Optimal Intensity Measures in Probabilistic Seismic Demand Models of Cable-Stayed Bridges Subjected to Pulse-Like Ground Motions

2019 ◽  
Vol 24 (2) ◽  
pp. 04018118 ◽  
Author(s):  
Jian Zhong ◽  
Jong-Su Jeon ◽  
Ya-Hui Shao ◽  
Liang Chen
Keyword(s):  
Ground Motions ◽  
Seismic Demand ◽  
Intensity Measures ◽  
Demand Models ◽  
Probabilistic Seismic Demand ◽  
Optimal Intensity ◽  
Cable Stayed Bridges

scholarly journals Optimal Seismic Intensity Measure Selection for Isolated Bridges under Pulse-Like Ground Motions

2019 ◽  
Vol 2019 ◽  
pp. 1-22 ◽  
Author(s):  
Linwei Jiang ◽  
Jian Zhong ◽  
Min He ◽  
Wancheng Yuan
Keyword(s):  
Ground Motions ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Demand ◽  
Intensity Measure ◽  
Demand Models ◽  
Seismic Force ◽  
Probabilistic Seismic Demand ◽  
Optimal Intensity ◽  
Isolated Bridges

Isolated bridges are commonly designed in the near-fault region to balance excessive displacement and seismic force. Optimal intensity measures (IMs) of probabilistic seismic demand models for isolated bridges subjected to pulse-like ground motions are identified in this study. Four typical isolated girder bridge types with varied pier height (from 4 m to 20 m) are employed to conduct the nonlinear time history analysis. Totally seven structure-independent IMs are considered and compared. Critical engineering demand parameters (EDPs), namely, pier ductility demands and bearing deformation along the longitudinal and transverse directions, are recorded during the process. In general, PGV tends to be the optimal IM for isolated bridges under pulse-like ground motions based on practicality, efficiency, proficiency, and sufficiency criterions. The results can offer effective guidance for the optimal intensity measure selection of the probabilistic seismic demand models (PSDMs) of isolated bridges under pulse-like ground motions.

scholarly journals Optimal Earthquake Intensity Measures for Probabilistic Seismic Demand Models of Base-Isolated Nuclear Power Plant Structures

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5163
Author(s):  
Duy-Duan Nguyen ◽  
Tae-Hyung Lee ◽  
Van-Tien Phan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Seismic Demand ◽  
Lumped Mass ◽  
Earthquake Intensity ◽  
Intensity Measures ◽  
Demand Models ◽  
Probabilistic Seismic Demand ◽  
Spectrum Intensity

The purpose of this study is to evaluate the optimal earthquake intensity measures (IMs) for probabilistic seismic demand models (PSDMs) of the base-isolated nuclear power plant (NPP) structures. The numerical model of NPP structures is developed using a lumped-mass stick model, in which a bilinear model is employed to simulate the force-displacement relations of base isolators. In this study, 20 different IMs are considered and 90 ground motion records are used to perform time-history analyses. The seismic engineering demand parameters (EDPs) are monitored in terms of maximum floor displacement (MFD), the maximum floor acceleration (MFA) of the structures, and maximum isolator displacement (MID). As a result, a set of PSDMs of the base-isolated structure is developed based on three EDPs (i.e., MFD, MFA, and MID) associated with 20 IMs. Four statistical parameters including the coefficient of determination, efficiency (i.e., standard deviation), practicality, and proficiency are then calculated to evaluate optimal IMs for seismic performances of the isolated NPP structures. The results reveal that the optimal IMs for PSDMs with respect to MFD and MID are velocity spectrum intensity, Housner intensity, peak ground velocity, and spectral velocity at the fundamental period. Meanwhile, peak ground acceleration, acceleration spectrum intensity, A95, effective peak acceleration, and sustained maximum acceleration are efficient IMs for PSDMs with respect to MFA of the base-isolated structures. On the other hand, cumulative absolute velocity is not recommended for determining the exceedance of the operating basis earthquake of base-isolated NPP structures.

Selection of Optimal Intensity Measures in Seismic Damage Analysis of Cable-Stayed Bridges Subjected to Far-Fault Ground Motions

2015 ◽  
Vol 09 (01) ◽  
pp. 1550003 ◽  
Author(s):  
Yu-Ye Zhang ◽  
Yong Ding ◽  
Yu-Tao Pang
Keyword(s):  
Low Cycle Fatigue ◽  
Ground Motions ◽  
Seismic Damage ◽  
Peak Ground Velocity ◽  
Damage Analysis ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Optimal Intensity ◽  
Far Fault ◽  
Cable Stayed Bridges

The intensity measures of ground motions are closely related to the damage of bridge structures. However, it is difficult for engineers to select these parameters to predict the potential damage of cable-stayed bridges under earthquakes. This paper investigated the correlation between the intensity measures of far-fault ground motions and the damage of cable-stayed bridges. 322 far-fault ground motions were selected, and 26 available intensity measures in the literatures were chosen to carry out comparative analysis on a cable-stayed bridge with a single pylon. The nonlinear finite element model of this bridge was built, considering the stiffness degradation of concrete and low-cycle fatigue effect of steel. It is concluded in this study that velocity spectral intensity (VSI) is the optimal intensity measure for seismic damage analysis of cable-stayed bridges subjected to far-fault ground motions, followed by spectral acceleration at fundamental period and Housner intensity. Five commonly used intensity measures, namely peak ground acceleration (PGA), the ratio of PGA to peak ground velocity (PGA/PGV), specific energy density (SED), predominant period (Tp) and mean period (Tm), demonstrate low correlations with the bridge damage. In particular, there is very weak correlation between the conventionally used PGA and the seismic damage of cable-stayed bridges.

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