• Title/Summary/Keyword: design load capacity

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Investigation of design methods in calculating the load-carrying capacity of mortise-tenon joint of timber structure

  • Hafshah Salamah;Seung Heon Lee;Thomas H.-K. Kang
    • Earthquakes and Structures
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    • v.25 no.5
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    • pp.307-323
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    • 2023
  • This study compares two prominent design provisions, National Design Specification (NDS) and Eurocode 5, on load-carrying capacity calculations and failure analysis for mortise-tenon joints. Design procedures of double-shear connection from both provisions were used to calculate load-carrying capacity of mortise-tenon joints with eight different bolt sizes. From this calculation, the result was validated using finite element analysis and failure criteria models. Although both provisions share similar failure modes, their distinct calculation methods significantly influence the design load-carrying capacity values. Notably, Eurocode 5 predicts a 6% higher design load-carrying capacity for mortise-tenon joints with varying bolt diameters under horizontal loads and 14% higher under vertical loads compared to NDS. However, the results from failure criteria models indicate that NDS closely aligns with the actual load-carrying capacity. This indicates that Eurocode 5 presents a less conservative design and potentially requires fewer fasteners in the final timber connection design. This evaluation initiates the potential for the development of a wider range of timber connections, including mortise-tenon joints with wooden pegs.

A study on case analysis for loading capacity standard establishment of bi-directional pile load test (BD PLT) (양방향말뚝재하시험의 재하용량 기준 설정을 위한 사례분석 연구)

  • Choi, Yong-Kyu;Seo, Jeong-Hae;Kim, Sang-Il
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.377-384
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    • 2008
  • In the bi-directional pile load test (BD PLT) for pile load test of Mega foundation, loading capacity specification were not specified exactly. Therefore there are so many confusions and variations of maximum 2 times in loading capacity are come out. In this study, specifications of bi-directional pile load test (BD PLT) were considered. Based on cases of the bi-directional pile load test performed in domestic areas, maximum equivalent test load, test load increasing ratio and sufficiency ratio of design load were analyzed. It can be known that the loading capacity specification of bi-directional pile load test must be defined as 1-directional test load that is established as more than 2 times of design load.

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A Study on Design Parameters to Improve Load Capacity of Spiral Grooved Thrust Bearing (스파이럴 그루브 스러스트 베어링의 부하용량 향상을 위한 설계 변수에 대한 연구)

  • 강지훈;김경웅
    • Tribology and Lubricants
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    • v.18 no.3
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    • pp.181-186
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    • 2002
  • A numerical analysis is undertaken to show the influence of bearing design parameters on the load capacity of air lubricated spiral grooved thrust bearing. The governing equation derived from the mass balance is solved by the finite difference method. Optimal values for various design parameters are obtained to maximize the load capacity. The design parameters are the groove angle, the groove width ratio, the groove height ratio, and the seal ratio.

Load-Carrying Capacity Assessment of Deteriorated Rural Bridge

  • Kim, Han-Joong;Kim, Jong-Ok;Yang, Seung-Ie
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.44 no.7
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    • pp.36-45
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    • 2002
  • Most of rural bridges have passed 30 years of age since they were built, which have to support unexpected overload caused by changed design load and excessive amount of transportation. For these rural bridges, repairs and replacements are needed. Even though there have been attempt to estimate the safety of existing bridges deteriorated with major defects, those approaches must rely on the observable damage and subsequent decisions are made subjectively. To avoid the high cost of rehabilitation, the bridge rating must correctly represent the present load-carrying capacity. Rating engineers use a methods such as Allowable Stress Design (ASD), Load Factor Design (LFD), and Load Resistance Factor Design (LRFD) to evaluate the bridge load carrying capacity. In this paper, the load rating methods are introduced, and it is illustrated how to use the load test data from literature survey. Load test is conducted to the bridge that was built 30 years ago in rural area. From load test results, new maintenance method is suggested instead of the bridge replacement.

A Study for the Development of Pile Design Method Considering Settlement and Compression (침하량과 압축량을 고려한 말뚝의 설계법 개발을 위한 연구)

  • Lim, Jong-Seok;Ha, Hyuk;Jung, Sang-Kyun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.1287-1294
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    • 2006
  • A pile is compressed with settlements when loading and bearing capacity is altered along relative displacement of pile/soil on settlement and compression. Settlements of pile displaying limit skin friction is different from displaying tip resistance. Therefore, it is an error in traditional method that bearing capacity of pile is estimated from the sum of limit skin fraction and tip resistance. Accordingly, development of design method considering behavior of load-settlement is needed. In this study, we would like to establish the base for development of design method considering bearing capacity altering along displacement on settlement and compression. For this, we established system and substance of design method. And in order to establish relationship of load-settlement of pile on the type of soil, we analyzed and arranged existing database and pile loading test. On design method, settlement is assumed gradually on each capacity level being assumed gradually. Bearing capacity developing on the pile is obtained on each settlement level. Until the obtained bearing capacity will be equal to assumed capacity, this process is continued with increasing settlement. Load-settlement curve for soil classification is sketched in the process computing settlement on assumed capacity. This design method will be materialized by computation program.

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A study on the improvement of the digging load capacity of an excavator by CAD technique (CAD에 의한 엑스카 베이터(excavator)의 굴삭능력 향상에 관한 연구)

  • 박찬기;이장무
    • Journal of the korean Society of Automotive Engineers
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    • v.4 no.2
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    • pp.24-34
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    • 1982
  • In order to improve the digging load capacity of a domestic excavator model. computer aided design(CAD) technique was applied to the optimum design of the excavator boom. From this study, the digging load capacity of both the bucket cylinder and the dipperstick cylinder could be made about same and the overall digging load capacity could be increased by about 50%, also, the computer program package developed in this study can be flexibly applied to the design of other construction machines by changing and/or adding a few subprograms and the input data.

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A Study on the Loading Capacity Standard of Bi-directional Pile Load Test (BD PLT) (양방향말뚝재하시험의 재하용량 기준에 관한 연구)

  • Choi, Yongkyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.6C
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    • pp.379-388
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    • 2008
  • In the bi-directional pile load test (BD PLT) for pile load tests of Mega pile foundations, loading capacity standard is not specified exactly. Therefore there are so many confusions in performing the BD PLT and variations up to maximum 2 times in loading capacity are come out. In this study, standards of bi-directional pile load test (BD PLT) were considered. Based on cases of the bi-directional pile load test performed in domestic areas, maximum equivalent test load, test load increasing ratio, loading capacity increasing ratio and sufficiency ratio of design load were analyzed. It could be known that the loading capacity standard of bi-directional pile load test must be defined as 1-directional loading capacity and also must be established as more than 2 times of design load.

Estimation of Bearing Capacity for Open-Ended Pile Considering Soil Plugging (폐색정도를 고려한 개단말뚝의 지지력 산정)

  • 백규호
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.397-404
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    • 2002
  • The bearing capacity of open-ended piles is affected by the degree of soil plugging, which is quantified by the IFR. There is not at present a design criterion for open-ended piles that explicitly considers the effect of IFR on pile load capacity In order to investigate this effect, model pile load tests using a calibration chamber were conducted on instrumented open-ended piles. The results of these tests show that the IFR increases with increasing relative density and increasing horizontal stress of soils. The unit base and shaft resistances decrease with increasing IFR. Based on the results of the model pile tests, new empirical relations for base load capacity and shaft load capacity of open-ended piles are proposed. In order to check the accuracy of predictions made with the proposed equations, the equations were applied to the full-scale pile load test preformed in this study, Based on the comparisons with the pile load test results, the proposed equations appear to produce satisfactory predictions.

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A Study on Design Parameters to Improve Load Capacity of Spiral Grooved Thrust Bearing (스파이럴 그루브 형상의 스러스트 베어링의 부하용량 향상을 위한 설계 변수에 대한 연구)

  • 강지훈;김경웅
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.06a
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    • pp.257-262
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    • 2001
  • A numerical analysis is undertaken to show tile influence of bearing design parameters on tile load capacity of air lubricated spiral grooved thrust bearing. The governing equation derived from the mass balance is solved by the finite difference method. Optimal values for various design parameters are obtained to maximize the load capacity. The design parameters are the groove angle, the groove width ratio, the groove height ratio, arid the seal ratio.

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Experimental Study on the Load Carrying Performance and Driving Torque of Gas Foil Thrust Bearings (가스 포일 스러스트 베어링의 하중지지 성능 및 구동 토크에 관한 실험적 연구)

  • Kim, Tae Ho;Lee, Tae Won;Park, Moon Sung;Park, Jungmin;Kim, Jinsung;Jeong, Jinhee
    • Tribology and Lubricants
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    • v.31 no.4
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    • pp.141-147
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    • 2015
  • Gas foil thrust bearings (GFTBs) have attractive advantages over rolling element bearings and oil film thrust bearings, such as oil-free operation, high speed stability, and high-temperature operation. However, GFTBs have lower load carrying capacity than the other two types of bearings owing to the inherent low gas viscosity. The load carrying capacity of GFTBs depends mainly on the compliance of the foil structure and the formed hydrodynamic wedge, where the gas pressure field is generated between the top foil and the thrust runner. The load carrying capacity of the GFTBs is very important for the suitable design of oil-free turbomachinery with high performance. The aim of the present study is to identify the characteristics of the load carrying performance of GFTBs. A new test rig for the experimental measurements is designed to provide static loads up to 800 N using a pneumatic cylinder. The maximum operating speed of the driving motor is 30,000 rpm. A series of experimental tests—lift-off test, static load performance test, and maximum load capacity test—estimate the performance of a six-pad GFTB, in terms of the static load, driving torque, and temperature. The maximum load capacity is determined by increasing the static load until the driving torque rises suddenly with a sharp peak. The test results show that the torque and temperature increase linearly with the static load. The estimated maximum load capacity per unit area is approximately 80.5 kPa at a rotor speed of 25,000 rpm. The test results can be used as a design guideline for GFTBs for realizing oil-free turbomachinery.