• Title/Summary/Keyword: Load carrying

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Evaluation of Load Carrying Capacity of RC Slab Bridges Considering Moment Redistribution (모멘트 재분배를 고려한 RC 슬래브교의 내하력 평가)

  • Kim Hu Seung;Kim Dae Joong;Yum Hwan Seok;Kim Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.335-338
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    • 2005
  • This paper describes a proposal for evaluation load carrying capacity of reinforced concrete slab bridges considering the moment redistribution. Recognition of redistribution of moments can be important because it permits a more realistic appraisal of the actual load-carrying capacity of a structure, thus leading to improved economy. In addition, it permits the designer to modify, within limits, the moment diagrams for which members are to be designed. The predicted results shows that moment redistribution are different from estimated by the current KCI, ACI 318-02, EC2 provisions, and propose reasonable load carrying capacity of the reinforced concrete slab bridge.

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Fatigue Strength of the Load-Carrying Cruciform Fillet Welded Joints Using the Hot-Spot Stress (Hot-Spot 응력을 이용한 하중전달형 십자형 필렛 용접재의 피로강도 평가)

  • Park, Jong-Min;Choi, Won-Sik;Kwon, Soon-Hong;Noh, Byeong-Wook
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.1
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    • pp.20-26
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    • 2007
  • In this study, fatigue strength of load-carrying cruciform fillet welded joints were evaluated using a new method proposed by Yamada, for geometric or structural stress in welded joint, that is, one-millimeter stress below the surface in the direction corresponding to the expected crack path. Validity of the method is verified by analyzing fatigue test results for load-carrying cruciform welded specimens has different size of weld toe radius, leg length and plate thickness reported in literature. Structural stress concentration factor for 1mm below the surface was calculated by finite element analysis for each specimen respectively. When compared to the basic fatigue resistance curve offered by BS7608, the one-millimeter stress method shows conservative evaluation for load-carrying cruciform fillet welded joints.

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Evaluation of Piping Integrity in Thinned Main Feedwater Pipes

  • Park, Young-Hwan;Kang, Suk-Chull
    • Nuclear Engineering and Technology
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    • v.32 no.1
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    • pp.67-76
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    • 2000
  • Significant wall thinning due to flow accelerated corrosion(FAC)was recently reported in main feedwater pipes in 3 Korean pressurized water reactor(PWR) plants. The main feedwater pipes in one plant were repaired using overlay weld method at the outside of pipe, while those in 2 other plants were replaced with new pipes. In this study, the effect of the wall thinning in the main feedwater pipes on piping integrity was evaluated using finite element method. Especially, the effects of both the overlay weld repair and the stress concentration in notch-type thinned area on the piping integrity were investigated. The results are as follows : (1) The piping load carrying capacity may significantly decrease due to FAC. In special, the load carrying capacity of the main feedwater pipe was reduced by about 40% during about 140 months operation in Korean PWR plants. (2) By performing overlay weld repair at the outside of pipe, the piping load carrying capacity can increase and the stress concentration level in the thinned area can be reduced.

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A Study on the Fatigue Strength Evaluation of Load-Carrying Fillet welded Cruciform Joints (하중전달 십자형 필렛 용접부의 피로강도 평가에 관한 연구)

  • Lee, Yong-Bok;Nam, Byung-Chan;Park, In-Kju;Chung, Chin-Sung;Kim, Ho-Kyung
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.200-205
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    • 2000
  • Fatigue failure modes of load-carrying cruciform weld joints are dependent on the characteristics of the fatigue crack initiation and propagation from the weld toe or the weld root. In this study, constant amplitude fatigue tests on load-carrying fillet welded specimen carried out, and fatigue strengths were evaluated. Also, an attempt is made to develop a new analytical model with more accuracy to predict the fatigue crack propagation life of fillet welded cruciform joints of SWS 490B steels containing lack of penetration defects. From the result of this study, fatigue crack growth characteristics of load-carrying fillet welded cruciform joints, containing lack of penetration defects are found to be affected by the weld geometry, stress range and microstructures of the weld zone.

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A Case Study on the Effect of Damaged Expansion Joint for Safety Assessment of Highway Bridges

  • Kim, Kwang-Il;Chai, Won-Kyu;Lee, Myeong-Gu;Son, Young-Hyun
    • International Journal of Safety
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    • v.9 no.2
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    • pp.16-21
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    • 2010
  • In this study, the variations of transformed impact factors and load carrying capacity of highway bridges measured from the state of expansion joint are evaluated. the field loading tests were performed on the highway bridge with damaged expansion joint to investigate the variation of the load carrying capacity. From the field loading tests in case that damaged expansion joint exist or do not exist, the static displacements and dynamic displacements were measured, and TIF were calculated, respectively. dynamic test is performed in order to estimate dynamic displacement and TIF according to the level of damage of expansion joint. From the results of TIF, the load carrying capacity of highway bridges with damaged expansion joint were estimated.

An Improvement for Evaluating Load Carrying Capacity by Passing Vehicles of PSC-BOX Bridge (PSC박스 교량의 통행차량에 의한 내하력 평가기법 개선)

  • Shin, Jae-In;Park, Chang-Ho;Lee, Sang-Sun;Lee, Beyong-Ju
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.4
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    • pp.147-151
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    • 2007
  • Load testing is an effective means in calculating the rating value of bridge. In Korea, load carrying capacity of bridge is modified by response modification factor that is determined from comparisons of measured values and analysis results. This paper presents the development of a method for determining the response modification factor, using traffic load. The proposed method is based on the results of computer simulations of traffic action effects. A comparison between the proposed method and the present method shows good agreement in estimating the modified load carrying capacity of bridges.

A comparison of different modes of load carriage : an evaluation

  • Lee, K.S.
    • Proceedings of the ESK Conference
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    • 1992.10a
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    • pp.104-112
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    • 1992
  • The objectives of this study were: (a) to find the maximum ac- ceptable weight which can be carried for 8 hours using a psycho- physical method for front, side (one hand and two hands) and back carrying, and (b) to develop models which could predict the ac- ceptable maximum weight in carrying using isometric strength and anthropometric data. A series of laboratory experiments were conducted to find the maximum acceptable weight in front side and back carrying. Six college students participated in the experiment. It was found that subjects were willing to carry the heaviest load using two-hand side carrying (average maximum acceptable weight: 7.76 kg). Back carrying was the close second with 6.62 kg. Also, there was a significant difference (p< 0.01) in maximum acceptable weight for carrying between one-hand (4.40kg) and two-hand side carrying.

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Study on the Load-Carrying Capacity of Finite-Width Slider Bearing with Wavy Surface (표면웨이브가 존재하는 유한폭 슬라이더 베어링의 지지하중 특성에 관한 연구)

  • Shin, Jung-Hun;Lee, Gi-Chun;Park, Jong-Won;Kang, Bo-Sik;Kim, Kyung Woong
    • Tribology and Lubricants
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    • v.29 no.1
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    • pp.13-18
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    • 2013
  • Slider bearing is a widely used load-carrying element in the industry. While a large number of studies have investigated the effect of overall surface curvature, very few have considered sinusoidal surface. Recently, consideration of surface roughness/waviness or intentional wave design has been identified as an important issue in the manufacture of hard disk driver, mechanical seal, hydraulic machine, and etc. This study investigated the load-carrying capacity of a finite-width slider bearing with a wavy surface. Film thickness ratios, length-width ratio, ambient pressure, amplitude, and partial distribution were selected as the simulation parameters. The calculation results showed that the load-carrying capacity rapidly varied at small film thickness ratio, but the waviness near the area of minimum film thickness made much more influence with an increase in film thickness ratio. As the length-width ratio of bearing was increased, ambient pressure became more influential at small film thickness ratios. Furthermore a particular partial distribution of the wavy area led to higher load-carrying capacity than did the whole distribution. Consequently, the results of this study are expected to be of use in surface micro-machining of finite-width slider bearings.

Theoretical and experimental study on load-carrying capacity of combined members consisted of inner and sleeved tubes

  • Hu, Bo;Gao, Boqing;Zhan, Shulin;Zhang, Cheng
    • Structural Engineering and Mechanics
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    • v.45 no.1
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    • pp.129-144
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    • 2013
  • Load-carrying capacity of combined members consisted of inner and sleeved tubes subjected to axial compression was investigated in this paper. Considering the initial bending of the inner tube and perfect elasto-plasticity material model, structural behavior of the sleeved member was analyzed by theoretic deduction, which could be divided into three states: the elastic inner tube contacts the outer sleeved tube, only the inner tube becomes plastic and both the inner and outer sleeved tubes become plastic. Curves between axial compressive loads and lateral displacements of the middle sections of the inner tubes were obtained. Then four sleeved members were analyzed through FEM, and the numerical results were consistent with the theoretic formulas. Finally, experiments of full-scale sleeved members were performed. The results obtained from the theoretical analysis were verified against experimental results. The compressive load-lateral displacement curves from the theoretical analysis and the tests are similar and well indicate the point when the inner tube contacts the sleeved tube. Load-carrying capacity of the inner tube can be improved due to the sleeved tube. This paper provides theoretical basis for application of the sleeved members in reinforcement engineering.

Numerical Investigation of Load Carrying Capacity of Geogrid-Encased Stone Columns under Foundation Load (구조물 기초하중 작용시 지오그리드 보강 쇄석말뚝의 하중지지 특성에 관한 수치해석 연구)

  • Yoo, Chung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.25 no.11
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    • pp.75-86
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    • 2009
  • This paper presents the results of a numerical investigation on load carrying capacity of geogrid-encased stone columns to use as load carrying column(s) supporting a foundation load. A validated 3D stress-pore pressure coupled model that can effectively show rapid drainage capability of stone columns and encasement effect of geogrid was adopted and a parametric study was carried out on a number of influencing factors. It is shown that the geogrid encased stone columns can be effectively used as foundation load supporting columns in soft ground. The results of numerical investigation were presented so that the relationship between the load carrying capacity of geogrid-encased stone columns and the influencing factors can be identified. Practical implications of the findings are also discussed.