• Title, Summary, Keyword: seismic behavior

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Structural redundancy of 3D RC frames under seismic excitations

  • Massumi, Ali;Mohammadi, Ramin
    • Structural Engineering and Mechanics
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    • v.59 no.1
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    • pp.15-36
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    • 2016
  • The components of the seismic behavior factor of RC frames are expected to change as structural redundancy increases. Most researches indicate that increasing redundancy is desirable in response to stochastic events such as earthquake loading. The present paper investigated the effect of redundancy on a fixed plan for seismic behavior factor components and the nonlinear behavior of RC frames. The 3D RC moment resistant frames with equal lateral resistance were designed to examine the role of redundancy in earthquake-resistant design and to distinguish it from total overstrength capacity. The seismic behavior factor and dynamic behavior of structures under natural strong ground motions were numerically evaluated as the judging criteria for structural seismic behavior. The results indicate that increasing redundancy alone in a fixed plan cannot be defined as a criterion for improving the structural seismic behavior.

Effects of the nonlinear behavior of lead-rubber bearings on the seismic response of bridges

  • Olmos, B.A.;Roesset, J.M.
    • Earthquakes and Structures
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    • v.1 no.2
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    • pp.215-230
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    • 2010
  • The main objectives of this work were to investigate the effects of the nonlinear behavior of the isolation pads on the seismic response of bridges with rubber bearings, and to identify when base isolation improved their seismic performance. To achieve these objectives a parametric study was conducted designing a set of bridges for three different soil types and varying the number of spans, span lengths, and pier heights. The seismic responses (accelerations, displacements and pier seismic forces) were evaluated for three different structural models subjected to three earthquakes with different dynamic characteristics. The first represented bridges without base isolation; the second corresponded to the same bridges including now rubber bearings as an isolation system, with linear elastic behavior that shifted the natural period of the bridge by a factor of 2 to 4. In the third model the seismic response of bridges supported on lead-Rubber bearings was studied accounting for the nonlinear behavior of the lead. The results show clearly the importance of the nonlinear behavior on the seismic performance of the bridges.

Seismic Analysis of Underground RC Structures considering Interface between Structure and Soil (경계면 요소를 고려한 지하 철근콘크리트 구조물의 지진해석)

  • 남상혁;변근주;송하원;박성민
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.87-92
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    • 2000
  • The real situation of an underground reinforced concrete(RC) structure with the surrounding soil medium subjected to seismic load is quite difficult to be simulated through an expensive work and, even if it is possible to arrange such an experiment, it will be too expensive. So development of analytical method can be applied usefully to seismic design and seismic retrofit through an analysis of seismic behavior and seismic performance evaluation. A path-dependent constitutive model for soil that can estimate the response of soil layer is indispensible for dealing with kinematic interaction of RC/soil entire system under seismic loads. And interface model which deals with the dynamic interaction of RC/soil entire system is also necessary. In this study, finite element analysis program that can consider path-dependent behavior of RC and soil, and interfacial behavior between RC and soil is developed for rational seismic analysis of RC/soil entire system. Using this program, nonlinear behavior of interface between RC and soil is analyzed, and the effect of interfacial behavior to entire system is investigated.

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The Seismic Behavior of the Truss-Arch Structure by Lead Rubber Bearing and Friction Pendulum System with Seismic Isolation (납고무받침 면진장치와 마찰진자 면진장치에 의한 트러스-아치 구조물의 지진거동 비교)

  • Kim, Gee-Cheol;Seok, Keun-Yung;Kang, Joo-Won
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.374-379
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    • 2008
  • The purpose of seismic isolation system among them is to lengthen the period of structure and make its period shift from the dominant period of earthquake. In this study, the seismic behavior of arch structure with lead rubber bearing(LRB) and friction pendulum system(FPS) is analyzed. The arch structure is the simplest structure and has the basic dynamic characteristics among large spatial structures. Also, Large spatial structures have large vertical response by horizontal seismic vibration, unlike seismic behavior of normal rahmen structures. When horizontal seismic load is applied to the large spatial structure with isolation systems, the horizontal acceleration response of the large spatial structure is reduced and the vertical seismic response is remarkably reduced.

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Study on seismic behavior and seismic design methods in transverse direction of shield tunnels

  • He, Chuan;Koizumi, Atsushi
    • Structural Engineering and Mechanics
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    • v.11 no.6
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    • pp.651-662
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    • 2001
  • In order to investigate the seismic behavior and seismic design methods in the transverse direction of a shield tunnel, a series of model shaking table tests and a two-dimensional finite element dynamic analysis on the tests are carried out. Two kinds of static analytical methods based on ground-tunnel composite finite element model and beam-spring element model are proposed, and the validity of the static analyses is verified by model shaking table tests. The investigation concerns the dynamic response behavior of a tunnel and the ground, the interaction between the tunnel and ground, and an evaluation of different seismic design methods. Results of the investigation indicate that the shield tunnel follows the surrounding ground in displacement and dynamic characteristics in the transverse direction; also, the static analytical methods proposed by the authors can be used directly as the seismic design methods in the transverse direction of a shield tunnel.

Predictions of Seismic Behavior of Reinforced Concrete Bridge Columns

  • Kim Tae-Hoon;Kim Woon-Hak;Lee Kwang-Myong;Shin Hyun-Mock
    • Journal of the Korea Concrete Institute
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    • v.16 no.3
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    • pp.441-450
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    • 2004
  • The objectives of this study are to investigate the seismic behavior of reinforced concrete bridge columns and to provide the data for developing improved seismic design criteria. The accuracy and objectivity of the assessment process can be enhanced by the use of sophisticated nonlinear finite element analysis program. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The low-cycle fatigue damage of both concrete and reinforcing bars has been also considered in order to predict a reliable seismic behavior. The proposed numerical method for the prediction of seismic behavior of reinforced concrete bridge columns is verified by comparison with the reliable experimental results.

Analysis of seismic response of 3-span continuous curved bridges (3경간 연속곡선교의 지진응답 특성분석)

  • Kim, Sang-Hyo;Lee, Sang-Woo;Cho, Kwang-Il;Park, Boung-Kyu
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.380-387
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    • 2005
  • Little has been understood about the seismic behavior of curved bridges due to the different structural characteristics compared to straight bridges. In this study, a simple numerical model, widely used for seismic analysis, is modified for a more realistic estimation of the seismic behavior. The seismic response of curved bridges obtained with the modified simple numerical model was compared with the result using a more sophisticated model to verify the feasibility. Seismic analyses were performed on three-span continuous curved bridges, which is a structural system widely used in highway structures. Numerical model of the three-span continuous curved bridges were subjected to seismic loads in diverse directions. From the result of the analysis. it was found that the direction of the seismic load have significant effect of the seismic behavior of curved bridges when the central angle exceeds 90 degrees.

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Seismic Performance Evaluation of RC Bridge Piers using Capacity Spectrum and Energy Analysis (역량스펙트럼 및 에너지분석을 이용한 RC교각의 내진성능평가에 관한 연구)

  • 정영수;박종협
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.361-367
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    • 2001
  • This research aims at evaluating the seismic performance of the R/C bridge piers, which were seismically designed in accordance with the seismic provision of limited ductile behavior of Eurocode 8. Pseudo dynamic test for six(6) circular RC bridge piers has been carried out so at to investigate their seismic performance subjected to experted artificial earthquake motions. The objective of this experimental study is to investigate the hysteretic behavior of reinforced concrete bridge piers. Important test parameters are confinement steel ratio, input ground motion, etc. The seismic behavior of circular concrete piers under artificial ground motions has been evaluated through displacement ductility, energy analysis, capacity spectrum. It can be concluded that RC bridge piers designed in the seismic code of limited ductile behavior of Eurocode 8 have been determined to show good seismic performance even under expected artificial earthquakes in moderate seismicity region.

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Seismic behavior of rebar-penetrated joint between GCFST column and RGC beam

  • Li, Guochang;Fang, Chen;An, Yuwei;Zhao, Xing
    • Steel and Composite Structures
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    • v.19 no.3
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    • pp.547-567
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    • 2015
  • The paper makes the experimental and finite-element-analysis investigation on the seismic behavior of the rebar-penetrated joint between gangue concrete filled steel tubular column and reinforced gangue concrete beam under low cyclic reversed loading. Two specimens are designed and conducted for the experiment to study the seismic behavior of the rebar-penetrated joint under cyclic loading. Then, finite element analysis models of the rebar-penetrated joint are developed using ABAQUS 6.10 to serve as the complement of the experiment and further analyze the seismic behavior of the rebar-penetrated joint. Finite element analysis models are also verified by the experimental results. Finally, the hysteretic performance, the bearing capacity, the strength degradation, the rigidity degradation, the ductility and the energy dissipation of the rebar-penetrated joint are evaluated in detail to investigate the seismic behavior of the rebar-penetrated joint through experimental results and finite element analysis results. The research demonstrates that the rebar-penetrated joint between gangue concrete filled steel tubular column and reinforced gangue concrete beam, with full and spindle-shaped load-displacement hysteretic curves, shows generally the high ductility and the outstanding energy-dissipation capacity. As a result, the rebar-penetrated joint exhibits the excellent seismic performance and meets the earthquake-resistant requirements of the codes in China. The research provides some references and suggestions for the application of the rebar-penetrated joint in the projects.

The Study of detailng for concrete reinforcement and Seismic Analysis Method for Underground Reinforced Concrete Box Structures (지하 철근 콘크리트 박스 구조물의 내진해석방법 및 철근 배근 상세에 관한 연구)

  • Lee, Myoung-Soo;Han, Sang-Chel
    • Proceedings of the KSR Conference
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    • pp.1215-1222
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    • 2005
  • The object of this thesis is an study on detailing for concrete reinforcement and analytical study for seismic behavior of underground reinforced concrete box structures using the established seismic analytical method. Using the established seismic analytical method that has been presented in various documents seismic behavior of buried reinforce concrete box structures is compared. From the comparsion, it is shown that feasibility and detailing detailng for concrete reinforcement and seismic method for seismic analysis of buried reinforced concrete box structures.

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