• Title/Summary/Keyword: bearing estimation

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Strength Evaluation of Slender Steel Reinforced Concrete Beam-Columns

  • Chung, Jinan;Choi, Seongmo;Kim, Dongkyu
    • Architectural research
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    • v.3 no.1
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    • pp.61-70
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    • 2001
  • The paper is intended to propose design strength of slender steel reinforced beam-columns by using the modified superposed method. The design of composite members is carried out by a superposed strength method in AIJ (Architectural Institute of Japan) design method. The bearing capacities of the steel part and the concrete part have to be determined separately and then added to a combined capacity. Authors have proposed a new superposed method in a modified form for the slender composite beam-columns and reinforced column. The modified superposed method is adopted for the slender steel reinforced beam-columns. Validation of the modified superposed method is undertaken by comparison with analytical results calculated assuming a sine curve deflected shape of the beam-columns, and with the test results conducted in Japan.

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Sonar-based yaw estimation of target object using shape prediction on viewing angle variation with neural network

  • Sung, Minsung;Yu, Son-Cheol
    • Ocean Systems Engineering
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    • v.10 no.4
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    • pp.435-449
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    • 2020
  • This paper proposes a method to estimate the underwater target object's yaw angle using a sonar image. A simulator modeling imaging mechanism of a sonar sensor and a generative adversarial network for style transfer generates realistic template images of the target object by predicting shapes according to the viewing angles. Then, the target object's yaw angle can be estimated by comparing the template images and a shape taken in real sonar images. We verified the proposed method by conducting water tank experiments. The proposed method was also applied to AUV in field experiments. The proposed method, which provides bearing information between underwater objects and the sonar sensor, can be applied to algorithms such as underwater localization or multi-view-based underwater object recognition.

Estimation of resistance coefficient of PHC bored pile by Load Test (재하시험에 의한 PHC 매입말뚝의 저항계수 산정)

  • Park, Jong-Bae;Kwon, Young-Hwan
    • Land and Housing Review
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    • v.8 no.4
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    • pp.233-247
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    • 2017
  • In Europe and the USA, the use of limit state design method has been established, and the Korea Ministry of Land, Transport and Maritime Affairs has implemented the bridge substructure design standard based on the critical state. But Korean piling methods and ground conditions are different from Europe and USA, the limit state design method can not be used immediately. In this study, the resistance coefficient was proposed by comparing and analyzing the results of the static load test(9 times) and dynamic load tests(9 times of EOID and 9 times of Restrike) with the bearing capacity calculated by Meyerhof(LH design standard, Road bridge design standard) method and surcharge load method(using Terzaghi's bearing capacity coefficient and Hansen & Vesic's bearing capacity coefficient). The previous LHI study showed the resistance coefficient of the LH design standard was 0.36 ~ 0.44, and this research result showed the resistance coefficient was 0.39 ~ 0.48 which is about 8% higher than the previous study. In this study, we tried to obtain the resistance coefficient mainly from the static load test and the resistance coefficient was 0.57 ~ 0.69(Meyhof method : LH design standard) based on the ultimate bearing capacity and the resistance coefficient was 0.49 ~ 0.60(Meyhof method : LH design standard) based on the Davissons bearing capacity. The difference of the resistance coefficient between the static and dynamic load test was greater than that we expected, we proposed the resistance coefficient(0.52 ~ 0.62 : Meyerhof method: LH design standard) using the modified bearing capacity of the dynamic load test. Summarizing the result, the coefficient of resistance obtained from the static and dynamic load tests was 0.35 ~ 0.76, which is greater than 0.3 suggested by the Road bridge design standard, so the economical design might be possible using the coefficient of resistance proposed by this study.

Estimation of the Axial Stiffness of Reinforcing Piles in Vertical Extension Structures (수직증축 공동주택 하부 신설 보강말뚝의 축강성 산정)

  • Kim, Do-Hyun;Jeong, Sang-Seom;Cho, Hyun-Chul
    • Journal of the Korean Geotechnical Society
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    • v.35 no.12
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    • pp.35-44
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    • 2019
  • In this study, the axial stiffness of reinforcing piles (Kvr) for the vertical extension remodeling structures was estimated through 3D finite element analysis. In the computation of the minimum required axial stiffness of reinforcing piles, proposed maximum axial stiffness of old and deteriorated existing piles (Kve) based on theoretical and experimental approaches will be applied. Through this, the required increase rate of axial stiffness of reinforcing piles in order to support the increased structural loading was proposed for end-bearing and friction piles by different slenderness ratio (L/D). The numerical model was validated by comparing the computed results with actual field measurements. Based on the computed results, it was concluded that the end-bearing reinforcing pile needs 44% - 67% increase in axial stiffness to deal with the deterioration of existing piles and support the additional structural load due to vertical extension remodeling.

New Design Method for Pile Group Under Vertical Load (연직하중을 받는 무리말뚝의 새로운 설계 방법)

  • 이수형;정충기
    • Journal of the Korean Geotechnical Society
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    • v.19 no.1
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    • pp.31-40
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    • 2003
  • Current design of pile group is based on the estimation of the overall bearing capacity of a pile group from that of a single pile using a group efficiency. However, the behaviors of a pile group are influenced by various factors such as the method of pile installation, pile-soil-pile interaction, cap-soil-pile interaction, etc. Thus, it is practically impossible to take into account these factors reasonably with the only group efficiency. In this paper, a new method for the design of pile groups is proposed, where the significant factors affecting the behavior of a pile group are considered separately by adopting several efficiencies. Furthermore, in the proposed method, the load transfer characteristics of piles and the difference of pile behaviors with respect to the pile locations in group can be taken into account. The efficiencies for the method are determined using the settlement failure criterion, which is consistent with the concept of allowable settlement fur structures. The efficiencies calculated from the results of existing model tests are presented, and the bearing capacity of a pile group in the other model test is calculated and compared with that from the test result to verify the validity of the proposed method.

Assessment of Design Criteria for Bearing Capacity of Rock Socketed Drilled Shaft (암반에 근입된 현장타설말뚝의 지지력 산정기준에 대한 평가)

  • 백규호;사공명
    • Journal of the Korean Geotechnical Society
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    • v.19 no.4
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    • pp.95-105
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    • 2003
  • The existing design criteria f3r the estimation of ultimate bearing capacity of drilled shaft socketed into rock masses are mainly obtained from the ultimate pile load capacities, which are determined by inconsistent failure criteria. Therefore, these design criteria generally produce difffrent predictions even for drilled shaft in the same condition. In this paper, the accuracies of the existing design criteria are investigated to develop an optimized design process for drilled shaft socketed into rock masses. Reasonable and consistent ultimate capacities of drilled shafts socked into rock masses, necessary far the check of accuracies of predictions, are determined by applying a specific failure criterion to a total of 11 pile load test results. A comparison between the predicted and the measured load capacities shows that ultimate base load capacities calculated from Zhang and Einstein's equation and NAVFAC are close to the measured values. Rosenberg and Journeaux's equation produces satisfactory prediction f3r ultimate side load capacity.

Estimation of the Bearing Capacity in Pile Load Tests Using the Maximum Curvature (말뚝재하시험(載荷試驗)에서 최대곡율(最大曲率)을 이용(利用)한 지지력(支持力) 추정(推定))

  • Hwang, Jung Kyu;Ryu, Jeong Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.3
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    • pp.155-161
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    • 1993
  • It is usually very expensive and often impractical to extend a load test on a large pile until collapse. Many graphical or mathematical methods have been attempted to estimate the bearing capacity from the results of a vertical load test without having to load the pile to failure. According to Fellenius, the failure value must be based on some mathematical rule and generate a repeatable value that is independent of scale relations and the opinions of the individual interpreter. This study presents the method which may estimate the failure load using the maximum curvature to apply Kondner's theory from the results of a loading test which cannot be extended until the failure load is reached.

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A Study on Skin Friction Estimation of Drilled Shaft Socketed in Weathered Granite by IGM's Theory (화강풍화암에 근입된 현장타설말뚝의 주면마찰력 산정에 대한 IGM 이론의 적용)

  • Hong, Soon Taek;Lee, Jong In;Shin, Young Wan;Lee, Seung Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.6C
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    • pp.241-250
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    • 2011
  • The design method of IGM proposed by FHWA to predict bearing capacities of drilled shaft socketed in weathered granite has been used generally. In this study, site investigations were performed in a pilot test site, and disturbance and roughness were measured. Geotechnical properties were assorted as cohesive material and undisturbed and smooth surface. A simple relationship was proposed to predict unconfined strength ($q_u$) of weathered granite using static load test results, load transfer test results and N values. It was confirmed that the design method to estimate bearing capacities of drilled shaft could improve IGM's theory for weathered granite from this research.

A Study of Postural Sway and Dynamic Standing Balance with Low Back Pain (요통환자의 자세동요와 동적기립균형에 관한 연구)

  • Yang, Dae-Jung;Song, Tae-Ho;Lim, Ho-Yong;Ahn, Yeon-Jun;Park, Seung-Kyu;Kim, Yeong-Rok
    • Journal of Korean Physical Therapy Science
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    • v.11 no.2
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    • pp.18-26
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    • 2004
  • The purpose of this study was to compare difference of the static and dynamic balance in normal subject and LBP subject and recognizes about postural sway. The subjects of this study included 30 normal subjects and 30 LBP subjects. By using Active balance system, the static balance was measured by unit path length, circumference area, weight bearing, stabilometry length, while the dynamic balance was measured by step evaluation. Statistically analyzed using independent t-test to search static balance and dynamic balance difference in two groups. Postural sway appeared greatly in patient group than normal group in analysis result of static balance and postural sway was big in patient group of when closed eye and normal group and patient group did show statistical significance in unit path length, circumference area. Weight support of normal group was shared equally in weight bearing rate, but weight support of patient group stewed less to pain side. Anterior step time and Task achieve time of dynamic balance were spent more in patient group than normal group. Desire to be used to useful information to lay treatment policy about set-up and action of when quantification result of valued postural balance treats low back pain patient by objective tool, in the fixture, more researches in postural estimation desire that is enforced abuzz.

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Stiffness effect of fitting interference for a shrunk rotor (열박음 로터에서 간섭량의 강성 효과)

  • 김영춘;박희주;박철현;김경웅
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.319-324
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    • 2003
  • In general industrial rotating machinery is operated under 3,600 rpm as rotating speed and designed to have critical speed that is above operating speed. So, there was no problem to operate rotating machine under critical speed. But nowadays, they should be operated more than the frist critical speed as usual with the trend of high speed, large scale and hish precision in industries. In case of the large rotor assembly as the trend of large scale, using fitting method of disk or cylinder on shaft is rising for the convenience of assembly and cutting down of manufacturing cost. The shrink fitting is used to assemble lamination part on shaft for manufacturing of rotor of motor or generator in many cases and also is widely used for other machinery. In rotating system, which is compose of rotor and bearing, the critical speed is determined from inertia and stiffness for the rotor and bearings. In case of fitting assembly, analysis and design of the rotor is not easy because the rotor stiffness is determined depend on a lot of factors such as shaft material/dimension, disk material/dimension and assembled interference etc. Therefore designer who makes a plan for hish-speed rotating machine should design that the critical speed is located out of operating range, as dangerous factors exist in it. In order to appropriate design, an accurate estimation of stiffness and damping is very important. The stiffness variation depend on fitting interference is a factor that changes critical speed and if it's possible to estimate it, that Is very useful to design rotor-bearing system. In this paper, the natural frequency variation of the rotor depends on fitting interference between basic shaft and cylinder is examined by experimentation. From the result, their correlation is evaluated quantitatively using numerical analysis that is introduced equivalent diameter end the calculation criteria is presented for designer who design fitting assembly to apply with ease for determination of appropriate interference.

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