A Modified Algorithm to identify the strongest velocity pulse in three orthogonal components of ground motions

2021 ◽  
Vol 146 ◽  
pp. 106749
Author(s):  
Tianci Zhao ◽  
Boming Zhao
Keyword(s):  
Ground Motions ◽  
Velocity Pulse ◽  
Orthogonal Components ◽  
Modified Algorithm

Conditional Ground-Motion Model for Damaging Characteristics of Near-Fault Ground Motions Based on Instantaneous Power

2020 ◽  
Vol 110 (6) ◽  
pp. 2828-2842
Author(s):  
Esra Zengin ◽  
Norman Abrahamson
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Accurate Estimation ◽  
Spectral Acceleration ◽  
Motion Model ◽  
Velocity Pulse ◽  
Near Fault ◽  
Instantaneous Power ◽  
Ground Motion Model ◽  
Short Time

ABSTRACT The velocity pulse in near-fault ground motions has been used as a key characteristic of damaging ground motions. Characterization of the velocity pulse involves three parameters: presence of the pulse, period of the pulse, and amplitude of the pulse. The basic concept behind the velocity pulse is that a large amount of seismic energy is packed into a short time, leading to larger demands on the structure. An intensity measure for near-fault ground motions, which is a direct measure of the amount of energy arriving in short time, called instantaneous power (IP (T1)), is defined as the maximum power of the bandpass-filtered velocity time series measured over a time interval of 0.5T1, in which T1 is the fundamental period of the structure. The records are bandpass filtered in the period band (0.2T1−3T1) to remove the frequencies that are not expected to excite the structure. Zengin and Abrahamson (2020) showed that the drift is better correlated with the IP (T1) than with the velocity pulse parameters for records scaled to the same spectral acceleration at T1. A conditional ground-motion model (GMM) for the IP is developed based on the 5%-damped spectral acceleration at T1, the earthquake magnitude, and the rupture distance. This conditional GMM can be used for record selection for near-fault ground motions that captures the key features of velocity pulses and can lead to a better representation of the median and variability of the maximum interstory drift. The conditional GMM can also be used in a vector hazard analysis for spectral acceleration (T1) and IP (T1) that can be used for more accurate estimation of drift hazard and seismic risk.

Shear Resistant Behavior of RC Columns Subjected to Axial Pulse-Like Ground Motions

2013 ◽  
Vol 639-640 ◽  
pp. 832-835
Author(s):  
Wei Feng Zhao ◽  
Xiao Quan Hu ◽  
Qin Chen
Keyword(s):  
Axial Velocity ◽  
Ground Motions ◽  
Time History ◽  
Load Ratio ◽  
Spectral Ratio ◽  
Shear Capacity ◽  
Velocity Pulse ◽  
Rc Columns ◽  
Shear Span ◽  
Earthquake Records

The shear-resistant behavior of reinforced concrete (RC) columns subjected to axial velocity pulse-like ground motions was studied. Single RC columns with the constant vertical and horizontal fundamental period were used to investigate the influences of fault-distance of earthquake records, vertical to horizontal acceleration spectral ratio of earthquake records, initial axial load ratio and shear span ratio of RC column, on the shear-resistant behavior of RC columns. a suite of 18 strong ground motion records from Chi-chi earthquake divided into three fault-distance groups were taken as excitations to execute nonlinear dynamic time history analysis. The results demonstrated that axial velocity pulse-like earthquake action (fault-distance) had significant influences on the shear resistant-resistant of RC columns. Shear-resistant behavior (shear capacity/shear demand) increases with the increasing of fault-distance. Fault-distance and shear span ratio had a certain coupling influences on the shear-resistant behavior of RC columns.

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.

Shaking Table Test Study on Seismic Responses of Base-Isolated Buildings under Near-Fault Ground Motions

2014 ◽  
Vol 1020 ◽  
pp. 457-462
Author(s):  
Miao Han ◽  
Yan Ling Duan ◽  
Huan Sun
Keyword(s):  
Shaking Table Test ◽  
Ground Motions ◽  
Shaking Table ◽  
Scale Model ◽  
Seismic Responses ◽  
Velocity Pulse ◽  
Isolation System ◽  
Near Fault ◽  
Test Study ◽  
Isolated Structures

The shaking table tests of a 1:7 scale model of three-floor steel frame base-isolated building was completed to study the seismic responses of base-isolated buildings under near-fault ground motions. Under the action of the typical near-fault seismic wave, the seismic responses of base-isolated structures increase with the increase of PGA. The maximum story displacements of super-structure decrease with increase of story. The velocity pulse has an adverse effect to acceleration responses of base-isolated structures. The isolation effect of base-isolated super-structures is still favorable under near-fault ground motions, but it will be necessary to add damping in isolation system or limit the displacement of bearings to prevent the excessive deformation of isolation layer.

Dynamic Rupture Study of Near-Field Velocity Pulses during the 2016 Kumamoto Earthquake, Japan

2021 ◽  
Author(s):  
Kenichi Tsuda
Keyword(s):  
Ground Motions ◽  
2016 Kumamoto Earthquake ◽  
Dynamic Rupture ◽  
Velocity Pulse ◽  
Geometrical Properties ◽  
Kumamoto Earthquake ◽  
Near Fault ◽  
The 2016 Kumamoto Earthquake ◽  
Simulated Ground Motions ◽  
Shallow Part

ABSTRACT Simulating the ground motions of future earthquakes requires a proper understanding and modeling of source, path, and site effects. Ground motions recorded during recent earthquakes very close to their ruptured faults provide new evidence of the importance of source effects and suggest that physics-based rupture modeling is critical to account for them. Here, we develop dynamic rupture models to simulate the near-fault ground motions generated by the 2016 Kumamoto, Japan, earthquake (Mw 7.0) at Nishihara village, which feature a large-amplitude velocity pulse. Comparison of mainshock and foreshock waveforms suggests that the source of the velocity pulse is on the Futagawa fault segment located very close to the site. Our dynamic models use the spectral element method and are built upon a previous kinematic description of the event via a so-called “characterized source model,” with three strong-motion generation areas (SMGAs) on the assumed fault plane. We first develop a reference model that reproduces the main features of the rupture process in agreement with previous results of kinematic source inversion. We then examine the sensitivity of the simulated near-fault ground motions to the frictional parameters (critical slip-weakening distance and stress drop) in the shallow part of the fault and to the geometrical properties of the shallow SMGA. Even assuming drastically different frictional properties in the shallow part of the fault, the amplitude of the simulated ground motions was affected little. On the other hand, changes of geometrical properties of the shallow SMGA generated large differences in simulated ground motions. The results indicate that geometrical features of the shallow SMGA played a more important role in generating near-fault ground motions with velocity pulses as observed at Nishihara village during the 2016 Kumamoto earthquake.

Experimental Study of Near-Fault Effect on Sloshing Mode of Storage Liquid in Tanks

2019 ◽  
Author(s):  
Juin-Fu Chai ◽  
Fan-Ru Lin ◽  
Wei-Hung Hsu ◽  
Tzu-Chieh Chien ◽  
Zhi-Yu Lai ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Ground Motions ◽  
Prediction Equation ◽  
Resonant Response ◽  
Spent Fuel ◽  
Velocity Pulse ◽  
Near Fault ◽  
Resonant Effect ◽  
Sloshing Mode

Abstract The long period velocity pulse is recognized as one of the characteristics of near-fault ground motions, and hence the response of vibration modes with lower frequencies will be amplified owing to the resonant effect. In general, the sloshing frequency of storage liquid is low and the period is similar to the pulse period of near-fault ground motions. Compared to the far-field ground motions, the induced sloshing height will be amplified by the near-fault ground motions. Therefore, it is worth paying attention to the resonant effect of near-fault ground motions on the sloshing mode of storage liquid in tanks. An experiment was implemented to study the resonant response of sloshing mode. The purpose of this experiment is to estimate the slosh height and the associated total volume of water splashing out of the tank under near-fault ground motions, and also to determine the relationship between the resonant response and the input velocity pulse. This paper aims to describe the test plan in detail, and it consists of (1) design of the scaled storage tank and water depth, (2) selection and processing of the input motions including the original near-fault ground motions, extracted velocity pulse or extracted bandpass signals for resonance analysis, and also impulse motion for free vibration, (3) setup of measure instrument, and (4) the experimental procedures as well. Preliminary analysis results are compared with the code-specified values that is determined by the industrial standards and guidelines for general seismic conditions. It is noted that the proposed prediction equation can be applied to the seismic design and evaluation of spent fuel pool in nuclear power plants.

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