• 제목/요약/키워드: 한계하중법

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Secondary Buckling Behavior Analysis on the Ship's Plate under Combined Load(Lateral Pressure Load and Axial Compressive Load) (조합하중을 받는 선체판부재의 2차좌굴거동 해석)

  • Park Joo-Shin;Ko Jae-Yong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.12 no.1 s.24
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    • pp.67-74
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    • 2006
  • The ship plating is generally subjected to combined in-plane load and lateral pressure loads. In-plane loads include axial load and edge shear, which are mainly induced by overall hull girder bending and torsion rf the vessel. Lateral pressure is due to water pressure and cargo. These load components are not always applied simultaneously, but more than one can normally exist and interact. Hence, for more rational and safe design rf ship structures, it is of crucial importance to better understand the interaction relationship of the buckling and ultimate strength for ship plating under combined loads. Actual ship plates are subjected to relatively small water pressure except for the impact load due to slamming and panting etc. The present paper describes an accurate and fast procedure for analyzing the elastic-plastic large deflection behavior up to the ultimate limit state of ship plates under combined loads. In this paper, the ultimate strength characteristics of plates under axial compressive loads and lateral pressure loads are investigated secondary buckling behavior through ANSYS elastic-plastic large deflection finite element analysis with varying lateral pressure load level.

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A Study on the Lateral Pressure Effect under Axial Compressive Load of Ship Platings (종방향 압축력을 받는 선체판부재의 횡압력 영향에 관한 연구)

  • Park Joo-Shin;Ko Jae-Yong;Lee Jun-Kyo
    • Journal of Navigation and Port Research
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    • v.29 no.6 s.102
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    • pp.515-522
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    • 2005
  • The ship plating is generally subjected to. combined in-plane load and lateral pressure loads, In-plane loads include axial load and edge shear, which are mainly induced by overall hull girder bending and torsion of the vessel. Lateral pressure is due to. water pressure and cargo. These load components are nat always applied simultaneously, but mare than one can normally exist and interact. Hence, far mare rational and safe design of ship structures, it is af crucial importance to. better understand the interaction relationship af the buckling and ultimate strength far ship plating under combined loads. Actual ship plates are subjected to relatively small water pressure except far the impact load due to. slamming and panting etc. The present paper describes an accurate and fast procedure for analyzing the elastic-plastic large deflection behavior up to. the ultimate limit state of ship plates under combined loads. In this paper, the ultimate strength characteristics of plates under axial compressive loads and lateral pressure loads are investigated through ANSYS elastic-plastic large deflection finite element analysis with varying lateral pressure load level.

A Study on the Lateral Pressure Effect under Axial Compressive Load of Ship Platings (종방향 압축력을 받는 선체판부재의 횡압력 영향에 관한 연구)

  • Park, Joo-Shin;Ko, Jae-Yong;Lee, Jun-Kyo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.29 no.1
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    • pp.61-67
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    • 2005
  • The ship plating is generally subjected to combined in-plane load and lateral pressure loads. In-plane loads include axial load and edge shear, which are mainly induced by overall hull ginder bending and torsion of the vessel. Lateral pressure is due to water pressure and cargo. These load components are not always applied simultaneously, but more than one can normally exist and interact. Hence, for more rational and safe design of ship structures, it is of crucial importance to better understand the interaction relationship of the buckling and ultimate strength for ship plating under combined loads. Actual ship plates are subjected to relatively small water pressure except for the impact load due to slamming and panting etc. The present paper describes an accurate and fast procedure for analyzing the elastic-plastic large deflection behavior up to the ultimate limit state of ship plates under combined loads. In this paper, the ultimate strength characteristics of plates under axial compressive loads and lateral pressure loads are inverstigated through ANSYS elastic-plastic large deflection finite element analysis with varying lateral pressure load level.

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Vertical Direction Redistribution of Beam Moments in the Seismic Design of RC Frame (RC 골조의 내진설계에서 보 모멘트의 수직방향 재분배)

  • Kim, Dae-Kon
    • Journal of Korean Association for Spatial Structures
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    • v.11 no.1
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    • pp.57-66
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    • 2011
  • For the lateral load resistance of a RC frame in a medium risk seismic zone, the strength of lower story beams and columns should be larger than those of the upper stories. However, the lateral loads can be accommodated by redistributing design beam moments vertically as well as horizontally so all beams end up with identical strengths. This paper looks at the impact of the vertical redistribution of beam moments to provide identical beam strength over as many floors as possible. Two-bay six-story RC frame was designed with and without vertical beam moment redistribution and its seismic performance were evaluated by using push-over limit analysis and by non-linear time history dynamic analysis. Analytical results show that with the use of vertical beam moment redistribution the increase in the ductility demand is similar to the proportion of moment redistribution applied, but this additional demand is below the ductility capacity of well detailed RC members.

Redistribution of Negative Moments in Beams Subjected to Lateral Load (횡하중에 대한 휨재의 부모멘트 재분배)

  • Eom, Tae-Sung
    • Journal of the Korea Concrete Institute
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    • v.23 no.6
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    • pp.731-740
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    • 2011
  • Provisions for the redistribution of negative moments in KCI 2007 and ACI 318-08 use a method for continuous flexural members subjected to uniformly-distributed gravity load. Moment redistributions and plastic rotations in beams of reinforced concrete moment frames subjected to lateral load differ from those in continuous flexural members due to gravity load. In the present study, a quantitative relationship between the moment redistribution and plastic rotation is established for beams subjected to both lateral and gravity loads. Based on the relationship, a design method for the redistribution of negative moments is proposed based on a plastic rotation capacity. The percentage change in negative moments in the beam was defined as a function of the tensile strain of re-bars at the section of maximum negative moment, which is determined by a section analysis at an ultimate state using KCI 2007 and ACI 318-08. Span, reinforcement ratio, cracked section stiffness, and strain-hardening behavior substantially affected the moment redistribution. Design guidelines and examples for the redistribution of the factored negative moments determined by elastic theory for beams under lateral load are presented.

Feasibility Evaluation of CHS Diagrid Systems for Low/Mid-Rise Building Structure (원형강관 다이아그리드 시스템의 중저층 건축구조물 적용 타당성 평가)

  • Gam, Sam-Do;Kim, Tae-Jin;Kwak, Jin-I
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2009.04a
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    • pp.84-87
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    • 2009
  • 본 논문에서는 최근 초고층 건축물에 많이 활용되어지는 기둥-가새 시스템인 다이아그리드 시스템을 활용하여 중저층 건축물에 적용가능성을 평가하였다. 본 시스템은 튜브구조의 형태로 횡력에 대한 저항력이 우수하며 중력하중과 황하중을 기초와 지반에 안전하게 하중을 전달한다. 다이아그리드는 경사기둥과 보를 반복적으로 삼각형 형태로 배치되어 중력하중을 받을 경우 수직부재는 압축력을 보는 인장력을 받게 된다. 경사기둥과 보를 연결하는 접합부는 H-형강으로 설계 시 제작이 복잡하고 외관이 좋지 않다. 하지만 원형강관을 사용 할 경우 복합하지 않은 형태로 설계가 가능하고 외관이 우수하기 때문에 외부에 노출이 가능해진다. 또한 원형강관은 개방형 단면 부재에 비해 압축좌굴과 비틀림에 대한 성능 등이 우수하여 구조적인 성능이 우수하다. 원형강관을 이용하여 다이아그리드 시스템이 고층 건축물 뿐만 아니라 중저층 건축물에도 적용 타당성을 검토하였으며 원형강관 접합부 설계는 한계상태설계법이 사용 된 KBC2008(안)을 이용하여 설계하였다.

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The Ultimate Load Capacity of Plates by Elastic-Perfectly Plastic Model (탄성-완전소성모델에 의한 평판의 극한내하력 산정)

  • 박진환;정우성;우광성
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.12 no.1
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    • pp.1-14
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    • 1999
  • 선형탄성이론을 기초로 한 구조해석의 경우 사용하중상태에서의 변형과 응력은 만족할 만한 결과를 나타내지만, 항복후의 처짐과 파괴시의 극한하중 산정의 정확한 해석이 불가능하다. 평판의 극한해석시, 상한계 이론을 바탕으로 한 항복선 이론이 널리 사용되고 있으나 이론적으로 평판의 강도를 과대평가하게 된다. 그러므로, 임의의 하중조건과 경계조건에 대한 비선형 거동과 극한내하력을 산정할 수 있는 해석기법이 필요하다. 평판의 정확한 극한하중을 위해 p-Version 유한요소법을 제안하며, p-Version의 해석치를 범용 구조해석 프로그램인 ADINA의 결과와 문헌의 이론치와 비교하였다.

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Structural Responses of Composite-girder Bridges Due to Design Live Loads using Distribution Factor Method and Grillage Analysis (횡분배계수법과 평면격자 해석법을 이용한 합성거더교의 설계활하중 응답연구)

  • Jung, Myung-Rag;Yang, Hee-Sun;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.2
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    • pp.131-138
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    • 2015
  • In this paper, the modified live-load and designed formula are studied according to the fact the highway bridge design specifications are recently revised. The two examples for composite steel plates and PSC girder bridges are studied. The envelope is analyzed with the finite element models and lateral load distribution method applying the existing highway bridge specification(2010), the newly revised highway bridge specification(2015) and AASHTO LRFD. In case of composite steel plates, length changes between spans are studied, and in case of PSC girder. changes of the number of cross-beams and spans, and span-lengths, are analyzed.

A study on behavioral characteristics of concrete lining based on the equations of relaxed rock loads (이완하중 산정식에 따른 콘크리트라이닝 거동특성에 관한 연구)

  • Kim, Sang-Hwan;Park, Inn-Joon;Moon, Hoon-Ki;Shin, Yong-Suk
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.12 no.6
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    • pp.443-450
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    • 2010
  • A concrete lining of NATM tunnel had been considered as interior materials. But recently we consider it as structural materials. Therefore we must consider various loads. Relaxed rock load is a main load which decides thickness and reinforcement presence of concrete lining. In practice conservatively, Terzaghi's rock load theory has been accepted to estimate relaxed rock loads in urban subway tunnel design. This study investigates the equations of relaxed rock loads used in the design of NATM concrete lining. Structural analysis are executed based on various equations of relaxed rock loads, and concrete lining forces are compared.

Reliability Analysis of Fatigue Truck Model Using Measured Truck Traffic Statistics (통행차량 특성을 반영한 강교량 피로설계트럭의 피로파괴 신뢰도해석)

  • Shin, Dong Ku;Kwon, Tae Hyung;Park, Young Suk
    • Journal of Korean Society of Steel Construction
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    • v.19 no.2
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    • pp.211-221
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    • 2007
  • A structural reliability analysis of fatigue truck model for fatigue failure of highway steel bridges was performed by applying the Miner's fatigue damage rule expressed as a function of various random variables affecting fatigue damage. Among the variables, the statistical parameters for equivalent moment, impact factor, and loadometer were obtained by analyzing recently measured domestic traffic data, whereas the parameters on fatigue strength, girder distribution factor, and headway factor of the measured data available in the literature were used. The effects of various fatigue truck models, fatigue life, ADTT, fatigue detail category, loadometer, and gross vehicle weight of fatigue truck on the reliability index of fatigue damage were analyzed. It is expected that the analytical results presented herein can be used as a basic background material in the calibration of both fatigue design truck and fatigue load factor of LRFD specification.