scholarly journals Efficiency of Intensity Measures Considering Near- and Far-Fault Ground Motion Records

Geosciences ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 234
Author(s):  
Yeudy F. Vargas-Alzate ◽  
Jorge E. Hurtado
Keyword(s):  
Ground Motion ◽  
High Efficiency ◽  
Fragility Curves ◽  
Nonlinear Dynamic Response ◽  
Intensity Measures ◽  
Engineering Demand Parameter ◽  
Ground Motion Records ◽  
Seismic Response Of Buildings ◽  
Near Fault Ground Motion ◽  
Far Fault

This paper focuses on the identification of high-efficiency intensity measures to predict the seismic response of buildings affected by near- and far-fault ground motion records. Near-fault ground motion has received special attention, as it tends to increase the expected damage to civil structures compared to that from ruptures originating further afield. In order to verify this tendency, the nonlinear dynamic response of 3D multi-degree-of-freedom models is estimated by using a subset of records whose distance to the epicenter is lower than 10 Km. In addition, to quantify how much the expected demand may increase because of the proximity to the fault, another subset of records, whose distance to the epicenter is in the range between 10 and 30 Km, has been analyzed. Then, spectral and energy-based intensity measures as well as those obtained from specific computations of the ground motion record are calculated and correlated to several engineering demand parameters. From these analyses, fragility curves are derived and compared for both subsets of records. It has been observed that the subset of records nearer to the fault tends to produce fragility functions with higher probabilities of exceedance than the ones derived for far-fault records. Results also show that the efficiency of the intensity measures is similar for both subsets of records, but it varies depending on the engineering demand parameter to be predicted.

Ground Motion Intensity Measures for Rocking Building Systems

2017 ◽  
Vol 33 (4) ◽  
pp. 1533-1554 ◽  
Author(s):  
Mehrdad Shokrabadi ◽  
Henry V. Burton
Keyword(s):  
Ground Motion ◽  
Structural Response ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Braced Frame ◽  
Residual Drift ◽  
Engineering Demand Parameter ◽  
Frame System ◽  
Ground Motion Records ◽  
Steel Braced Frame

This paper investigates the effectiveness of various ground motion intensity measures (IMs) in estimating the structural response of two types of rocking systems: (a) a controlled rocking steel braced frame system with self-centering action and (b) a rocking spine system for reinforced concrete infill frames. The IMs are evaluated based on the dispersion in engineering demand parameter (EDP) predictions (efficiency) and the sensitivity of the conditional distributions of EDPs to the distributions of the magnitudes, distances and spectral shape parameter (ε) of ground motion records (sufficiency). The EDPs include maximum transient and residual story drifts and peak floor accelerations. The spectral acceleration averaged over a range of periods (Sa avg) is most effective for predicting transient and residual drift demands and peak ground acceleration (PGA) is generally the best predictor of peak floor accelerations. The proximity of the frequency range most affecting an EDP to that best reflected in an IM is found to be a good indicator of the performance of that IM.

scholarly journals Variation of Near Fault Ground Motion Intensity Measures Due to Filtering

2020 ◽  
Vol 3 (2) ◽  
pp. 841-849
Author(s):  
Esengul Cavdar ◽  
Gokhan Ozdemir ◽  
Ozkan Kale
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Low Frequency ◽  
Frequency Noise ◽  
Intensity Measures ◽  
Near Fault ◽  
Cutting Frequency ◽  
Ground Motion Records ◽  
Near Fault Ground Motion ◽  
High Pass

Ground motions recorded at near fault zones ensures rich low frequency contents, and high velocity pulse signals which may result in large shear force and displacement demands in structural elements. During the recording of these seismic events by accelerometers, low-frequency noise may sometimes accompany the signal. Thus, extracting this noise from recorded acceleration data is a crucial step of post-processing performed prior to use of acceleration time series in structural analyses for both design or assessment purpose. The objective of this study is to assess the effect of high-pass filtering on the intensity measures of ground motions. A set of near fault ground motions that comprises both pulse-like and non-pulse like characteristics were selected and they were subjected to filtering for various cutting frequency contents. As a function of filtering, variation in several intensity measures of filtered ground motions namely, PGD, PGV, PGA, PGV/PGA and significant duration were analyzed. It is revealed that changing the cutting frequency of high pass filtering considerably changes the intensity measures of ground motion records.

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 FRAGILITY ASSESSMENT AND RETROFIT OF A GOVERNMENT HOSPITAL BUILDING IN CHITTAGONG, BANGLADESH

2018 ◽  
Vol 30 (1) ◽  
Author(s):  
Md. AbulHasan ◽  
Md. Abdur Rahman Bhuiyan
Keyword(s):  
Ground Motion ◽  
Return Period ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Seismic Fragility ◽  
Earthquake Ground Motion ◽  
Type I ◽  
Type Ii ◽  
Ground Motion Records

Chittagong Medical College Hospital (CMCH) is one of the most important government hospitals in Bangladesh. It is located in the heart of Chittagong city, the only port city of Bangladesh. Bangladesh National Building Code (BNBC) is the only official document, which has been used since 1993 as guidelines for seismic design of buildings. As per the guidelines of BNBC, the CMCH building was designed for an earthquake ground motion having a return period of 200 years. However, the revised version of BNBC has suggested that the building structures shall be designed for an earthquake ground motion having a return period of 2475 years. It is mentioned that a single seismic performance objective, the life safety, of the building is considered in both versions of BNBC. Considering the significant importance of CMCH building in providing the emergency facilities during and after the earthquake, it is indispensable to evaluate its seismic vulnerability for the two types of earthquake ground motion records having return period of 200 (Type-I) and 2475 (Type-II) years. In this regard, this paper deals with the seismic vulnerability assessment of the existing ancillary building (AB) of CMCH. The seismic vulnerability of building is usually expressed in the form of fragility curves, which display the conditional probability that the structural demand (structural response) caused by various levels of ground shaking exceeds the structural capacity defined by a damage state. The analytical method based on elastic response spectrum analyses results is used in evaluating the seismic fragility curves of the building. To the end, 3-D finite element model of the building subjected to 18 ground motion records having PGA of 0.325g to 0.785g has been used in theresponse spectrum analysis in order to evaluate its inter-story-drift ratio (IDR), an engineeringdemand parameter (EDP) for developing fragility curves. The analytical results have shown thatstructural deficiencies exist in the existing ancillary building (AB) for the Type-II earthquakeground motion record, which requires the building to be retrofitted to ensure that the existingancillary building (AB) becomes functional during and after the Type-II earthquake groundmotion record.

Efficiency of ground motion intensity measures with earthquake-induced earth dam deformations

2020 ◽  
pp. 875529302093881
Author(s):  
Richard Armstrong ◽  
Tadahiro Kishida ◽  
DongSoon Park
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Earth Dam ◽  
Deformation Analysis ◽  
Embankment Dam ◽  
Natural Period ◽  
Intensity Measures ◽  
Embankment Dams ◽  
Engineering Demand Parameter ◽  
Almost All

In a seismic hazard analysis (SHA), the earthquake loading level should be predicted for one or more ground motion intensity measures (IMs) that are expected to relate well with the engineering demand parameters (EDPs) of the site. In this study, the goal was to determine the IMs that best relate to embankment dam deformations based on nonlinear deformation analysis (NDA) results of two embankment dams with a large suite of recorded ground motions. The measure utilized to determine the “best” IM was standard deviation in the engineering demand parameter (e.g., deformation) for a given IM, also termed “efficiency.” Results of the study demonstrated that for the NDA model used, Arias intensity (AI) was found to be the most efficient predictor of embankment dam deformations. In terms of pseudo-spectral acceleration (PSA)-based IMs, the PSA at short periods and then in the general range of the natural period of the dams was seen to be the most efficient IM, but was in almost all cases not as efficient as AI.

scholarly journals Evolution law of overall damage of concrete gravity dam under near-fault ground motion

2021 ◽  
Author(s):  
Yafei Zhai ◽  
Liaojun Zhang ◽  
Hanyun Zhang ◽  
Tianxiao Ma ◽  
Binghui Cui
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Gravity Dam ◽  
Gravity Dams ◽  
Near Fault ◽  
Concrete Gravity Dams ◽  
Fling Step ◽  
Ground Motion Records ◽  
Near Fault Ground Motion ◽  
Dynamic Damage

Abstract Strong earthquake cases of concrete gravity dams show that the foundation damage has an important influence on the seismic response and damage characteristics of the dam body. Compared with non-pulse ground motions, pulse-like near-fault ground motions have a wider response spectrum sensitive zone, which will cause more modes of the structure to respond, resulting in more serious damage to the structure. In order to study the real dynamic damage characteristics of concrete gravity dams under the action of near-fault ground motions, this paper takes Koyna gravity dam as the object and establishes a multi-coupling simulation model that can reasonably reflect the dynamic damage evolution process of dam concrete and foundation rock mass. A total of 12 near-fault ground motion records with three types of rupture directivity pulse, fling-step pulse and non-pulse are selected, deep research on the overall damage evolution law of concrete gravity dams. Considering the additional influence of different earthquake mechanisms, different site types and other factors on the study, the selected ground motion records are from the same seismic events (Chi-Chi), the same direction but different stations. The results show that the foundation of the concretes gravity dam often get damaged before the dam body under the action of strong earthquakes. Compared with the near-fault non-pulse ground motion, the structural damage of the gravity dam under the action of the near-fault directivity pulse ground motion is significantly increased, and causes greater damage and displacement response to the dam body. The near-fault fling-step pulse ground motion has the least impact on the dynamic response of the gravity dam structure.

scholarly journals Seismic Fragility Analysis of High Earth-Rockfill Dams considering the Number of Ground Motion Records

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Congcong Jin ◽  
Shichun Chi
Keyword(s):  
Ground Motion ◽  
Fragility Curves ◽  
Damage Index ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Settlement Rate ◽  
Earthquake Records ◽  
Rockfill Dam ◽  
Ground Motion Records ◽  
The Impact

This study analyzes the impact of the number of ground motions on the seismic fragility of a high earth-rockfill dam and the estimation of reasonable fragility parameters based on a sufficient number of earthquake records. In this paper, the vertical deformation is obtained using the three-dimensional finite element program DYNE3WAC combined with the Pastor–Zienkiewicz–Chan model and Biot dynamic consolidation theory. The relative seismic settlement rate is considered the damage index for the seismic fragility analysis of the dam. The fragility curves of the high earth-rockfill dam are determined by the multiple stripe analysis (MSA) method. A set of seismic waves is chosen based on the spectrum in the Chinese hydraulic structure seismic code. With an increasing number of earthquake records, the coefficients of variation (COV) of the mean and standard deviation (STD) of the relative seismic settlement rate decrease and tend to stabilize when the number of earthquake records reaches 34. The estimated fragility parameters θ and β are constant when the number of earthquake records exceeds 34. The requisite number of earthquake records for an accurate fragility estimation is determined by analyzing the lower and upper confidence intervals for the estimated θ and β. The 95% and 90% confidence interval can accurately estimate the fragility of a high earth-rockfill dam when the number of ground motion records reaches 36 and 32, respectively. The results of the fragility analysis demonstrate that the DYNE3WAC program and MSA method can provide an effective basis for determining fragility curves. Furthermore, the sensitivity analysis of earthquake records is essential for assessing the seismic fragility of high earth-rockfill dams.

Research on Seismic Response Estimation of Reinforced Concrete Pier under Pulse-Type Near-Fault Ground Motion

2013 ◽  
Vol 353-356 ◽  
pp. 1867-1870
Author(s):  
Yan Li Shen ◽  
Xiu Li Du ◽  
Qing Shan Yang
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Pushover Analysis ◽  
Elastic Response ◽  
Natural Period ◽  
Seismic Performance Evaluation ◽  
Near Fault ◽  
Pulse Type ◽  
Ground Motion Records ◽  
Near Fault Ground Motion

For estimating seismic response of pier-structure under near-fault ground motion, The typical pulse-type near-fault ground motion records were chosen to establish a record base, and three pier models with different natural period were established; The non-elastic response spectral displacement of ground motion was used to estimate the nonlinear response; The yield displacement of the nonlinear oscillator was defined based on the static pushover analysis result, and its influence on response estimation was studied. The study result is important for structural seismic response estimation by using the non-elastic response spectral displacement and the probability-based seismic performance evaluation.

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