• Title, Summary, Keyword: Displacement Limit

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Three-dimensional simplified slope stability analysis by hybrid-type penalty method

  • Yamaguchi, Kiyomichi;Takeuchi, Norio;Hamasaki, Eisaku
    • Geomechanics and Engineering
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    • v.15 no.4
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    • pp.947-955
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    • 2018
  • In this study, we propose a three-dimensional simplified slope stability analysis using a hybrid-type penalty method (HPM). In this method, a solid element obtained by the HPM is applied to a column that divides the slope into a lattice. Therefore, it can obtain a safety factor in the same way as simplified methods on the slip surface. Furthermore, it can obtain results (displacement and strain) that cannot be obtained by conventional limit equilibrium methods such as the Hovland method. The continuity condition of displacement between adjacent columns and between elements for each depth is considered to incorporate a penalty function and the relative displacement. For a slip surface between the bottom surface and the boundary condition to express the slip of slope, we introduce a penalty function based on the Mohr-Coulomb failure criterion. To compute the state of the slip surface, an r-min method is used in the load incremental method. Using the result of the simple three-dimensional slope stability analysis, we obtain a safety factor that is the same as the conventional method. Furthermore, the movement of the slope was calculated quantitatively and qualitatively because the displacement and strain of each element are obtained.

특정 사례터널 해석 결과 및 평가

  • Lee, Seung-Rae;O, Se-Bung;Baek, Gyu-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.123-132
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    • 1991
  • The GEOKST program was used to solve the tunnel example problem. The package can solve such geotechnical problem as excavation, embankment, foundations, etc., in which the soil can be modeled by various elastoplastic geomaterial models. The main objective was to consider the effects of excavation depth to the face of the tunnel on the stability of the ground and support system. Depended on the strength of the ground materials, the limit excavation depth without any support system could be established by analyzing three-dimensional excavation problem. In this given example problem, the strengths of the ground materials were enough for the stability of the tunnel without any support system up to fairly deep excavation and the maximum tunnel section displacement was stabilized as the excavation proceed. The asymptotic value was approximately the same as that of the plane strain analysis. Thus, assuming the plain strain condition and simulation the actual excavation procedure, the maximum tunnel section displacement was caculated after final step. The maximum calculated displacement occured at the top section of the tunnel geometry and was about 8mm.

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Crack Opening Displacement Analysis of Complex Cracked Pipes based on Enhanced Reference Stress Method (개선된 참조응력법을 이용한 복합균열이 존재하는 배관의 균열개구변위 계산)

  • Huh, Nam-Su;Kim, Yun-Jae;Kim, Young-Jin
    • Proceedings of the KSME Conference
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    • pp.80-86
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    • 2001
  • An engineering estimation equation for the crack opening displacement (COD) is proposed for a complex cracked pipe, based on the reference stress approach. To define the reference stress, a simple plastic limit load analysis for the complex cracked pipe subjected to combined bending and tension is performed considering the crack closure effect in the compressive-stressed region. Comparison with ten published test data and the results from existing method shows that the present method not only reduces non-conservatism associated with the existing method, but also provides consistent and overall satisfactory results.

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New Engineering Approach for Estimating Crack Opening Displacement of Complex Cracked Pipes (복합균열이 존재하는 배관의 균열개구변위 계산을 위한 새로운 공학적 계산식)

  • Kim, Yeong-Jin;Heo, Nam-Su;Kim, Yun-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.8
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    • pp.1235-1241
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    • 2001
  • An engineering estimation equation for the crack opening displacement(COD) is proposed for a complex cracked pipe, based on the reference stress approach. To define the reference stress, a simple plastic limit load analysis for the complex cracked pipe subjected to combined bending and tension is performed considering the crack closure effect in the compressive-stressed region. Comparison with ten published test data and the results from existing method shows that the present method not only reduces non-conservatism associated with the existing method, but also provides consistent and overall satisfactory results.

Study on the Limit Slenderness of a Double Outrigger System (이중 아웃리거 구조 시스템의 한계 세장비에 대한 연구)

  • Yang, Jae-Kwang;Kang, Ho-Geun;Park, Sung-soo
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.3
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    • pp.11-18
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    • 2018
  • Due to the recent overpopulation of urban cities, land shortage and soaring land prices have caused an increase in the demand for high-rise buildings. To build buildings on a limited land, the size of the building is important. Displacement control by horizontal loads in a skyscraper is critical to securing stability and usability of structures. Several systems have been proposed for efficient horizontal displacement control, and so far the study continues. Among them, the Outrigger System is a representative of the typical horizontal load resistance system. Although studies have been conducted so far to locate the optimal position of the outrigger, studies of the slenderness ratio of the buildings are still insufficient. Based on the Outrigger-Optimized Position equation, this study induces the calculation of the displacement of the outrigger installation building according to the slenderness ratio.

Estimation of Stiffness Limit for Railway Bridge Vibration Serviceability (진동사용성을 고려한 철도교량구조물의 강성한계 분석)

  • Jeon, Bub-Gyu;Kim, Nam-Sik;Kim, Sung-Il
    • Journal of the Korean Society for Railway
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    • v.11 no.5
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    • pp.489-498
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    • 2008
  • In general, deflection limit criteria of bridge design specifications have been considered based on static serviceability and structural stability. Dynamic serviceability induced from bridge vibration actually has not been included in the criteria. Thus, it is necessary for deflection limit to be considered in order to check dynamic service- ability on bridge vibration. In this study, The allowable displacement of Korea Railway Bridge Design Specifications is compared to the frequency domain comfort limit and analyzed france code and japanese code. Korea Railway Bridge Design Specifications is regulated based on the train speed. Such is because the vibration time duration is partly considered. but this criteria is not satisfied with comfort limit. and, it is estimated to be capable to provide deflection limit considering dynamic serviceability. In order to evaluate the dynamic serviceability of various types of railway bridges in current public were selected and their dynamic signals were measured. and the result of the bridge-train interaction analysis according to the changes in bridge stiffness was compared to the comfort limit to suggest the stiff-ness limit to the dynamic serviceability, which should conveniently be applied at the field.

Linear elastic and limit state solutions of beam string structures by the Ritz-method

  • Xue, Weichen;Liu, Sheng
    • Structural Engineering and Mechanics
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    • v.35 no.1
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    • pp.67-82
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    • 2010
  • The beam string structure (BSS) has been widely applied in large span roof structures, while no analytical solutions of BSS were derived for it in the existing literature. In the first part of this paper, calculation formulas of displacement and internal forces were obtained by the Ritz-method for the most commonly used arc-shaped BSS under the vertical uniformly distributed load and the prestressing force. Then, the failure mode of BSS was proposed based on the static equilibrium. On condition the structural stability was reliable, BSS under the uniformly distributed load would fail by tensile strength failure of the string, and the beam remained in the elastic or semi-plastic range. On this basis, the limit load of BSS was given in virtue of the elastic solutions. In order to verify the linear elastic and limit state solutions proposed in this paper, three BSS modal were tested and the corresponding elastoplastic large deformation analysis was performed by the ANSYS program. The proposed failure mode of BSS was proved to be correct, and the analytical results for the linear elastic and limit state were in good agreement with the experimental and FEM results.

Failure analysis of ribbed cross-laminated timber plates

  • Lavrencic, Marko;Brank, Bostjan
    • Coupled systems mechanics
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    • v.7 no.1
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    • pp.79-93
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    • 2018
  • The process of material failure i.e. cracks development and their propagation in an experiment related to the bending collapse of cross laminated timber plate with ribs is described. Numerical simulation of such an experiment by the nonlinear finite element method is presented. The numerical model is based on Hashin failure criteria, initially developed for unidirectional composites, and on material softening concept applied by the smeared crack approach. It is shown that such a numerical model can be used for an estimation of the limit load and the limit displacement of a cross laminated timber ribbed plate.

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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    • 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 Convergency of Tunnel Displacement using Control Chart Method (관리도 기법을 이용한 터널 변위수렴 특성에 관한 연구)

  • Yim, Sung-Bin;Kim, Sung-Kwon;Seo, Yong-Seok;Park, Si-Hyun
    • The Journal of Engineering Geology
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    • v.17 no.2
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    • pp.197-204
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    • 2007
  • Tunnel deformation happens by excavation. After installation of support, tunnel is gradually stabilized over time. Effect of excavation on tunnel behavior decreases as increase of distance from face. If the time that the displacement converges by tunnel stabilization is estimated, processes after stabilization can be advanced and economic loss can be reduced. In this study, the distance of displacement convergent point from face in the tunnel constructed on sedimentary rock is estimated using control chart method. As the results of analysis using a control of chart, displacements in a sedimentary rock tunnel are converged within 100 m from each tunnel face.