• Title/Summary/Keyword: indeterminate

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Application of the compressive-force path concept in the design of reinforced concrete indeterminate structures: A pilot study

  • Seraj, Salek M.;Kotsovos, Michael D.;Pavlovic, Milija N.
    • Structural Engineering and Mechanics
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    • v.3 no.5
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    • pp.475-495
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    • 1995
  • In the past, physical models have been proposed, in compliance with the concept of the compressive-force path, for the realistic design of various statically determinate structural concrete members. The present work extends these models so as to encompass indeterminate RC structural forms. Pilot tests conducted on continuous beams and fixed-ended portal frames have revealed that designing such members to present-day concepts may lead to brittle types of failure. On the other hand, similar members designed on the basis of the proposed physical models attained very ductile failures. It appears that, unlike current design approaches, the compressive-force path concept is capable of identifying those areas where failure is most likely to be triggered, and ensures better load redistribution, thus improving ductility. The beneficial effect of proper detailing at the point of contraflexure in an indeterminate RC member is to be noted.

Indeterminate Strut-Tie Model for Rational Design of Continuous RC Deep Beams (연속지지 RC 깊은 보의 합리적인 설계를 위한부정정 스트럿-타이 모델의 제안)

  • Chae, Hyun-Soo;Kim, Byung-Hun;Yun, Young-Mook
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.265-268
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    • 2006
  • Recently, many design standards recommend the use of a strut-tie model approach for design of structural concrete with D-region(s). However, since the design standards of the conventional strut-tie model approaches are suggested on the assumption of using a determinate strut-tie model, it is difficult to apply an indeterminate strut-tie model in the design of continuous deep beams. In this study, an indeterminate strut-tie model for continuous deep beams is proposed to resolve the problem, and the ultimate strengths of 35 continuous deep beams tested to failure are evaluated for the validity check of the proposed indeterminate strut-tie model. The analytical results by the proposed model are compared with those by the conventional approaches of ACI 318-99 and ACI 318-05.

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The Expressional Characteristics and Meanings of Indeterminacy in Fashion Illustrations (패션 일러스트레이션에 표현된 불확정성의 특성과 의미)

  • Kim, Soon Ja
    • Fashion & Textile Research Journal
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    • v.17 no.5
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    • pp.691-703
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    • 2015
  • Indeterminacy maintains that the simultaneous measurement of object location and speed is theoretically impossible. This study present indeterminacy as a theoretic tool to interpret a variety of expression characteristics that seem disorderly in recent fashion illustrations; in addition, it analyzes the characteristics and meaning of indeterminacy as expressed in fashion illustrations. This study reviews concepts and related theories on indeterminacy to examine characteristics of indeterminacy expressed in the arts and fashion; subsequently, indeterminacy characteristics found in fashion illustrations are analyzed. In expressing the fashion figure, indeterminacy finds expression in a distorted figure transformations that include a hybridized combination of heterogeneous forms that dismantle and reconstruct the human body. The hybridized body of combined machines, animals and plants indicates an indeterminate body endlessly transforming itself. Indeterminate space expression finds expression in space expression by projection with the overlapping and juxtaposition of irrelevant constituent elements as well as a space expression from the insertion of unexpected images. An unclarified inconclusive open space provides space with fluidity, causes space expansion and conveys inconclusive meaning. Indeterminate expressions found in fashion illustrations reveal the ambiguity and complexity of a post-modern society with polysemous aesthetic values and the expanded visual concepts of fashion illustrations.

A fast damage detecting technique for indeterminate trusses

  • Naderi, Arash;Sohrabi, Mohammad Reza;Ghasemi, Mohammad Reza;Dizangian, Babak
    • Structural Engineering and Mechanics
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    • v.75 no.5
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    • pp.585-594
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    • 2020
  • Detecting the damage of indeterminate trusses is of major importance in the literature. This paper proposes a quick approach in this regard, utilizing a precise mathematical approach based on Finite Element Method. Different to a general two-step method defined in the literature essentially based on optimization approach, this method consists of three steps including Damage-Suspected Element Identification step, Imminent Damaged Element Identification step, and finally, Damage Severity Detection step and does not need any optimizing algorithm. The first step focuses on the identification of damage-suspected elements using an index based on modal residual force vector. In the second step, imminent damage elements are identified among the damage-suspected elements detected in the previous step using a specific technique. Ultimately, in the third step, a novel relation is derived to calculate the damage severity of each imminent damaged element. To show the efficiency and quick function of the proposed method, three examples including a 25-bar planar truss, a 31-bar planar truss, and a 52-bar space truss are studied; results of which indicate that the method is innovatively capable of suitably detecting, for indeterminate trusses, not only damaged elements but also their individual damage severity by carrying out solely one analysis.

Factors Associated with Indeterminate and False Negative Results of QuantiFERON-TB Gold In-Tube Test in Active Tuberculosis

  • Cho, Ki-Won;Cho, Eun-Ha;Kwon, Soo-Hoon;Im, Sang-Hyuk;Sohn, In;Song, Sook-Hee;Kim, Hye-Ok;Kim, Su-Hyun
    • Tuberculosis and Respiratory Diseases
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    • v.72 no.5
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    • pp.416-425
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    • 2012
  • Background: The sensitivities and specificities of interferon-gamma release assays (IGRAs) vary among different population studies, and the data on the routine use of IGRAs are limited. The aim of this study was to evaluate the role of QuantiFERON-TB Gold In-Tube (QFT-GIT) test in the diagnosis of active tuberculosis. Methods: We conducted a prospective study, enrolling 77 patients with suspected pulmonary tuberculosis (TB), at a secondary care teaching hospital in Seoul. Results: In total, 12 (15.6%) patients showed indeterminate results due to positive control failure on the QFT-GIT test. Indeterminate results were significantly associated with the elderly, history of the intensive care unit stay, lymphocytopenia, especially low CD4 count, increased C-reactive protein and decreased protein levels. Of the 77 patients, 44 (57.1%) were diagnosed with active pulmonary tuberculosis, and the percentage of false negative results of the QFT-GIT was 36.4% (vs. 31.8% with TST). In the TB group with >65 years old (n=12), the proportions of the indeterminate (33.3% vs. 3.1%) and the false negative results (58.3% vs. 25.0%) of the QFT-GIT were significantly higher than in the younger TB group (n=32). Conclusion: Indeterminate and false negative results of QFT-GIT test were not infrequent in tuberculosis, especially in the elderly. Care should be considered for the interpretation with the elderly, immunocompromised, chronic and severely diseased patients.

The Evaluation of LBB Behavior and Crack Opening Displacement on Piping System under Bending Load (굽힘하중을 받는 배관계의 LBB거동 및 균열개구변위의 평가)

  • Nam, Ki-Woo;Ahn, Seok-Hwan;Ando, Kotoji
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.67-72
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    • 2001
  • The LBB behavior and the crack opening displacement after a crack penetrated wall thickness of statically indeterminate piping system were investigated in this study, compared with statically determinate piping system. The reduction of ultimate strength caused by a crack was relatively small in the statically indeterminate piping system. The statically indeterminate piping system has more safety margin for LBB behavior than the statically determinate piping system. The crack opening displacement could be evaluated by using the plastic rotation angle proposed to evaluate the crack opening displacement after crack penetration in pipe with a non-penetrating crack.

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Analysis of Statically Indeterminate Bearing-Shaft System and Prediction of the Behavior of Ball Bearing (베어링-축계의 부정정계 해석 및 볼베어링의 거동예측)

  • 김완두;한동철
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1993.12a
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    • pp.70-76
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    • 1993
  • From the analysis of shaft-bearing indeterminate system, moment and misalingment angle which was generated in bearing were determined. And the influence of span length between bearings on the fatigue life was established. The equation to estimate the cage rotational speed was proposed, and this equation was verified by the measuring of cage speed and shaft speed. And accoding to quasi-static analysis, the spinning speed of ball was determined.

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Analysis of Statically Indeterminate Bearing-Shaft System Prediction of the Behavior of Ball Bearing (부정정 베어링-축계의 해석 및 볼베어링의 거동예측)

  • 김완두;한동철
    • Tribology and Lubricants
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    • v.10 no.1
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    • pp.62-68
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    • 1994
  • The analysis of statically indeterminate bearing-shaft system was investigated. The moment loads and misalignment angles which were induced in the ball bearings were determined, and the influence of span length of this system on the moment loads and fatigue lives was identified. The sliding and spinning speeds between balls and raceways which affected the performance of ball bearing evaluated. The equation to estimate the cage speed of ball bearing under moment loads was proposed. This equation had been verified by the test results of measuring of cage speed, which was useful to the prediction of ball bearing under moment loads.

Algorithm for Topological Relationship On an Indeterminate Spatiotemporal Object (불확실한 시공간 객체에 관한 위상 관계 알고리즘)

  • Ji, Jeong-Hui;Kim, Dae-Jung;Ryu, Keun-Ho
    • The KIPS Transactions:PartD
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    • v.10D no.6
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    • pp.873-884
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    • 2003
  • So far, significant achievements have been studied on the development of models for spatial and spatiotemporal objects with indeterminate boundaries which are found in many applications for geographic analysis and image understanding. Therefore, in this paper we propose the spatiotemporal data model which is applicable for spatial and spatiotemporal objects with uncertainty. Based on this model, we defined topological relationships among the indeterminate spatiotemporal objects and designed the algorithm for the operations. For compatibility with existing spatial models, the proposed model has been designed by extending the spatiotemporal object model which is based on the open GIS specification. We defined indeterminate spatial objects, such as the objects whose position and the shape change discretely over time, and the objects whose shape changes continuously as well as the position. We defined topological relationships among these objects using the extended 9-IM. The proposed model can be efficiently applied to the management systems of natural resource data, westher information, geographic information. and so on.

Strut-tie model for two-span continuous RC deep beams

  • Chae, H.S.;Yun, Y.M.
    • Computers and Concrete
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    • v.16 no.3
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    • pp.357-380
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    • 2015
  • In this study, a simple indeterminate strut-tie model which reflects complicated characteristics of the ultimate structural behavior of continuous reinforced concrete deep beams was proposed. In addition, the load distribution ratio, defined as the fraction of applied load transferred by a vertical tie of truss load transfer mechanism, was proposed to help structural designers perform the analysis and design of continuous reinforced concrete deep beams by using the strut-tie model approaches of current design codes. In the determination of the load distribution ratio, a concept of balanced shear reinforcement ratio requiring a simultaneous failure of inclined concrete strut and vertical steel tie was introduced to ensure the ductile shear failure of reinforced concrete deep beams, and the primary design variables including the shear span-to-effective depth ratio, flexural reinforcement ratio, and compressive strength of concrete were reflected upon. To verify the appropriateness of the present study, the ultimate strength of 58 continuous reinforced concrete deep beams tested to shear failure was evaluated by the ACI 318M-11's strut-tie model approach associated with the presented indeterminate strut-tie model and load distribution ratio. The ultimate strength of the continuous deep beams was also estimated by the experimental shear equations, conventional design codes that were based on experimental and theoretical shear strength models, and current strut-tie model design codes. The validity of the proposed strut-tie model and load distribution ratio was examined through the comparison of the strength analysis results classified according to the primary design variables. The present study associated with the indeterminate strut-tie model and load distribution ratio evaluated the ultimate strength of the continuous deep beams fairly well compared with those by other approaches. In addition, the present approach reflected the effects of the primary design variables on the ultimate strength of the continuous deep beams consistently and reasonably. The present study may provide an opportunity to help structural designers conduct the rational and practical strut-tie model design of continuous deep beams.