• Title, Summary, Keyword: seismic behavior

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Analysis of Nonlinear Seismic Behavior of Reinforced Concrete Shear Wall Systems Designed with Special and Semi-Special Seismic Details (특수 및 준특수 상세에 따른 철근콘크리트 전단벽의 비선형 내진거동 해석)

  • Yoon, Sung-Joon;Lee, Kihak;Chun, Young-Soo;Kim, Tae-Wan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.1
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    • pp.43-51
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    • 2013
  • In this paper, analytical models for reinforced concrete shear wall systems designed based on Korean Building Code (KBC2009) are proposed, which have special and semi-special seismic details and are compared with experimental results for a verification of analytical models. In addition, semi-special seismic details aimed to improve constructability and enhance economic efficiency were proposed and evaluated. The analytical models were performed based on nonlinear static and dynamic analysis. Through the nonlinear analyses, two seismic details showed the similar seismic behavior from the cyclic test and the analytical models for the two different seismic details represented the behavior in terms of the initial stiffness, maximum strength and strength degradation. And newly proposed seismic details(semi-special) provided with similar hysterestic behavior as well as the maximum drift.

Seismic behavior factors of buckling-restrained braced frames

  • Kim, Jinkoo;Park, Junhee;Kim, Sang-Dae
    • Structural Engineering and Mechanics
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    • v.33 no.3
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    • pp.261-284
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    • 2009
  • The seismic behavior of a framed structure with chevron-type buckling restrained braces was investigated and their behavior factors, such as overstrength, ductility, and response modification factors, were evaluated. Two types of structures, building frame systems and dual systems, with 4, 8, 12, and 16 stories were designed per the IBC 2003, the AISC LRFD and the AISC Seismic Provisions. Nonlinear static pushover analyses using two different loading patterns and incremental dynamic analysis using 20 earthquake records were carried out to compute behavior factors. Time history analyses were also conducted with another 20 earthquakes to obtain dynamic responses. According to the analysis results, the response modification factors turned out to be larger than what is proposed in the provision in low-rise structures, and a little smaller than the code-values in the medium-rise structures. The dual systems, even though designed with smaller seismic load, showed superior static and dynamic performances.

Seismic behavior of Q690 circular HCFTST columns under constant axial loading and reversed cyclic lateral loading

  • Wang, Jiantao;Sun, Qing
    • Steel and Composite Structures
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    • v.32 no.2
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    • pp.199-212
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    • 2019
  • This paper presents an investigation on seismic behavior of out-of-code Q690 circular high-strength concrete-filled thin-walled steel tubular (HCFTST) columns made up of high-strength (HS) steel tubes (yield strength $f_y{\geq}690MPa$). Eight Q690 circular HCFTST columns with various diameter-to-thickness (D/t) ratios, concrete cylinder compressive strengths ($f_c$) and axial compression ratios (n) were tested under the constant axial loading and reversed cyclic lateral loading. The obtained lateral load-displacement hysteretic curves, energy dissipation, skeleton curves and ductility, and stiffness degradation were analyzed in detail to reflect the influences of tested parameters. Subsequently, a simplified shear strength model was derived and validated by the test results. Finally, a finite element analysis (FEA) model incorporating a stress triaxiality dependent fracture criterion was established to simulate the seismic behavior. The systematic investigation indicates the following: compared to the D/t ratio and axial compression ratio, improving the concrete compressive strength (e.g., the HS thin-walled steel tube filled with HS concrete) had a slight influence on the ductility but an obvious enhancement of energy dissipation and peak load; the simplified shear strength model based on truss mechanism accurately predicted the shear-resisting capacity; and the established FEA model incorporating steel fracture criterion simulated well the seismic behavior (e.g., hysteretic curve, local buckling and fracture), which can be applied to the seismic analysis and design of Q690 circular HCFTST columns.

The Seismic Behavior of the Truss-Arch Structure with Lead Rubber Bearing(LRB) (납-고무면진장치가 적용된 트러스-아치 구조물의 지진거동 분서)

  • Shin, Min -Gi;Kim, Gee-Cheol;Kang, Joo-Won
    • Proceeding of KASS Symposium
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    • pp.133-138
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    • 2008
  • In this study, the seismic behavior of arch structure with lead rubber bearing(LRB) 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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Seismic Behavior of Bridges with Sacrificial Energy-dissipating Devices (회생개념의 에너지소산장치의 적용에 따른 교량의 내진성능평가)

  • 김상효;이상우;김영훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.393-400
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    • 2003
  • Various types of dampers are widely adopted to reduce the seismic damages in bridges. However, dampers may be the improper solution especially in moderate seismic regions because dampers are costly for installation and require constant maintenance during life cycle. In this study, energy-dissipating sacrificial device is proposed, which sacrifices easily substitutable bridge members and dissipates the excessive energy during seismic excitations. In turns, the inelastic behavior of sacrificial members reduces the input energy of the major members, such as piers in bridges, and may prevent the major members from serious malfunction. A simplified mechanical model is developed to represent the behavior of sacrificial devices installed in a bridge. The hysteresis energy of piers is analyzed to certify performance of device under seismic loads applied to this mechanical model. The results from this study show that the proposed sacrificial energy-dissipating device can decrease excessive hysteresis energy and reduce the damage of piers under seismic excitation. Therefore, economical enhancement of the seismic performance of bridges may be possible by employing the proposed sacrificial energy-dissipating devices.

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The Seismic Behavior of the Truss-Arch Structure with Seismic Isolation (면진 트러스-아치 구조물의 지진거동 분석)

  • Kim, Gee-Cheol;Kim, Kwang-Il;Kang, Joo-Won
    • Journal of the Korean Association for Spatial Structures
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    • v.8 no.2
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    • pp.73-84
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    • 2008
  • The various systems as the seismic resistance systems are used to reduce the seismic response of structure. And the seismic isolation system among them is the system that reduces the seismic vibration to be transmitted from foundation to upper structure. The purpose of isolation system 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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Seismic behavior of steel column-base-connection equipped by NiTi shape memory alloy

  • Jamalpour, Reza;Nekooei, Masoud;Moghadam, Abdolreza Sarvghad
    • Structural Engineering and Mechanics
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    • v.64 no.1
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    • pp.109-120
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    • 2017
  • The behavior of moment resistant steel structures depends on both the beam-column connections and columns foundations connections. Obviously, if the connections can meet the adequate ductility and resistance against lateral loads, the seismic capacity of these structures will be linked practically to the performance of these connections. The shape memory alloys (SMAs) have been most recently used as a means of energy dissipation in buildings. The main approach adopted by researchers in the use of such alloys is firstly bracing, and secondly connecting the beams to columns. Additionally, the behavior of these alloys is modeled in software applications rarely involving equivalent torsional springs and column-foundation connections. This paper attempts to introduce the shape memory alloys and their applications in steel structural connections, proposing a new steel column-foundation connection, not merely a theoretical model but practically a realistic and applicable model in structures. Moreover, it entails the same functionality as macro modeling software based on real behavior, which can use different materials to establish a connection between the columns and foundations. In this paper, the suggested steel column-foundation connection was introduced. Moreover, exploring the seismic dynamic behavior under cyclic loading protocols and the famous earthquake records with different materials such as steel and interconnection equipment by superelastic shape memory alloys have been investigated. Then, the results were compared to demonstrate that such connections are ideal against the seismic behavior and energy dissipation.

Transverse seismic response of continuous steel-concrete composite bridges exhibiting dual load path

  • Tubaldi, E.;Barbato, M.;Dall'Asta, A.
    • Earthquakes and Structures
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    • v.1 no.1
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    • pp.21-41
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    • 2010
  • Multi-span steel-concrete composite (SCC) bridges are very sensitive to earthquake loading. Extensive damage may occur not only in the substructures (piers), which are expected to yield, but also in the other components (e.g., deck, abutments) involved in carrying the seismic loads. Current seismic codes allow the design of regular bridges by means of linear elastic analysis based on inelastic design spectra. In bridges with superstructure transverse motion restrained at the abutments, a dual load path behavior is observed. The sequential yielding of the piers can lead to a substantial change in the stiffness distribution. Thus, force distributions and displacement demand can significantly differ from linear elastic analysis predictions. The objectives of this study are assessing the influence of piers-deck stiffness ratio and of soil-structure interaction effects on the seismic behavior of continuous SCC bridges with dual load path, and evaluating the suitability of linear elastic analysis in predicting the actual seismic behavior of these bridges. Parametric analysis results are presented and discussed for a common bridge typology. The response dependence on the parameters is studied by nonlinear multi-record incremental dynamic analysis (IDA). Comparisons are made with linear time history analysis results. The results presented suggest that simplified linear elastic analysis based on inelastic design spectra could produce very inaccurate estimates of the structural behavior of SCC bridges with dual load path.

Seismic Fragility Analysis of Torsionally Irregular Wall Structures (평면 비대칭 벽식 구조물의 지진 취약도 분석)

  • Ha, Tae-Hyu;Hong, Sung-Gul
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.161-168
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    • 2005
  • Torsional behavior of eccentric structure under seismic loading may cause the stress and/or deformation concentration. Hence it is hard to estimate the seismic behavior of the structure with plan irregularity. This study suggests the method to setup the seismic fragility curve of the torsionally irregular structures. The suggested fragility curve may be acquired from the fragility surface defined on the D-R plan according to the estimated torsional behavior. The torsional behavior is predicted considering the inelastic region by adapting the inelastic stiffness of each wall. Finally the system displacement is converted to the spectral acceleration and the fragility curve for the seismic excitation level is presented. In addition, the fragility curve considering the excitation direction is proposed.

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Seismic analysis of CFST frames considering the effect of the floor slab

  • Huang, Yuan;Yi, Weijian;Nie, Jianguo
    • Steel and Composite Structures
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    • v.13 no.4
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    • pp.397-408
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    • 2012
  • This paper describes the refined 3-D finite element (FE) modeling of composite frames composed of concrete-filled steel tubular (CFST) columns and steel-concrete composite beams based on the test to get a better understanding of the seismic behavior of the steel-concrete composite frames. A number of material nonlinearities and contact nonlinearities, as well as geometry nonlinearities, were taken into account. The elastoplastic behavior, as well as fracture and post-fracture behavior, of the FE models were in good agreement with those of the specimens. Besides, the beam and panel zone deformation of the analysis models fitted well with the corresponding deformation of the specimens. Parametric studies were conducted based on the refined finite elememt (FE) model. The analyzed parameters include slab width, slab thickness, shear connection degree and axial force ratio. The influences of these parameters, together with the presence of transverse beam, on the seismic behavior of the composite frame were studied. And some advices for the corresponding seismic design provisions of composite structures were proposed.