• Title/Summary/Keyword: earthquake-resistant design

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Seismic Behavior of Inverted T-type Wall under Earthquake Part I : Verification of the Numerical Modeling Techniques (역T형 옹벽의 지진시 거동특성 Part I : 수치해석 모델링 기법의 검증)

  • Lee, Jin-sun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.1
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    • pp.1-8
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    • 2016
  • Permanent deformation plays a key role in performance based earthquake resistant design. In order to estimate permanent deformation after earthquake, it is essential to secure reliable response history analysis(RHA) as well as earthquake scenario. This study focuses on permanent deformation of an inverted T-type wall under earthquake. The study is composed of two separate parts. The first one is on the verification of RHA and the second one is on an effect of input earthquake motion. The former is discussed in this paper and the latter in the companion paper. The verification is conducted via geotechnical dynamic centrifuge test in prototype scale. Response of wall stem, ground motions behind the wall obtained from RHA matched pretty well with physical test performed under centrifugal acceleration of 50g. The rigorously verified RHA is used for parametric study to investigate an effect of input earthquake motion selection in the companion paper.

Earthquake Resistant Design Critieria for Cylindrical Liquid-Storage Steel tanks (원통형 액체저장 강탱크의 내진설계기준)

  • 국승규;이진호
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.2
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    • pp.19-28
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    • 1999
  • While the codifying works or the earthquake resistant design codes for buildings and bridges have been carried out progressively, such works for tank structures are still at the beginning steps. In case of the collapse of tank structures under seismic actions, substantially severe damages are expected due to the spillage of tank contents in addition to the direct economic losses of tanks and contents. Therefore not only the analysis and verification methods for the dynamic behavior of tank structures but also the measures of minimizing the damage propagation should be included in the codes for tank structures. In this paper the design concepts and principles, the analysis and verification methods as well as the measures against the damage propagation are set forth, which are mandatory for the preparation of the earthquake resistant design codes for cylindrical liquid-storage steel tanks.

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Pier Stiffness and Bridge Collapse Mechanism (교각 강성과 교량의 붕괴기구)

  • Kook, Seung-Kyu
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.2
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    • pp.187-192
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    • 2016
  • While structures are designed within elastic range by other designs, plastic behavior of structures should be verified and controlled in order to prevent structural collapse by the earthquake resistant design. No Collapse Requirement for typical bridges is to avoid falling down of superstructure by way of plastic behavior of certain structural elements and to operate emergency vehicles after earthquake. Such plastic behavior is restricted to connections or pier columns and appropriate measures are required for each case. Earthquake Resistant Design part of Roadway Bridge Design Code provides design processes for Ductile Collapse Mechanism by forming plastic hinges at pier columns. Also for bridges with reinforced concrete piers ductility-based design processes are provided as an appendix constructing Brittle Collapse Mechanism with connection yielding. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected and No Collapse Design procedure considering both Ductile and Brittle Collapse Mechanism is proposed together with revisions required for the Earthquake Resistant Design part.

Seismic Behavior of Inverted T-type Wall under Earthquake Part II : Effect of Input Earthquake Motion (역T형 옹벽의 지진시 거동특성 Part II : 입력 지진파의 영향)

  • Lee, Jin-sun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.1
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    • pp.9-19
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    • 2016
  • Permanent deformation plays a key role in performance based earthquake resistant design. In order to estimate permanent deformation after earthquake, it is essential to secure reliable response history analysis(RHA) as well as earthquake scenario. This study focuses on permanent deformation of an inverted T-type wall under earthquake. The study is composed of two separate parts. The first one is on the verification of RHA and the second one is on an effect of input earthquake motion. The former is discussed in companion paper and the latter in this paper. In order to investigate the effect of an input earthquake motion on the permanent deformation, three bins of spectral matched real earthquake records with different magnitude, regions, epicentral distance are constructed. Parametric study was performed using the verified RHA through the companion paper for each earthquake records in the bins. The most influential parameter affecting permanent displacement is magnitude. The other parameters describing earthquake motion are not significant enough to increase permanent displacement of the inverted T-type wall except for energy related parameters(AI, CI, SEI).

Design for earthquake-resistant short RC structural walls

  • Zygouris, Nick St.;Kotsovos, Gerasimos M.;Kotsovos, Michael D.
    • Earthquakes and Structures
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    • v.8 no.3
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    • pp.713-732
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    • 2015
  • The application of the compressive force path method for the design of earthquake-resistant reinforced concrete structural walls with a shear span-to-depth ratio larger than 2.5 has been shown by experiment to lead to a significant reduction of the code specified transverse reinforcement within the critical lengths without compromising the code requirements for structural performance. The present work complements these findings with experimental results obtained from tests on structural walls with a shear span-to-depth ratio smaller than 2.5. The results show that the compressive force path method is capable of safeguarding the code performance requirements without the need of transverse reinforcement confining concrete within the critical lengths. Moreover, it is shown that ductility can be considerably increased by improving the strength of the two bottom edges of the walls through the use of structural steel elements extending to a small distance of the order of 100 mm from the wall base.

Earthquake Resistant Design of Steel Box Bridges considering Failure Mechanism (파괴메카니즘을 고려한 강박스교량의 내진설계)

  • 국승규;이동휘
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.09a
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    • pp.330-337
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    • 2002
  • The objective of the earthquake resistant design of structures is to satisfy on the one side the minimization of damage requirement under earthquakes with high probability of occurrence during the design life and on the other side the no collapse requirement under the design seismic event with low probability of occurrence. The two requirements are satisfied with the minimum strength of substructure as well as the ductile failure mechanism presented in the codes. In this study seismic performance is evaluated with two bridges which have steel box superstructures and T type, II type piers as substructures. In order to satisfy the two requirements redesign of both substructures and steel bearings are carried out.

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Serviceability Limit State and Response Modification Factors (기능수행수준과 응답수정계수)

  • Kook, Seung-Kyu
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.2
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    • pp.149-154
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    • 2012
  • While the Earthquake Resistant Design Part of Korean Roadway Bridge Design Code provides design procedures for the No Collapse Requirement, requirements for the Serviceability Limit State are not clearly provided. The basic design method to meet the No Collapse Requirement is the spectrum analysis method using response modification factors and the Serviceability Limit State is determined by both the importance factor and the response modification factor applied in the design procedure. The importance factor can be simply applied according to the bridge importance category, however, in moderate/low seismic regions the application of the response modification factor may bring different result according to design conditions. In this study, for a typical bridge in the moderate/low seismic regions, determination procedures for the Serviceability Limit State are reviewed by carrying out earthquake resistant design and supplementary provisions for the Earthquake Resistant Design Part are identified based on the study results.

Effect of Damping Coefficients in Earthquakes Resistant Design with Viscous Dampers for Bridges (교량의 내진설계에 있어서 점성감쇠기능받침의 감쇠계수 영향평가)

  • 정상모
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.10a
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    • pp.399-406
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    • 2000
  • Viscous dampers have been utilized as bearings and STU`s (Shock Transmission Unit) in earthquake resistant designs for bridges. Some viscous dampers are used as energy dissipators on one hand, but some dampers such as STU`s are used as fixing devices during an earthquake on the other hand. This paper discusses the effect of viscous dampers on the response of bridge with respect to the magnitude of damping coefficients. For this purpose, a typical bridge was taken as an example, and time-history dynamic analysis have been carried out. The input seismic data used in the analyses are relevant to the response spectra in the Koreans design code. The results show that there is an optimum value of coefficient considered most effective in the design. A STU with a large value of coefficient seems to make its support fixed. The response of the bridge is not much sensitive to the variation of the damping coefficients.

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Behavior Factor of a Steel Box Bridge with Single Column Piers (단주교각 강박스교량의 거동계수)

  • 박준봉;김종수;국승규
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.228-235
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    • 2002
  • As the response spectrum method generally used in the earthquake resistant design is a linear method, the nonlinear behavior of a structure is to be reflected with a specific factor. Such factors are provided in the "Design Criteria for Roadwaybridges"as response modification factors and in the Eurocode 8, Part 2 as behavior factors. In this study a 5-span steel box bridge with single column piers is selected and the behavior factor is determined. The linear time history analyses are carried out with a simple linear model, where the nonlinear behavior of piers leading to the ductile failure mechanism is considered as predetermined characteristic curves.

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Progressive Collapse-Resistant Rotational Capacity Evaluation of WUF-W Connection by Fracture Index Analysis (파괴지수분석에 의한 WUF-W 접합부의 연쇄붕괴저항 회전능력평가)

  • Kim, Seonwoong
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.6
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    • pp.353-360
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    • 2018
  • This paper is to investigate the micro-behavior of the double-span beams with WUF-W seismic connection under combined axial tension and moment and to propose the rational rotational capacity of it for progressive collapse-resistant analysis and design addressing the stress and strain transfer mechanism. To this end, the behavior of the double-span beams under the column missing event is first investigated using the advanced nonlinear finite element analysis. The characteristics of fracture indices of double-span beams with WUF-W connection under combined axial tension and flexural moment are addressed and then proposed the rational rotational capacity as the basic datum for the progressive collapse-resistant design and analysis. The distribution of fracture indices related to stress and strain for the double-span beams is investigated based on a material and geometric nonlinear finite element analysis. Furthermore, the micro-behavior for earthquake and progressive collapse is explicitly different.