• Title/Summary/Keyword: strip load

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Impact of adjacent excavation on the response of cantilever sheet pile walls embedded in cohesionless soil

  • Singh, Akshay Pratap;Chatterjee, Kaustav
    • Geomechanics and Engineering
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    • v.30 no.3
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    • pp.293-312
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    • 2022
  • Cantilever sheet pile walls having section thinner than masonry walls are generally adopted to retain moderate height of excavation. In practice, a surcharge in the form of strip load of finite width is generally present on the backfill. So, in the present study, influence of strip load on cantilever sheet pile walls is analyzed by varying the width of the strip load and distance from the cantilever sheet pile walls using finite difference based computer program in cohesionless soil modelled as Mohr-Coulomb model. The results of bending moment, earth pressure, deflection and settlement are presented in non-dimensional terms. A parametric study has been conducted for different friction angle of soil, embedded depth of sheet pile walls, different magnitudes and width of the strip load acting on the ground surface and at a depth below ground level. The result of present study is also validated with the available literature. From the results presented in this study, it can be inferred that optimum behavior of cantilever sheet pile walls is observed for strip load having width 2 m to 3 m on the ground surface. Further as the depth of strip load below the ground surface increases below the ground level to 0.75 times excavation height, the bending moment, settlement, net earth pressure and deflection decreases and then remains constant.

Influence of Curbs and Median Strip on Wheel Load Distribution in Girder Bridges (거더교에서의 윤하중분배에 대한 연석과 중앙분리대의 영향에 관한 연구)

  • Oh, Byung-Hwan;Lim, Choon-Keun;Lew, Young;Kim, Kwang-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.455-460
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    • 2001
  • Generally, the contribution of curbs and median strip is not considered carefully in analysing and designing the girder bridges. There being curbs, the load given on interior girder relatively reduced and on exterior girder increased. Curbs and median strip reduce the load distribution factor by distributing the load given on girder fairly, In this paper, the Influence of curbs and median strip in wheel distribution through parameter study and lateral distribution test of PSC girder bridge was investigated. Finite-element analysis was performed with parameterizing the flexural rigidity of the girder, span length, girder spacing, median strip, curbs. The influence of curbs and median strip would increase with lowering rigidity of girder. In addition, curbs lower the load distribution factor of exterior and interior girders.

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Experimental Verification of Set-Up Reference Values for the Determination of Downcoiling Tension in Hot Strip Mill (열간압연시 권취장력 설정기준치의 실험적 검증)

  • 공성락;강용기;김영환;문영훈
    • Transactions of Materials Processing
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    • v.10 no.1
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    • pp.53-58
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    • 2001
  • Set-up reference values, used in determining the optimum downcoiling tension, we experimentally verified in this study. During the actual downcoiling, the strip suffers both tension and bending force through the rotation of mandrel. Therefore, simulative test which can measure both tension and bending resistance of strip was performed to estimate set-up reference value for strip tension during downcoiling operations. The values obtained from the simulative test were correlated with the yield stress which has conventionally been used as reference values for downcoiling tension. The correlative analysis showed that the yield stress of strip can be a good reference value for downcoiling tension. Furthermore, the bending load also shows strong correlation with simulated values due to the close relationship between yield stress and bending load.

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Study on LSDC Design for Coiling Shape Control of Hot Strip Mills (열간압연 권취형상 제어를 위한 LSDC 설계에 관한 연구)

  • Lee, Sang Ho;Park, Hong Bae;Park, Cheol Jae
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.9
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    • pp.869-874
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    • 2015
  • We developed an LSDC (Load Shift and Load Distribution Control) technology in order to improve coil quality and productivity by reducing tension fluctuation especially for the tail of the strip in the down coiler in hot strip mills. To adapt the new controller, the torque and speed distribution between the zero pinch roll, pinch roll, and mandrel are needed. The proposed controller is a combination of an LSC to share the tension between the mill stand and the mandrel, and an LDC to shift the torque load from the zero pinch roll to the pinch roll. From the simulation, the proposed controller is verified under the torque disturbance. Using a field test, the torque deviation decreased by nearly 50% through utilization of the LSDC control.

Buckling analysis of laminated composite cylindrical shell subjected to lateral displacement-dependent pressure using semi-analytical finite strip method

  • Khayat, Majid;Poorveis, Davood;Moradi, Shapour
    • Steel and Composite Structures
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    • v.22 no.2
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    • pp.301-321
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    • 2016
  • The objective of this paper is to investigate buckling behavior of composite laminated cylinders by using semi-analytical finite strip method. The shell is subjected to deformation-dependent loads which remain normal to the shell middle surface throughout the deformation process. The load stiffness matrix, which is responsible for variation of load direction, is also throughout the deformation process. The shell is divided into several closed strips with alignment of their nodal lines in the circumferential direction. The governing equations are derived based on the first-order shear deformation theory with Sanders-type of kinematic nonlinearity. Displacements and rotations of the shell middle surface are approximated by combining polynomial functions in the meridional direction and truncated Fourier series along with an appropriate number of harmonic terms in the circumferential direction. The load stiffness matrix, which is responsible for variation of load direction, is also derived for each strip and after assembling, global load stiffness matrix of the shell is formed. The numerical illustrations concern the pressure stiffness effect on buckling pressure under various conditions. The results indicate that considering pressure stiffness causes buckling pressure reduction which in turn depends on various parameters such as geometry and lay-ups of the shell.

Push-out test on the one end welded corrugated-strip connectors in steel-concrete-steel sandwich structure

  • Yousefi, Mehdi;Ghalehnovi, Mansour
    • Steel and Composite Structures
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    • v.24 no.1
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    • pp.23-35
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    • 2017
  • Current form of Corrugated-strip connectors are not popular due to the fact that the two ends of this form need to be welded to steel face plates. To overcome this difficulty, a new system is proposed in this work. In this system, bi-directional corrugated-strip connectors are used in pairs, and only one of their ends is welded to the steel face plates on each side. The other end is embedded in the concrete core. To assemble the system, common welding devices are required, and welding process can be performed in the construction sites. By performing the Push-out test under static loading, the authors experimentally assess the effects of geometric parameters on ductility, failure modes and the ultimate shear strength of the aforesaid connectors. For this purpose, sixteen experimental samples are prepared and investigated. For fifteen of these samples, one end of the shear connectors is welded to steel face plates, and the other end is embedded in the concrete. Another experimental sample is prepared in which both ends are welded to the steel face plates. According to the achieved results, several relations are proposed for predicting the ultimate shear strength and load vs. interlayer slip (load-slip) behavior of corrugated-strip connectors. Moreover, these formulas are compared with those of the well-known codes and standards. Accordingly, it is concluded that the authors' relations are more reliable.

A Study on Increase of Bearing Capacity of Dense Sandy Ground installed by Vertical Micropiles (연직 마이크로파일이 설치된 조밀한 모레지반의 지지력 증가에 관한 연구)

  • 최상민;임종철;이태형;공영주
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.355-362
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    • 2001
  • Since micropiles were conceived in Italy in the early 1950s, which have been widely used for In-situ reinforcement, bearing pile or the concept of combination in the world-wide. The meaning of micropiles usually differs from that of a general deep foundation. Because the load capacity of it was mainly affected by skin friction. Also, it could be obtained the improvement effects of load capacity or ground's rigidity by the unitary behavior of ground and micropiles. In this study, The model tests were peformed on the dense sand where micropiles are set to the vertical direction. Strip footing was used in it. Steel bars of dia. 2 and 4㎜ were used in model tests of which the sand was attached on the surface, and the length of it was changed as 2B to 6B(where, B is width of strip footing) Through this process, the load capacity were analyzed from the test results in the relationship between load and displacement.

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A Study on Failure Mechanism of Reinforced Earth Retaining Wall under Strip Load (대상하중하의 보강토옹벽의 파괴 메카니즘에 관한 연구)

  • 유남재;김영길
    • Geotechnical Engineering
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    • v.7 no.4
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    • pp.35-48
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    • 1991
  • Based on centrifuge model tests, the failure mechanism of reinforced earth retaining wall under strip load was investigated in this paper. Tests were performed by changing the materials of reinforcing strips, strip lengths, and strip arrangements. The strips were strain-gauged to measure the tensions in strips. The results were analyzed and compared with various design methosds in use to verify their feasibility. Consequently, a centrifuge model test was an effective method of investigating the behavior of reinforced earth retaining wall. The 2 : 1 stress diffusion method showed comparable results with tests in estimating the capacity of the reinforced earth wall under strip load. The superposition of tensions due to selfweight of the backfill and strip load was valid to estimate total tensions mobilized in strips. Using the elasticity theory to estimate the maximum tension mobilized in strips due to surcharge, while solutions of Boussinesq and Westergaard underestimated less tensions than the measured valises, Frohlich solution showed the comparable results with tests.

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Assessment of transient vibrations of graphene oxide reinforced plates under pulse loads using finite strip method

  • Mirjavadi, Seyed Sajad;Forsat, Masoud;Barati, Mohammad Reza;Hamouda, A.M.S.
    • Computers and Concrete
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    • v.25 no.6
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    • pp.575-585
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    • 2020
  • Based on a refined shear deformation finite strip, transient vibrations of graphene oxide powder (GOP) reinforced plates due to external pulse loads have been investigated. The plate has uniformly and linearly distributed GOPs inside material structure. Applied pulse loads have been selected as sinusoidal, linear and blast types. Such pulse loads result in transient vibrations of the GOP-reinforced plates which are not explored before. Finite strip method (FSM) has been performed for solving the equations of motion and then inverse Laplace transform technique has been employed to derive transient responses due to pulse loading. It is reported in this study that the transient responses of GOP-reinforced plates are dependent on GOP dispersions, GOP volume fraction, type of pulse loading, loading time and load locations.

Optimal Design of Strip Casting Roll (박판 주조 롤의 최적설계)

  • Park, Cheol-Min;Kang, Tae-Wook;Park, Gyung-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.11
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    • pp.2466-2473
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    • 2002
  • In twin roll strip casting process, the design of casting roll is the most important equipment for producing strip. Analyses of heat transfer and deformation for the casting roll are carried out by using the finite element program, ANSYS. Both the elastic deformation and the elasto-plastic deformation under a thermal load are considered in the analysis. Optimization to minimize the volume of roll is performed under the various thermal loads such as the heat flux and the roll speed. Design variables are defined by diameters and positions of the cooling hole in the roll , Although the thermal load remarkably varies, the design variables and objective function are found to be consistent.