• Title/Summary/Keyword: seismic performance

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Study of seismic performance and favorable structural system of suspension bridges

  • Zhang, Xin-Jun;Zhang, Chao
    • Structural Engineering and Mechanics
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    • v.60 no.4
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    • pp.595-614
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    • 2016
  • By taking the Runyang Highway Bridge over the Yangtze River with 1490 m main span as example, structural response of the bridge under the horizontal and vertical seismic excitations is investigated by the response spectrum and time-history analysis of MIDAS/Civil software respectively, the seismic behavior and the influence of structural nonlinearity on the seismic response of the bridge are revealed. Considering the aspect of seismic performance, the suitability of employing the suspension bridge in super long-span bridges is investigated as compared to the cable-stayed bridge and cable-stayed-suspension hybrid bridge with the similar main span. Furthermore, the effects of structural parameters including the span arrangement, the cable sag to span ratio, the side to main span ratio, the girder height, the central buckle and the girder support system etc on the seismic performance of the bridge are investigated by the seismic response spectrum analysis, and the favorable earthquake-resistant structural system of suspension bridges is also discussed.

Experimental study on seismic performances of steel framebent structures

  • Liang, Jiongfeng;Gu, Lian S.;Hu, Ming H.
    • Earthquakes and Structures
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    • v.10 no.5
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    • pp.1111-1123
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    • 2016
  • To study seismic performance of steel frame-bent structure, one specimen with one-tenth scale, three-bay, and five-story was tested under reversed cyclic lateral load. The entire loading process and failure mode were observed, and the seismic performance indexes including hysteretic loops, skeleton curve, ductility, load bearing capacity, drift ratio, energy dissipation capacity and stiffness degradation were analyzed. The results show that the steel frame-bent structure has good seismic performance. And the ductility and the energy dissipation capacity were good, the hysteresis loops were in spindle shape, which shape were full and had larger area. The ultimate elastic-plastic drift ratio is larger than the limit value specified by seismic code, showing the high capacity of collapse resistance. It can be helpful to design this kind of structure in high-risk seismic zone.

Evaluation of seismic performance factors for steel DIAGRID structural system design

  • Lee, Dongkyu;Shin, Soomi;Ju, Youngkyu
    • Earthquakes and Structures
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    • v.10 no.4
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    • pp.735-755
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    • 2016
  • This article presents a proposed analytical methodology to determine seismic force-resisting system R-values for steel diagrid framed systems. As current model building codes do not explicitly address the seismic design performance factors for this new and emerging structural system, the purpose of this study is to provide a sound and reliable basis for defining such seismic design parameters. An approach and methodology for the reliable determination of seismic performance factors for use in the design of steel diagrid framed structural systems is proposed. The recommended methodology is based on current state-of-the-art and state-of-the practice methods including structural nonlinear dynamic analysis techniques, testing data requirements, building code design procedures and earthquake ground motion characterization. In determining appropriate seismic performance factors (R, ${\Omega}_O$, $C_d$) for new archetypical building structural systems, the methodology defines acceptably low values of probability against collapse under maximum considered earthquake ground shaking.

Seismic Performance of Wind-Designed Diagrid Tall Steel Buildings in Regions of Moderate Seismicity and Strong Wind

  • Kim, Seonwoong;Lee, Kyungkoo
    • Steel and Composite Structures
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    • v.14 no.2
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    • pp.155-171
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    • 2013
  • This study analytically evaluated the seismic performance of wind-designed diagrid tall steel buildings in regions of moderate/low seismicity and strong winds. To this end, diagrid tall steel buildings with varying wind exposure and slenderness ratio (building height-to-width ratio) conditions were designed to satisfy the wind serviceability criteria specified in the Korean Building Code and the National Building Code of Canada. A series of seismic analyses were then performed for earthquakes having 43- and 2475- year return periods utilizing the design guidelines of tall buildings. The analyses demonstrated the good seismic performance of these wind-designed diagrid tall steel buildings, which arises because significant overstrength of the diagrid system occurs in the wind design procedure. Also, analysis showed that the elastic seismic design process of diagrid tall steel buildings might be accepted based on some wind exposures and slenderness ratios.

Seismic performance of RC-column wrapped with Velcro

  • Kwon, Minho;Seo, Hyunsu;Kim, Jinsup
    • Structural Engineering and Mechanics
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    • v.58 no.2
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    • pp.379-395
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    • 2016
  • A seismic strengthening method using Velcro is proposed to improve the seismic performance of columns in RC frame structures. The proposed method was evaluated experimentally using three fabricated RC specimens. Velcro was wrapped around the columns of the RC-frame specimen to prevent concrete spall falling. The reinforcing performance of the Velcro was determined from comparison of results on seismic performance (i.e., strength, displacement, failure mode, displacement ductility capacity and amount of dissipated energy). As the displacement of the reinforced specimens was increased, the amount of dissipated energy increased drastically, and the displacement-ductility-capacity of the reinforced specimens also increased. The final failure mode of RC frame structure was changed. As a result, it was concluded that the proposed seismic strengthening method using Velcro could be used to increase the displacement ductility of RC columns, and could be used to change the final failure mode of RC-frame structures.

Cyclic testing of weak-axis steel moment connections

  • Lee, Kangmin;Li, Rui;Jung, Heetaek;Chen, Liuyi;Oh, Kyunghwan
    • Steel and Composite Structures
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    • v.15 no.5
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    • pp.507-518
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    • 2013
  • The seismic performance of six types of weak-axis steel moment connections was investigated through cyclic testing of six full-scale specimens. These weak-axis moment connections were the column-tree type, WUF-B type, FF-W type, WFP type, BFP-B type and DST type weak-axis connections. The testing results showed that each of these weak-axis connection types achieved excellent seismic performance, except the WFP and the WUF-B types. The WFP and WUF-B connections displayed poor seismic performance because a fracture appeared prematurely at the weld joint due to stress concentrations. The column-tree type connection showed the best seismic behavior such that the story drift ratio could reach 5%.

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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    • 2001.04a
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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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A Basic Study on an Application of the Modified Epoxy Mortar for Seismic Reinforcement (내진보강을 위한 변성에폭시 모르터 활용방안 기초연구)

  • Kim, Boo-Young;Yang, Seongpil;Kim, Sangho;Son, Kiyoung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.176-177
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    • 2014
  • Although the modified epoxy mortar can be applied to the reinforcement for RC member, the mortar has been little used in construction site. In addition, there is a few studies regarding the experiment as the material improving the seismic performance. Therefore, this study is to propose an effective reinforcement alternative for RC Ordinary Moment Resisting Frame (OMRF) through evaluation of seismic performance and economic analysis. The findings of this study can be utilized as the basic data in construction sites when the modified epoxy mortar is applied for seismic performance reinforcement.

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Seismic Performance of Gravity-Load Designed Post-Tensioned Flat Plate Frames (중력하중으로 설계된 포스트텐션 플랫플레이트 골조의 내진성능)

  • Park, Young-Mi;Rew, Youn-Ho;Han, Sang-Whan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.127-128
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    • 2010
  • The purpose of this study is to evaluate the seismic performance of gravity-designed post tensioned (PT) flat plate frames with and without slab bottom reinforcement passing through the column. For the PT flat plate frames, the slab bottom reinforcement is often omitted since the requirement for the slab bottom reinforcement for PT flat plates is not clearly specified in ACI 318-08. This study evaluates the seismic performance of the model frames was evaluated by conducting nonlinear time history analysis. The seismic performance of PT flat plate frames is significantly improved by placing slab bottom reinforcement passing through the column.

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Seismic Performance of Precast Beam-Column Joints with Thru-Connectors (관통형 연결재로 연결된 PC 보-기둥 맞댐 접합의 내진성능에 관한 실험적 연구)

  • Park, Seok-June;Park, Soon-Kyu
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.83-84
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    • 2010
  • Precast beam column joints with thru-connectors are developed from precedent study. The seismic performance is evaluated by experimental method. The test results of the precedent study showed that failure modes for all specimens were a compression failure by characteristics of unbonded tendon. Thus, variable considered in the research program for a tensile failure include the use of dog-boned longitudinal steel and concrete confined with steel spirals. The analysis of structural characteristics and evaluation of seismic performance of specimens was conducted by the experimental way. Comparison of result with the test specimens indicates that seismic performance is higher than the precedent study due to concrete confinement effect from steel spirals.

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