• Title/Summary/Keyword: Special calculation

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Axial compression ratio limit values for steel reinforced concrete (SRC) special shaped columns

  • Chen, Zongping;Xu, Jinjun;Chen, Yuliang;Xue, Jianyang
    • Steel and Composite Structures
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    • v.20 no.2
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    • pp.295-316
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    • 2016
  • This paper presents the results of experimental investigation, numerical calculation and theoretical analysis on axial compression ratio limit values for steel reinforced concrete (SRC) special shaped columns. 17 specimens were firstly intensively carried out to investigate the hysteretic behavior of SRC special shaped columns subjected to a constant axial load and cyclic reversed loads. Two theories were used to calculate the limits of axial compression ratio for all the specimens, including the balanced failure theory and superposition theory. It was found that the results of balanced failure theory by numerical integration method cannot conform the reality of test results, while the calculation results by employing the superposition theory can agree well with the test results. On the basis of superposition theory, the design limit values of axial compression ratio under different seismic grades were proposed for SRC special shaped columns.

A design of transcendental function arithmetic unit for lighting operation of mobile 3D graphic processor (모바일 3차원 그래픽 프로세서의 조명처리 연산을 위한 초월함수 연산기 구현)

  • Lee, Sang-Hun;Lee, Chan-Ho
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.715-718
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    • 2005
  • Mobile devices is getting to include more functions according to the demand of digital convergence. Applications based on 3D graphic calculation such as 3D games and navigation are one of the functions. 3D graphic calculation requires heavy calculation. Therefore, we need dedicated 3D graphic hardware unit with high performance. 3D graphic calculation needs a lot of complicated floating-point arithmetic operation. However, most of current mobile 3D graphics processors do not have efficient architecture for mobile devices because they are based on those for conventional computer systems. In this paper, we propose arithmetic units for special functions of lighting operation of 3D graphics. Transcendental arithmetic units are designed using approximation of logarithm function. Special function units for lighting operation such as reciprocal, square root, reciprocal of square root, and power can be obtained. The proposed arithmetic unit has lower error rate and smaller silicon area than conventional arithmetic architecture.

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Back calculation and solution Technique of E-modulus by FWD′s deflection data in Pavement (FWD 처짐치에 의한 포장층 탄성계수 역산 및 해석기법)

  • 위성동
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.188-200
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    • 2002
  • In this study, a pavement evaluation method is introduced by a case study of the measurement data obtained in Incheon International Airport. Based on the results obtained by both visual inspection and automobile inspection equipments, the pavement surface condition is evaluated and used for maintenance and rehabilitation strategy for pavement. In addition, the special attention was given to the back calculation and solution technique of E-modulus by FWD's deflection data in Pavement.

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Fire design of concrete encased columns: Validation of an advanced calculation model

  • Zaharia, R.;Dubina, D.
    • Steel and Composite Structures
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    • v.17 no.6
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    • pp.835-850
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    • 2014
  • The fire resistance of composite steel and concrete structures may be determined by using the simplified methods provided in EN 1994-1-2. For the particular situations not covered by the standard, an advanced calculation model might be applied, using special purpose programs for the analysis of structures in fire. The validation of these programs has always been an important issue for software developers, but also for designers and authorities. Clause 4.4.4 from EN 1994-1-2 refers to the validation of the advanced calculation models and states that these models must be validated through relevant test results. The paper presents the calculation of fire resistance of the composite columns in a high-rise building built in Romania, and focusses on the validation of the calculation model (computer program SAFIR), for this particular case. This validation, asked by the Romanian authorities, considers the available experimental results of a fire test, performed on a similar composite steel-concrete column.

A Study of Radiation Current on Linear Antennas According to Mutual Impedance (상호Impedance에 의한 선형안테나상의 전류분포에 관하여)

  • 황인종
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.4 no.4
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    • pp.22-27
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    • 1967
  • The general mutual impedance expression for two staggered parallel, centerfed, linear antennas of unequal length and confirmed that the general expression being applied to a special case, reduced to the equation presented by other. Furthermore, calculation is done for a special cast, and it is confirmed that the general mutual impedance expression is applicable to the calculation of radiative curreut distribution on antenna system given above.

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Reliability and Accuracy Analyses of Prediction Equations for Settlement Calculation of Shallow Foundations Constructed on Sandy Soils (사질토 지반에 시공된 얕은 기초 침하예측식의 신뢰도 및 정확도 분석)

  • Lim, Yu-Jin
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.3
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    • pp.77-86
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    • 2008
  • A database program is constructed by collecting all information related to shallow foundations such as measured load-settlement data, foundation shapes and sizes, properties of soils under the foundation and various measured data obtained from field investigation methods including CPT, PMT and SPT etc.. Based on the database program, a special program module is developed for performing statistical analyses of reliability and accuracy of predicting equations used for calculation of settlement of the shallow foundations. Special interests are focused not only on the settlement, but also on the settlement to width ratio (s/B). Results of the reliability and accuracy analyses on five available settlement equations are provided. Conclusions based on the provided results can be confirmed by extending number of related reliable data about the shallow foundations and can be adapted as guidelines for design of the shallow foundations.

Experimental and finite element studies of special-shape arch bridge for self-balance

  • Lu, Pengzhen;Zhao, Renda;Zhang, Junping
    • Structural Engineering and Mechanics
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    • v.35 no.1
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    • pp.37-52
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    • 2010
  • Special-shape arch bridge for self-balance (SBSSAB) in Zhongshan City is a kind of new fashioned spatial combined arch bridge composed of inclined steel arch ribs, curved steel box girder and inclined suspenders, and the mechanical behavior of the SBSSAB is particularly complicated. The SBSSAB is aesthetic in appearance, and design of the SBSSAB is artful and particular. In order to roundly investigate the mechanical behavior of the SBSSAB, 3-D finite element models for spatial member and shell were established to analyze the mechanical properties of the SBSSAB using ANSYS. Finite element analyses were conducted under several main loading cases, moreover deformation and strain values for control section of the SBSSAB under several main loading cases were proposed. To ensure the safety and rationality for optimal design of the SBSSAB and also to verify the reliability of its design and calculation theories, the 1/10 scale model tests were carried out. The measured results include the load checking calculation, lane loading and crowd load, and dead load. A good agreement is achieved between the experimental and analytical results. Both experimental and analytical results have shown that the SBSSAB is in the elastic state under the planned test loads, which indicates that the SBSSAB has an adequate load-capacity. The calibrated finite-element model that reflects the as-built conditions can be used as a baseline for health monitoring and future maintenance of the SBSSAB.

Axial compressive behavior of special-shaped concrete filled tube mega column coupled with multiple cavities

  • Wu, Haipeng;Qiao, Qiyun;Cao, Wanlin;Dong, Hongying;Zhang, Jianwei
    • Steel and Composite Structures
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    • v.23 no.6
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    • pp.633-646
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    • 2017
  • The compressive behavior of special-shaped concrete filled tube (CFT) mega column coupled with multiple cavities is studied by testing six columns subjected to cyclically uniaxial compressive load. The six columns include three pentagonal specimens and three hexagonal specimens. The influence of cavity construction, arrangement of reinforcement, concrete strength on failure feature, bearing capacity, stiffness, and residual deformation is examined. Experimental results show that cavity construction and reinforcements make it possible to form a combined confinement effect to in-filled concrete, and the two groups of special-shaped CFT columns show good elastic-plastic compressive behavior. As there is no axial bearing capacity calculation method currently available in any Code of practice for special-shaped CFT columns, values predicted by normal CFT column formulas in GB50936, CECS254, ACI-318, EC4, AISCI-LRFD, CECS159, and AIJ are compared with tested values. The calculated values are lower than the tested values for most columns, thus the predicted bearing capacity is safe. A reasonable calculation method by dividing concrete into active and inactive confined regions is proposed. And high accuracy shows in estimating special-shaped CFT columns either coupled with multiple cavities or not. In addition, a finite element method (FEM) analysis is conducted and the simulated results match the test well.

A study on the Line impedance calculation method in electrified railway system (전기철도에서 급전선로의 line impedance 계산에 관한 연구)

  • Lee, Chun-Bae;Lee, Jong-Woo
    • Proceedings of the KSR Conference
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    • 2004.06a
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    • pp.1308-1312
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    • 2004
  • Transmission line impedance calculation has been tried for obtaining exact value. The method proposed by Carson contains indefinite complex integral. Although the Carson solution is proposed with power series, the solution is limited and valid at special range of frequency. In this paper, we proposed a simplified Carson solution by analytical method using ground transmission line return current. This method calculate the transmission line impedance easily.

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On the Design Impact Pressure in the Rules and Regulations of ISO and Classification Societies (선급 및 ISO에 나타난 설계충격 하중에 관하여)

  • Lee, June
    • Journal of Korea Ship Safrty Technology Authority
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    • s.31
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    • pp.60-70
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    • 2011
  • The slamming impact pressures at the bottom area of the Open60' are evaluated by the rules and regulations of various organizations - ISO and classification societies. The enhanced performance of the modern racing yacht in terms of speed which achieves well over 20 knots needs special consideration. The calculated design impact pressures are compared a experimental results. Severe difference can be found in these calculation results but the final conclusion shall be obtained after the scantling calculation under the evaluated design impact pressure so far.

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