-Centro seismic wave, it analyzed and compared the dynamic to static ratios which were calculated by the following four vertical seismic calculation methods respectively: the simplified method of specification, the mode-superposition response spectrum methods based on the horizontal earthquake affecting coefficients and the vertical acceleration response spectrum respectively, and the time history analysis method. Analysis shows that: For the seismic effect, the time history analysis method is larger than the other three methods, and the method based on the vertical acceleration response spectrum is closer to the time history analysis method. Owing to large difference of the four methods for seismic effect, various methods should be adopted to ensure the safety of vertical seismic design.

Response History Analysis for the Design of New Buildings in the NEHRP Provisions and ASCE/SEI 7 Standard: Part III - Example Applications Illustrating the Recommended Methodology

2017 ◽  
Vol 33 (2) ◽  
pp. 419-447 ◽  
Author(s):  
Reid B. Zimmerman ◽  
Jack W. Baker ◽  
John D. Hooper ◽  
Stephen Bono ◽  
Curt B. Haselton ◽  
...  
Keyword(s):  
Ground Motions ◽  
Structural Systems ◽  
The Third ◽  
History Analysis ◽  
Target Spectrum ◽  
Response History Analysis ◽  
Tectonic Settings ◽  
Local Results ◽  
New Buildings ◽  
Selection Of

This paper represents the third part of a series of four publications on response history analysis for new buildings. Three real-building examples designed to a prior version of the building code are chosen, having a range of target spectrum characteristics, tectonic settings, and structural systems to test the new procedure and document its appropriate implementation. This paper describes the process of determining both MCER spectra and scenario spectra for all three examples. It explores selection of appropriate recorded ground motions and the procedure for scaling and spectrally matching to a maximum direction spectrum. Global results such as drift and treatment of unacceptable response, and local results such as force-and deformation-controlled acceptance criteria checks, are shown for each example. Practical guidance is given on implementing response history analysis for engineers employing the new Chapter 16.

Response Spectrum Analysis Method of Footbridge Lateral Vibration under Man-Bridge Interaction

2013 ◽  
Vol 838-841 ◽  
pp. 1165-1169
Author(s):  
Yu Nan ◽  
Zhi Gang Song ◽  
Shi Jiao
Keyword(s):  
Design Method ◽  
Response Spectrum ◽  
Damping Ratio ◽  
Interaction Model ◽  
Dynamic Interaction ◽  
Stride Frequency ◽  
Social Force ◽  
Acceleration Response ◽  
Weighting Method ◽  
Acceleration Response Spectrum

Based on the uniform experimental design method and combining with the additional lateral pedestrian role derived from social force, this paper establishes human-bridge dynamic interaction model and calculates dynamic response of simply supported structures with different span, damping ratio, walking stride frequency and other parameters under the man-bridge dynamic interaction. The acceleration response spectrum is obtained by FFT transform of acceleration response. Then RMS-acceleration response spectrum is calculated in accordance with ISO overall frequency weighting method and the response spectrum envelope formula is fitted by parametric analysis.

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