• Title/Summary/Keyword: cross-tie

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Determination of strut efficiency factor for concrete deep beams with and without fibre

  • Sandeep, M.S.;Nagarajan, Praveen;Shashikala, A.P.;Habeeb, Shehin A.
    • Advances in Computational Design
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    • v.1 no.3
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    • pp.253-264
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    • 2016
  • Based on the variation of strain along the cross section, any region in a structural member can be classified into two regions namely, Bernoulli's region (B-region) and Disturbed region (D-region). Since the variation of strain along the cross section for a B-region is linear, well-developed theories are available for their analysis and design. On the other hand, the design of D-region is carried out based on thumb rules and past experience due to the presence of nonlinear strain distribution. Strut-and-Tie method is a novel approach that can be used for the analysis and design of both B-region as well as D-region with equal importance. The strut efficiency factor (${\beta}_s$) is needed for the design and analysis of concrete members using Strut and Tie method. In this paper, equations for finding ${\beta}_s$ for bottle shaped struts in concrete deep beams (a D-region) with and without steel fibres are developed. The effects of transverse reinforcement on ${\beta}_s$ are also considered. Numerical studies using commercially available finite element software along with limited amount of experimental studies were used to find ${\beta}_s$.

Reinforced concrete corbels strengthened with carbon fiber reinforced plastics

  • Lu, Wen-Yao;Yu, Hsin-Wan;Chen, Chun-Liang;Yang, Tzong-Hwan;Lin, Yu-Sin
    • Computers and Concrete
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    • v.10 no.3
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    • pp.259-276
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    • 2012
  • A total of nine reinforced concrete corbels were tested, in this study. Six were externally strengthened with carbon fiber reinforced plastics (CFRP), in the horizontal direction. The cross-sectional area of CFRP and the shear span-to-effective depth ratios are the parameters considered, in this study. Test results indicate that the higher the cross-sectional area of CFRP, the higher is the shear strength of the corbels, and the lower the shear span-to-effective depth ratios, the higher is the shear strength of corbels. The shear strength predicted by the design provisions in section 11.8 of the ACI Code, the strut-and-tie model in Appendix A of the ACI Code, and the softened strut-and-tie (SST) model were compared with the test results. The comparisons show that both the strut-and-tie model in Appendix A of the ACI Code, and the SST model can accurately predict the shear strength of reinforced concrete corbels, strengthened with CFRP.

An aspect of 'Family' demonstrated in Chinese New Period women's novels - Focusing on 『The Bathing Woman』 - (중국 신시기 여성소설에 나타난 가족 담론의 일면 - 티에닝(铁凝)의 『목욕하는 여인들(大浴女)』를 중심으로 -)

  • Choi, Eun Jeong
    • Cross-Cultural Studies
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    • v.35
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    • pp.59-78
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    • 2014
  • This article is written on the ground that one of the major characteristics of Chinese New Period women's novels is about family dissolution and calling and it is examined based on analysis of "The Bathing Woman" by Tie Ning. In "The Bathing Woman", the family seems 'Regular' externally but it is actually fragmented internally. The author offers patriarchal perspective on 'Family' from the eyes of daughter of the family. The problems are classified into three categories. First, it is the problem of exclusiveness embedded in the essential characteristic of family represented by blood relation. Second, it is the research on the reason for family dissolution. Tie Ning finds the reason at 'Unmotherly mother, that is the lack of maternal instinct. Third, it is the expectation of the restoration of dissolved family. Tie Ning's indication of 'Family' is equal to 'Mother' and 'Mother' is the source and power that can heal and restore the dissolved family in her novel. It is expansion of maternal instinct represented by protection and caring into 'Practical action' and it is meaningful in a way that it expands the principle of maternal instinct and sublimates it into universal morality. However, it should not be overlooked that it could be another moral system that could suppress the females in other ways.

Redoable Tie-Over Dressing Using Multiple Loop Silk Threads

  • Jo, Hyeon Jong;Kim, Jun Sik;Kim, Nam Gyun;Lee, Kyung Suk;Choi, Jae Hoon
    • Archives of Plastic Surgery
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    • v.40 no.3
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    • pp.259-262
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    • 2013
  • After skin grafting, to prevent hematoma or seroma collection at the graft site, a tie-over dressing has been commonly used. However, although the conventional tie-over dressing by suture is a useful method for securing a graft site, refixation is difficult when repeated tie-over dressing is needed. Therefore, we recommend a redoable tie-over dressing technique with multiple loops threads and connecting silk threads. After the raw surface of each of our cases was covered with a skin graft, multiple loop silk thread attached with nylon at the skin graft margin. We applied the ointment gauze and wet cotton/fluffy gauze over the skin graft, then fixed the dressing by connecting cross-counter multiple loop thread with connecting silk threads. When we opened the tie-over dressing by cutting the connecting silk threads, we repeated the tie-over dressing with the same method. The skin graft was taken successfully without hematoma or seroma collection or any other complications. In conclusion, we report a novel tie-over dressing enabling simple fixation of the dressing to maintain proper tension for wounds that require repetitive fixation. Further, with this reliable method, the skin grafts were well taken.

Stress-Strain Behavior of Confined Concrete Columns according to Transverse Reinforcement Volumetric Ratio (횡방향 구속철근비에 따른 교각요소부재의 응력-변형 거동)

  • Oh Byung Hwan;Kim Ki Wan;Chioi Seung Won;Lee Jae Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.37-40
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    • 2004
  • An experimental study was conducted to investigate the stress-strain behavior of confined concrete columns according to transverse reinforcement volumetric ratio. Uniaxial loading tests of eleven column specimens$(250\times100\times500mm)$ with rectangular section were conducted to study effect of confinement. The main variables in this test are transverse reinforcement volumetric ratio and cross tie arrangement. the results indicate that the strength and the ductility of confined concrete columns are subjected to transverse reinforcement volumetric ration and cross tie arrangement.

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Influence of Concrete Strength and Lateral Ties on Behavior of High-Strength Concrete Columns (고강도 콘크리트 기둥의 거동에 미치는 콘크리트 강도와 띠철근의 영향)

  • Lee, Young-Ho;Chung, Heon-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.2
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    • pp.245-253
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    • 2002
  • This study was focused on the effect of concrete strength and lateral ties of concrete columns using high-strength concrete. Thirty-six concrete columns with 20cm square cross-section were tested. Experimental parameters included the concrete strength, the distribution of longitudinal bars and the volumetric ratio, yield strength, spacing of lateral ties. From the experiments, we found that: 1) the increasing rate of the strength and ductility of concrete columns caused by confinement of lateral ties was decreasing, as the concrete strength increased. 2) The high volumetric ratio and the reduction of tie spacing had a tendency to enhance the strength and improve the ductility. 3) The high-strength concrete columns required high volumetric ratio of lateral ties to maintain the proper strength and ductility. It was observed that the current AIK design code to specify the maximum tie spacing of high-strength concrete columns led to the poor strength and ductility for seismic design.

Online Tie Formation in Enterprise Social Media

  • Yongsuk Kim;Gerald C. (Jerry) Kane
    • Asia pacific journal of information systems
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    • v.29 no.3
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    • pp.382-406
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    • 2019
  • We study the antecedents to tie formation on an (Facebook-like) enterprise social media platform implemented to support cross-boundary connections. Research has produced mixed findings regarding the role of social media in cultivating bridging vs. closed networks. We examine the tie formation patterns of 1,386 enterprise social media users over a two-year period. Specifically, we observe who became (or chose not s become) "friends" with whom at the dyadic level and relate the decisions to various mechanisms that affect one's network to expand, constrain, or bridge. Using logistic and OLS regressions, we find that users tend to form ties via reciprocity and transitivity (with friends of friends), both of which help expand one's network. We also find strong networking tendency toward functional and hierarchical homophily (same business unit and same rank, respectively), which is likely to constrain one's network (closed network structure). We find that one's participation in various online interest groups is likely to open one's network (bridging network structure) while no evidence found for preferential attachment. Overall, we find that enterprise social media offers features, some of which are likely to foster bridging while others foster closed networks via different mechanisms.

Characteristics of stress-strain relations of confined rectangular sectional concrete elements with various lateral reinforcement ratios and cross-ties (횡철근비와 cross-tie가 다른 횡구속 사각단면 콘크리트의 응력-변형률 특성)

  • Jeong, Hyeok-Chang;Park, Tae-Soo;Sun, Chang-Ho;Kim, Ick-Hyun;Lee, Jong-Seok
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.89-92
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    • 2006
  • In order to achieve target ductility the stress-strain relation of confined concrete is indispensible. In this study the specimens with different transverse reinforcement ratios were tested. The test results were compared with empirical equations and the characteristics of confinement effect were investigated.

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Development of Corner-Supported Auto Climbing Formwork System (강합성코어벽을 활용한 코너지지형 거푸집시스템 개발)

  • Hong, Geon-ho;Shim, Woo-Kyung
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.7
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    • pp.171-178
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    • 2019
  • Auto Climbing Formwork System (ACS) for construction of high-rise building is a construction method for automatically lifting the formwork system supported by the anchor on the pre-constructed concrete wall. It has excellent construction speed and quality, but it has the possibility of structural failure depending on the quality of concrete and also has low economical efficiency due to the use of foreign technology. In order to overcome these problems, this study conducted an optimum design for the development of a new concept of Corner Supported Auto Climbing System (CS-ACS) in conjunction with the development of corner steel-reinforced concrete core wall system. For the design the formwork system, the basic module and structural member compositions were planned, and the structural analysis program was used to analyze the optimum member's cross section and spacing. As a result, the horizontal displacement and the stress of the horizontal members were influenced by the spacing more than the cross-section of the member. On the other hand, vertical members did not affect the displacement and stress of the formwork system. The form tie was very effective in controlling the displacement when adjusting the spacing of the horizontal members, but when the spacing of the form tie is more than 1,500mm, it is analyzed that form tie is yielding in basic module. When the span of the formwork system is more than 30m, it is analyzed that the basic module needs to be changed because of the increase of overall displacement.