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Tsutomu Usami - One of the best experts on this subject based on the ideXlab platform.
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applicability of Pushover Analysis based seismic performance evaluation procedure for steel arch bridges
Engineering Structures, 2004Co-Authors: Zhihao Lu, Hanbin Ge, Tsutomu UsamiAbstract:An investigation on the application of a capacity and demand prediction procedure based on a nonlinear Pushover Analysis and an equivalent single-degree-of-freedom (ESDOF) system approximation for seismic performance evaluation of steel arch bridges, as well as limitations of the Pushover Analysis is presented here. The procedure is applied to the transverse direction of two representative arch bridges with different spans for capacity and demand estimation. Displacement capacities are obtained by conducting Pushover Analysis until the ultimate state of the structure is reached, determined by a failure criterion proposed for thin-walled steel members governed by the local buckling-induced failure. Displacement demands under major earthquakes are estimated by ESDOF systems formulated using Pushover Analysis results. Capacities and demands are then compared with those from rigorous nonlinear time–history analyses on multi-degree-of-freedom (MDOF) models for verification and acceptable accuracy of the Pushover Analysis-based procedure is evidenced. Furthermore, applicability of the Pushover Analysis involving the fundamental mode only for seismic performance evaluation is extensively investigated considering the higher mode effect. A factor to account for higher mode contribution to seismic response is proposed and an applicable range of using the Pushover Analysis is quantitatively specified.
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Seismic response predictions of multi‐span steel bridges through Pushover Analysis
Earthquake Engineering & Structural Dynamics, 2003Co-Authors: Yi Zheng, Tsutomu UsamiAbstract:In the new trend of seismic design methodology, the static Pushover Analysis is recommended for simple or regular structures whilst the time-history Analysis is recommended for complex structures. To this end, the applicable range of the Pushover Analysis has to be clarified. This study aims at investigating the applicability of Pushover Analysis to multi-span continuous bridge systems with thin-walled steel piers. The focus is concentrated on the response demand predictions in longitudinal or transverse directions. The Pushover Analysis procedure for such structures is firstly summarized and then parametric studies are carried out on bridges with different types of superstructure-pier bearing connections. The considered parameters, such as piers' stiffness distribution and pier–0.5ptdeck stiffness ratio, are varied to cover both regular and irregular structures. Finally, the relation of the applicability of Pushover Analysis to different structural formats is demonstrated and a criterion based on the higher modal contribution is proposed to quantitatively specify the applicable range. Copyright © 2003 John Wiley & Sons, Ltd.
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seismic response predictions of multi span steel bridges through Pushover Analysis
Earthquake Engineering & Structural Dynamics, 2003Co-Authors: Yi Zheng, Tsutomu UsamiAbstract:In the new trend of seismic design methodology, the static Pushover Analysis is recommended for simple or regular structures whilst the time-history Analysis is recommended for complex structures. To this end, the applicable range of the Pushover Analysis has to be clarified. This study aims at investigating the applicability of Pushover Analysis to multi-span continuous bridge systems with thin-walled steel piers. The focus is concentrated on the response demand predictions in longitudinal or transverse directions. The Pushover Analysis procedure for such structures is firstly summarized and then parametric studies are carried out on bridges with different types of superstructure-pier bearing connections. The considered parameters, such as piers' stiffness distribution and pier–0.5ptdeck stiffness ratio, are varied to cover both regular and irregular structures. Finally, the relation of the applicability of Pushover Analysis to different structural formats is demonstrated and a criterion based on the higher modal contribution is proposed to quantitatively specify the applicable range. Copyright © 2003 John Wiley & Sons, Ltd.
Matjaž Dolšek - One of the best experts on this subject based on the ideXlab platform.
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envelope based Pushover Analysis procedure for the approximate seismic response Analysis of buildings
Earthquake Engineering & Structural Dynamics, 2014Co-Authors: Marko Brozovič, Matjaž DolšekAbstract:SUMMARY An envelope-based Pushover Analysis procedure is presented that assumes that the seismic demand for each response parameter is controlled by a predominant system failure mode that may vary according to the ground motion. To be able to simulate the most important system failure modes, several Pushover analyses need to be performed, as in a modal Pushover Analysis procedure, whereas the total seismic demand is determined by enveloping the results associated with each Pushover Analysis. The demand for the most common system failure mode resulting from the ‘first-mode’ Pushover Analysis is obtained by response history Analysis for the equivalent ‘modal-based’ SDOF model, whereas demand for other failure modes is based on the ‘failure-based’ SDOF models. This makes the envelope-based Pushover Analysis procedure equivalent to the N2 method provided that it involves only ‘first-mode’ Pushover Analysis and response history Analysis of the corresponding ‘modal-based’ SDOF model. It is shown that the accuracy of the approximate 16th, 50th and 84th percentile response expressed in terms of IDA curves does not decrease with the height of the building or with the intensity of ground motion. This is because the estimates of the roof displacement and the maximum storey drift due to individual ground motions were predicted with a sufficient degree of accuracy for almost all the ground motions from the analysed sets. Copyright © 2013 John Wiley & Sons, Ltd.
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Envelope‐based Pushover Analysis procedure for the approximate seismic response Analysis of buildings
Earthquake Engineering & Structural Dynamics, 2013Co-Authors: Marko Brozovič, Matjaž DolšekAbstract:SUMMARY An envelope-based Pushover Analysis procedure is presented that assumes that the seismic demand for each response parameter is controlled by a predominant system failure mode that may vary according to the ground motion. To be able to simulate the most important system failure modes, several Pushover analyses need to be performed, as in a modal Pushover Analysis procedure, whereas the total seismic demand is determined by enveloping the results associated with each Pushover Analysis. The demand for the most common system failure mode resulting from the ‘first-mode’ Pushover Analysis is obtained by response history Analysis for the equivalent ‘modal-based’ SDOF model, whereas demand for other failure modes is based on the ‘failure-based’ SDOF models. This makes the envelope-based Pushover Analysis procedure equivalent to the N2 method provided that it involves only ‘first-mode’ Pushover Analysis and response history Analysis of the corresponding ‘modal-based’ SDOF model. It is shown that the accuracy of the approximate 16th, 50th and 84th percentile response expressed in terms of IDA curves does not decrease with the height of the building or with the intensity of ground motion. This is because the estimates of the roof displacement and the maximum storey drift due to individual ground motions were predicted with a sufficient degree of accuracy for almost all the ground motions from the analysed sets. Copyright © 2013 John Wiley & Sons, Ltd.
S. Chandrasekaran - One of the best experts on this subject based on the ideXlab platform.
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Seismic Evaluation of Multi-Storey RC Frame Using Modal Pushover Analysis
Nonlinear Dynamics, 2006Co-Authors: S. ChandrasekaranAbstract:The recently developed Pushover Analysis procedure has led a new dimension to performance-based design in structural engineering practices. With the increase in the magnitude of monotonic loading, weak links and failure modes in the multi-storey RC frames are usually formed. The force distribution and storey displacements are evaluated using static Pushover Analysis based on the assumption that the response is controlled by fundamental mode and no mode shift takes place. Himalayan-Nagalushai region, Indo-Gangetic plain, Western India, Kutch and Kathiawar regions are geologically unstable parts of India and some devastating earthquakes of remarkable intensity have occurred here. In view of the intensive construction activity in India, where even a medium intensity tremor can cause a calamity, the authors feel that a completely up-to-date, versatile method of aseismic Analysis and design of structures are essential. A detailed dynamic Analysis of a 10-storey RC frame building is therefore performed using response spectrum method based on Indian Standard Codal Provisions and base shear, storey shear and storey drifts are computed. A modal Pushover Analysis (MPA) is also carried out to determine the structural response of the same model for the same acceleration spectra used in the earlier case. The major focus of study is to bring out the superiority of Pushover Analysis method over the conventional dynamic Analysis method recommended by the code. The results obtained from the numerical studies show that the response spectrum method underestimates the response of the model in comparison with modal Pushover Analysis. It is also seen that modal participation of higher modes contributes to better results of the response distribution along the height of the building. Also Pushover curves are plotted to illustrate the displacement as a function of base shear.
Zhang Yan-qing - One of the best experts on this subject based on the ideXlab platform.
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Pushover Analysis for Seismic Performance of Pile-Supported Wharf Structures
Journal of Ship Mechanics, 2011Co-Authors: Zhang Yan-qingAbstract:Seismic design is important for pile-supported wharf structure built in the severe earthquake region.In order to understand seismic performance of pile-supported structure,the displacement Analysis is required in the seismic design.The general framework of nonlinear Pushover Analysis for wharf is presented in this paper.The relationship between effective damping and displacement ductility factor is formulated based on hysteretic characteristic of wharf under cyclic load.The procedure to locate the performance point on the envelop curve,which corresponds to the target displacement,is illustrated.To identify the validity of Pushover Analysis,time history Analysis is performed to obtain dynamic response of the wharf under sixteen input motions.The displacement requirement obtained by Pushover Analysis is proved to be close to the average displacement calculated by time history Analysis.The result shows that Pushover Analysis is a powerful tool for seismic design and Analysis of pile-supported wharf in practical engineering.
Wu Peng - One of the best experts on this subject based on the ideXlab platform.
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Research on Pushover Analysis method for seismic performance of pile-supported wharf structure
Hydro-Science and Engineering, 2010Co-Authors: Wu PengAbstract:The fundamental principle of Pushover Analysis is illustrated in this paper.The relation formula on equivalent damping and displacement ductility factor is calculated based on hysteretic characteristic for piles as applied herein,and a Pushover Analysis method which can be used to assess seismic performance of pile-supported wharf structure is presented using response spectrum obtained from Code for Seismic Design of Buildings.The displacement demand of a pile-supported wharf structure is evaluated considering iterative program.The conclusion of a comparison between estimated value applying statical Analysis and the average target displacement results estimated by time-history Analysis of 16 seismic records collected at home and abroad is shown.It′s proved Pushover Analysis method is fit for Analysis and evaluation of seismic performance of wharf structure due to adjacent results.
