• Title/Summary/Keyword: Ultimate Analysis

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A Numerical Analysis Study for Estimation of Ultimate Bearing Capacity and An Analysis of the High Capacity Bi-directional Pile Load Tests of the Large-diameter Drilled Shafts (대구경 현장타설말뚝의 대용량 양방향 말뚝재하시험 분석 및 극한지지력 추정을 위한 수치해석 연구)

  • Nam, Moonsuk;Kim, Sangil;Hong, Seokwoo;Hwang, Seongchun;Choi, Yongkyu
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.10
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    • pp.63-72
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    • 2011
  • The high capacity bi-directional pile load test is an optimum pile load test method for high-rised buildings. Especially, a high pressure and double-acting bi-directional pile load testing, a special type of the high capacity bi-directional pile load test, is the most practical way to overcome limitations of loading capacities and constraints of field conditions, which was judged to be a very useful test method for requiring high loading capacities. Total of 2 high capacity bi-directional pile load tests(P-1 and P-2) were conducted in high-rised building sites in Korea. Based on the field load test results, the sufficiency ratio of loading capacities to design loads for P-1 and P-2 were 3.3 and 2.1, respectively. For P-2, the load test could not verify the design load if 1-directional loads applied slightly smaller than the actual applied load. Also, high capacity bi-directional pile load tests were difficult to determine an ultimate state of ground or piles, although the loads were applied until their maximum loads. Hence, finite element analyses were conducted to determine their ultimate states by calibrating and extrapolate with test results.

Analysis of Load-Settlement Behaviour Characteristics of Granular Compaction Piles from the Model Tests (모형실험에 의한 조립토 다짐말뚝의 하중-침하 관련 거동특성 분석)

  • Kim, Hong-Taek;Kang, Yun
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.4
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    • pp.33-45
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    • 2004
  • In the present study, more systematic laboratory model tests under various conditions are carried out to investigate load-sharing characteristics among the granular pile and adjacent soils and bearing capacity characteristics with different pile lengths. Further to evaluate effects of both a loading area and a spacing of pile installation on the bearing capacity and bearing capacity characteristics of each pile in group, model test results are also analyzed for the purpose of an efficient design of granular compaction piles. From the analysis of the model test results, it is found that the ultimate capacity of granular compaction group piles increases with a decrease in the installation distance among granular piles. It is also found that the dominant failure mode of the granular compaction piles is bulging failure. It is further realized that the length of a granular pile could not significantly affect on the ultimate granular pile capacity.

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Analysis of Structural Performance of Wood Composite I and Box Beam on Cross Section Component (II) - Calculation and Analysis of Ultimate Loads - (단면구성요소(斷面構成要素)에 관(關)한 목질복합(木質複合) I 및 Box형(形) 보의 구조적(構造的) 성능(性能) 분석(分析) (II) - 최대하중(最大荷重)의 계산(計算) 및 해석(解析) -)

  • Oh, Sei-Chang;Lee, Phil-Woo
    • Journal of the Korean Wood Science and Technology
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    • v.19 no.3
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    • pp.62-71
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    • 1991
  • An evaluation of bending test of composite I and Box beams for determining the ultimate strength limit design criteria was presented. Maxium loads of composite I beams were found in beams composed of thicker upper flanges and/or vertical LVL flanges. These loads of plywood web beams were greater than those of PB web beams. Maximum loads of unsymmetrical box beams were less than those of symmetrical box beams. Thus, it took on different phase in box type beams. Ultimate loads of composite beams were greater than those of solid. The failure of composite beams were abrupt and failure mode was classified into following categories; Edgewise shear failure in web, delamination in flange-web joint, tension failure and tearing in LVL flanges, and web delamination. These failures of composite beams were appeared at the mixed mode. The influence factor affecting the performance of tested composite beams was shear strength of PB-web composite beams and compressive strength in plywood-web composite beams. It was also assumed that the influence factors on structural performance on composite beams were flange quality, web material and geometry of cross section. As one of the design methods resisting to compressive stress that was required in the case of small span to depth ratio and deep beams. composite I-beams composed of thicker upper flanges comparing to lower flanges were very effective in structural performance.

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A Study on the Ultimate Strength According to the Boundary Condition of a Ship Plate under Thrust (압축하중을 받는 선체판의 경계조건에 따른 최종강도에 관한 연구)

  • 고재용;박주신;이돈출
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2002.11a
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    • pp.89-93
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    • 2002
  • One of the primary factors like plate structure in ship is redundancy structure that is comparable with ocean structure and frame structure. The more component material becomes buckling collapsed locally the less structure stiffness becomes accordingly. As a result, by increasing the load distribution of my other subsidiary structure continually component member collapses, therefore the structure could be in danger of collapse. So, in order to interpret this phenomenon precisely, the study on boundary condition of the ship's plate and post-buckling analysis must be considered In this study, the rectangular plate is compressed by the in-plane load Buckling & Ultimate strength characteristics are applied o be the elasto-plasticity large deformation by ansys code with F.E.M method On this basis, elasto-plasticity of the plain plate are investigated. This study proved elasto-plasticity behaviour of the ship's plate in accordance with boundary condition based on the series analysis in case of the compressive load operation

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Ultimate Strength of branch-rotated T-joints in Cold-formed Square Hollow Sections - Chord flange failure mode - (지관이 회전된 냉간성형 각형강관 T형 접합부의 최대내력(I) - 주관 플랜지 파괴모드 -)

  • Bae, Kyu Woong;Park, Keum Sung;Kang, Chang Hoon;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.14 no.5 s.60
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    • pp.657-664
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    • 2002
  • This paper described the ultimate strength and deformation limit of the new uniplanar T-joints in cold-formed square hollow sections. In the configuration of the new T-joint, only a branch member is orientated to a chord member at 45 degrees in the plane of the truss. This study focused on the branch-rotated T-joints that were governed by chord flange failure in previous studies. Test results of the T-joint in cold-formed square hollow sections revealed a deformation limit of 3%B for $16.7{\leq}2{\gamma}(=B/T){\leq}33.3$ and $0.27{\leq}{\beta}(=b1/B){\leq}0.6$. The existing strength formulae for traditional T-joint were determined and a new yield-line model for the branch-rotated T-joint proposed. Finally, the strength formula on the yield-line analysis was compared with test results and the application range of the proposed formula recommended.

A Study on the Tripping Behaviour of Stiffened Plate according to the Stiffener type (Stiffener형상에 따른 보강판의 트리핑거동에 관한 연구)

  • 고재용;박주신;박성현
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.89-94
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    • 2004
  • A steel plated is typically composed of plate panels. The overall failure of the structure is certainly affected and can be governed by the bulking and plastic collapse of these individual members. In the ultimate limit state design, therefore, a primary task is to accurately calculate the buckling and plastic collapse strength of such structural members. Structural elements making up steel palated structures do not work separately, resulting in high degree of redundancy and complexity in contrast to those of steel framed structures. To enable the behavior of such structures to be analyzed, simplifications or idealizations must essentially be made considering the accuracy need and degree of complexity of the analysis to be used. Generally the more complex the analysis the greater is the accuracy that may be obtained. The aim of this study is the investigation of the effect of the tripping behaviour including section characteristic for a plate under uniaxial compression. For this purpose of study, in used elasto-plasticity deformation FEA method are used for this study.

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Characteristic of Bearing Capacity of Shallow Foundation upon Clay Ground Replaced by Sands Depending on Bearing Capacity Ratio (모래로 치환된 점토지반의 지지력비에 따른 얕은 기초의 지지력 특성)

  • Ha, Young-Min;Jung, Min-Hyung;Sin, Hyo-Hee;Lee, Song
    • Journal of the Korean Geotechnical Society
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    • v.27 no.11
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    • pp.17-25
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    • 2011
  • In this study, we considered the bearing capacity of strip footing over clay layers partially replaced by sand. The FEM analysis is performed to calculate the ultimate bearing capacity. Partial replacement is defined by multiples of footing width(B) and inclination of sides. The cases(B'=inf.) of sand layers equal to clay layers are preferentially conducted. The baring capacity of B'=inf. is comparative value for bearing capacity of partial replacement layers. ${\beta}$ is the ratio of ultimate bearing capacity of B'=inf and partial ultimate bearing capacity replacement. ${\beta}$ is used to analyze the characteristic of bearing capacity of clay layers partially replaced by sand. Each of the three undrained shear strengths of clay and friction angles of sand is considered. The result of this analysis shows that ${\beta}$ depends on sand depth.

Thermal-hydraulic Analysis of Operator Action Time on Coping Strategy of LUHS Event for OPR1000 (OPR1000형 원전의 최종열제거원 상실사고 대처전략 및 운전원 조치 시간에 따른 열수력 거동 분석)

  • Song, Jun Kyu
    • Journal of the Korean Society of Safety
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    • v.35 no.5
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    • pp.121-127
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    • 2020
  • Since the Fukushima nuclear accident in 2011, the public were concerned about the safety of Nuclear Power Plants (NPPs) in extreme natural disaster situations, such as earthquakes, flooding, heavy rain and tsunami, have been increasing around the world. Accordingly, the Stress Test was conducted in Europe, Japan, Russia, and other countries by reassessing the safety and response capabilities of NPPs in extreme natural disaster situations that exceed the design basis. The extreme natural disaster can put the NPPs in beyond-design-basis conditions such as the loss of the power system and the ultimate heat sink. The behaviors and capabilities of NPPs with losing their essential safety functions should be measured to find and supplement weak areas in hardware, procedures and coping strategies. The Loss of Ultimate Heat Sink (LUHS) accident assumes impairment of the essential service water system accompanying the failure of the component cooling water system. In such conditions, residual heat removal and cooling of safety-relevant components are not possible for a long period of time. It is therefore very important to establish coping strategies considering all available equipment to mitigate the consequence of the LUHS accident and keep the NPPs safe. In this study, thermal hydraulic behavior of the LUHS event was analyzed using RELAP5/Mod3.3 code. We also performed the sensitivity analysis to identify the effects of the operator recovery actions and operation strategy for charging pumps on the results of the LUHS accident.

The Analysis of Collapse Load of Thick Pressure Cylinder under External Hydrostatic Pressure (외압을 받는 두꺼운 원통형 내압용기의 붕괴하중 해석)

  • Lee, Jae-Hwan;Park, Byoungjae
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.2
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    • pp.175-186
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    • 2019
  • Number of studies on the buckling of thin cylindrical pressure vessels, such as submarine pressure hull and pipe with a large ratio of diameter/thickness, have been carried out in the naval and ocean engineering. However, research about thick cylinder pressure vessel has not been active except for the specific application in nuclear area. There are not many papers for the estimation of buckling and ultimate load capacity of thick cylinders for the deep sea usage. Thus, it is important to understand the theoretical bases of the buckling and collapse process and the derivation process of such loads for the proper design and structural analysis. The objective of this study is to survey the collapse behavior, to analyse and clarify the derivation procedure and to estimate the ultimate collapse load for thick cylinder by analyzing relevant books and papers. It is found that the yielding begins at the internal surface of the thick cylinder and plasticity develops from the internal surface to the external surface to generate collapse. Also the initial imperfection of cylinder develops flattening and consequently accelerates buckling and finally ultimate collapse. By comparing the collapse loads of aluminum thick cylinder by applying equations herein, it is shown that the equations analyzed are appropriate to obtain collapse load for thick cylinder.

Analysis of Estimation of Ultimate Lateral Capacity of Pile in Multi-Layered Soil Using CPT Results and Proposal of Modified Lateral Earth Pressure (다층조건에서 CPT를 이용한 말뚝의 극한수평지지력 평가 분석 및 수정 수평토압분포 제안)

  • Hong, Jung-Moo;Kyung, Doo-Hyun;Kang, Beong-Joon;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.25 no.6
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    • pp.47-57
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    • 2009
  • In this study, the ultimate lateral load capacity of pile driven into multi-layered soil was estimated using cone penetration test results and a method was proposed to reflect multi-layered soil conditions. For multi-layered specimens prepared with different relative density at different layers, the cone penetration tests and lateral pile load tests were conducted. Based on the test results, measured and estimated values of the ultimate lateral load were compared and analyzed. The estimated results were obtained from the methods proposed by Broms (1964), Petrasovits & Award (1972) and Prasad & Chari (1999). The method was proposed for modifying the earth pressure distribution of Prasad & Chari (1999) to consider multi-layered soil conditions. From the analysis, it was seen that results obtained from the proposed method showed improvement with less data scatter similarly to those obtained from Broms (1964) and Petrasovits & Award (1972)'s methods.