• Title/Summary/Keyword: 기존 내진 보강

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The Experimental Study on the Seismic Strengthening Effect of FRP Circular Tube on the Circular Bridge Piers (기존 교각의 FRP 원통관을 이용한 내진보강의 실험연구)

  • 황윤국;윤순종;김정호;최영민;박경훈;권태규
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.973-978
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    • 2003
  • This paper describes the experimental study on seismic strengthening effect of circular bridge columns with poor lap-splice details using FRP(Fiber Reinforced Plastic) wrapping, The as-built column suffered brittle failure due to the deterioration of lap-spliced longitudinal reinforcement without developing its flexural capacity or any ductility, The strengthening columns using FRP wrapping showed significant improvement in seismic performance due to FRP's confinement effect.

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Parametric Fragility Analysis of Steel Highway Bridges (매개변수를 고려한 강도로교의 취약도분석)

  • Choi, Eunsoo;Choi, Il-Yoon
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.09a
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    • pp.334-343
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    • 2003
  • 본 논문의 목적은 스팅베어링의 기존교량과 납-고무베어링(Lead-Rubber Bearing)으로 내진 보강된 교량에 대해서 갭(Gap)의 크기가 교량의 지진 취약도에 미치는 영향에 대해서 평가하였다. 이를 위해서 다경간 단순교(Multi-Span Simply Supported Bridge)와 다경간 연속교(Muti-Span Continuous Bridge)를 대상으로 취약도 분석을 실시하였다 또한 다양한 크기의 갭사이즈를 도입하여 해석을 실시하였다. 이를 통해서 갭사이즈의 변화가 각 교량의 구성품에 미치는 영향을 확률적으로 평가할 수 있었고, 합성된 취약도 곡선을 이용하여 최적의 갭사이즈를 확정할 수 있었다.

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Seismic Performance Evaluation According to Seismic Retrofit Techniques of Existing School Buildings (기존 학교건축물의 내진보강기법에 따른 내진성능평가)

  • Kang, Jong
    • Journal of the Korean Society of Industry Convergence
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    • v.15 no.1
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    • pp.29-36
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    • 2012
  • Reinforced concrete shear walls and X-type steel braces were applied in seismic retrofit techniques for seismic performance evaluation of school buildings constructed in accordance with standard design announced by the ordinance of the ministry of construction in 1980s. Seismic performance evaluation was based on FEMA 356 using response spectrum as elastic analysis and conducted to pushover analysis with nonlinear static analysis. The maximum displacement ratio between floors in 4th and 3rd floors of the existing school buildings was less than 1.0%, which was functioning level in FEMA 356. However, because plastic hinge occurs somewhat in structural members according to the results of pushover analysis, partial reinforcement will be required. X-direction of the maximum lateral displacement of reinforced concrete shear walls than X-type steel braces was 45% and 32% in 4th and 3rd floors of school buildings, and Y-direction was 18% and 17%, respectively.

Damage Probabilities according to the Structural Characteristics of Bridges and the Determination of Target Ductilities (교량의 구조특성에 따른 손상확률과 목표연성도 결정)

  • Sun, Chang-Ho;Lee, Jong-Seok;Kim, Ick-Hyun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.3
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    • pp.1-10
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    • 2010
  • The target performance of a current seismic design code is to achieve collapse-prevention in order to minimize casualties. Existing structures are also being retrofitted to meet this target performance. This seismic performance seems to have been achieved in recent great overseas earthquakes, but the accompanying enormous economic loss is pointed out as a new problem. A new seismic design concept over the current target performance is required to reduce economic loss, in which a target performance is determined by the damage probability in order to control the damage levels of structures. In this study, the seismic behavior of bridges having different characteristics was investigated by nonlinear seismic analyses, and fragility curves with respect to a reference damage level were derived. Based on these results, the characteristics of target ductilities satisfying a target damage probability were investigated.

Seismic-performance Experiments of Circular Shear Piers Considering Effects of Rebar Corrosion, Lap splice and Axial Load (철근부식, 겹침이음 및 축하중의 영향을 고려한 원형 전단 교각의 내진성능실험)

  • Lee, Soo-Hyung;Lee, Seung-Geon;Lee, Hyerin;Hong, Kee-Jeung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.6
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    • pp.143-153
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    • 2021
  • The corroded pier that has corrosion of the tranverse steel, main steel and lapsplice directly affects the seismic performance. The corrosion of the tranvese and main steel directly reduce the shear strength and bendig strength. If steel corrosion occurs in lap splice, the flexural strength and flexibility of existing corroded pier that are not seismic design are significantly reduced. In addition, as the axial force acting on the pier increase the shear strength. Considering these effects. In this stuydy, we cosidered steel corrosion, lap splice and axial force, for a reasonable evaluation of seismic-performance. It is confirmed that flexular failure occurs at pies where shear failure is expected to occur due to corrosion of reinforcement. These failure modes and their reason are analyzed, and necessary considerations are presented for seismic reinforcement.

The Consideration of the Necessity of Seismic Retrofitting for Existing High Speed Rail Bridge in Accordance with Design Guidelines Improvements (설계기준 개선에 따른 기존 고속철도 교량 내진보강 필요성 고찰)

  • Kim, Do-Kyoun;Jang, Han-Teak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.1
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    • pp.445-453
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    • 2013
  • This paper was calculated the earthquake load using ELFP(Equivalent Lateral Force Procedure) and RSA(Response Spectrum Analysis) for PSC Box Girder representative bridges by the Phase of KTX designed by ELFP and verified the difference of these analyses. It have been modeled 3 dimensional FE model of 5 bridges using a commercial FEM program for the comparison of these analyses using a commercial FEM program and were compared the earthquake load. It has been to confirm the increase of the difference ELFP of RSA calculated to seismic ground acceleration according to the ground condition and natural period. It is mean that the necessity of seismic reinforcement due to the application of a larger of earthquake load than designed earthquake load form the seismic performance evaluation result according to the difference of calculated earthquake loads.

Seismic Performance of Precast Infill Walls with Strain-Hardening Cement Composite (변형경화형 시멘트 복합체를 사용한 프리캐스트 끼움벽판의 내진성능)

  • Kim, Sun-Woo;Jeon, Esther;Kim, Yun-Su;Ji, Sang-Kyu;Jang, Gwang-Soo;Yun, Hyun-Do
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.89-92
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    • 2008
  • The seismic behavior of the lightly reinforced concrete frames (LRCFs) was controlled by the nonductile behavior of the critical regions. These critical regions require retrofit to improve the seismic behavior of the lightly reinforced concrete frames. Critical column end regions must be retrofit to increase the global ductility capacity. The objective of this research is to evaluate structural strengthening performance of lightly reinforced concrete frame with Strain hardening cement composite(SHCC) experimentally. The experimental investigation consisted of a cyclic load tests on 1/3-scale models of precast infill walls. Reinforcement detail of infill wall was variables in the experiment. The experimental results, as expected, show that the multiple crack pattern, strength, ductility and energy dissipation capacity are superior for specimen with SHCC infill wall due to bridging of fibers and stress redistribution in cement matrix.

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Capacity Evaluation of Steel Damper Attached to Outside of Frame (골조 외부에 부착한 강재댐퍼의 성능 평가)

  • Lee, Hyun-Ho
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.4
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    • pp.382-388
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    • 2017
  • In this study, a basic study was carried out on the external strengthening method of public buildings. A steel damper is installed outside the specimen with a rocking wall and connected to the frame. Two specimens were fabricated, and the non-reinforced specimens utilized the existing results. As a result of evaluating the envelope curve, strength, stiffness and energy dissipation capacity, it was evaluated that the strength enhancement of the RW_P specimen externally reinforced plate damper was evaluated to be excellent. In addition, RW_S specimens with external S type damper shows a gentle envelop curve after maximum load, and it can be confirmed that the damper properly dissipates the seismic energy.

The Study on Improvement Methods for The Seismic Performance of Port Structures (항만 구조물의 내진성능 향상을 위한 배면 지반의 보강방안에 관한 연구)

  • Kim, Byung-Il;Hong, Kang-Han;Kim, Jin-Hae;Han, Sang-Jae
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.4
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    • pp.151-165
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    • 2019
  • In this study, the four types of improvement methods (increase self weight and reducing sliding force etc.) were proposed depending on install location with compaction grouting to improve seismic performance of existing port structure and optimal methods by analyzing the effects of improvement (stability, constructability and economy) by theoretical and numerical methods. From the dynamic time history analysis for artificial seismic waves, the results indicated that the horizontal displacement after improvement decreased compared to before improvement, however the displacement reduction effect among improvement methods was not significantly different. Slope stability based on the strength reduction method and the limit equilibrium analysis method, it is confirmed that the passive pile method is more safe than other methods. It is due to the shear strength at the failure surface is increased. In addition, the analysis of constructability and economy showed that the reduction of earth pressure method (type 02) and the passive pile method (type 03) are excellent. However, in the case of the passive pile method is concerned that there is a shortage of design cases and the efficiency can be reduced depend on various constraints such as ground conditions.

Analysis on the Flexural Behavior of Existing Reinforced Concrete Beam-Column Structures Infilled with U-Type Precast Wall Panel (U형 프리캐스트 콘크리트 벽패널로 채운 기존 철근 콘크리트 보-기둥 구조물의 휨 거동 분석)

  • Son, Guk-Won;Yu, Sung-Young;Lim, Cheol-Woo;Ju, Ho-Seong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.5
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    • pp.56-66
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    • 2015
  • This study aims at developing a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were performed on one unreinforced beam-column specimen and two reinforced specimens with U-type precast wall panels. Seismic resistant test of anchored and welded steel plate connections manifested an average of 2.8 times increase in the maximum loading (average 591.8 kN) in comparison to unreinforced beam-column specimen. The maximum drift ratios were also shown between 1.4% and 2.7%. An analytical study was performed while assuming the RC column on the right side and the vertical element of the reinforced PC panel to behave in completely composite manner and the RC column on the left side and PC panel to behave in completely non-composite manner when loading was exerted from upper right end of RC frame of specimen to its left side. It was found with the assumptions that the overall flexural behavior in principle agreed with the experimental result.