Seismic assessment of a cable-stayed arch bridge under three-component orthotropic earthquake excitation

2020 ◽  
pp. 136943322094875 ◽  
Author(s):  
Salar Farahmand-Tabar ◽  
Majid Barghian
Keyword(s):  
Ground Motion ◽  
Numerical Study ◽  
Epicentral Distance ◽  
Ground Motions ◽  
Dynamic Responses ◽  
Earthquake Excitation ◽  
Arch Bridge ◽  
Stay Cables ◽  
Horizontal Ground Motion ◽  
Ground Motion Records

The occurred damages during the past significant earthquakes have proved that vertical seismic excitation has tremendous effect on bridges. Three-component earthquake excitations are preferred to resemble the earthquakes. In this article, a cable-stayed arch bridge, a new type of bridge with the hybrid system of half-through arch and stay-cables, was analyzed under a set of different earthquake excitations (more than 21 ground motion records). Both vertical and horizontal components of the ground motions were considered to act simultaneously at the bridge supports. By using different three-component earthquake excitations, the dynamic responses of the bridge, including the displacements and accelerations of the main parts of the bridge, were obtained. The effects of various parameters such as soil type, epicentral distance, spatial variation of the ground motions, and dimensional variation of the structure were investigated. The results of the numerical study indicate that the cable-stayed arch bridge subjected to both horizontal and vertical components of earthquakes are more vulnerable than those subjected to horizontal ground motion only.

scholarly journals Simulation of non-stationary stochastic ground motions based on recent Italian earthquakes

2021 ◽  
Author(s):  
Fabio Sabetta ◽  
Antonio Pugliese ◽  
Gabriele Fiorentino ◽  
Giovanni Lanzano ◽  
Lucia Luzi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Stochastic Simulations ◽  
Model Parameters ◽  
Motion Model ◽  
Arias Intensity ◽  
Time Frequency ◽  
Ground Motion Model ◽  
Ground Motion Records

AbstractThis work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.

Numerical Modeling of Near Fault Seismic Ground Motion for Denali Fault

2021 ◽  
Vol 12 (2) ◽  
pp. 0-0
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Numerical Study ◽  
Ground Motions ◽  
Numerical Results ◽  
Fault Rupture ◽  
Ground Acceleration ◽  
Denali Fault ◽  
Near Fault ◽  
Good Agreement

An effective earthquake (Mw 7.9) struck Alaska on 3 November, 2002. This earthquake ruptured 340 km along Susitna Glacier, Denali and Totschunda faults in central Alaska. The peak ground acceleration (PGA) was recorded about 0.32 g at station PS10, which was located 3 km from the fault rupture. The PGA would have recorded a high value, if more instruments had been installed in the region. A numerical study has been conducted to find out the possible ground motion record that could occur at maximum horizontal slip during the Denali earthquake. The current study overcomes the limitation of number of elements to model the Denali fault. These numerical results are compared with observed ground motions. It is observed that the ground motions obtained through numerical analysis are in good agreement with observed ground motions. From numerical results, it is observed that the possible expected PGA is 0.62 g at maximum horizontal slip of Denali fault.

A Monte Carlo approach to seismic hazard analysis

1999 ◽  
Vol 89 (4) ◽  
pp. 854-866 ◽  
Author(s):  
John E. Ebel ◽  
Alan L. Kafka
Keyword(s):  
Monte Carlo ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Epicentral Distance ◽  
Ground Motions ◽  
Source Parameters ◽  
Parametric Models ◽  
Earthquake Catalog ◽  
Attenuation Relations ◽  
Ground Motion Attenuation

Abstract We have developed a Monte Carlo methodology for the estimation of seismic hazard at a site or across an area. This method uses a multitudinous resampling of an earthquake catalog, perhaps supplemented by parametric models, to construct synthetic earthquake catalogs and then to find earthquake ground motions from which the hazard values are found. Large earthquakes extrapolated from a Gutenberg-Richter recurrence relation and characteristic earthquakes can be included in the analysis. For the ground motion attenuation with distance, the method can use either a set of observed ground motion observations from which estimates are randomly selected, a table of ground motion values as a function of epicentral distance and magnitude, or a parametric ground motion attenuation relation. The method has been tested for sites in New England using an earthquake catalog for the northeastern United States and southeastern Canada, and it yields reasonable ground motions at standard seismic hazard values. This is true both when published ground motion attenuation relations and when a dataset of observed peak acceleration observations are used to compute the ground motion attenuation with distance. The hazard values depend to some extent on the duration of the synthetic catalog and the specific ground motion attenuation used, and the uncertainty in the ground motions increases with decreasing hazard probability. The program gives peak accelerations that are comparable to those of the 1996 U.S. national seismic hazard maps. The method can be adapted to compute seismic hazard for cases where there are temporal or spatial variations in earthquake occurrence rates or source parameters.

scholarly journals Probabilistic sensitivity analysis of two suspension bridges in Istanbul, Turkey to near- and far-fault ground motion

2012 ◽  
Vol 12 (2) ◽  
pp. 459-473 ◽  
Author(s):  
Ö. Çavdar
Keyword(s):  
Ground Motion ◽  
Dynamic Responses ◽  
Suspension Bridges ◽  
Near Fault ◽  
Internal Forces ◽  
Ground Motion Records ◽  
Far Fault ◽  
Sensitivity Method ◽  
Mcs Method ◽  
Strong Ground

Abstract. The aim of this paper is to compare the near-fault and far-fault ground motion effects on the probabilistic sensitivity dynamic responses of two suspension bridges in Istanbul. Two different types of suspension bridges are selected to investigate the near-fault (NF) and far-fault (FF) ground motion effects on the bridge sensitivity responses. NF and FF strong ground motion records, which have approximately identical peak ground accelerations, of the Kocaeli (1999) earthquake are selected for the analyses. Displacements and internal forces are determined using the probabilistic sensitivity method (PSM), which is one type of stochastic finite element method. The efficiency and accuracy of the proposed algorithm are validated by comparison with results of the Monte Carlo Simulation (MCS) method. The displacements and internal forces obtained from the analyses of suspension bridges subjected to each fault effect are compared with each other. It is clearly seen that there is more seismic demand on displacements and internal forces when suspension bridges are subjected to NF and FF ground motion.

scholarly journals Seismic Response of a Base Isolated Cable-Stayed Bridge Under Near-Fault Ground Motion Excitations

2018 ◽  
Vol 15 (1) ◽  
pp. 1-14
Author(s):  
Ahad Javanmardi ◽  
Zainab Ibrahim ◽  
Khaled Gheadi ◽  
Mohammed Jameel ◽  
Usman Hanif ◽  
...  
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Nonlinear Dynamic Analysis ◽  
Dynamic Responses ◽  
Base Shear ◽  
Seismic Behaviour ◽  
Isolation System ◽  
Near Fault ◽  
Cable Stayed Bridge ◽  
Near Fault Ground Motion

Nowadays, development of cable-stayed bridges is increasing around the world. The mitigation of seismic forces to these bridges are obligatory to prevent damages or failure of its structural members. Herein, this paper aimed to determine the near-fault ground motion effect on an existing cablestayed bridge equipped with lead-rubber bearing. In this context, Shipshaw cable-stayed bridge is selected as the case study. The selected bridge has a span of 183.2 m composite deck and 43 m height of steel tower. 2D finite element models of the non-isolated and base isolated bridges are modelled by using SAP2000. Three different near-fault ground motions which are Tabas 1978, Cape Mendocino 1992 and Kobe 1995 were subjected to the 2D FEM models in order to determine the seismic behaviour of the bridge. The near-fault ground motions were applied to the bridge in the longitudinal direction. Nonlinear dynamic analysis was performed to determine the dynamic responses of the bridge. Comparison of dynamic response of nonisolated and base isolated bridge under three different near-fault ground motions were conducted. The results obtained from numerical analyses of the bridge showed that the isolation system lengthened the period of bridge and minimised deck displacement, base shear and base moment of the bridge. It is concluded that the isolation system significantly reduced the destructive effects of near-fault ground motions on the bridge.

A Stochastic Model for Simulating Vertical Pulseless Near-Fault Seismic Ground Motions

2021 ◽  
Author(s):  
Xi Zhong Cui ◽  
Yong Xu Liu ◽  
Han Ping Hong
Keyword(s):  
Stochastic Model ◽  
Ground Motion ◽  
Ground Motions ◽  
Time History ◽  
Structural Deformation ◽  
Time Frequency ◽  
Motion Models ◽  
Near Fault ◽  
Simulation Techniques ◽  
Ground Motion Records

ABSTRACT The vertical near-fault seismic ground-motion component can cause significant structural deformation and damage, which can be evaluated from time history analysis using actual or synthetic ground-motion records. In this study, we propose a new stochastic model for the vertical pulseless near-fault ground motions that depends on earthquake magnitude, rupture distance, and site condition. The proposed model is developed based on the time–frequency characteristics of 606 selected actual vertical record components in strike-slip earthquakes. The use and validation of the model are presented using simulated records obtained by two simulation techniques. For the validation, the statistics of time–frequency-dependent power spectral acceleration estimated from the simulated records using the proposed stochastic model are compared with those from the actual records and the ground-motion models available in the literature.

Relations between MaxRotD50 and Some Horizontal Components of Ground-Motion Intensity Used in Practice

2021 ◽  
Author(s):  
Alan Poulos ◽  
Eduardo Miranda
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Ground Motions ◽  
Geometric Mean ◽  
The Other ◽  
Horizontal Projection ◽  
Site Class ◽  
Engineering Research ◽  
Natural Logarithm ◽  
Horizontal Ground Motion

ABSTRACT The most commonly used intensity measure of ground motion in earthquake engineering is the 5% damped spectral ordinate, which varies in different directions. Several different measures have been proposed over the years to combine the intensity of the two horizontal recorded ground motions to derive ground-motion models as well as for design purposes. This study provides the relation to seven previously used measures of horizontal ground motion with respect to a recently proposed orientation-independent measure of horizontal ground-motion intensity referred to as MaxRotD50. This new measure of horizontal intensity is defined as the median value of the maximum spectral ordinate of two orthogonal directions computed for all possible nonredundant orientations. The relations are computed using 5065 pairs of horizontal ground motions taken from the database of ground motions recorded in shallow crustal earthquakes in active tectonic regions developed as part of the Pacific Earthquake Engineering Research Center’s Next Generation Attenuation-West2 project. Empirically derived period-dependent relations are presented for three quantities that permit transforming any of the seven other definitions of horizontal ground-motion intensity to MaxRotD50, namely, (1) geometric mean of the ratio of MaxRotD50 to any of the seven other measures of intensities, (2) standard deviation of the natural logarithm of the ratio of MaxRotD50 to any of the seven other measures of intensities, and (3) the correlation between the natural logarithm of the ratio of MaxRotD50 to the other measures of intensities and the natural logarithm of the other measure of intensity. In addition, the influence of site class at the recording station, earthquake magnitude, and distance to the horizontal projection of the rupture is examined on the geometric mean of the ratio of MaxRotD50 to the median intensity of all nonredundant orientations (i.e., RotD50), showing negligible influence of site class and only a relatively small influence of magnitude and distance.

Turkey-Adjusted NGA-W1 Horizontal Ground Motion Prediction Models

2016 ◽  
Vol 32 (1) ◽  
pp. 75-100 ◽  
Author(s):  
Zeynep Gülerce ◽  
Bahadır Kargoığlu ◽  
Norman A. Abrahamson
Keyword(s):  
Ground Motion ◽  
Strong Ground Motion ◽  
Prediction Models ◽  
Ground Motions ◽  
Site Amplification ◽  
Motion Prediction ◽  
Ground Motion Prediction ◽  
Data Set ◽  
Horizontal Ground Motion ◽  
Strong Ground

The objective of this paper is to evaluate the differences between the Next Generation Attenuation: West-1 (NGA-W1) ground motion prediction models (GMPEs) and the Turkish strong ground motion data set and to modify the required pieces of the NGA-W1 models for applicability in Turkey. A comparison data set is compiled by including strong motions from earthquakes that occurred in Turkey and earthquake metadata of ground motions consistent with the NGA-W1 database. Random-effects regression is employed and plots of the residuals are used to evaluate the differences in magnitude, distance, and site amplification scaling. Incompatibilities between the NGA-W1 GMPEs and Turkish data set in small-to-moderate magnitude, large distance, and site effects scaling are encountered. The NGA-W1 GMPEs are modified for the misfit between the actual ground motions and the model predictions using adjustments functions. Turkey-adjusted NGA-W1 models are compatible with the regional strong ground motion characteristics and preserve the well-constrained features of the global models.

Identification of Pulse Periods in Near‐Fault Ground Motions Using the HHT Method

2019 ◽  
Vol 109 (6) ◽  
pp. 2384-2398 ◽  
Author(s):  
Xiaoyu Chen ◽  
Dongsheng Wang ◽  
Rui Zhang
Keyword(s):  
Ground Motion ◽  
Time Course ◽  
Ground Motions ◽  
Flexible Structures ◽  
Peak Ground Velocity ◽  
Damage Effect ◽  
Near Fault ◽  
Long Period ◽  
Frequency Components ◽  
Ground Motion Records

Abstract Large‐amplitude and long‐period pulses are observed in velocity time histories of near‐fault ground‐motion records. The pulses in these records have significant damage effect on flexible structures due to their long‐period property; therefore, more attention should be paid to the frequency components in the ground motion. Based on the identification of frequency components in the original record, a new method based on the Hilbert–Huang transform (HHT) is proposed here. A ground‐motion record can be decomposed into several intrinsic mode functions (IMFs) that carry different frequency components by the HHT without contamination from any a prior function. Only two fixed parameters, the peak ground velocity (PGV)/peak ground acceleration (PGA) ratio and the energy change of every IMF, are used to classify pulse‐like ground‐motion records. The inherent pulses of these records can also be extracted, based on the selection of IMFs for which PGV/PGA ratios are larger than 0.12 and energy changes that are greater than 0.1. For multipulse cases, all the pulses can be captured after extracting once, and the time course of inherent pulses can also be obtained. Then, pulse periods are calculated based on the solutions of instantaneous frequency of the peak for the extracted pulses. All the periods obtained using the HHT method can be verified by the results obtained from Baker’s wavelet method. The 24 controversial records that are discussed in previous studies are examined here as well. The HHT method is a complete procedure that includes the classification of pulse‐like ground motions, the extraction of velocity pulses, and the solution of pulse periods. It works well for multipulse records, especially because it can provide the exact timing of all the inherent pulses.

scholarly journals Orientation effects of horizontal seismic components on longitudinal reinforcement in R/C frame elements

2012 ◽  
Vol 12 (1) ◽  
pp. 1-10 ◽  
Author(s):  
K. G. Kostinakis ◽  
A. M. Athanatopoulou ◽  
I. E. Avramidis
Keyword(s):  
Ground Motion ◽  
Cross Sections ◽  
Linear Response ◽  
Ground Motions ◽  
Longitudinal Reinforcement ◽  
Analysis And Design ◽  
History Analysis ◽  
Response History Analysis ◽  
Internal Forces ◽  
Horizontal Ground Motion

Abstract. The present paper investigates the influence of the orientation of recorded horizontal ground motion components on the longitudinal reinforcement of R/C frame elements within the context of linear response history analysis. For this purpose, three single-story buildings are analyzed and designed for 13 recorded bi-directional ground motions applied along the horizontal structural axes. The analysis and design is performed for several orientations of the recording angle of the horizontal seismic components. For each orientation the longitudinal reinforcement at all critical cross sections is calculated using four methods of selecting the set of internal forces needed to compute the required reinforcement. The results show that the reinforcement calculated by three of the applied methods is significantly affected by the orientation of the recording angle of ground motion, while the fourth one leads to results which are independent of the orientation of the recording angle.

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