Amplification of seismic demands in inter-storey-isolated buildings subjected to near fault pulse type ground motions

2021 ◽  
Vol 147 ◽  
pp. 106771
Author(s):  
Arijit Saha ◽  
Sudib Kumar Mishra
Keyword(s):  
Ground Motions ◽  
Seismic Demands ◽  
Near Fault ◽  
Pulse Type

A simplified iterative approach for testing the pulse derailment of light rail vehicles across a viaduct to near-fault earthquake scenarios

2021 ◽  
pp. 095440972098741
Author(s):  
Ling-Kun Chen ◽  
Peng Liu ◽  
Li-Ming Zhu ◽  
Jing-Bo Ding ◽  
Yu-Lin Feng ◽  
...  
Keyword(s):  
Ground Motions ◽  
Simulation Software ◽  
Light Rail ◽  
Rail Transit ◽  
Light Rail Transit ◽  
Seismic Responses ◽  
Near Fault ◽  
Rail Vehicle ◽  
Pulse Type ◽  
The Impact

Near-fault (NF) earthquakes cause severe bridge damage, particularly urban bridges subjected to light rail transit (LRT), which could affect the safety of the light rail transit vehicle (“light rail vehicle” or “LRV” for short). Now when a variety of studies on the fault fracture effect on the working protection of LRVs are available for the study of cars subjected to far-reaching soil motion (FFGMs), further examination is appropriate. For the first time, this paper introduced the LRV derailment mechanism caused by pulse-type near-fault ground motions (NFGMs), suggesting the concept of pulse derailment. The effects of near-fault ground motions (NFGMs) are included in an available numerical process developed for the LRV analysis of the VBI system. A simplified iterative algorithm is proposed to assess the stability and nonlinear seismic response of an LRV-reinforced concrete (RC) viaduct (LRVBRCV) system to a long-period NFGMs using the dynamic substructure method (DSM). Furthermore, a computer simulation software was developed to compute the nonlinear seismic responses of the VBI system to pulse-type NFGMs, non-pulse-type NFGMs, and FFGMs named Dynamic Interaction Analysis for Light-Rail-Vehicle Bridge System (DIALRVBS). The nonlinear bridge seismic reaction determines the impact of pulses on lateral peak earth acceleration (Ap) and lateral peak land (Vp) ratios. The analysis results quantify the effects of pulse-type NFGMs seismic responses on the LRV operations' safety. In contrast with the pulse-type non-pulse NFGMs and FFGMs, this article's research shows that pulse-type NFGM derail trains primarily via the transverse velocity pulse effect. Hence, this study's results and the proposed method can improve the LRT bridges' seismic designs.

Simulation of Palu IV Bridge Collapse using Near-Fault Ground Motions

2019 ◽  
Author(s):  
Iswandi Imran ◽  
Budi Santoso ◽  
Ary Pramudito ◽  
Muhammad Kadri Zamad
Keyword(s):  
Spatial Variation ◽  
Ground Motions ◽  
Time History ◽  
Seismic Demand ◽  
Fault Line ◽  
Near Fault ◽  
Failure Simulation ◽  
Bridge Collapse ◽  
Pulse Type ◽  
Bridge Bearing

<p>The earthquake near Palu, Sulawesi (Indonesia) on September 28, 2018 with a magnitude of M7.4 was caused by a shallow strike-slip of Palu-Koro fault. The earthquake and the subsequent tsunami have caused the collapse of the Ponulele Bridge (Palu IV Bridge). The steel box bowstring arch bridge was located near-fault regions (within 1,5 km from fault line) that have not been identified during the design process. This bridge may have been damaged by the presence of fling-step pulses in the near-fault pulse-type ground motions that increases the damaging potential of such ground motions. This paper presents the failure simulation of the bridge subjected to the near fault pulse type time history with spatial variation ground motions applied on multiple bridge supports. From the simulation, it is concluded that the near fault effects and the spatial variation of the ground motion have increased significantly the seismic demand on the bridge. This increase causes the failure in the anchorage of the bridge bearing system.</p>

Impact of Near-Fault Ground Motions on the Efficiency of Viscous-Damping Systems

2016 ◽  
Author(s):  
Yin-Nan Huang ◽  
Chia-Ren Liu
Keyword(s):  
Energy Dissipation ◽  
Ground Motions ◽  
Viscous Damping ◽  
Major Focus ◽  
Seismic Demands ◽  
Single Degree ◽  
Near Fault ◽  
Long Period ◽  
The Impact ◽  
Damping Systems

Energy dissipation systems can effectively reduce the seismic demands of structures and protect them from damage. However, the effectiveness of the systems is not entirely independent from the dynamic characteristics of ground motions and may be challenged by long-period velocity pulses in near-fault ground motions. The major focus of this study is to clarify the impact of the characteristics of near-fault ground motions on the effectiveness of energy dissipation systems, particularly, structures equipped with viscous dampers. A series of response-history analyses are conducted using single degree-of-systems (SDOF) with periods varying between 0.2 and 5 seconds and damping ratios between 5% and 50% and subjected to fault-normal components of 91 sets of near-fault ground motions identified in a literature prepared by Prof. Jack Baker in 2007. The effectiveness of damping in reducing seismic demands of SDOF systems subjected to near-fault motions are discussed and a model are proposed to describe their relationship.

DEVELOPMENT OF AN IMPROVED INTENSITY MEASURE IN ORDER TO REDUCE THE VARIABILITY IN SEISMIC DEMANDS UNDER NEAR-FAULT GROUND MOTIONS

2012 ◽  
Vol 06 (02) ◽  
pp. 1250012 ◽  
Author(s):  
A. YAHYAABADI ◽  
M. TEHRANIZADEH
Keyword(s):  
Seismic Performance ◽  
Ground Motions ◽  
Intensity Measure ◽  
Seismic Performance Assessment ◽  
Seismic Demands ◽  
Demand Prediction ◽  
Near Fault ◽  
Long Period ◽  
Short Period ◽  
Pseudo Spectral

Intensity measure (IM) which describes the strength of an earthquake record plays an important role in the seismic performance assessment of structures. An improved IM that can reduce the variability in seismic demands helps reducing the number of records necessary to predict the seismic performance with sufficient accuracy. In this study, an improved RMS-based IM is developed based on the results obtained from incremental dynamic analyses of short-to relatively long-period frames under an ensemble of near-fault pulse-like earthquake records. It is observed that the root-mean-square value of pseudo spectral accelerations, (Sa) rms , is generally superior to that of spectral velocities, (Sv) rms , in seismic demand prediction under near-fault records. To compute (Sa) rms as IM, two appropriate period ranges are suggested for short- and moderated-to relatively long-period frames, respectively. Comparing the efficiency of (Sa) rms with several advanced IMs shows that (Sa) rms is more efficient in predicting the inelastic response and collapse capacity of short-period frames. It is also found that intensity measure (Sa) rms is sufficient with respect to the magnitude and source-to-site distance for all frames of various heights under near-fault ground motions.

Identification Methods of Important Parameters for Near-Fault Pulse-Type Ground Motions

2012 ◽  
Vol 594-597 ◽  
pp. 1688-1691
Author(s):  
Ming Li ◽  
Qiao Jin ◽  
Yong Liu ◽  
He Yuan ◽  
Zhe Zhe Sun
Keyword(s):  
Ground Motion ◽  
Peak Velocity ◽  
Ground Motions ◽  
Velocity Pulse ◽  
Identification Methods ◽  
Near Fault ◽  
Pulse Type ◽  
Pulse Peak ◽  
Motion Parameters ◽  
Near Fault Ground Motion

during the process of fitting or synthesizing near-fault ground motion，parameters of the equivalent velocity pulse need to be decided based on seismic records．Thus, it is a key problem that how to identify these parameters from the records．Pulse period and pulse peak velocity are important parameters in the equivalent velocity pulse models．In this study，various methods on identifying these parameters are reviewed．It is shown that all the existing methods have limitations，especially for the irregular seismic records．Finally，problems need to be further studied is pointed out.

scholarly journals Seismic Response of Skewed Integral Abutment Bridges under Near-Fault Ground Motions, Including Soil–Structure Interaction

2021 ◽  
Vol 11 (7) ◽  
pp. 3217
Author(s):  
Qiuhong Zhao ◽  
Shuo Dong ◽  
Qingwei Wang
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Ground Motions ◽  
Integral Abutment ◽  
Skew Angle ◽  
Nonlinear Dynamic Response ◽  
Integral Abutment Bridges ◽  
Near Fault ◽  
Abutment Bridges ◽  
Pulse Type

Studies on the seismic response of skewed integral abutment bridges have mainly focused on response under far-field non-pulse-type ground motions, yet the large amplitude and long-period velocity pulses in near-fault ground motions might have significant impacts on bridge seismic response. In this study, the nonlinear dynamic response of an skewed integral abutment bridge (SIAB) under near-fault pulse and far-fault non-pulse type ground motions are analyzed considering the soil–structure interaction, along with parametric studies on bridge skew angle and compactness of abutment backfill. For the analyses, three sets of near-fault pulse ground motion records are selected based on the bridge site conditions, and three corresponding far-field non-pulse artificial records are fitted by their acceleration response spectra. The results show that the near-fault pulse type ground motions are generally more destructive than the non-pulse motions on the nonlinear dynamic response of SIABs, but the presence of abutment backfill will mitigate the pulse effects to some extent. Coupling of the longitudinal and transverse displacements as well as rotation of the bridge deck would increase with the skew angle, and so do the internal forces of steel H piles. The influence of the skew angle would be most obvious when the abutment backfill is densely compacted.

Displacement-Based Probabilistic Seismic Demand Analyses of Earth Slopes in the Near-Fault Region

2016 ◽  
Vol 32 (2) ◽  
pp. 1141-1163 ◽  
Author(s):  
Adrian Rodriguez-Marek ◽  
Jian Song
Keyword(s):  
Ground Motions ◽  
Seismic Demands ◽  
Adequate Treatment ◽  
Ground Shaking ◽  
Nonlinear Seismic Response ◽  
Near Fault ◽  
Probabilistic Seismic Demand ◽  
Earth Slopes ◽  
Displacement Based ◽  
Fault Region

Near-fault pulses can result in high seismic demands on slopes in the proximity of a fault. A probabilistic methodology to capture the effects of near-fault pulses on seismically-induced slope displacements is proposed. This methodology allows for a separate and more adequate treatment of the sliding displacement of slopes when these are subject to pulse-like near-fault forward directivity motions. Simplified pulse parameters are used to predict displacements for cases where the near-fault pulses may induce resonances in the slope. The method explicitly includes the effects of near-fault pulses both on the ground shaking and nonlinear seismic response of slopes. An example application illustrates the use of the proposed procedure. Results show that the proposed approach increases the predicted earthquake-induced displacements of earth slopes located near the fault. Finally, the proposed procedure generates hazard deaggregation plots that are a useful tool for selecting ground motions for the design of slopes near faults.

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