• Title/Summary/Keyword: wall

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Plastic Limit Loads for Through-Wall Cracked Pipes Using 3-D Finite Element Limit Analyses (3차원 유한요소 한계해석을 이용한 관통균열 배관의 소성한계하중)

  • Huh Nam-Su;Kim Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.5 s.248
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    • pp.568-575
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    • 2006
  • The present paper provides plastic limit load solutions of axial and circumferential through-wall cracked pipes based on detailed three-dimensional (3-D) finite element (FE) limit analysis using elastic-perfectly-plastic behavior. As a loading condition, axial tension, global bending moment, internal pressure, combined tension and bending and combined internal pressure and bending are considered for circumferential through-wall cracked pipes, while only internal pressure is considered for axial through-wall cracked pipes. Especially, more emphasis is given for through-wall cracked pipes subject to combined loading. Comparisons with existing solutions show a large discrepancy in short through-wall crack (both axial and circumferential) for internal pressure. In the case of combined loading, the FE limit analyses results show thickness effect on limit load solutions. Furthermore, the plastic limit load solution for circumferential through-wall cracked pipes under bending is applied to derive plastic $\eta\;and\;{\gamma}$-factor of testing circumferential through-wall cracked pipes to estimate fracture toughness. Being based on detailed 3-D FE limit analysis, the present solutions are believed to be meaningful fur structural integrity assessment of through-wall cracked pipes.

Seismic capacity of brick masonry walls externally bonded GFRP under in-plane loading

  • Wang, Quanfeng;Chai, Zhenling;Wang, Lingyun
    • Structural Engineering and Mechanics
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    • v.51 no.3
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    • pp.413-431
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    • 2014
  • By carrying out the experiment of eight pieces of brick masonry walls with pilaster strengthened by Glass fiber reinforced polymer (GFRP) and one piece of normal masonry wall with pilaster under low reversed cyclic loading, the failure characteristic of every wall is explained; Seismic performances such as hysteresis, stiffness and its degeneration, deformation, energy consumption and influence of some measures including strengthening means, reinforcement area proportion between GFRP and wall surface, "through-wall" anchor on reinforcement effects are studied. The test results showed that strengthening modes have little influence on stiffness, stiffness degeneration and deformation of the wall, but it is another thing for energy consumption of the wall; The ultimate load, deformation and energy consumption of the walls reinforced by glass fiber sheets was increased remarkably, rigidity and its degeneration was slower; Seismic performance of the wall which considers strengthening means, reinforcement area proportion between GFRP and wall surface, "through-wall" anchor at the same time is better than under the other conditions.

Seismic behavior of steel frames with replaceable reinforced concrete wall panels

  • Wu, Hanheng;Zhou, Tianhua;Liao, Fangfang;Lv, Jing
    • Steel and Composite Structures
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    • v.22 no.5
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    • pp.1055-1071
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    • 2016
  • The paper presents an innovative steel moment frame with the replaceable reinforced concrete wall panel (SRW) structural system, in which the replaceable concrete wall can play a role to increase the overall lateral stiffness of the frame system. Two full scale specimens composed of the steel frames and the replaceable reinforced concrete wall panels were tested under the cyclic horizontal load. The failure mode, load-displacement response, deformability, and the energy dissipation capacity of SRW specimens were investigated. Test results show that the two-stage failure mode is characterized by the sequential failure process of the replaceable RC wall panel and the steel moment frame. It can be found that the replaceable RC wall panels damage at the lateral drift ratio greater than 0.5%. After the replacement of a new RC wall panel, the new specimen maintained the similar capacity of resisting lateral load as the previous one. The decrease of the bearing capacity was presented between the two stages because of the connection failure on the top of the replaceable RC wall panel. With the increase of the lateral drift, the percentage of the lateral force and the overturning moment resisted by the wall panel decreased for the reason of the reduction of its lateral stiffness. After the failure of the wall panel, the steel moment frame shared almost all the lateral force and the overturning moment.

Experiments of Wave Heights in front of a Perforated Wall under Obliquely Incident Waves:Monochromatic Wave Conditions (경사입사파 조건에서 유공벽 전면의 파고분포에 대한 실험:규칙파 조건)

  • Lee, Jong In;Kim, Young Taek
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.5B
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    • pp.301-312
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    • 2012
  • This study investigates the wave height distributions in front of a perforated wall generated by obliquely incident monochromatic waves through laboratory experiments conducted in a wave basin. Attention is paid to the difference or similarity between a plain wall and a perforated wall. And the investigation is focused on the chamber width and side wall effects of a perforated wall on the propagation characteristics of waves. The main results of this study show that the normalized wave height along a perforated wall is a significant difference compare to a plain wall cases. The side wall in the chamber suppresses the growth of the stem waves.

Characterization of Cell Wall Proteins from the soo1-1/ret1-1 Mutant of Saccharomyces cerevisiae

  • Lee, Dong-Won;Kim, Ki-Hyun;Chun, Se-Chul;Park, Hee-Moon
    • Journal of Microbiology
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    • v.40 no.3
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    • pp.219-223
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    • 2002
  • In order to investigate the function of Soo1p/${\alpha}$-COP during post-translational modification and intra-cellular transport of cell wall proteins in Saccharomyces cerevisiae, cell wall proteins from the soo1-1/ret1-1 mutant cells were analyzed. SDS-PAGE analysis of biotin labeled cell wall proteins suggested that the soo1-1 mutation impairs post-translational modification of cell wall proteins, such as N- and/ or Ο-glycosylation. Analysis of cell wall proteins with antibodies against ${\beta}$-1,3-glucan and ${\beta}$-1,6-glucan revealed alteration of the linkage between cell wall proteins and ${\beta}$-glucans in the soo1-1 mutant cells. Compositional sugar analysis of the cell wall proteins also suggested that the soo1-1 mutation impairs glycosylation of cell wall protein in the ER, which is crucial for the maintenance of cell wall integrity.

A Study on Behavior Characteristics of Segmental Retaining Wall (조립식 블럭 옹벽의 거동특성에 관한 연구)

  • Lee, Jundae
    • Journal of the Korean GEO-environmental Society
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    • v.9 no.4
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    • pp.15-21
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    • 2008
  • From the practical point of view, general retaining wall systems, such as gravity wall, cantilever wall and reinforced wall, have several problems. As a countermeasure, precast block type retaining wall systems have been developed and used for the various purposes of construction. The retaining wall systems can be applied not only for mechanical purpose but environmentally friendly aspects by changing the shapes of surface plates and planting on the surface plates. On the other hand, the bulging failure was dominant near the center of wall height. Therefore, an individual block has to be estimated for the stability problem related to turnover and the for design of gravity block type wall. On the basis of this result, the optimum section of the wall has to be determined.

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Application of a CFD Model for the Design of a Settling Basin Inlet Structure (침전지 유입부 설계를 위한 CFD 모형의 적용)

  • Kim, Nam Il;Kim, Dae Geun;Yu, Chang Hwan;Kim, Tae Young
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.3
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    • pp.318-322
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    • 2005
  • We applied a commercially available computational fluid dynamics model, FLOW-3D, to design a settling basin inlet structure for the intended O sewage plant. In addition, we analyzed the extent to which the inlet sewage water was distributed as a result, firstly, of the location and width of a submerged baffle wall and, secondly, of the opening ratio of a baffle wall with opening holes. The application results show that the flow is unstable due to the generation of eddies in both sides of the submerged baffle wall when the submerged baffle wall is located close to the inlet. The eddies and subsequent instability also occur when the submerged baffle wall is located close to the baffle wall with opening holes. Moreover, the discharge that passes through the midsection of the settling basin increases as the width of the submerged baffle wall increases. At the O sewage plant, when the submerged baffle wall with a width of 2.4 m was located 2 m from the inlet structure and the opening ratio of the baffle wall was 7 percent, the most satisfactory distribution of the inlet sewage water occurred at the entrance of the settling basin.

Developments and applications of a modified wall function for boundary layer flow simulations

  • Zhang, Jian;Yang, Qingshan;Li, Q.S.
    • Wind and Structures
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    • v.17 no.4
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    • pp.361-377
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    • 2013
  • Wall functions have been widely used in computational fluid dynamics (CFD) simulations and can save significant computational costs compared to other near-wall flow treatment strategies. However, most of the existing wall functions were based on the asymptotic characteristics of near-wall flow quantities, which are inapplicable in complex and non-equilibrium flows. A modified wall function is thus derived in this study based on flow over a plate at zero-pressure gradient, instead of on the basis of asymptotic formulations. Turbulent kinetic energy generation ($G_P$), dissipation rate (${\varepsilon}$) and shear stress (${\tau}_{\omega}$) are composed together as the near-wall expressions. Performances of the modified wall function combined with the nonlinear realizable k-${\varepsilon}$ turbulence model are investigated in homogeneous equilibrium atmosphere boundary layer (ABL) and flow around a 6 m cube. The computational results and associated comparisons to available full-scale measurements show a clear improvement over the standard wall function, especially in reproducing the boundary layer flow. It is demonstrated through the two case studies that the modified wall function is indeed adaptive and can yield accurate prediction results, in spite of its simplicity.

Mechanical behavior test and analysis of HEH sandwich external wall panel

  • Wu, Xiangguo;Zhang, Xuesen;Tao, Xiaokun;Yang, Ming;Yu, Qun;Qiu, Faqiang
    • Advances in concrete construction
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    • v.13 no.2
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    • pp.153-162
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    • 2022
  • Prefabricated exterior wall panel is the main non-load-bearing component of assembly building, which affects the comprehensive performance of thermal insulation and durability of the building. It is of great significance to develop new prefabricated exterior wall panel with durable and lightweight characteristics for the development of energy-saving and assembly building. In the prefabricated sandwich insulation hanging wall panel, the selection of material for the outer layer and the arrangement of the connector of the inner and outer wall layers affect the mechanical performance and durability of the wall panels. In this paper, high performance cement-based composites (HPFRC) are used in the outer layer of the new type wall panel. FRP bars are used as the interface connector. Through experiments and analysis, the influence of the arrangement of connectors on the mechanical behaviors of thin-walled composite wall panel and the panel with window openings under two working conditions are investigated. The failure modes and the role of connectors of thin-walled composite wallboard are analyzed. The influence of the thickness of the wall layer and their combination on the strain growth of the control section, the initial crack resistance, the ultimate bearing capacity and the deformation of the wall panels are analyzed. The research work provides a technical reference for the engineering design of the light-weight thin-walled and durable composite sandwich wall panel.

Acceleration data and shape change characteristics of a gravity quay wall according to inclination condition grades

  • Su-Kyeong Geum;Jong-Han Lee;Dohyoung Shin;Jiyoung Min
    • Structural Engineering and Mechanics
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    • v.90 no.6
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    • pp.591-600
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    • 2024
  • This study investigated the acceleration response and shape change characteristics of a gravity quay wall according to the magnitude of the applied acceleration. The quay wall was defined as a port facility damaged by the Kobe earthquake. Four experimental scenarios were established based on the inclination condition grades, considered to be a significant defect factor in the quay wall. Then, the shaking table test was conducted using scaled-down quay wall models constructed per each scenario. The ground acceleration was gradually increased from the peak ground acceleration (PGA) of 0.1 g to 0.7 g. After each ground acceleration test, acceleration installed on the wall and backfill ground and inclination on the top of the wall were measured to assess the amplification of peak response acceleration and maximum response amplitude and the change in the inclination of the quay wall. This study also analyzed the separation of the quay wall from the backfill and the crack pattern of the backfill ground according to PGA values and inclination condition grades. The result of this study shows that response acceleration could provide a reasonable prediction for the changes in the inclination of the quay wall and the crack generation and propagation on the backfill from a current inclination condition grade.