• Title, Summary, Keyword: 휨 저항성능

Search Result 155, Processing Time 0.051 seconds

An Experimental Study on Flexural Strength of Deep Corrugated Steel Plate Composite Members by Steel Grade and Reinforcement Method (강종 및 보강방법에 따른 대골형 파형강판 합성부재의 휨성능에 관한 실험적 연구)

  • Kim, Yongjae;Oh, Hongseob
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.21 no.2
    • /
    • pp.1-12
    • /
    • 2017
  • In this study, It was purpose to provide preliminary data for extension of the applicability of deep corrugated steel plate composite members by steel grade and shear reinforcement method. From the result of flexural test on deep corrugated plates composite members using GR40 and SS590, positive moment capacity was increased about 28% by SS590 steel. But to change steel grade was proved to have insignificant effects for increasement of negative moment capacity. In the moment test result of same overlapping length, Increasement rate of positive and negative moment capacity was not significantly improved by increasing the number of bolt. It was estimated to be due to the characteristics of bolt connection such as distance between centers of bolts, edge distance of bolt. In the test result on the spacing of shear reinforcement, positive moment capacity was increased and deformation of negative moment was reduced as the distance decrease. In the test result on the shape of shear reinforcement, positive and negative moment resistance was increased about 2% ~ 7% by U shaped shear reinforcement. In conclusion It was estimated that moment capacity of deep corrugated steel plate composite members are depend on steel grade of deep corrugated steel plate, spacing of shear reinforcement and reinforcing bar.

The Structural Behavior and Performance by Span-to-Depth Ratio in Composite Structure of Sandwish System (셀 형상비에 따른 강.콘크리트 복합구조체의 구조적 거동 및 성능)

  • 정연주;정광회;김병석
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.14 no.2
    • /
    • pp.181-192
    • /
    • 2001
  • 이 논문은 샌드위치식 강-콘크리트 복합구조체에서 상하 강판과 격벽으로 구성되는 셀의 형상비가 거동과 성능에 미치는 영향을 다루었다. 이 구조체에서 셀 형상비는 하중전달 메카니즘과 하중분배능력을 변화시킨다. 따라서 셀 형상비에 따라 부재의 응력수준과 하중저항능력이 변화한다. 이 연구에서는 셀 형상비가 이 구조체의 거동과 성능에 미치는 영향을 규명하기 위해, 두 종류의 샌드위치식 복합구조체에 대해 다양한 셀 형상비를 설정하여 비선형 구조해석을 수행하였다. 해석결과로부터 셀 형상비에 따른 하중전달 메카니즘과 부채 응력에서의 차이점을 도출하였으며, 이들 차이점을 바탕으로 셀 형상비가 전단성능, 휨성능, 하중저항성능에 미치는 영향을 분석하였고, 파괴모드와 연성에 미치는 영향에 대해서도 간략히 언급하였다. 연구결과, 셀 형상비가 증가함에 따라 하부 강판과 콘크리트의 응력수준이 낮아지는 결과를 나타내었다. 이것은 각 부재의 유효휨강성과 유효전단강성 증가를 나타내며, 따라서 구조체의 하중저항성능도 향상되는 것으로 판단된다. 특히 셀 형상비의 증가에 따른 성능향상에서 전단성능이 휨성능에 비해 더 큰 효과를 나타내며, 이러한 차이는 파괴모드와 연성에도 영향을 미칠 것으로 판단된다. 즉, 셀 형상비가 증가함에 따라 구조물의 거동 및 파괴모드는 점차적으로 전단에서 휨으로 변화하고, 이에 따라 구조물의 연성도 점차적으로 향상될 것으로 판단된다.

  • PDF

A Study on the Moment and Shear Resisting Performance of Steel Girder - R/C Column Connection (철골 보 - 철근콘크리트 기둥 접합부의 휨 및 전단 저항성능에 관한 연구)

  • Choi, Kwang Ho
    • Journal of Korean Society of Steel Construction
    • /
    • v.12 no.4
    • /
    • pp.429-436
    • /
    • 2000
  • The composite system, which is consisted of the steel girder and reinforced concrete column has some advantages in the structural efficiency and the construction productivity by complementing the shortcomings between the two materials. This research is aimed at the development of the composite beam-column connection system by which the steel beam can be connected to the R/C column with smooth stress transfer. And, to ensure safety of this system, the tests of moment and shear resisting performance have been carried out for actual size specimen. From the test, the connection system has been preyed to take good resistance and stress transfer between steel girder and reinforced concrete column.

  • PDF

Demand Strength Spectrums of Low-Rise Reinforced Concrete Buildings Consisted of Extremely Brittle, Shear and Flexural Failure Systems (극취성·전단·휨파괴형 수평저항시스템으로 구성된 저층 철근콘크리트 건물의 요구 내력 스펙트럼)

  • Lee, Kang-Seok;Kim, Jeong-Hee;Oh, Jae-Keun
    • Journal of the Korea Concrete Institute
    • /
    • v.19 no.5
    • /
    • pp.529-537
    • /
    • 2007
  • The purpose of this study is to discuss how strength and ductility of each system in low-rise reinforced concrete buildings composed of extremely brittle, shear and flexural failure lateral-load resisting systems have influence on seismic capacities of the overall system, which is based on nonlinear seismic response analyses of single-degree-of-freedom structural systems. In order to simulate the triple lateral-load resisting system, structures are idealized as a parallel combination of two modified origin-oriented hysteretic models and a degrading trilinear hysteretic model that fail primarily in extremely brittle, shear and flexure, respectively. Stiffness properties of three models are varied in terms of story shear coefficients, and structures are subjected to various ground motion components. By analyzing these systems, interaction curves of demand strengths of the triple system for various levels of ductility factors are finally derived for practical purposes. The result indicates that demand strength levels derived can be used as a basic information for seismic evaluation and design criteria of low-rise reinforced concrete buildings having the triple lateral-load resisting system.

Enhancement of Impact Resistance of Layered Steel Fiber Reinforced High Strength Concrete Beam (층 구조를 갖는 강섬유 보강 고강도 콘크리트 보의 충격저항성능 향상)

  • Yoo, Doo-Yeol;Min, Kyung-Hwan;Lee, Jin-Young;Yoon, Young-Soo
    • Journal of the Korea Concrete Institute
    • /
    • v.24 no.4
    • /
    • pp.369-379
    • /
    • 2012
  • The collapse of concrete structures by extreme loads such as impact, explosion, and blast from terrorist attacks causes severe property damage and human casualties. Concrete has excellent impact resistance to such extreme loads in comparison with other construction materials. Nevertheless, existing concrete structures designed without consideration of the impact or blast load with high strain rate are endangered by those unexpected extreme loads. In this study, to improve the impact resistance, the static and impact behaviors of concrete beams caste with steel fiber reinforced concrete (SFRC) with 0~1.5% (by volume) of 30 mm long hooked steel fibers were assessed. Test results indicated that the static and impact resistances, flexural strength, ductility, etc., were significantly increased when higher steel fiber volume fraction was applied. In the case of the layered concrete (LC) beams including greater steel fiber volume fraction in the tensile zone, the higher static and impact resistances were achieved than those of the normal steel fiber reinforced concrete beam with an equivalent steel fiber volume fraction. The impact test results were also compared with the analysis results obtained from the single degree of freedom (SDOF) system anaysis considering non-linear material behaviors of steel fiber reinforced concrete. The analysis results from SDOF system showed good agreement with the experimental maximum deflections.

A Study on Method of Evaluation for Deck Pavement (교면포장의 평가 방법 고찰)

  • Jo, Shin Haeng;Jo, Nam June;Jang, Jung Soon;Baek, Yu Jin;Kim, Nak Seok
    • 한국방재학회:학술대회논문집
    • /
    • /
    • pp.86-86
    • /
    • 2011
  • 토목 기술의 발달로 장대교량이 증가함에 따라 교면 포장도 더 심각한 진동 및 충격, 기상조건에 노출되게 된다. 교면 포장은 차량의 주행의 편리성뿐 아니라 교량 구조물을 보호해야 하는 역할도 함께 수행하기 때문에 일반 토공부의 포장과 다른 성능을 필요로 한다. 교면 포장의 특수함을 감안하여 교면 포장의 품질을 평가하고, 설계와 적용시 반영 한다면 교량의 내구 연한 및 시공, 유지관리 비용을 절감 할 수 있을 것이다. 본 논문에서는 교면 포장에 요구되는 성능을 조사하고, 교면 포장 특히, 장대 교량 적용시 교면 포장의 성능 평가를 위한 평가 방법을 고찰하였다. 교면 포장의 가장 큰 구조적 특징은 교량의 진동과 휨에 의해 포장이 받게 되는 휨응력이다. 특히 교량의 장경간화에 따라 더 큰 진동과 변형을 경험하게 되는 교면 포장은 그에 따른 충분한 휨 추종성과 피로 저항성을 확보하여야 한다. 기존 토공부 포장에서는 실험이 간단한 원통형 공시체를 이용한 간접인장강도 모드의 실험으로 피로 성능을 평가하였으나, 교면 포장은 실제 거동 특성과 유사한 빔 피로 시험 모드가 보다 신뢰성이 높을 것으로 판단된다. 빔 피로시험 모드로는 3점, 4점, 5점 휨 피로 시험 모드가 있으며, 각각의 모드는 지지점의 개수, 재하점의 개수에 따라 다른 거동 특성을 평가 할 수 있다. 최근 개발된 5점 휨 시험의 경우 교량에서 발생하는 부(-)모멘트를 모사할 수 있어 보다 현실적인 검증이 가능할 것으로 예상된다. 이 외에도 실제 크기 모형을 이용하여 윤하중을 가하는 Full-scale 모델의 경우 비용과 시간이 많이 소요되는 단점이 있으나 가장 신뢰성이 높은 방법이라고 할 수 있다. 교면 포장은 교량구조부로 수분이 침투되는 것을 막아주는 역할을 하여야 하며, 특히 해상 교량의 경우의 염분과 겨울철 사용되는 제빙화학제는 콘크리트의 열화와 강구조물의 부식을 발생시키므로 교면 포장의 방수 성능 검토는 매우 중요한 역할을 한다. 일반 토공부 포장과 달리 교면 포장은 하부층이 대기에 노출되어 있기 때문에 겨울철에 더 낮은 온도로 포장체의 온도가 내려가게 되고, 온도가 떨어진 포장층은 스티프니스가 증감함에 따라 저온 균열의 발생확율이 높아지며, 휨추종성도 나빠질 가능성이 높다. 따라서 저온에서의 균열 저항성 및 스티프니스를 평가하는 것은 교면 포장 재료의 중요한 인자 중 하나이다. 포장과 포장 하부층의 접착은 포장층의 일체화된 거동을 할 수 있게 하기 때문에 내구성 향상에 중요하다. 특히 교량과 같이 진동과 변형이 많은 경우에 있어 포장 접착층의 성능은 포장과 교량 구조물의 파손에 더 큰 영향을 미치게 된다. 접착성능은 실내에서의 직접인장모드와 전단접착강도 시험 모드의 실험이 있으며, 현장에서 측정하는 Pull-off 실험 등이 있다. 최근에 교통량과 중차량의 증가와 더불어 교량이 장경간화 되어 가면서 평가방법과 기준을 과거보다 엄격하게 할 필요성이 있다. 하지만 현실은 교면포장에 대한 시방규정이 모호하기 때문에 본 논문에서 제시한 국내외의 다양한 평가방법을 통해 적절한 교면포장의 성능을 평가하고 교면포장의 거동특성에 대한 이해를 함으로써 보다 발전된 교량기술을 확보할 수 있을 것이다.

  • PDF

Material Properties of Concrete Produced with Limestone Blended Cement (석회석 혼합 시멘트로 제조된 콘크리트의 기초 물성)

  • Bang, Jin-Wook;Kwon, Seung-Jun;Shin, Kyung-Joon;Chung, Woo-Jung;Kim, Yun-Yong
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.19 no.2
    • /
    • pp.125-132
    • /
    • 2015
  • This paper presents an experimental investigation in order to evaluate fresh and hardened properties of LP (Limestone Powder) blended cement concrete. The cement contents of the mixtures are replaced by LP in the range of 10%, 15%, 25%, and 35%, while a control mixture is prepared with only OPC (Ordinary Portland Cement). The fresh concrete properties like slump and air content are similar to those of control mixture up to 35% of replacement ratio of LP, however a delay in setting time is evaluated. The hardened properties including compressive strength, flexural strength, and rapid freezing and thawing resistance shows similar results of control mixture up to 15% of replacement. Relatively lower strength development is evaluated over 25% replacement of LP. For accelerated carbonation test, resistance to carbonation rapidly decreases with increasing LP replacement ratio due to the limited amount of $Ca(OH)_2$. From the study, LP replacement under 15% can be adopted considering reduction of strength and resistance to carbonation.

An Experimental Study on the Behavior of T-type Modular Composite profiled Beams (T형 모듈단면 합성 프로파일보의 거동에 관한 실험적 연구)

  • Ahn, Hyung Joon;Lee, Seong Won;Ryu, Soo Hyun
    • Journal of Korean Society of Steel Construction
    • /
    • v.20 no.4
    • /
    • pp.539-548
    • /
    • 2008
  • This study aims to determine the applicability of the previously published T-type modular profile beam in the manner of producing specimens designed specially for the said purpose, determining their bending and shear behaviors depending on the presence of shear reinforcement, and analyzing the results in comparison with the theoretical equation of plastic deformation. The modular profile beam contributes to bending and shear resistance with the addition of the profile to the form function, and enhances the molding performance through the modular concept. The experimental results showed that the TS series specimens with shear reinforcement have bending behaviors superior to those of the T series specimens without shear reinforcement, which suggests that the used shear reinforcement appropriately bears the shear force. However, it was considered that all the specimens except for the T1-1 specimen failed to have adequate bending performance because of the intermodular slipping caused by the shear failure of the bolts. It is expected that further studies on the T-type modular profile beam, in which shear connectors will be considered as a variable,be performed to develop optimal intermodular connection methods.

An Experimental Study on the Mechanical Properties of Porous Concrete Using Coal Ash and Polymer (석회석 골재를 사용한 강섬유보강 포러스콘크리트의 강도특성에 관한 실험적 연구)

  • Lee, Byung-Jae;Park, Seong-Bum;Jang, Young-Il;Jeon, Heum-Jin;Lee, Taek-Woo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.685-688
    • /
    • 2008
  • Concrete is strong on the compressive property, but weak on the tensile and flexural properties. To improve these problems, the reinforcing bar is used in concrete. But porous concrete with steel fiber has a weak point when exposed to air, because porous concrete has the vast continuous void on its inside and steel fiber is easily rusted by air. For these reasons, this study investigated the void ratio, compressive strength, bending strength and bending toughness as steel fiber mixing ratio and target void ratio. From test results, actual void ratio and strength properties increased as the mixing ratio of steel fiber increase. In case the mixing ratio of steel fiber over the fixed ratio, strength is decreased. And from the toughness evaluation, compared to the porous concrete which isn't mixed with steel fiber, the deflection variation efficiency is remarkably improved. Consequently we can confirm the possibility of porous concrete with steel fiber for the secondary product and pavement material to improve strength and bending resistance efficiency.

  • PDF

A Study on the Flexural Performance of Steel Fiber-Reinforced Beams lightly Reinforced Below the Minimum Steel Reinforcement (최소철근량 이하로 보강된 강섬유보강 보의 휨성능 고찰)

  • Kang, Duk-Man;Park, Yong-Gul;Moon, Do-Young
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.21 no.3
    • /
    • pp.35-44
    • /
    • 2017
  • In this study, steel fiber-reinforced concrete beams with ordinary steel reinforcements, that are below minimum steel reinforcement amount specified in domestic concrete structure design code, were tested in flexure until failure. Steel reinforcement ratio considered were 44%, 66%, 78% and 100% of the minimum steel reinforcement. Considered steel fiber volume fractions were 0.25%, 0.50%, 0.75% and 1.00%. In results, it is confirmed that steel fibers greatly improve crack performance. Also, the steel fibers contributed to increment in yield load not in ultimate load. But the increment was not greater than the reduction by steel reinforcement reduction. The use of steel fibers in RC beams lightly reinforced below the minimum reinforcement ratio specified design code reduced ductility greatly. Consequently, steel reinforcement ratio in steel fiber-reinforced beams lightly reinforced below the minimum steel reinforcement should be increased in order to enhance proper ductility.