• Title/Summary/Keyword: axial restraint

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Behaviour of steel joints under fire loading

  • da Silva, Luis Simoes;Santiago, Aldina;Real, Paulo Vila;Moore, David
    • Steel and Composite Structures
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    • v.5 no.6
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    • pp.485-513
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    • 2005
  • This paper presents a state-of-the-art on the behaviour of steel joints under fire loading and some recent developments in this field, currently being carried out by the authors. Firstly, a review of the experimental research work on steel joints is presented, subdivided into isolated member tests, sub-structure tests and tests on complete building structures. Special emphasis is placed on the seventh Cardington test, carried out by the authors within a collaborative research project led by the Czech Technical University in Prague. Secondly, a brief review of various temperature distributions within a joint is presented, followed by a discussion of the behaviour of isolated joints at elevated temperature, focussing on failure modes and analytical procedures for predicting the moment-rotation behaviour of joints at elevated temperature. Finally, a description of the coupled behaviour of joints as part of complete structures is presented, describing previous work and investigations on real fire (including heating and cooling phases) currently being carried out by the authors.

Compressive Behavior of Micropile According to Pile Spacing and Embedded Pile Angle in Sand (사질토 지반에 설치된 마이크로파일의 설치간격 및 설치각도에 따른 압축거동특성)

  • Kyung, Doo-Hyun;Kim, Ga-Ram;Kim, Dae-Hong;Shin, Ju-Ho;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.29 no.12
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    • pp.57-67
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    • 2013
  • Micropile technology has evolved continuously since its instruction by Fernando Lizzi in the 1950s. The effects of group micropile have been researched by many researchers. The effects of group micropile differ and change with pile length, pile spacing (S), pile angle (${\theta}$) and pile embedded conditions. In the present study, the effects of resistance increase and settlement reduction from micropiles were investigated through a series of axial load tests. For the study, axial load tests were performed using mat, group micropiles and micropiled-raft (MPR) in various pile spacing and pile angle conditions. As the result, the effects of resistance of micropiled-raft were 80% (3D) to 110% (7D) of the total resistance of mat and group micropile. The effects of settlement restraint of micropiled-raft were 20% (S=3D, ${\theta}=45^{\circ}$) to 70% (7D, ${\theta}=15^{\circ}$) of settlement of mat foundation.

Deformation Capacity of Inverted V-Type Brace Strengthened by Built-up Non-welded Buckling Restraint Element (조립형 무용접 좌굴방지재로 보강된 역V형 가새의 변형성능)

  • Kim, Sun Hee;Moon, Ji Young;Choi, Sung Mo
    • Journal of Korean Society of Steel Construction
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    • v.27 no.3
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    • pp.261-271
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    • 2015
  • Steel concentrically braced frame is an efficient system that can acquire resistance against the lateral force of buildings with the least amount of quantity. In this study is intended to proceed on the research of schemes for reinforcement by supplementing previously installed H-formed brace with non-welded cold-formed plastic stiffening materials restricting the flexure and buckling and acquire a consistent strength on the tensile and compressive force. As for the measures of supplementing previously-installed inverted V-formed braced frame, stiffening materials in the previous studies were converted to weak-axial supplementing materials to suggest a specific scheme evaluating the structural function through an experiment of members, interpretation of members, and frame-focused experiment. Reinforced brace satisfied the requirement to be prevent AISC brace from being ruptured due to imbalanced strength in the beam.

A Study on the Mechanical Properties of Concrete Filled Steel Tube Column under Centric Axial Load (중심축력을 받는 콘크리트 충전강관 기둥의 역학적 거동 특성에 관한 연구)

  • 박정민;김화중
    • Magazine of the Korea Concrete Institute
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    • v.7 no.5
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    • pp.133-144
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    • 1995
  • This study investigated to the properties of structural behaviors through a series of experiment with the key parameter, such as diameter-to-thickness(D/t) ratio, selenderness ratio of steel t~ube and strength of concrete under loading condition simple confined concrete by steel tube as a fundmental study on adaptability with structural members in high-rise building. The obtained results are sumnarised as follow. (1) The fracture mode of confined concrete was presented digonal tension fracture in the direction of $45^{\circ}$ with compression failure at the end of specimen in stub column, but the fracture mode of long column was assumed an aspect of bending fracture transversely. (2) The deformation capacity and ductility effect was increased by confine steel tube for concrete. (3) 'The emprical formula to predict the ultimate capacity of confined concrete by steel tube and concrete filled steel tube column using restraint of concrete considered D / t ratio, selenderness ratio of steel tube anti strength of' concrete were proposed.

Buckling Characteristics of Ship Bottom Plate - On the Stiffener Restraint Effects - (선박 선저외판의 좌굴특성에 관한 연구 - 보강재의 구속영향 검토 -)

  • Juh-H. Ham;Ul-N. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.31 no.4
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    • pp.130-138
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    • 1994
  • Bottom plates of empty hold are subjected to not only water pressure but also bi-axial inplane loads, specially in the alternate full loading full loading condition of bulk carrier. This kind of plate behaviours is very difficult to be explained and to be estimated using common buckling design guide in the initial design stage of hull structure, therefore, some more concrete studies for this plate structure was performed based on the currently developed buckling estimation formula. In this buckling formula, torsional stiffness effects of edge stiffener are included additionally and effects of elastic buckling strength of plate panel are treated as characteristic value problem. Also considering boundary stiffener effects and inplane and lateral loading, evaluation of bottom plate scantling using this formula, calculated results using various classification regulation of buckling strength and results of first report approach are compared each other and useful guides using developed formula for bottom plate scantling design are discussed.

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Earthquake Fragility Analysis of a Buried Gas Pipeline (매설가스배관의 지진 취약도 해석)

  • Lee, Do-Hyung;Jeon, Jeong-Moon;Oh, Jang-Kyun;Lee, Du-Ho
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.5
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    • pp.65-76
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    • 2010
  • In this paper, earthquake fragility analysis has been comparatively performed with regard to a buried gas pipeline of API X65 which has been widely used in Korea. For this purpose, a nonlinear time-history analyses has been carried out for 15 different analytical models of a buried gas pipeline in terms of the selected 12 sets of earthquake ground motions with 0.1g of scaling interval. Following that, earthquake fragility analyses have been conducted using the maximum axial strain of the pipeline obtained from the nonlinear time-history analyses. Parameters under consideration for subsequent earthquake fragility analyses are soil conditions, end-restraint conditions, burial depth and the type of pipeline. Comparative analyses reveal that whereas the first three parameters influence the fragility curves, particularly soil conditions amongst the three parameters, the last parameter has a little effect on the curves. In all, the present study can be considered as a benchmark fragility analysis of a buried gas pipeline in the absence of an earthquake fragility analysis of the pipeline and thus is expected to be a useful source regarding earthquake fragility analyses of a buried gas pipelines.