• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.163-174
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• 2004

A number of experiments were performed to investigate the punching shear strength of flat plate-column connections. According to the experiments, the punching shear strength varies significantly with design parameters such as the column size of the connection, reinforcement ratio, and boundary condition. However, current design methods do not properly address the effects of such design parameters. In the present study, a theoratical approach using Rankine's failure cirterion was attempted to define the failure mechanism of the punching shear According to the study, the failure mechanism can be classified into the compression-controlled and the tension-controlled, depending on the amount of bottom re-bars placed at the connection, and the punching shear strength is also significantly affected by the flexural damage of slab. Based on the finding, a new strength model of punching shear was developed, and verified by the comparisons with existing experiments and nonlinear finite element analyses. The comparisons show that the proposed strength model addressing the effects of various design parameters can predict accurately the punching shear strength, compared to the existing strength models.

• Journal of the Korean Geotechnical Society
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• v.26 no.6
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• pp.39-44
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• 2010

In case of the design method, which is used in the inside and outside of the country, on corrugated multi plate structures, section modulus would be determined by assuming 2-dementioanl equivalent section of those structures. However, it is impossible to consider 3-dimentional effects when 2-dimentional design method is applied since structures are reinforced with a pattern of the 1200, 1600 mm reinforcements except the 800 mm reinforcement. Thus, in this study, technical specification standard is analyzed for the existing corrugated multi plate design methods, and section strengths, moments, and so on of equivalent and practical sections are compared and estimated using 3-dimentional FEM (finite element method) for semicircles and architectural features widely used. Based on the results of that analysis, analytical basis for 3-dimentional design of the CBS-RIB is suggested.

• Journal of Korean Society of Steel Construction
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• v.29 no.5
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• pp.341-352
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• 2017

Well designed group bolted connections can exhibit excellent ductile behavior through the bearing mechanism until the occurrence of shear rupture in the bolt or in the connecting plate. This excellent ductility can be utilized in favor of economical connection design. In this study, comprehensive tests on single-bolt bearing connections were conducted and analyzed considering bearing boundary conditions. The primary objective was to propose a generalized bearing strength and load-deformation relationship that can be used for designing group-bolted connections. To this end, new bearing strength formula, deformation limits as well as new load-deformation relationship were first proposed. Especially the proposed load-deformation relationship can reflect the stiffness, strength, and geometrical boundary conditions of the joint. The proposed formula and relationship are validated based on test results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1729-1733
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• 2007

In this paper, we have carried out some tests for analyzing the effects of optical fiber characteristics and piping structures in designing a Customer Cabling System with optical fibers. In this tests, the loss characteristics due to the number of curvatures and the radius of curvature with bending to establish an optical fiber have analyzed particularly. We can confirm that the test results satisfy the current technical regulations in both cases of the number of curvatures and the radius of curvatures. Also, in particular, since there is no loss in an optical cable under the current radius of curvature, that is 30mm, the radius criteria of curvature needs to be revised. These tests results will be so useful to revise and establish a customer cabling system for FTTH.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1164-1169
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• 2014

Overturning of concrete poles are occurred annually due to natural disaster such as a typhoon. The present code for the resisting moment and the safety on overturning of concrete poles in inclined ground is inadequate. In this study, the concept of the code for those in flat ground is applied to calculate the resisting moment in inclined ground using general analysis program L-Pile Plus13.8. According to the analytical results, the resisting moment in inclined ground is rapidly decrease as increasing the slope angle although the embedded depth are added by the additional embedded depth on the code. It is revealed that the capacity in inclined ground is equivalent to that in flat ground if additional embedded depth is increased from 1.5 to 3 times.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.55-66
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• 1991

Presented is a study on the realistic determination of design loads and design criteria for bridge structures. The current bridge design code does not consider realistically the uncertainties inherent in loads and resistances and thus the level of safety varies greatly among the bridge spans. The resonable bridge design loads and design criteria which exhibit uniform reliability among various bridge spans are therefore derived in the present paper. The proposed design loads are determined from the analysis of numerous data obtained from actual traffic survey and the design criteria are based on the advanced concept of load and resistance factor format. The live load factors take into account resonably the effects of traffic volume increase. The proposed design loads and design criteria show uniform safety level for various bridge spans and reasonably consider the effects of traffic volume increase. The present study provides useful and valuable data for new version of our bridge design code.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.823-823
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• 2012

최근 우리나라는 아열대성 기후로 변함에 따라 예측 불가능한 강우 형태가 자주 발생하고 있으며, 강우량의 경우 과거에는 발생하지 않았던 고강도의 강우가 빈번하게 발생하고 있는 실정이다. 그러나 기존 농경지 배수시설의 경우 고강도의 강우에 부족한 기준을 가지고 있어 침수에 불리한 구조를 가지고 있다. 또한, 국가경제발전과 국민 식생활 패턴 변화 등으로 논(수도작) 위주에서 원예 특용작물 등 밭작물 중심으로의 작부체계로 변화함에 따라 적정한 배수체계 개선방안이 요구된다. 따라서 현행 설계기준 강우보다 많은 강우가 단시간에 내리는 국지적 집중호우가 발생하여 배수시설물의 배제 능력 부족으로 인한 침수, 배수불량 등의 농경지 침수피해를 대비할 수 있는 배수설계기준이 필요한 상황으로, 기존 배수시설 설계기준에 대한 빈도별 계획강수량, 계획홍수량, 계획홍수위 등을 현재까지의 수문기상자료로 재검토하여 강우패턴변화를 고려한 적정 설계기준(안)을 평가하고 재해 대비 능력 부족한 농업기반시설(배수장, 배수문, 배수로 등)의 효율적인 관리 방안을 마련하겠다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.1 no.1
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• pp.21-32
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• 1981

Recent trends in design standards development in some European countries and U.S.A. have encouraged the use of probabilistic limit sate design concepts. Reliability based design criteria such as LSD, LRFD, PBLSD, adopted in those advanced countries have the potentials that they afford for symplifying the design process and placing it on a consistent reliability bases for various construction materials. A reliability based design criteria for RC flexural members are proposed in this study. Lind-Hasofer's invariant second-moment reliability theory is used in the derivation of an algorithmic reliability analysis method as well as an iterative determination of load and resistance factors. In addition, Cornell's Mean First-Order Second Moment Method is employed as a practical tool for the approximate reliability analysis and the derivation of design criteria. Uncertainty measures for flexural resistance and load effects are based on the Ellingwood's approach for the evaluation of uncertainties of loads and resistances. The implied relative safety levels of RC flexural members designed by the strength design provisions of the current standard code were evaluated using the second moment reliability analysis method proposed in this study. And then, resistance and load factors corresponding to the target reliability index(${\beta}=4$) which is considered to be appropriate level of reliability considering our practices are calculated by using the proposed methods. These reliability based factors were compared to those specified by our current ultimate strength design provisions. It was found that the reliability levels of flexural members designed by current code are not appropriate, and the code specified resistance and load factors were considerably different from the reliability based resistance and load factors proposed in this study.

• Proceedings of the Korean Society for Information Management Conference
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• 1997.08a
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• pp.199-202
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• 1997

본 연구는 국내에서 제작한 데이터베이스의 품질을 평가하고자 4개의 문헌 데이터베이스를 선정하여 각 데이터베이스를 정확성, 일관성, 완전성, 현행성 등 네가지 기준에 따라 분석하였다. 실험결과는 각 평가기준별로 정리되었으며 그에 대한 최우선 대책을 제안했다. 데이터베이스의 품질은 정보 검색과 서비스에서 매우 중요한 것이므로 시스템 설계자나 이용자 모두 데이터베이스의 품질에 대해 넓은 안목을 갖추고 체계적인 분석을 수행하여야 하며 이와 함께 제도적인 뒷받침도 이루어져야 할 것이다.

• Journal of Korean Society of Steel Construction
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• v.27 no.4
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• pp.399-410
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• 2015

Concrete filled steel tube(CFT) has outstanding deformation capacity and strength in comparison with reinforced concrete or steel tube. CFT drilled shaft, which is developed large shear force due to seismic load and soil liquefaction, is designed as large diameter. However, shear design equations of the current standards do not consider bond stress of CFT and it results in extremely conservative design. Currently, previous studies for improving shear equations scarcely exist and are impossible applied to large CFT drilled shafts since these studies focus on only small scale experimental research. In this study, eventually to propose improving shear equation of large diameter CFT, it is preliminary research to compare and investigate the previous studies and current standards.