scholarly journals Simplification of earthquake accelerograms for quick nonlinear time history analyses by using modified Inverse Fourier Transform

2012 ◽  
Author(s):  
A. Faroughi ◽  
M. Hosseini
Keyword(s):  
Fourier Transform ◽  
Inverse Fourier Transform ◽  
Time History ◽  
Nonlinear Time History Analyses ◽  
Nonlinear Time History ◽  
Earthquake Accelerograms

scholarly journals Comparison of Novel Seismic Protection Devices to Attenuate the Earthquake Induced Energy

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 73
Author(s):  
Osman Hansu ◽  
Esra Mete Güneyisi
Keyword(s):  
Lateral Displacement ◽  
Time History ◽  
Seismic Protection ◽  
Base Shear ◽  
Seismic Demands ◽  
Nonlinear Time History Analyses ◽  
History Of ◽  
Protection Devices ◽  
Nonlinear Time History ◽  
Better Than

This study addresses an alternative use of viscous dampers (VDs) associated with buckling restrained braces (BRBs) as innovative seismic protection devices. For this purpose, 4-, 8- and 12-story steel bare frames were designed with 6.5 m equal span length and 4 m story height. Thereafter, they were seismically improved by mounting the VDs and BRBs in three patterns, namely outer bays, inner bays, and all bays over the frame heights. The structures were modeled using SAP 2000 software and evaluated by the nonlinear time history analyses subjected to the six natural ground motions. The seismic responses of the structures were investigated for the lateral displacement, interstory drift, absolute acceleration, maximum base shear, and time history of roof displacement. The results clearly indicated that the VDs and BRBs reduced seismic demands significantly compared to the bare frame. Moreover, the all-bay pattern performed better than the others.

scholarly journals Seismic Performance of a Green Roof Structure

2021 ◽  
Vol 13 (8) ◽  
pp. 4278
Author(s):  
Svetlana Tam ◽  
Jenna Wong
Keyword(s):  
Green Roof ◽  
Time History ◽  
Green Roofs ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Roof Structure ◽  
Nonlinear Time History Analyses ◽  
Vegetated Roofs ◽  
Nonlinear Time History ◽  
The Impact

Sustainability addresses the need to reduce the structure’s impact on the environment but does not reduce the environment’s impact on the structure. To explore this relationship, this study focuses on quantifying the impact of green roofs or vegetated roofs on seismic responses such as story displacements, interstory drifts, and floor level accelerations. Using an archetype three-story steel moment frame, nonlinear time history analyses are conducted in OpenSees for a shallow and deep green roof using a suite of ground motions from various distances from the fault to identify key trends and sensitivities in response.

Correlation between Damage Indexes in Knee Bracing Frames Subjected to Earthquakes

2011 ◽  
Vol 255-260 ◽  
pp. 2350-2354
Author(s):  
Kamran Faraji ◽  
Mahmoud Miri
Keyword(s):  
Structural Damage ◽  
Steel Frames ◽  
Time History ◽  
Deformation Energy ◽  
Hysteretic Behavior ◽  
Nonlinear Time History Analysis ◽  
Damage Level ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Earthquake Accelerograms

For vulnerability assessment of structures, different damage indexes have been established by researchers that estimate the structural damage level. In these indexes different parameters have been used for calculating structural damage level. In this paper, damage indexes based on deformation, energy and cycle hysteretic behavior are investigated in order to find a correlation between their numerical values. The selected damage indexes are calculated and compared by applying them in nonlinear time history analysis of low and intermediate rise knee braced steel frames subjected to a set of seven earthquake accelerograms. Correlations between various indexes have been presented graphically and approximate conversion formulas are also provided.

Influence of Earthquake Attack Angle on Seismic Demands for Structures under Bi-Directional Ground Motions

2011 ◽  
Vol 255-260 ◽  
pp. 2330-2334 ◽  
Author(s):  
Yu Zhang ◽  
Quan Wang Li ◽  
Jian Sheng Fan
Keyword(s):  
Seismic Design ◽  
Ground Motions ◽  
Time History ◽  
Earthquake Excitation ◽  
Seismic Demands ◽  
3 Dimensional ◽  
Nonlinear Time History Analyses ◽  
Modification Factor ◽  
Structural Responses ◽  
Nonlinear Time History

The earthquake may attack the structural building from any angle, but in current seismic design codes, this type of uncertainty is seldom accounted. The uncertainty associated with the direction of earthquake excitation was considered in this paper, and its effect on structural responses was investigated. For this purpose, a simple 3-dimensional model with symmetric plan was established, which had fundamental periods ranged from 0.1s to 5.0s, and was subjected to a set of 30 ground motion pairs for which both linear and nonlinear time history analyses were performed. Analyzing results showed that, on average, the elastic roof acceleration is 32% underestimated, and the inelastic roof displacement is 18% underestimated if the variation of earthquake excitation direction is not consider. Recognizing this, a modification factor for the seismic demand was proposed thorough a statistical analysis, which guarantees a probability of 95% design safety

scholarly journals A Wavelet-based Approach for Truncating Pulse-like Records

2021 ◽  
Author(s):  
Vicky Dimakopoulou ◽  
Michalis Fragiadakis ◽  
Ioannis Taflampas
Keyword(s):  
Ground Motion ◽  
Near Field ◽  
Time History ◽  
Response Spectra ◽  
Degree Of Freedom ◽  
Seismic Performance Assessment ◽  
Analysis And Design ◽  
Nonlinear Time History Analyses ◽  
Ground Motion Records ◽  
Nonlinear Time History

Abstract The seismic performance assessment of structures using truncated pulse-like ground motion records is discussed. It is shown that it is possible to truncate pulse-like signals using a novel wavelet-based definition that identifies the duration of the predominant velocity pulse. The truncated time history can efficiently reproduce the increased seismic demand that near-field records typically produce. Substituting the original ground motion with the truncated signal, significantly accelerates structural analysis and design. The truncated signal is the part of the original accelerogram that coincides with the duration of the predominant pulse, which is identified using a wavelet-based procedure, previously proposed by the authors. Elastic and inelastic response spectra and nonlinear time history analyses for SDOF (single-degree-of-freedom) systems are first studied. Subsequently a nine-storey steel frame is examined in order to demonstrate the performance of the proposed approach on a multiple-degree-of-freedom system. The proposed approach is found very efficient for pulse-like ground motions, while it is also sufficient for many records that are not characterized as such.

Beam-column modeling and seismic fragility analysis of a prestressed segmental concrete tower for wind turbines

2020 ◽  
Vol 23 (8) ◽  
pp. 1715-1727
Author(s):  
Yuqi Cao ◽  
Minjuan He ◽  
Renle Ma ◽  
Rongchang Yang ◽  
Feng Liang
Keyword(s):  
Time History ◽  
Element Model ◽  
Column Model ◽  
Average Curvature ◽  
Proposed Model ◽  
Nonlinear Time History Analyses ◽  
Engineering Demand Parameter ◽  
Earthquake Action ◽  
Nonlinear Time History ◽  
Good Agreement

As the development of wind energy in earthquake areas advances, the seismic performance of concrete supporting towers has become an important subject. A beam-column model is developed for a prestressed segmental concrete tower supporting a wind turbine considering the properties of dry joints. The proposed model is in good agreement with the solid element model deformation results and the field test modal results. Based on the beam-column model, nonlinear time history analyses considering uncertainties are conducted to evaluate the behavior of the prototype tower under earthquake action. In the process, a new engineering demand parameter, called the average curvature, is defined. The results are compared with those based on a conventional engineering demand parameter. The availability of the prototype tower under earthquake action and the effectiveness of the newly defined engineering demand parameter are validated.

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