• Title, Summary, Keyword: 단부 구조물

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Detection of Damage at the Ends of Members using Finite Model Updating and Semi Rigid Connection Model (모델개선기법과 반강접 접합부 모델을 이용한 부재단부 손상탐지)

  • Yu, Eun-Jong;Kim, Seung-Nam;Lee, Hyun-Kook;Choi, Hang
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.692-695
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    • 2010
  • 일반적으로 모델개선에서는 부재단위의 강성을 파악하기 때문에 구조물의 취약부인 부재단부의 손상이 집중될 경우 손상의 형태를 세밀히 파악하기 어려우며 손상된 구조물의 거동을 정확하게 모사하기 어려운 단점이 있었다. 이를 해결하기 위해서는 부재 단부에 발생한 손상을 고려할 수 있는 좀 더 정밀한 해석 모델을 통한 모델개선이 필요하다. 본 연구에서는 부재 단부에 반강접 접합을 가지는 해석모델을 사용해 모델 개선을 실시하고 이를 통해 접합부의 손상 평가와 손상 구조물의 거동을 파악하였다. 제안된 방법을 5층 1경간의 RC 벽식 실험체의 손상탐지에 적용하였으며 그 결과 부재단위 모델을 사용할 때보다 더욱 정확하게 구조물의 손상을 평가하고 거동을 모사할 수 있었다.

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An Experimental Study on Flexural Performance Evaluation of RC Beams Strengthened with Anchored CFRP Plates (CFRP판을 단부정착한 RC보의 휨성능 개선에 관한 실험적 연구)

  • Kim, Hyung-Jin;Hong, Ki-Nam;Han, Sang-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.4
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    • pp.167-174
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    • 2006
  • The purpose of this paper is to analyse and compare experimentally flexural behavior of RC beams strengthened with CFRP plates by different methods, which are divided into three classes: externally-bonded without end anchorage, externally-bonded with end anchorages, and anchored after prestressing of CFRP plates. Test results show that the RC beams strengthened with end anchorages have the improvement of ductility and flexural performance evaluation including ultimate strength and deflection, compared with only external bonding. Especially, RC beams with prestressed and anchored CFRP plates increase ultimate strength and ductility significantly.

Energy Absorption of Collision Post Based on North American CFR Regulations for Railway Vehicles (철도차량의 북미 CFR 법규에 대한 충돌 기둥에너지 흡수에 관한 연구)

  • Kim, Seung-Tech;Jeong, Ji-Ho;Choi, Jeong-Yong;Woo, Kwan-Je
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.8
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    • pp.935-943
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    • 2012
  • In accidents involving the collision of railway vehicles, there is a risk that structural members might penetrate the cab frame of the railway vehicle in the space in which the driver or passengers are seated. To reduce this risk, worldwide, studies on the collision of railway vehicles are underway. In North America, the Code of Federal Regulations (CFR) was revised in 2010 to include crush criteria for a collision and the corner post in an end frame. In this study, a crush analysis and crush test for a collision post and a crash analysis for a rigid cylinder were performed according to the CFR. The analysis and test results were compared and reviewed. This study aims to determine the usefulness of crush analysis for developing various end frames, and to understand the crush and crash characteristics and review the accuracy of the analysis.

Evaluation on Bearing Capacity of End Girder Member with Local Corrosion (지점부 부재의 부식손상에 따른 강거더 단부 지압강도 평가)

  • Ahn, Jin Hee;Lee, Won Hong;Kim, In Tae;Jeong, Young Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.5
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    • pp.74-82
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    • 2017
  • Localized corrosions damages in their structural sections can be occurred affected by installed environment conditions with high temperature as near the coastline and humidity or their poor maintenance situation. In bearing supports of steel bridges, especially, lower web and vertical stiffener in end girder support can be easily corroded because of relatively higher humidity due to the narrow space in the end of girder and the wetted accumulated sediments affected by rain water or antifreezing admixture leaked from expansion joint. It can be related to change in their structural performance. In this study, thus, bearing strength test specimens were fabricated considering corrosion damage in the web and vertical stiffeners and the change in their bearing strengths were experimentally evaluated. From the test results, localized corrosion damage of structural members in the end girder affected the bearing strength of end girder support, especially, localized corrosion damage of the vertical stiffener relatively highly affected their bearing strengths.

Analytical Research on Flexural Strengthened by FREP of RC Structure (RC 구조물의 FREP 휨 보강을 위한 해석적 연구)

  • Kang Sung-Hoo;Park Sun-Joon;Kim Min-Sung
    • Journal of the Korea Concrete Institute
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    • v.16 no.4
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    • pp.493-500
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    • 2004
  • FREP(Fiber Reinforced Epoxy Panel) are used for strengthening the damaged RC beams due to its good tensile strength, low weight, resistance to corrosion, and easy applicability. This study sets up structure equation for FREP bending reinforcement before and during the usage of RC beam. It finds the difference and finds the mechanical characteristics of rip-off failure that is caused by stress concentration in reinforcement material cutting part to estimate the performance of bending reinforcement. The result of this research can be summarized as two main consequences. The main failure of FREP reinforced concrete beam is rip-off failure and it evaluated rip-off failure of RC reinforcing bean based on the test and analytical conditions of this study. It found that stress was concentrated due to rapid change of bending rigidity in reinforced cutting part as a result of excessive reinforcement thickness of FREP. It resulted in rip-off failure. It means that it should evaluate the rip-off failure when designing reinforcement. It analyzed the reinforcement effect according to reinforced period for FREP. It found that reinforcement effect of P-Type that was reinforced during the usage decreased compared to I-Type that was reinforced before the usage. So when reinforcing a existing structure that is being used, it should consider the stress that is produced due to the fixed load.

An Experimental Study on the Flexural Strengthening Effect of Reinforced Concrete Beams Flexural Strengthened by CFRP (CFRP로 보강된 철근콘크리트 보의 휨 보강효과에 관한 실험적 연구)

  • Kim, Jae-Hun;Park, Sung-Moo;Kang, Joo-Won;Shin, Seung-Hyup
    • Journal of the Korean Association for Spatial Structures
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    • v.6 no.2
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    • pp.123-129
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    • 2006
  • Recently, many researches have been conducted about reinforced concrete structures strengthened with FRP plates. In case of structures strengthened with FRP plates, the issue of premature debonding FRP plate has been raised through many previous researches. The purpose of this paper is what structural behavior and flexaural capacity of reinforced concrete beams which are strengthened for flexure is investigated about the using secondary ironware in the method of external bonded CFRP plate, and the method of near surface mounted CFRP-Rod. Also, in order to evaluate flexural capacity, experiments of the reinforced concrete beams with exteranl bonded CFRP plate and near surface mounted CFRP-Rod have been compared and investigated.

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Flexural Behavior of RC Beams Strengthened with CFRP Plate Using Multi-directional Channel-type Anchorage System (다방향 채널형 단부정착장치를 이용한 CFRP판 보강 RC 보의 휨거동)

  • Hong, Ki Nam;Han, Sang Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.2
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    • pp.171-180
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    • 2008
  • The aim of this paper is to clarify the structural performance of RC beams strengthened with Carbon Fibre Reinforced Polymer(CFRP) plates using channel-type anchorage system. Twelve RC beams were specifically designed without and with a channel-type anchorage system, which was carefully detailed to enhance the benefits of the strengthening plates. All the twelve beams were identical in terms of their geometry but varied in their internal reinforcement, concrete strength. All the beams were tested under four point bending and extensively instrumented to monitor strains, cracking, load capacity and failure modes. The structural response of all the twelve beams is then critically analyzed in terms of deformability, strength and failure processes. It is shown that with a channel-type anchorage system, a brittle debonding failure of a strengthened beam can be transformed to an almost ductile failure with well-defined enhancement of structural performance in terms of both deformation and strength.

Evaluation of Shear Capacity on PC Girder-PC Beam Joint (PC 큰 보-PC 작은 보 접합부의 전단성능 평가)

  • Moon, Jeong Ho;Oh, Young Hun;Lim, Jae Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.166-174
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    • 2011
  • The object of this study is to evaluate the structural shear capacity of the PC girder-PC beam joint. The dapped end of PC beam and the ledger of PC girder are usually designed to design load. If the end of PC beam can be designed with continuous end, the dapped end of PC beam and the ledger of PC girder do not need to resist to all loads except dead load and construction load. The experimental program was carried out with 7 specimens containing the variable factors as the anchored method of the hanger bar, design load, be or not exist of ledger bars. As a result, the continuity of the dapped end and the ledger were ensured their safety although the design load was only the dead load and the construction load. The shear critical section was expanded toward the effective depth d, the distance from the supported position of the beam. If the ledger is designed according to PCI Design Handbook, the structural system of the ledger is as to the cantilever slab system. But the ledger of this study is as to the 3 side fixed slab system. Therefore the design of the ledger by PCI Design Handbook will lead to highly conservative results.

Effect of Vertical Load on Fragmentation by Demolition of Model Concrete Pillar (콘크리트 기둥의 발파해체시 파쇄도에 미치는 수직하중의 영향)

  • Kim, Seung-Kon;Park, Hoon;Yang, Hyung-Sik
    • Explosives and Blasting
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    • v.20 no.3
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    • pp.97-109
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    • 2002
  • 본 연구에서는 콘크리트 기둥 발파시 단부 조건을 고려하여 수직 하중에 따른 발파에 의한 파쇄형태를 비교하였다. 또한 파쇄도에 대한 정량적인 해석을 위해 상·하단부의 무게비와 각 방향별 단면의 면적비를 비교하였으며, 장전층을 달리한 모형 구조물 발파해 체시 각 층별 기둥의 파쇄형태와 방향별 면적비를 비교하여, 전체적인 구조물의 파쇄도를 비교하였다.

Evaluation of Post-Buckling Residual Strength of H-Section Steel Column for Both Ends are Fixed Condition (양단고정 단부구속에 따른 H 형 강재기둥의 좌굴 후 잔존내력 평가)

  • Abebe, Daniel Yeshewawork;Choi, Jae Hyouk;Kim, Jin Hyang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.1
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    • pp.83-88
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    • 2013
  • Progressive collapse is a chain reaction of failures propagating throughout a portion of a structure that is disproportionate to the original local failure. When column members are subjected to unexpected load (compression load), they will buckle if the applied load is greater than the critical load that induces buckling. The post-buckling strength of the columns will decrease rapidly, but if there is enough residual strength, the members will absorb the potential energy generated by the impact load to prevent progressive collapse. Thus, it is necessary to identify the relationship of the load-deformation of a column member in the progressive collapse of a structure up to final collapse. In this study, we carried out nonlinear FEM analysis and based on deflection theory, we investigated the load-deformation relationship of H-section steel columns when both ends were fixed.