scholarly journals Required Time Gap Between Mainshock and Aftershock for Dynamic Analysis of Structures

2021 ◽  
Author(s):  
Roohollah M. Pirooz ◽  
Soheila Habashi ◽  
Ali Massumi
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Strong Motion ◽  
Degree Of Freedom ◽  
Vibration Period ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Rest Time ◽  
Time Gap ◽  
Earthquake Sequences

Abstract Despite the various studies carried out to evaluate the effects of seismic sequences on structures, the matter of the time gap required to be considered between the mainshock and its corresponding aftershocks in dynamic analyses has never been focused on directly. This subtle but in the meantime effective subject, influences on the amount of accumulated damage caused by earthquake sequences. In the present study, 244 near fault ground motion components from 122 earthquakes were applied to a wide variety of single degree of freedom systems having vibrating period of 0.05 to 7 seconds with linear and nonlinear behavior. Furthermore, 2 planar steel moment-resisting frames, having 3 and 12 stories, were subjected to a set of 30 ground motion components. The purpose of this investigation was to estimate the required time for the structures to cease the free vibration at the end of the mainshock. The main purpose is to generate an estimation that is function of structural system’s parameters and the strong motion duration. Excellent correlations were obtained between the rest time and the following parameters: the combination of natural period of single degree of freedom systems, as well as the strong motion duration of earthquake sequences. In consequence, a formula is proposed which estimates the required optimized rest-time of a structure based on natural vibration period, as well as the duration of strong motion. Additionally, results obtained from the dynamic analysis of the steel frames validate the rest-time values achieved from the proposed formula.

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.

Ground Motion Prediction Model for the Peak Inelastic Displacement of Single-Degree-of-Freedom Bilinear Systems

2018 ◽  
Vol 34 (3) ◽  
pp. 1177-1199 ◽  
Author(s):  
Pablo Heresi ◽  
Héctor Dávalos ◽  
Eduardo Miranda
Keyword(s):  
Prediction Model ◽  
Ground Motion ◽  
Degree Of Freedom ◽  
Motion Prediction ◽  
Ground Motion Prediction ◽  
Vibration Period ◽  
Single Degree Of Freedom ◽  
Inelastic Displacement ◽  
Single Degree ◽  
Proposed Model

This paper presents a ground motion prediction model (GMPM) for estimating medians and standard deviations of the random horizontal component of the peak inelastic displacement of 5% damped single-degree-of-freedom (SDOF) systems, with bilinear hysteretic behavior and 3% postelastic stiffness ratio, directly as a function of the earthquake magnitude and the distance to the source. The equations were developed using a mixed effects model, with 1,662 recorded ground motions from 63 seismic events. In the proposed model, the median is computed as a function of the vibration period and the normalized strength of the system, as well as the event magnitude and the Joyner-Boore distance to the source. The standard deviation of the model is computed as a function of the vibration period and the normalized strength of the system. The proposed model has the advantage of not requiring an auxiliary elastic GMPM to predict the median and dispersion of peak inelastic displacement.

Dynamic analysis of single-degree-of-freedom systems (DYANAS): A graphical user interface for OpenSees

2018 ◽  
Vol 177 ◽  
pp. 395-408 ◽  
Author(s):  
Georgios Baltzopoulos ◽  
Roberto Baraschino ◽  
Iunio Iervolino ◽  
Dimitrios Vamvatsikos
Keyword(s):  
User Interface ◽  
Dynamic Analysis ◽  
Graphical User Interface ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Single Degree

scholarly journals Dynamical analysis of a single degree-of-freedom impact oscillator with impulse excitation

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771661 ◽  
Author(s):  
Jun Wang ◽  
Yongjun Shen ◽  
Shaopu Yang
Keyword(s):  
Periodic Motion ◽  
Dynamical Behavior ◽  
Degree Of Freedom ◽  
Dynamical Response ◽  
Restitution Coefficient ◽  
Impact Oscillator ◽  
Vibration Period ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Impulse Excitation

In this article, the dynamical behavior of a single degree-of-freedom impact oscillator with impulse excitation is studied, where the mass impacts at one stop and is shocked with impulse excitation at the other stop. The existing and stability conditions for periodic motion of the oscillator are established. The effects of system parameters on dynamical response are discussed under different initial velocities. It is found that smaller shock gap than impact gap could make the periodic motion more stable. The decrease in natural frequency would consume less impact energy, make the vibration frequency smaller, and reduce the vibration efficiency. Finally, the dynamical properties are further analyzed under a special case, that is, the shock gap approaches zero. It could be seen that the larger shock coefficient and impact restitution coefficient would make vibration period smaller. Based on the stability condition, there are an upper limit for the product of shock coefficient and impact restitution coefficient, so that a lower limit of corresponding vibration period exists.

scholarly journals Dynamic Response of RC Cantilever Beam by Equivalent Single Degree of Freedom Method on Elastic Analysis – A Review on Transformation Factors and Dynamic Magnification Factors

2018 ◽  
Vol 159 ◽  
pp. 01005
Author(s):  
Sri Tudjono ◽  
Patria Kusumaningrum
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Cantilever Beam ◽  
Mode Shape ◽  
Degree Of Freedom ◽  
Elastic Analysis ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Magnification Factors ◽  
Method Analysis

The response of multi-degree-of-freedom (MDOF) structure can be correlated to the response of an equivalent single-degree-of-freedom (SDOF) system, implying that the response is controlled by a single, unchanged mode shape. This equivalent SDOF method is eminent as an approximate method of dynamic analysis. In this study, equivalent SDOF method analysis is carried out on RC cantilever beam subjected to dynamic blast loading to review the transformation factors (TFs) provided by TM5-1300 code.

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