• Magazine of the Korea Concrete Institute
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• v.7 no.1
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• pp.156-164
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• 1995

P-${\Delta}$ analysis by use of the equivalent colurnn stiffness determined by Momcnt curvature-Thrust curves provides relatively precise analytical results for unbraced reinforced concrete columns, however it needs a complicated arialytical procedure. Equ~valent col~rnn stiffness equations are proposed for a simple analytical procedure which are ckterrnined by the Moment-Curvature Thrust curves of the practically useable sections. Thc proposed stiffness equations are appiled to P-${\Delta}$ analysis and rnornent magnifier method to compare with the selected test result. Use of the proposed stiffness equations may slrnplify the P-${\Delta}$ i.rialvtica1 procedure and improve the accuracy of moment magnifier niethod.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.259-267
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• 2004

Most steel frame structures are constructed to one side without considering the arrangement of major-minor axis of column and bracing. This research presents more safety and economic efficiency can be obtained by just rearrangement of major-minor axis. Because most of steel-frame structures are excessively designed with Allowable Stress Design, and it needs to be changed to other specifications. The arrangement of major-minor axis of column is partly referred in AISC-LRFD, but still insufficient. This study compared with the each result from rearrangement of major-minor axis of column, arrangement of bracing, the connecting method of bracing, and consequence with different specifications. Moreover it demonstrated the direction of more economically optimized design.

• Magazine of the Korea Concrete Institute
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• v.9 no.2
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• pp.145-151
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• 1997

In concrete mix design we need the informations of the codes, the specifications, and the experiences of experts. However we can't consider all factors regarding concrete mix design. The final acceptance depends on concrete quality control test results. In this process we meet the uncertainties of materials. temperature, site environmental situations, personal skillfulness. and errors in calculations and testing process. Then the mix design adjustments must be made. Concrete mix design and adjustments arc somewhat complicated, time-consuming. and uncertain tasks. In this paper, as a tool to minimize the uncertainties and errors the neural network is applied to the concrete mix design. Input data to train and test the neural network are obtained numerically from the results of design following the concrete standard specifications of Korea. The 28-days compressive strengths which are variate according to the uncertainties and errors are considered. The results show that neural networks have a strong potential as a tool for concrete mix design.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.4
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• pp.53-60
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• 1986

This study is directed to propose a probability based LRFD design code, which could possibly replace the traditional USD provisions of the current code, based on the AFOSM reliability theory. The uncertainties of resistances and load effects for each R.C. structural elements are evaluated and adopted considering our practice, and a set of rational target reliability indices are selected based on the calibration with the reliability of the current R.C. design code and by considering the desired hierarchy of safety level. Then, a set of common load factors are chosen from the results of load and resistance factors which are computed by AFOSM method using the Rackwitz-Fiessler's efficient practical algorithm which is to transform the non-normal variables into the equivalent normal variables. It may be asserted that the proposed LRFD code for the R.C. building structures may have to be incorporated into the current RC. design codes as a design provision corresponding to the USD provisions of the current R.C. design code.

• Magazine of the Korea Concrete Institute
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• v.27 no.2
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• pp.18-21
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• 2015

• Journal of the Korean GEO-environmental Society
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• v.8 no.3
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• pp.51-57
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• 2007

In the design of slopes during rainfall, the groundwater level is assumed to be located at the ground surface, based on the change in characteristics of rainfall. In addition, stability investigations are performed for large cut slopes in the design of slopes while standard inclinations specified in the design criteria are applied for the slopes that stability investigations are not performed. In spite of the strengthened criteria of groundwater location, slope failures continuously occur during heavy rainfall, regardless of magnitude of slopes. In order to investigate the cause of the failures, stability investigations have been performed on standard inclination of slopes suggested in the design criteria for both dry and rainfall cases by ground condition in this research. Despite that standard inclination of slopes specified in the design criteria should be stable for both dry and rainfall cases, the results show that standard factor of safety has not been obtained in many cases; more than 50% of total cases for dry cases and more than 65% of total cases for rainfall case. Based on the results, this paper indicates the problems in the current design criteria and proposes the plans for establishment of countermeasure.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.497-500
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• 2008

In order to prevent deterioration of reinforced concrete structures exposed to marine environment, performance based durability design than the design by conventional deemed-to-satisfy rule should be concerned. For example, even though chloride threshold level, which is a major parameter for durability design, is defined as a 1.2 $kg/m^3$ in the Korean concrete specification, it shows that the chloride threshold level leads to over design in its real application so that realistic value should be determined for the performance design. In this paper, not only the probabilistic properties of chloride threshold level obtained from published data are taken into account, but also the experimental results of the probabilistic properties using surface chloride content, diffusion coefficient, cover depth are considered in the assessment utilizing the concept of performance based durability design. In computation, the Monte Carlo Simulation (MCS) is used to perform an assessment due to chloride attack for a target submerged tunnel box. This study found that the specification on current chloride threshold level should be modified for more rational and accurate assessment and design.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.29-31
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• 2010

This study investigated the typical standards of B kind of standard specification related to home and abroad forms design and compared them, and the results can be summarized as follows. In case of domestic standards, regulations on most forms design was described relatively in detail. and in case of CTEA among them, it included detailed contents of load conditions, lifting and subsidence. In case of abroad standards, the design regulations are only simply mentioned, not in detail, in ACI, CEB-FIP and BS, and JCI and JASS were similar to domestic KCI and KASS regulations. As to structural calculation in forms design regulations, most of domestic regulations included detailed matters on structural calculation, among them, CTEA shows the most detailed matters on it. On the other hand, it could be known that in case of abroad standards, most standards do not include matters on structural calculation except ACI, JCI and JASS.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.281-286
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• 2001

최근, 경제적 이점과 전단강도의 증가효과로 인하여, 파형 Plate의 사용이 증가하여 있다. 일반 Plate에 대해서는 현재 거의 모든 시방서에 설계기준이 제시되어 있으나, 파형 Plate의 전단강도에 대한 규정은 제시되지 않은 실정이다. 따라서 설계자가 파형 Plate의 여러 기하 조건에 따른 전단강도의 관계를 알아보았으며, 수치해석에는 8절점 박판 쉘요소를 사용했다. 수치해석을 통하여 파형 Plate에 있어서 파형의 크기, 곡률, 파형 Plate의 두께에 따라 전단강도를 결정할 수 있는 식을 제안하였으며, 제안식은 파형 Plate가 일반 Plate에 비해 상당히 큰 전단강도를 갖는다는 것을 보여준다.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.2
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• pp.59-66
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• 2022

The purpose of this study was to suggest the landscaping repair work classification, the standard for securing the independence of and establishing the scope of landscaping repair works. Standard construction specifications currently specify the landscaping repair work classification around the planting construction, while standard work estimate does not include the field of landscaping. The landscaping construction specifications and the standard work estimate in the construction industry should be, however, applied, so it is difficult to specifically understand what is the landscaping repair work classification in the cultural heritage industry. From 1961 to 1980, not only the tree planting but also a variety of landscaping facilities had been specified as the landscaping repair works, and it was found that all of these work classifications are established as the landscaping repair work classifications in the construction industry. A total of 20 work classifications were verified by comprehensively arranging those specified in notices of tender for working drawing services for cultural heritages during three years, from 2018 to 2020, except for those for the maintenance and Dancheong of architectures, plant protection and conservation. All 20 work classifications corresponded to the landscaping work classifications in the construction industry. On the basis of the landscaping work classifications in the construction industry, this study divided the landscaping repair work classifications into site-building and shaping, planting work, facility construction, paving work, ecological landscape architectural construction and vegetation maintenance, by considering the specialty of cultural heritage space.