• 제목/요약/키워드: Structural Weight

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Lightweight Design of a Modular Bridge for Railway Infrastructure Systems (철도 인프라 적용 교량형 조립식 모듈의 경량화 설계)

  • Im, Jae Moon;Shin, Kwang Bok;Park, Jae Hyun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.25 no.6
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    • pp.471-478
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    • 2016
  • This paper describes a method to design a lightweight modular bridge for a railway infrastructure system. A lightweight design was achieved using the material selection method. Aluminum extrusions and honeycomb sandwich composites were selected as the best materials to reduce the weight of the upper structure of a conventional modular bridge made of carbon-steel material. The structural integrity of the lightweight modular bridge was evaluated under vertical and wind loads. The twisting and bending natural frequencies were also evaluated to investigate its dynamic characteristics. The results showed that the structural integrity and natural frequencies of the lightweight modular bridge, made of aluminum extrusion and sandwich composites, satisfied the design requirements. Moreover, it was found that the weight of the conventional modular bridge made of carbon steel could be reduced by a maximum of 47% using lightweight materials.

Structural Evaluation of the 300 Ton Goliath Crane (골리앗 크레인의 구조안정성 검증)

  • Shin, Sung-Hwan;Kim, Jeong-Kyeong;Song, Chul-Ki;Kim, Bum-Keun;Bae, Tae-Han;Kim, Joong-Moon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.11
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    • pp.1515-1520
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    • 2011
  • Structural analysis and evaluation for the 300ton Goliath Crane were conducted with an FEM tool. The Golliath Crane has a 300 ton hoisting weight, a 110 m span and a 50 m lift. All loads such as the self weight, crane traveling load, trolley traveling load, wind load, and earthquake force, etc., that are indicat in the reference standards, were inputted as various severe conditions affecting the crane. The deformation and equivalent stress (von Mises stress) were evaluated for the crane structures.

Moment-Curvature Relation of Concrete Filled Circular Steel Tubular Beam with Nonlinear Stress-Strain Properties (비선형 응력-변형률 특성을 갖는 콘크리트 충전 원형강관 보의 모멘트-곡률 관계)

  • Park, Woo-Jin
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.3
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    • pp.195-202
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    • 2005
  • This paper presents moment-curvature analytical method of concrete filled steel tubular members considering intensity increase phenomenon by triaxial compression stress generation. For this purpose, this study considers buckling characteristics about compression department of steel members that filled up light weight and normal concrete. The analytical results are compared with the test results. Even if beam that filled up light weight concrete was calculated moment-curvature relationship easily analytically and could know that analytical results estimates as well agreed with the test results in case filled up normal concrete. In addition, the efficiency and applicabilities of the proposed moment curvature relationship algorithm are verified through conventional experimental results.

Relative Dynamic Modulus of Elasticity Comparison of the Eco-friendly Lightweight Concreate According to the Experimental Method (시험방법에 따른 친환경 경량콘크리트의 상대동탄성 계수 비교)

  • Lee, Soo-Hyung;Lee, Han-Baek
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.05a
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    • pp.181-182
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    • 2016
  • We developed eco-friendly lightweight concrete in order to apply eco-friendly lightweight concrete into structural wall or slab of shallow depth urban railway system. However, since lightweight aggregate has different structural feature of porous and it has been overvalued at current KS standard when applied, we did compare the characteristics of freezing and thawing of normal weight aggregate concrete by comparative test method(KS, ASTM). According to test method, there was a big difference of dynamic elastic modulus in lightweight concrete rather than in normal weight aggregate concrete. The big absorption factor in lightweight aggregate is main reason for that. For more detail, in KS law in which only 14 days water curing is carried out, the big amount of moisture in lightweight aggregate is frozen and high heaving pressure occurs and finally that lead to destruction of lightweight concrete. Therefore, it is considered that in case of lightweight concrete, resistibility against freezing and thawing has been undervalued in domestic KS law compared to ASTM law, which is overseas standard. So, a variety of examination about testing criteria and rule would be necessary for exact assessment of lightweight concrete.

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Corrosion Inhibition Properties of Steel bars in Reinforced Concrete Using Superplasticizer with Air Entrained Agent (고성능AE감수제를 사용한 콘크리트의 철근부식 저항성)

  • Lee, Mun-Hwan;Jung, Mi-Kyung;Oh, Se-Chul;Bae, Kyu-Woong;Seo, Chee-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.4 no.4
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    • pp.149-160
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    • 2000
  • As systematic methodologies are required for the evaluation on the durability of reinforced concrete structure, it is necessary to study and examine every factor which deteriorates the durability of structures. This paper aims to define factors affecting rebar corrosion and to establish a basis for a prediction of serviceability, regarding a state of harmful corrosion as a state when crack begins on the surface of concrete. The study results are followings; The corrosive current has changed by types of mixture, and this property enables the evaluations of corrosion resistance by mixture and concrete cover. The specimen using AE superplasticizer has better corrosion-resistance properties than non-AE specimen, as well those having low W/C and high unit cement weight. The procedure for calculation of durable year in this study is able to use as an indicator to establish mixture factors such as unit cement weight, W/C, amount of admixture, etc.

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A Parametric Study on Bulkhead Plate of Orthotropic Steel Deck Bridge (강바닥판교의 벌크헤드 플레이트에 관한 매개변수 연구)

  • 공병승;김진만
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.333-339
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    • 2003
  • Recently, the bridges become greater according to development of a construction technology. This phenomenon requires long span bridge, so that increases the dead weight. The orthotropic steel deck bridges have much advantages such as the light dead weight and the reduction of construction period. And almost whole process of carried out is manufactured at factory, so it can cause the increase of quality authoritativeness. But orthotropic steel deck bridge is consist of structure by welding, it can not avoid a lot of welding jobs, defects and transformation by welding are becoming problem accordingly. Specially, topical stress concentration phenomenon in cross connection area of longitudinal and transverse rib causes fatigue failure. The Bulkhead Plate for prevention of this stress concentration phenomenon was applied by changing the orthotropic steel deck of Williamsburg bridge in USA. But, it is principle that a Bulkhead Plate is not established in the domestic design standard. Therefore, it is estimated that the study for installation of Bulkhead Plate is needed. This treatise with considering these circumstances proves efficiency of Bulkhead Plate and will be presented optimal design details through finite element analysis according to change the geometrical of Bulkhead Plate and tile cross-connection area of longitudinal and transverse rib.

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Local zooming genetic algorithm and its application to radial gate support problems

  • Kwon, Young-Doo;Jin, Seung-Bo;Kim, Jae-Yong;Lee, Il-Hee
    • Structural Engineering and Mechanics
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    • v.17 no.5
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    • pp.611-626
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    • 2004
  • On the basis of a structural analysis of radial gate (i.e. Tainter gate), the current paper focuses on weight minimization according to the location of the arms on a radial gate. In spite of its economical significance, there are hardly any previous studies on the optimum design of radial gate. Accordingly, the present study identifies the optimum position of the support point for a radial gate that guarantees the minimum weight satisfying the strength constraint conditions. This study also identifies the optimum position for 2 or 3 radial arms with a convex cylindrical skin plate relative to a given radius of the skin plate curvature, pivot point, water depth, ice pressure, etc. These optimum designs are then compared with previously constructed radial gates. Local genetic and hybrid-type genetic algorithms are used as the optimum tools to reduce the computing time and enhance the accuracy. The results indicate that the weights of the optimized radial gates are appreciably lower than those of previously constructed gates.

High-Stiffness Structure Design of 8-Axis Multi-tasking Machine for Automotive Powertrain Shafts (자동차 파워 트레인 샤프트 가공용 8축 복합가공기의 고 강성 구조설계에 관한 연구)

  • Moon, Dong-Ju;Cho, Jun-Hyun;Choi, Yun-Seo;Hwang, In-Hwan;Lee, Jong-Chan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.2
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    • pp.78-83
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    • 2016
  • The development of an exclusive 8-axis multi-tasking machine to finish multiple cutting processes by a single piece of power equipment for securing the high-precision machining and high productivity of the series of shafts (a core part of the automotive powertrain that delivers engine power) is needed. The rigidity of the structure must be improved and the weight of the structure must be reduced to develop a multi-tasking machine with high precision and high productivity. In this paper, we perform a static structural analysis of the initial design of the multi-tasking machines and compare the results of the multi-tasking machines improved by the reinforced design and the results of the initial one. According to the results of the structural analysis, the rigidity of the reinforced machine was increased and the overall weight was decreased. Therefore, the productivity was increased.

Life-Cycle Cost Optimization of Slab Bridges with Lightweight Concrete (경량 콘크리트를 이용한 슬래브교의 생애주기비용 최적설계)

  • 정지승;조효남;최연왕;민대홍;이종순
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.04a
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    • pp.257-264
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    • 2002
  • This study presents a life-cycle cost (LCC) effectiveness of a concrete with lightweight aggregate. A number of researchers have made their efforts to develop a lightweight concrete, since it is difficult to apply conventional concrete using general aggregate to heavy self-weight structures such as long span bridges. In this study, an optimum design for minimizing the life-cycle cost of concrete slab bridges is performed to evaluate the life cycle cost effectiveness of the lightweight concrete relative to conventional one from the standpoint of the value engineering. The data of physical properties for new concrete can be obtained from basic experimental researches. The material properties of conventional one are acquired by various reports. This study presents a LCC effectiveness of newly developed concrete, which is made by artificial lightweight aggregate. A number of researchers have made their efforts to develop a lightweight concrete, since it is difficult to apply conventional concrete using general aggregate to heavy self-weight structures such as long span bridges. From the results of the numerical investigation, it may be positively stated that the new concrete lead to, the longer span length, the more economical slab bridges compared with structures using general concrete.

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Whole learning algorithm of the neural network for modeling nonlinear and dynamic behavior of RC members

  • Satoh, Kayo;Yoshikawa, Nobuhiro;Nakano, Yoshiaki;Yang, Won-Jik
    • Structural Engineering and Mechanics
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    • v.12 no.5
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    • pp.527-540
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    • 2001
  • A new sort of learning algorithm named whole learning algorithm is proposed to simulate the nonlinear and dynamic behavior of RC members for the estimation of structural integrity. A mathematical technique to solve the multi-objective optimization problem is applied for the learning of the feedforward neural network, which is formulated so as to minimize the Euclidean norm of the error vector defined as the difference between the outputs and the target values for all the learning data sets. The change of the outputs is approximated in the first-order with respect to the amount of weight modification of the network. The governing equation for weight modification to make the error vector null is constituted with the consideration of the approximated outputs for all the learning data sets. The solution is neatly determined by means of the Moore-Penrose generalized inverse after summarization of the governing equation into the linear simultaneous equations with a rectangular matrix of coefficients. The learning efficiency of the proposed algorithm from the viewpoint of computational cost is verified in three types of problems to learn the truth table for exclusive or, the stress-strain relationship described by the Ramberg-Osgood model and the nonlinear and dynamic behavior of RC members observed under an earthquake.