scholarly journals Engineering characterization of ground motion. Task I. Effects of characteristics of free-field motion on structural response

1984 ◽  
Author(s):  
R.P. Kennedy ◽  
S.A. Short ◽  
K.L. Merz ◽  
F.J. Tokarz ◽  
I.M. Idriss ◽  
...  
Keyword(s):  
Ground Motion ◽  
Free Field ◽  
Structural Response

On Ground Motion Intensity Indices

2007 ◽  
Vol 23 (1) ◽  
pp. 147-173 ◽  
Author(s):  
Rafael Riddell
Keyword(s):  
Ground Motion ◽  
Seismic Analysis ◽  
Structural Response ◽  
Frequency Range ◽  
Ground Acceleration ◽  
Essential Point ◽  
Sensitive Region ◽  
Peak Ground Motion ◽  
Degradation Models

The characterization of strength of earthquake demands for seismic analysis or design requires the specification of a level of intensity. Numerous ground motion intensity indices that have been proposed over the years are being used for normalizing or scaling earthquake records regardless of their efficiency. An essential point of this study is that a ground motion index is appropriate, or efficient, as long as it can predict the level of structural response. This study presents correlations between 23 ground motion intensity indices and four response variables: elastic and inelastic deformation demands, and input energy and hysteretic energy; nonlinear responses are computed using elastoplastic, bilinear, and bilinear with stiffness degradation models. As expected, no index is found to be satisfactory over the entire frequency range. Indeed, indices related to ground acceleration rank better in the acceleration-sensitive region of the spectrum; indices based on ground velocity are better in the velocity-sensitive region and, correspondingly, generally occur in the displacement-controlled region. Despite frequent criticism, the peak ground motion parameters passed the test successfully. A ranking of indices is presented, thus providing a choice of the most appropriate one for a particular application in the frequency range of interest.

Local characterization of free-field ground motion and effects of wave passage

1980 ◽  
Vol 70 (6) ◽  
pp. 2229-2244
Author(s):  
J. E. Luco ◽  
D. A. Sotiropoulos
Keyword(s):  
Ground Motion ◽  
Seismic Waves ◽  
Plane Waves ◽  
Free Field ◽  
Seismic Source ◽  
Phase Velocities ◽  
Propagation Medium ◽  
Local Characterization ◽  
Wave Passage

abstract A simple model of the seismic source and of the propagation medium is used to obtain a local representation of the free-field ground motion in terms of a small number of equivalent dispersive plane waves. Numerical values for the equivalent phase velocities entering in the representation are presented for different epicentral distances and source depths. Based on the local characterization of the free-field motion, estimates of the magnitude of the effects of nonvertically incident seismic waves on the response of foundations and structures are presented.

scholarly journals Effect of Frequency Characteristics of Ground Motion on Response of Tuned Mass Damper Controlled Inelastic Concrete Frame

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 74
Author(s):  
Md Motiur Rahman ◽  
Tahmina Tasnim Nahar ◽  
Dookie Kim
Keyword(s):  
Ground Motion ◽  
Structural Response ◽  
Tuned Mass Damper ◽  
Frequency Characteristics ◽  
Building Frames ◽  
Concrete Frame ◽  
Finite Element Software ◽  
Mass Damper ◽  
Lateral Displacements ◽  
Modal Mass

This paper investigates the performance of tuned mass damper (TMD) and dynamic behavior of TMD-controlled concrete structure considering the ground motion (GM) characteristics based on frequency content. The effectiveness of TMD in reducing the structural response and probability of collapse of the building frames are affected by the frequency characteristics of GMs. To attenuate the seismic vibration of the buildings, the TMD controlled building has been designed based on the modal analysis (modal frequencies and modal mass participation ratio). In this study, to investigate the performance of TMD, four different heights (i.e., 3, 5, 10, 20 stories) inelastic concrete moment-resisting frames equipped with TMDs are developed using an open-source finite element software. A series of numerical analyses have been conducted using sixty earthquakes classified into three categories corresponding to low, medium, and high-frequency characteristics of GMs. To evaluate the proposed strategy, peak lateral displacements, inter-story drift, and the probability of collapse using fragility analysis have been investigated through the structures equipped with and without TMD. The results appraise the effect of TMD and compare the seismic responses of earthquake frequency contents and the vibration control system of the inelastic building frames.

CHARACTERIZATION OF LIQUEFACTION RESISTANCE OF SAND: EFFECT OF INITIAL FABRIC

2014 ◽  
Vol 08 (01) ◽  
pp. 1450001 ◽  
Author(s):  
BO LI ◽  
XIANGWU ZENG ◽  
HAO YU
Keyword(s):  
Depositional Environment ◽  
Design Method ◽  
Free Field ◽  
Recent Experience ◽  
Permeability Test ◽  
Fabric Anisotropy ◽  
Liquefaction Resistance ◽  
Liquefaction Potential ◽  
Centrifuge Tests

The micro-fabric of deposition reflects the imprints of its geologic and stress history, its depositional environment, and its weathering history. Recent experience shows that the fabric anisotropy does influence the static and dynamic behavior of granular materials. In this study, a series of centrifuge tests are conducted to investigate the effects of fabric anisotropy on the dynamic response in the free field. The results show the acceleration, pore pressure, and residual settlement is significantly affected by the fabric anisotropy of the ground, which shows the liquefaction resistance of the ground. Meanwhile, the response of acceleration is analyzed in frequency domain, which shows that the model prepared by 90° absorbs more energy than that of 0°. To verify the effects induced by the initial fabric, permeability test are conducted and related to the liquefaction potential. The results indicate the fabric anisotropy should be incorporated into the design method.

scholarly journals An approach to quantify the influence of ground motion uncertainty on elastoplastic system acceleration in incremental dynamic analysis

2017 ◽  
Vol 20 (11) ◽  
pp. 1744-1756 ◽  
Author(s):  
Peng Deng ◽  
Shiling Pei ◽  
John W. van de Lindt ◽  
Hongyan Liu ◽  
Chao Zhang
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Structural Response ◽  
Incremental Dynamic Analysis ◽  
Degree Of Freedom ◽  
Maximum Acceleration ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Performance Based Earthquake Engineering

Inclusion of ground motion–induced uncertainty in structural response evaluation is an essential component for performance-based earthquake engineering. In current practice, ground motion uncertainty is often represented in performance-based earthquake engineering analysis empirically through the use of one or more ground motion suites. How to quantitatively characterize ground motion–induced structural response uncertainty propagation at different seismic hazard levels has not been thoroughly studied to date. In this study, a procedure to quantify the influence of ground motion uncertainty on elastoplastic single-degree-of-freedom acceleration responses in an incremental dynamic analysis is proposed. By modeling the shape of the incremental dynamic analysis curves, the formula to calculate uncertainty in maximum acceleration responses of linear systems and elastoplastic single-degree-of-freedom systems is constructed. This closed-form calculation provided a quantitative way to establish statistical equivalency for different ground motion suites with regard to acceleration response in these simple systems. This equivalence was validated through a numerical experiment, in which an equivalent ground motion suite for an existing ground motion suite was constructed and shown to yield statistically similar acceleration responses to that of the existing ground motion suite at all intensity levels.

Conditioned Simulation of Ground-Motion Time Series at Uninstrumented Sites Using Gaussian Process Regression

2021 ◽  
Author(s):  
Aidin Tamhidi ◽  
Nicolas Kuehn ◽  
S. Farid Ghahari ◽  
Arthur J. Rodgers ◽  
Monica D. Kohler ◽  
...  
Keyword(s):  
Time Series ◽  
Gaussian Process ◽  
Ground Motion ◽  
San Francisco ◽  
Earthquake Engineering ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Free Field ◽  
Gaussian Process Regression ◽  
Motion Time

ABSTRACT Ground-motion time series are essential input data in seismic analysis and performance assessment of the built environment. Because instruments to record free-field ground motions are generally sparse, methods are needed to estimate motions at locations with no available ground-motion recording instrumentation. In this study, given a set of observed motions, ground-motion time series at target sites are constructed using a Gaussian process regression (GPR) approach, which treats the real and imaginary parts of the Fourier spectrum as random Gaussian variables. Model training, verification, and applicability studies are carried out using the physics-based simulated ground motions of the 1906 Mw 7.9 San Francisco earthquake and Mw 7.0 Hayward fault scenario earthquake in northern California. The method’s performance is further evaluated using the 2019 Mw 7.1 Ridgecrest earthquake ground motions recorded by the Community Seismic Network stations located in southern California. These evaluations indicate that the trained GPR model is able to adequately estimate the ground-motion time series for frequency ranges that are pertinent for most earthquake engineering applications. The trained GPR model exhibits proper performance in predicting the long-period content of the ground motions as well as directivity pulses.

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