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 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.

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.

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 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.

Analysis of Ice Response Spectra with Nonlinear Interpolation Method

2011 ◽  
Vol 243-249 ◽  
pp. 93-96
Author(s):  
Ling Ling Jia ◽  
Hang Jing ◽  
Yang Han
Keyword(s):  
Interpolation Method ◽  
Response Spectrum ◽  
Response Spectra ◽  
Linear Interpolation ◽  
New Method ◽  
Amplification Coefficient ◽  
Acceleration Response ◽  
Nonlinear Interpolation ◽  
Linear Interpolation Method ◽  
Ice Resistance

In this paper, the successive computation formulas of ice response spectrum are derived and deduced based on the assumption of nonlinear interpolation method. And with the new way, the ice response spectrum of two true different ice temporal curves are analysized. The results indicate that the ice spectra value obtained by the new method is a litter greater than the values of the called precision method. And the error of the acceleration response spectra amplification coefficient is only 0.53%. therefore, this ice response spectra method presented by this paper can meet the request of precision. As this method is more preciser than linear interpolation method, it can be used in the design of ice resistance.

scholarly journals ACCELERATION RESPONSE SPECTRUM AND EFFECTIVE DURATION OF LEBAK EARTHQUAKE JANUARY 23, 2018 IN JAKARTA REGION

2019 ◽  
Vol 4 (1) ◽  
pp. 21-30
Author(s):  
Muhammad Fikri Hayqal Hiola ◽  
Bambang Sunardi
Keyword(s):  
Response Spectrum ◽  
Capital City ◽  
Acceleration Response ◽  
South Indian ◽  
Significant Acceleration ◽  
Acceleration Data ◽  
Statistical Analysis Method ◽  
Acceleration Response Spectrum ◽  
Motion Characteristics ◽  
Very High

Jakarta is the capital city of Indonesia with a very high population density low to the upper distribution of buildings which causes many areas of Jakarta to have a high vulnerability to natural disasters, one of which is an earthquake. One of the earthquakes felt this year was Lebak Banten Earthquake January 23, 2018, with a magnitude 6.1 at 13.34 local time. The depth of the earthquake was 61 Km at -7.09o S - 106.03o E, in the South Indian Ocean of Java Island. The epicenter was 43 km from Cilangkahan Village, Malingping Sub-district, Lebak District, Banten. We analyze the ground motion characteristics in the Jakarta area using 3 component acceleration data at Jakarta City Hall Office (JAKO) and Tanjung Priok Maritime Station (JATA) with dynamic statistical analysis method. The effective duration and earthquake response spectrum are determined using the acceleration data. In this study, the active period of the earthquake was calculated using the Trifunac and Brady method. The results of the analysis show that the most significant acceleration spectrum at JAKO station is found in component E of 0.07742 g in the period of 0.54 s while for the most significant acceleration spectrum JATA station found in component N of 0.04572 g in the period of 0.58 s. The effective duration obtained at JAKO stations was 56.76 s and JATA station 63.47 s. These results indicate that in the case of the Lebak earthquake, the further region from the epicenter of the earthquake has an effective duration which is relatively longer.

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