• Title/Summary/Keyword: time-history analysis

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Seismic performance of skewed highway bridges using analytical fragility function methodology

  • Bayat, M.;Daneshjoo, F.
    • Computers and Concrete
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    • v.16 no.5
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    • pp.723-740
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    • 2015
  • In this study, the seismic performance of skewed highway bridges has been assessed by using fragility function methodology. Incremental Dynamic Analysis (IDA) has been used to prepare complete information about the different damage states of a 30 degree skewed highway bridge. A three dimensional model of a skewed highway bridge is presented and incremental dynamic analysis has been applied. The details of the full nonlinear procedures have also been presented. Different spectral intensity measures are studied and the effects of the period on the fragility curves are shown in different figures. The efficiency, practicality and proficiency of these different spectral intensity measures are compared. A suite of 20 earthquake ground motions are considered for nonlinear time history analysis. It has been shown that, considering different intensity measures (IM) leads us to overestimate or low estimate the damage probability which has been discussed completely.

Seismic performance evaluation of a building structure using direct displacement-based design method (직접변위설계법을 이용한 건축물의 지진응답 산정)

  • 김진구;방성혁
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.569-576
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    • 2001
  • In this study a procedure for evaluation of performance point using direct displacement-based design method was developed to enhance the applicability of the method. Parametric study has been performed for the natural period of the structure, yield strength, and the stiffness after the first yield. The proposed method was also applied to a 10-story steel frame. To verify the accuracy of the result, the results from capacity spectrum analysis and time history analysis were compared. The results of the proposed method turned out to match well with the results of capacity spectrum method and the time history analysis.

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Equivalent Static Analysis of Progressive Collapse Using Equivalent Load for Stiffness (강성등가하중을 이용한 등가정적 연쇄붕괴 해석)

  • Hwang, Young-Chul;Kim, Gye-Joong;Kim, Chee-Kyeong
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.375-380
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    • 2007
  • The goal of this paper is to develop a rational static method which consider efficiently the dynamic effect of the gravity load following sudden removal of element. For this goal this paper introduce the equivalent load for element stiffness which is a preceding research result and will develop equivalent static analysis which will be able to predict the maximum behavior considering dynamic effect. Some examples are provided to verify it. Equivalent static analysis is compared with the analysis method which is recommended by the GSA2003 guidelines and the time-history analysis which is the most accurate for dynamic behavior.

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A Study on Dynaniic Analysis for Earthquake Design of cable-stayed Bridges (사장교의 내진설계를 위한 동적해석에 관한 연구)

  • 이진휴;이재영;이장춘
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.36 no.1
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    • pp.103-115
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    • 1994
  • The dynamic earthquake analysis of plane cable-stayed bridge structures was formulated and implemented into a computer program which analyzes plane cable-stayed bridge structu- res subjected to initial cable tensions, member dead and live loads and seismic loads. Cable-stayed bridges were modelled as multi-degrees of freedom systems with lumped- mass. Various earthquake responses such as dynamic deflection, bending moment, shear force and cable tension were investigated by the dynamic analyses in the form of the time history analysis. The time history analysis was based on the mode superposition method. The study revealed that Fan-l type cable-syayed bridges is generally superior to other types for the earthquake proof even though aspects of deflection and section force of each type presents respective advantages and disadvantages. The study provided a method to design the sections of cable-stayed bridges under seismic loads with various design parameters related to structural types. The study is expected to be useful for effective design of cable-stayed bridges with conside- ration of earthquake.

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Design of Viscous Dampers Using Nonlinear Static Analysis (비탄성 정적해석을 이용한 점성감쇠기의 설계)

  • 김진구;최현훈
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.257-264
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    • 2000
  • Nonlinear dynamic time history analysis of a structure with energy dissipation devices is complicated and time consuming. In this regard the nonlinear static analysis is a practical alternative for evaluating the earthquake resisting capacity of a structure. In this study the nonlinear static response of a structure was obtained first, and the equivalent viscous modal damping ratio required to satisfy the performance objective was computed in the capacity spectrum format. Then proper amount of viscous dampers were installed to provide the required damping. Parametric study has been performed for the period of the structure, yield strength, and the stiffness after the first yield. According to the earthquake time history analysis results, the maximum displacement of the model structure with viscous dampers designed in accordance with the proposed method corresponds well with the target displacements that was used in the beginning of the design process.

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Method of the Calibration of earthquake Ground Motions for Seismic Design (내진설계를 위한 지진 입력하중 조정 방법)

  • 공도환
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.20-27
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    • 1998
  • In the current seismic design codes design earthquake is usually defined as the earthquake with the 90 percent probability of not being exceeded in the life time of a structure which is assumed as 50 years equivalent to the earthquake with 475 year recurrence period. However the life time of tall building structures may be much longer than 50 yers. The current seismic design code requires the modal analysis or dynamic time history analysis for the buildings with the height exceeding a certain height limit. The objective of this study is to collect the earthquake ground motion(EQGM) which can be used for dynamic time history analysis for tall buildings. For this purpose linear elastic design response spectrum (LEDRS) in the code is scaled to account for the recurrence period of the design earthquake. The earthquake ground motions which has been recorded are calibrated to fit the scaled LEDRS. The set of calibrated EQGM can be treated as design EQGM for the design of tall building with longer lifetime than ordinary building.

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Response of self-centering braced frame to near-field pulse-like ground motions

  • Rahgozar, Navid;Moghadam, Abdolreza S.;Aziminejad, Armin
    • Structural Engineering and Mechanics
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    • v.62 no.4
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    • pp.497-506
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    • 2017
  • A low damage self-centering braced frame equipped with post-tensioning strands is capable of directing damage to replaceable butterfly-shaped fuses. This paper investigates the seismic performance of rocking braced frame under near-field pulse-like ground motions compared to far-field records. A non-linear time history analysis is performed for twelve self-centering archetypes. A sensitivity analysis is carried out to examine the influences of ground motion types and modeling parameters. Findings represent the proper efficiency of the self-centering system under both far-field and near-field pulse-like ground motions.

An evaluation of the seismic response of symmetric steel space buildings

  • Yon, Burak
    • Steel and Composite Structures
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    • v.20 no.2
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    • pp.399-412
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    • 2016
  • This paper evaluates the seismic response of three dimensional steel space buildings using the spread plastic hinge approach. A numerical study was carried out in which a sample steel space building was selected for pushover analysis and incremental nonlinear dynamic time history analysis. For the nonlinear analysis, three earthquake acceleration records were selected to ensure compatibility with the design spectrum defined in the Turkish Earthquake Code. The interstorey drift, capacity curve, maximum responses and dynamic pushover curves of the building were obtained. The analysis results were compared and good correlation was obtained between the idealized dynamic analyses envelopes with and static pushover curves for the selected building. As a result to more accurately account response of steel buildings, dynamic pushover envelopes can be obtained and compared with static pushover curve of the building.

Reinforced concrete core-walls connected by a bridge with buckling restrained braces subjected to seismic loads

  • Beiraghi, Hamid
    • Earthquakes and Structures
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    • v.15 no.2
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    • pp.203-214
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    • 2018
  • Deflection control in tall buildings is a challenging issue. Connecting of the towers is an interesting idea for architects as well as structural engineers. In this paper, two reinforced concrete core-wall towers are connected by a truss bridge with buckling restrained braces. The buildings are 40 and 60-story. The effect of the location of the bridge is investigated. Response spectrum analysis of the linear models is used to obtain the design demands and the systems are designed according to the reliable codes. Then, nonlinear time history analysis at maximum considered earthquake is performed to assess the seismic responses of the systems subjected to far-field and near-field record sets. Fiber elements are used for the reinforced concrete walls. On average, the inter-story drift ratio demand will be minimized when the bridge is approximately located at a height equal to 0.825 times the total height of the building. Besides, because of whipping effects, maximum roof acceleration demand is approximately two times the peak ground acceleration. Plasticity extends near the base and also in major areas of the walls subjected to the seismic loads.

Seismic Perfomance Evaluation of Wind-Designed Steel Highrise Buildings Based on Linear Dynamic Analysis (내풍설계된 철골조 초고층건물의 선형동적해석에 의한 내진성능평가)

  • Lee, Cheol-Ho;Kim, Seon-Woong
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.177-184
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    • 2005
  • Even in moderate to low seismic regions like Korean peninsular where wind loading usually governs the structural design of a tall building, the probable structural impact of the design basis earthquake or the maximum credible earthquake on the selected structural system should be considered at least in finalizing the design. In this study, by using response spectrum analysis and time history analysis method, seismic performance evaluation was conducted for wind-designed concentrically braced steel highrise buildings. Input ensemble was normalized to be compatible with expected peak ground acceleration. The analysis results showed that wind-designed concentrically braced steel highrise buildings possess significantly increased elastic seismic capacity due to the system overstrength resulting from the wind-serviceability criterion and the width-to-thickness ratio limits on steel members. The time history analysis tended to significantly underestimated the seismic response as compared to response spectrum analysis. Further detailed studies regarding selection and scaling scheme of input ground motions is needed.

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