• 한국지진공학회논문집
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• 제25권1호
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• pp.21-32
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• 2021

Concrete masonry prisms are strengthened with steel fiber-reinforced mortar (SFRM) overlay and tested for compressive and diagonal tension strength. Masonry prisms are produced in poor condition considering standard workmanship for masonry buildings in Korea. Amorphous steel fibers are adopted for SFRM, and appropriate mixing ratios of SFRM are derived considering constructability and strength. Masonry prisms are strengthened with different fiber volume ratios, while numerous strengthened faces and additional reinforcing meshes are produced for compression and diagonal tension tests. Compression and diagonal tension strength are increased by up to 122% and 856%, respectively, and the enhancement effect for diagonal tension strength was superior compared to compression strength. Finally, the test results and strength prediction equations based on existing literature and regression analysis are compared.

• Earthquakes and Structures
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• 제25권3호
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• pp.209-221
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• 2023

The Mw=7.7 (Pazarcık-Kahramanmaraş) and Mw=7.6 (Elbistan-Kahramanmaraş) earthquakes that occurred in Türkiye on 06.02.2023 with 9 hours' intervals, caused great losses of life and property as the biggest catastrophe in the instrumental period. The earthquakes affecting an area of 14% of the country were enormous and caused a great deal of loss of life and damage. Numerous buildings have collapsed or damaged at different levels, both in the city centers and in rural areas. Within the scope of this study, masonry structure damage built from different types of materials in the earthquake region was taken into consideration. In this study, the damage and causes of such masonry structures that do not generally receive engineering services were examined and explained in detail. Insufficient interlocking between wall-wall and wall-roof, inadequate masonry, lack of horizontal and vertical bond beams, usage of low-strength materials, poor workmanship, and heavy earthen roof are commonly caused to structural damages. Separation at the corner point and out-of-plane mechanism in structural walls, and heavy earthen roof damages are common types of damage in masonry structures.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.629-635
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• 2011

Retentions are generally considered to be intended to act as a powerful tool to incentivize contractors/subcontractors to remedy defective work in cases of non-performance. This study attempts to establish the extent to which retentions can be used for this purpose by investigating case law connected with insurance and defective work. One of the significant questions is whether retentions are sufficient to deal with construction defects or value of retentions in the rectification of defects is illusory. The cost to repair a defect may vary depending on a number of components including type, cause, magnitude and the construction stage at which the defect occurs. It is expected that a review of existing cases on defective workmanship will provide an insight on the issues and whether retentions are effective in their intended function. In order to establish their functionality, the study described in this paper investigated 6 construction insurance cases to identify the critical issues and the causes of dispute. It was found that the nature and the cause of defects were different in each case. It was also established that certain defect types not covered by insurance may be covered by retentions - potentially one of the key uses of a retention strategy. It is expected that the findings will assist in forming a view on the quantum of money that may be required paving the way for a first time understanding on a rational basis for setting up retention regime.

• 한국의상디자인학회지
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• 제11권2호
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• pp.99-115
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• 2009

Recently, the development of design of cultural goods is focusing on excessively workmanship-oriented craft items. However, an advanced strategy that is practical and develops market-oriented goods in the world needs to be suggested from now on and the selection of goods item aimed to world market is very urgent. Therefore, the purpose of this study was to design practical and worldwide market-oriented shoes with Korean traditional image as a cultural goods. As software tools, 2D Adobe Illustrator Adobe Photoshop and 3D MAX 8.0 Photoshop CS were used to design the shoes. From 8 types of pattern design to which Koran traditional pattern was applied and 7 types of shoe design to which Korean traditional shoes were applied, 60 types of planar shoes design coating developed pattern designs were made. Furthermore, 3D design of cultural goods of shoe made possible to observe it three-dimensionally and accurately from the top, the front and the side respectively. Finally, 43 types of cultural goods of shoe to which Korean traditional shoes were applied were designed successfully according to traditional patterns and colors. The systematic database was established based on the developed pattern design of the shoes and might make the best use of the development of related design of cultural goods. Although there were partly some limitations in the aspects of design and material development of Korean traditional shoes, this study would help the economics of shoe industry in Korea producing high value-added products.

• 복식
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• 제30권
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• pp.295-306
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• 1996

A large quantity of exhumed clothing found for recent 20 years has becom-e the material for making a concrete clarification of the structure of clothing in the Chosun dynasty. Exhumed clothing means the clothing found in the coffin when the grave of the ancestor buried several hundred several hundred years ago is removed to another pla-ce and it is almost comprised of ordinary clothes of the grave-owner not mourning clothes as well as clothing and ornaments in the period between the 15th cen-tury and th 19th century. This research is intended to inquire into the kind of chimas in the 16th century before the Imjin Japancese Invasion of Korea during 1592-1598. The after effect of the Imjin Japanese In-vasion was generally reflected in clothing them and the structure of clothing in the Chosun dynasty began to overshadew its di-chotomy with the Imjin Japanese I vasion of Korea as the point. Accordingly this research is concerned with the study of the chima system of the early Chosun dynasty which shows that there is a common point of the identical form though clothing was exhumed in different graves. Therefore it was possible to grasp women's clothing that was fashionable at that time The object for research is the women in the upper class of the 16th century whose representative characteristics are depicted as follows: 1. Women in the upper class wore the splendid clothing similar to the ordinary clothing of court ladies. 2. The division of ordinary chima and ceremonial chima appeared in the concrete. 3. Ceremonial chima had its extra width and length and exhibited its exaggerated silhouette. in particular it had a various forms of over-pleats made at its center front which play a role in supplementing discomfort in walking. This associate bustle and crinolin styles through which the modern design of clothing can be glimpsed. 4. The opposite phenomenon was shown that has been perceived up to now such as folding at the right plain seam the treatment of the edge-and the like. 5. The elaboration of manual needlework shows the culmination of women's workmanship.

• 한국항공우주학회지
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• 제30권8호
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• pp.94-102
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• 2002

위성은 일단 한번 발사하고 나면 운용궤도상에서 수리 및 회수가 거의 불가능하기 때문에 위성에 들어가는 모든 개발 부품들은 완벽한 설계, 충분한 해석, 고 작업도의 제작, 그리고 다양한 시험을 수반하여 충분한 검증을 받게 된다. 그럼에도 불구하고 실패가 일어날 수 있으며, 이러한 실패에 대비하기 위해 여분의 부품을 탑재하여 일부 부품의 실패에도 불구하고 정상적인 작동을 할 수 있도록 설계한다. 본 논문에서는 현재 전자통신연구원에서 개발중인 통신방송위성의 중계기에 대한 신뢰도 분석과 함께 어떠한 방법을 이용하여 여분의 부품을 구성하는 것이 신뢰도 측면에서 최적화되는 설계인지 분석하였다. 이를 위하여 여러 가지 여분의 부품을 구성하는 방법 및 각각의 경우에 대한 결과를 비교하였다.

• Computers and Concrete
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• 제12권2호
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• pp.131-149
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• 2013

Various types of reinforcement splicing methods have been developed and implemented in reinforced concrete construction projects for achieving the continuity of reinforcements. Due to the complicated reinforcement arrangements and the difficulties in securing bar spacing, the traditional lap splicing method, which has been widely used in reinforced concrete constructions, often shows low constructability and difficulties in quality control. Also, lap spliced regions are likely to be over-reinforced, which may not be desirable in seismic design. On the other hand, mechanical splicing methods can offer simple and clear arrangements of reinforcement. In order to utilize the couplers for the ribbed-deformed bars, however, additional screw processing at the ends of reinforcing bars is typically required, which often lead to performance degradations of reinforced concrete members due to the lack of workmanship in screw processing or in adjusting the length of reinforcing bars. On the contrary, the use of screw-ribbed reinforcements can easily solve these issues on the mechanical splicing methods, because it does not require the screw process on the bar. In this study, the mechanical coupler suitable for the screw-ribbed reinforcements has been developed, in which any gap between the reinforcements and sleeve device can be removed by grouting high-flow inorganic mortar. This study presents the uniaxial tension tests on the screw-ribbed reinforcement with the mechanical sleeve devices and the cyclic loading tests on RC columns with the developed coupler. The test results show that the mechanical sleeve connection developed in this study has an excellent splicing performance, and that it is applicable to reinforced concrete columns with a proper confinement by hoop reinforcement.

• Steel and Composite Structures
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• 제23권3호
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• pp.273-283
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• 2017

In this paper, it is aimed to present a detail investigation related to structural behavior of laterally unrestrained steel cantilever roof of tribune with slender cross section. The structure is located in Tutak town in $A{\breve{g}}r{{\i}}$ and collapsed on October 25, 2015 at eastern part of Turkey is considered as a case study. This mild sloped roof structure was built from a variable I beam, and supported on steel columns of 5.5 m height covering totally $240m^2$ closed area in plan. The roof of tribune collapsed completely without any indication during first snowfall after construction at midnight a winter day, fortunately before the opening hours. The meteorological records and observations of local persons are combined together to estimate the intensity of snow load in the region and it is compared with the code specified values. Also, the wide/thickness and height/thickness ratios for flange and web are evaluated according to the design codes. Three dimensional finite element model of the existing steel tribune roof is generated considering project drawings and site investigations using commercially available software ANSYS. The displacements, principal stresses and strains along to the cantilever length and column height are given as contour diagrams and graph format. In addition to site investigation, the numerical and analytical works conducted in this study indicate that the unequivocal reasons of the collapse are overloading action of snow load intensity, some mistakes made in the design of steel cantilever beams, insufficient strength and rigidity of the main structural elements, and construction workmanship errors.

• 대한토목학회논문집
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• 제13권5호
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• pp.123-134
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• 1993

본 연구는 퍼지?이론을 도로포장(道路鋪裝)의 공용성(共用性) 평가에 응용하기 위하여 수행되었다. 포장의 견실도(堅實度)와 포장에 가해지는 외력 및 포장의 현재상태에 근거하여 포장을 평가하는 모델을 개발하였다. 퍼지 종합평가를 위하여 설정된 거리등급지수(Gd)의 값이 가장 적절히 균형을 이루도록 5등급의 등급퍼지?과 3등급의 경중(輕重)퍼지?을 설정하였다. 또한 평가기준과 그에 상응하는 퍼지등급척도를 제시하였으며 설정된 평가기준에 준하여 공용성을 평가하는 컴퓨터 프로그램을 개발하였다. 이 프로그램은 각 항목에 대한 Input 값을 질의 문답식으로 화면을 통하여 문의하고 자판을 통하여 사용자가 넣어 주어 수행되도록 작성되었다. 본 연구에서 제시된 퍼지이론에 근거한 포장공용성(鋪裝共用性) 추정기법을 실제 data를 이용하여 수행하여 본 결과 일정도로의 미래 기능수행가능성 추정과, 시범구간의 Gd 값과의 비교 수치를 사용한다면 그 실용가능성이 높음을 알 수 있었다.

• Steel and Composite Structures
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• 제21권3호
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• pp.589-604
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• 2016

Kenya has recently experienced worrying collapse of buildings during construction largely attributable to the poor quality of in-situ concrete and poor workmanship. The situation in the country is further compounded by rapid deterioration of infrastructure, hence necessitating the development of alternative structural systems such as concrete filled unplasticized poly vinyl chloride (UPVC) tubes as columns. The work herein adds on to the very limited and scanty work on use of UPVC tubes in construction. This study presents the findings of experimental and analytical work which investigated the structural response of composite concrete filled UPVC tubes under compressive load regime. UPVC pipes are cheaper than steel tubes and can be used as formwork during construction and thereafter as an integral part of column. Key variables in this study included the strength of infill concrete, the length to diameter ratio (L/D) of the plastic tube, as well as the diameter to thickness ratio (D/2t) of the plastic tube. Plastic tubes having varying diameters and heights were used to confine concrete of different strengths. Results obtained in the study clearly demonstrate the effectiveness of UPVC tubes as a confining medium for infill concrete, attributable to enhanced composite interaction between the UPVC tube and infill concrete medium. It was determined that compressive strength of the composite column specimens increased with increased concrete strength while the same decreased with increased column height, albeit by a small margin since all the columns considered were short columns. Most importantly, the experimental confined concrete strength increased significantly when compared to unconfined concrete strength; the strength increased between 1.18 to 3.65 times the unconfined strength. It was noted that lower strength infill concrete had the highest confined strength possibly due to enhanced composite interaction with the confining UPVC tube. The study further proposes an analytical model for the determination of confined strength of concrete.