Synthesis of a vector-valued intensity measure for improved prediction of seismic demands in Inter-Story-Isolated (ISI) buildings subjected to near fault ground motions

2021 ◽  
Vol 248 ◽  
pp. 113241
Author(s):  
Arijit Saha ◽  
Sudib Kumar Mishra
Keyword(s):  
Ground Motions ◽  
Intensity Measure ◽  
Seismic Demands ◽  
Near Fault ◽  
Vector Valued

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.

A spectral-acceleration-based combination-type earthquake intensity measure for high-rise stack-like structures

2019 ◽  
Vol 23 (7) ◽  
pp. 1350-1366 ◽  
Author(s):  
Yikun Qiu ◽  
Changdong Zhou ◽  
Siha A ◽  
Guangwei Zhang
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Spectral Acceleration ◽  
Intensity Measure ◽  
Earthquake Intensity ◽  
Intensity Measures ◽  
Higher Modes ◽  
High Rise ◽  
Near Fault ◽  
Period Elongation

Ground motion intensity measures are of great importance for the seismic design of structures. A well-chosen intensity measure will reduce the detailed ground motion record selection effort for the nonlinear dynamic structural analyses. In this article, a spectral-acceleration-based combination-type earthquake intensity measure is presented. This intensity measure considers the higher modes effect and period elongation effect due to nonlinear deformation at the same time. The modal mass participation factors are determined to take weighting coefficients and the product of elastic first-mode period T1 and a constant C is expressed to represent the elongated period. Therefore, the proposed intensity measure is a combination of earthquake ground motion characteristics, elastic structural responses, higher modes participation, and the period elongation effect due to inelastic structural behaviors. Four three-dimensional models of reinforced concrete stack-like structures including a 240 m-high chimney, a 180 m-high chimney, a 120 m-high chimney, and a 42.3 m-high water tower are established and analyzed in ABAQUS to investigate the correlation between the intensity measure and the maximum curvatures under 44 far-field ground motions and 28 near-fault ground motions with a pulse-like effect. With the optimal vibration modes and the proper period elongation coefficient, the efficiency of the introduced intensity measure is compared with the other 15 intensity measures. The results indicate that the proposed intensity measure is believed to be a good choice for high-rise stack-like structures, especially under the near-fault ground motions with pulse-like effect.

On the Use of Vector-Valued Intensity Measure to Predict Peak and Cumulative Demands of Steel Frames under Narrow-Band Motions

2014 ◽  
Vol 595 ◽  
pp. 137-142 ◽  
Author(s):  
Edén Bojórquez ◽  
Alfredo Reyes-Salazar ◽  
Sonia E. Ruiz
Keyword(s):  
Narrow Band ◽  
Ground Motions ◽  
Steel Frames ◽  
Spectral Shape ◽  
Intensity Measure ◽  
Intensity Measures ◽  
Energy Demands ◽  
Long Duration ◽  
Story Drift ◽  
Vector Valued

In this study, various alternative vector-valued ground motion intensity measures (IMs) are used to estimate maximum inter-story drifts and hysteretic energy demands of steel framed buildings under long duration narrow-band ground motions. The vectors are based on the spectral acceleration at first mode of the structure as first parameterSa (T1). As the second parameter of the vector,IMsrelated to peak, integral and spectral shape parameters are selected. It is concluded that spectral-shape-based vector-valuedIMshave the best relation with maximum inter-story drift and energy demands in steel frames subjected to narrow-band earthquake ground motions.

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.

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