• Title/Summary/Keyword: Lift pier

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A Study on the Lift Pier and Equipment of Design Criteria for Effective Vessel Management in the Marina (마리나 항만의 효율적인 선박 관리를 위한 상하가 시설 및 장비의 설계기준에 관한 연구)

  • Moon, Jung-Hwan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.6
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    • pp.654-661
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    • 2018
  • This paper analyzes the type of facilities and equipment of the marina port and analyzes its lift facilities (lift pier) and equipment (marine mobile lift). It set up the lift facilities and equipment standards. Depending on the gross tonnage of vessels in operation in Korea, the required inner width of lift piers is 5.50 m for 35-ton vessels, and 6.20 m for 50-ton vessels. The inside width of the marine mobile lift is 6.10 m for 35-ton vessels, and 6.80 m for 50-ton vessels. There are two places where the target ship can be lifted from the lift pier installed on the domestic marina, and other marinas' lift piers inner widths are insufficient by about 0.35 ~ 0.50 m. Among the marine mobile lifts in operation, there were two apparatuses that secured the inside width necessary to lift the target vessel. Other marine mobile lifts' inner widths are insufficient by about 0.3 ~ 0.6 m.

The Experimental Study of Distribution Characteristics of Lift-force Acting under Pier Deck (잔교상판(棧橋床板)에 작용(作用)하는 양압력(揚壓力) 분포특성(分布特性)에 관한 실험적(實驗的) 연구(硏究))

  • Park, Sang Kil;Park, Hyun Soo;Ahn, Ik Seong;Kim, Woo Saeng
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1B
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    • pp.83-90
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    • 2009
  • This study describes the characteristics of distribution of lift-force acting under pier deck through physical experiment. The shape of peak wave pressure was sharp when compressed air existed but was not sharp without that. Values of lift-force was different between edge point and center point in the same block. Distribution of lift-force was expressed differently owing to dimensionless of deck length (l/L), wave steepness (H/L), clearance height per wave height (D/H). The dimensionless factor of D/H affected on the lift-force the clearance between still water surface and decks. This decided the maximum of lift-force. In the case of the same values of D/H, the lift-force are changed by the wave steepness (H/L). Because (D/H) become smaller as the wave steepness (H/L) is increased the height of decks must be decided with the condition which don't have the clearance with $D_{max}$ for the stable design of deck of pier. Effect of reducing lift force was greater in the on-shore than the off-shore according to compressed air existence. This researches points out that design of deck should retain compressed air in order to reduce wave lift force.

A Study of the Thermal Analysis for the Crack Control of Underground Pier Footing (지하 교각 기초의 온도균열 제어를 위한 수화열 해석 연구)

  • Park, Weon-Tae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.2
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    • pp.91-101
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    • 2006
  • Lately, massive concrete structures are increasingly built. In such massive structures, the heat of hydration of mass concrete causes thermal cracks. To avoid thermal crack, methods widely acceptable for practical use are pre-cooling, pipe cooling and control of placing height. Thermal stress analysis is performed to find the way of controlling the thermal crack of pier footing mat in this paper. The footing mat model for the analysis is $12m{\times}14m$area and 3m height. The analysis results are compared with method of control of lift height and method of pipe cooling. The analysis results show that thermal crack can be removed by method of placing control and pipe cooling at footing mat placed on the ground.

A Study on Fatigue Analysis, Reliability and Life Expectancy of a Double Link Type Level Luffing Jib Crane (이중 링크 형식 수평 인입 집 크레인의 피로 해석, 신뢰도 및 수명 예측에 관한 연구)

  • 허철원;문덕홍
    • Journal of the Korean Society of Safety
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    • v.16 no.4
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    • pp.65-73
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    • 2001
  • This paper is a study on the fatigue analysis using BS5400 Part10(1980), code of practice for fatigue for a double link type level luffing jib crane which has been operated since the crane was built in 1985 at a domestic pier. South Korea. In addition, on the basis of the design lift due to fatigue analysis and the number of cracks detected from the nondestructive test the structural reliability and the residual life of the crane is predicted by evaluating the expected development of detectable fatigue oracle during the next five to ten years using Paris's Law for predicting fatigue crack growth and Gaussian probability density function to be reasonable for stress ranges below the mean values determined by laboratory tests. The statistical data used for the analysis of the structural reliability and life expectancy is given in the above referred code.

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The Effect of Legs Difference on The Trunk Muscle Activities With and Without Winging Scapular During Scapular Protraction in Prone-Bridge Position (엎드린 교각운동 자세에서 견갑골 전인 운동 시 익상 유무에 따른 다리 들기 차이가 체간근의 근 활성도에 미치는 영향)

  • Kim, Hee-gon;Hwang, Byeong-jun;Kim, Jong-woo
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.24 no.2
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    • pp.29-36
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    • 2018
  • Background: The purpose of this study was to investigate the effect of leg lift difference on serratus and upper trapezius when exercising in a scapula in a prone position, a typical waist stabilization exercise for subjects with a winged scapula. Method: Twenty normal adults and 20 subjects with winged scapula participated in the experiment. The surface EMG recordings were obtained from external oblique muscle and internal oblique muscle during scapula protraction exercise. The presence or absence of winging of the shoulder bone was measured using an electronic digital caliper for the distance the medial border of the scapula is lifted to the rear. In prostrate pier movement posture in both groups, both legs supporting, dominant leg lifting, and non-dominant leg lifting including the scapula protraction were conducted respectively. Results: In the results of comparison between the two groups, the dominant external oblique muscle and the non-dominant internal oblique muscle tended to increase according to the difference of the leg lifting of normal people. In the winged scapula group, internal oblique muscle showed increased muscle activity more than external oblique muscle. Conclusion: It was most effective to exercise with lifting the same position leg for strengthening the same external oblique muscle, and the opposite internal oblique muscle. Also, it is effective to exercise in prone pier movement posture for trunk stability. In addition, internal oblique muscle shows increased muscle activity in subjects with winged scapula. Therefore, appropriate adjustment of external oblique muscle and internal oblique muscle may have a positive effect on scapula dysfunction for trunk stability.

Bearing Damage Analysis of Bridges Considering the Probabilistic Characteristics of Earthquake and Structural Properties (지진하중 및 교량구조물의 확률적 특성을 고려한 받침손상위험도 분석)

  • 김상효;마호성;이상우;김철환
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.10a
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    • pp.346-353
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    • 2002
  • The risk of bearing failure is evaluated through the seismic response analysis of a bridge considering the probabilistic characteristics of structural properties such as the mass of superstructure, the stiffness of pier, and the translational and rotational stiffness of the foundation as well as seismic loadings during the bridge service lift. The effect of pounding between adjacent vibration units on the risk of bearing failure is also investigated. The probabilistic characteristics of structural properties are obtained by the Monte Carlo simulations based on the probabilistic characteristics of basic random variables included in the structural properties. From the simulation results, the failure probability of fixed bearings attached on the abutment is found to be much higher than those placed on the piers. It is also found that the pounding effect significantly increases the failure probability of bearings. In the simply supported bridges, the risk of bearing failure increases as the number of bridge spans increase. Therefore, the failure probability of fixed bearing due to the effects of pounding phenomena and the number of bridge spans should be considered in the seismic desist of bearings.

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