• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.238-239
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• 2017

Waterproofing is a very important process in terms of durability of buildings. The materials used for waterproofing work to protect the concrete structure from external deterioration factors. In particular, the waterproofing materials applied to the exterior of the concrete structure have various problems due to changes in the external environment and variables in the construction process. The waterproof layer is repeatedly dried and shrunk according to changes in the external moisture environment, and the surface may be deteriorated due to exposure to long-term sunlight. In the case of the roof waterproofing in the structure, the waterproof layer which does not have a sufficient curing period shows much swelling and floating phenomenon. These defects, such as swelling and lifting, account for most of the defects that occur in the waterproof layer of the concrete slabs. Generally, it is difficult to expect the same level of performance as the initial state even if the waterproofing work is repaired when a defect occurs. Therefore, it is possible to reduce the defects of the waterproof layer such as swelling and lifting by forming a waterproof layer which can be integrated with the concrete surface by using a polyurethane type waterproofing material having a relatively low defective ratio compared to other waterproofing materials. So in this study, the basic properties of polyurethane waterproof sheet reinforced with non-woven fabric are investigated in order to understand field applicability.

• Structural Engineering and Mechanics
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• v.65 no.5
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• pp.601-609
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• 2018

Steel bolts are used in the construction industry for a large variety of applications that range from fixing permanent installations to temporary fixtures. In the past much research has been focused on developing destructive testing techniques to estimate their pull-out load carrying capacity with very little attention to develop non-destructive techniques. In this regards the presented research work details the combined use of ultrasonic pulse velocity and Schmidt hammer tests to identify anchor bolts with faculty installation and to estimate their pull-out strength by relating it to the Schmidt hammer rebound value. From experimentation, it was observed that the load capacity of bolt depends on its embedment length, diameter, bond quality/concrete strength and alignment. Ultrasonic pulse velocity test is used to judge the quality of bond of embedded anchor bolt by relating the increase in ultrasonic pulse transit time to the presence of internal pours and cracks in the vicinity of steel bolt and the surrounding concrete. This information combined with the Schmidt hammer rebound number, R, can be used to accurately identify defective bolts which resulted in lower pull-out strength. 12 mm diameter bolts with embedment length of 70 mm and 50 mm were investigated using constant strength concrete. Pull-out load capacity versus the Schmidt hammer rebound number for each embedment length is presented.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.94-103
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• 2018

As of July 1, 2017, the method of quality management of construction equipment had been changed completely. In case of manufacturing and distributing pipe supports, the support length according to the safety certification standard shall be not more than 6 m and the compressive strength shall be not less than 40,000 N at the maximum height. However, the field tests for the quality control standard were usually performed at 3.5 m when the length of the pipe supports is 3.5 m to 4.0 m, and the compression strength was specified to be more than 35,300 N. This difference in the two standards can cause confusion in practice. In this study, the compression load of the pipe supports was tested and found to be more than 30% defective. Therefore, it is necessary to review the modification of the safety certification and quality standards to improve the standard requirements.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.50
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• pp.27-59
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• 2011

This article attempts to describe and analyze the rules on the service provider's duty to provide his service in conformity with the contract under the Draft Common Frame of Reference (here-in-after DCFR), which are applied to construction, storage, design and factual information contracts. It categorizes such rules in accordance with the requirements of conformity with the contract, the time when the service provided must be in conformity with the contract, and the exemptions of the service provider's duty. On the basis of such categorization, it examines the rules on the service provider's duty in each type of service contract under the DCFR. By doing so, it seeks to figure out how the members of EU compromised on the various issues of the service provider's duty under the DCFR which is regarded as the first uniformed legislation in the area of the service contract. This may provide some guidance to the legislators of domestic law for their amendment or interpretation of their laws. In addition to them, this article also seeks to point out problems in terms of their interpretations and gaps in their rules to cover various aspects of non-conformity and put forward some solutions for such problems and gaps.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.153-155
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• 2006

We constructed the null mutants of fission yeast Schizosaccharomyces pombe spSac3 gene that is homologous to budding yeast Saccharomyces cerevisiae SAC3 involved in mRNA export out of nucleus. Tetrad analysis showed that the spSac3 is essential for vegetative growth. The spSac3 mutants harboring pREP81X-spSac3 plasmid showed poly(A)+ RNA export defect in the presence of thiamine. These results suggest that spSac3 is also involved in mRNA export from the nucleus.

• Journal of the Korea Safety Management & Science
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• v.24 no.1
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• pp.11-19
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• 2022

In order to find out the management and sanitation status of protective gear provided at the construction site, a case study and survey were conducted by visiting the site. As a result of the case study, inspection and management, disinfection, and storage of protective equipment were insufficient in both workplaces with less than 50 employees and workplaces with more than 100 employees. As a result of the survey, workers(66.2%), said they did not know how to identify hard hats(67.6.%), how to identify bad hard hats(60.8%), and how to identify bad safety belts (73.0%), even though workers(66.2%) were educated on protective gear, and those in charge of protective gear Non-specified(56.8%), regular inspection of the provided protective equipment was not performed(82.4%), and disinfection was not performed(90.5%). Therefore, as a management plan to maintain the performance of personal protective equipment, educational aspects, regular training on protective equipment, training on how to identify defective protective equipment, management of recording papers, technical aspects, strengthening of standards for placement of dedicated safety managers in small workplaces, participation of workers' representatives when selecting protective equipment, and selection of protective equipment for workers Providing opportunities, administrative aspects of protective equipment regulation and management, introduction of sanitary and cleanliness system, and selection of personnel in charge of protective equipment management were suggested.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.2
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• pp.31-40
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• 2020

As private sewage treatment facilities in Korea are constantly concerned about the distribution and poor construction of defective products, minimum standards for each unit process applicable to the planning and design of sewage treatment facilities are deemed necessary. The problems and requirements of the analysis results of the operation status discussed in this study are as follows. 1) Strengthening education of supervisor of private sewage treatment facility. 2) Poor operation and management of Sewage treatment facilities. 3) A mandatory review of sewage treatment facilities for less than 2 ㎥/day of facilities other than sewage treatment zones. 4) Necessity of management of sewage treatment facility in feedstocks. 5) As a result of the technical review, Improvement plans for Ineligible facility are needed. It is also necessary to prepare a guidebook for design construction and maintenance by investigating and analyzing guidelines and data related to domestic and foreign private sewage treatment facilities.

• Journal of Korean Society of Steel Construction
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• v.16 no.4 s.71
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• pp.407-414
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• 2004

Bridges in common use are expected to have more varieties of load in their connected members and bolts than in construction. Faults in connection members or bolts occur so often according to the time flow. One of the purposes of this study is to find out the behavior and structural features of high-tension bolted joints with faults that are very difficult and cost much to find out through experimentation with finite element analysis. Another purpose of this study is to provide sufficient data, estimated experimental results, and the scheme of the test plate for an economical experimental study in the future. Surveys of bridges with a variety of faults and statistical classifications of their faults were performed, as was a finite element analysis of the internal stress and the sliding behavior of standard and defective bridge models. The finite element analysis of the internal stress was performed according to the interval of the bolt, the thickness of the plate, the distance of the edge, the diameter of the bolt, and the expansion of the construction. Furthermore, the analysis explained the sliding behavior of high-tension bolt joints and showed the geometric non-linear against the large deformation, and the boundary non-linear against the non-linear in the contact surface, including the material non-linear, to best explain the exceeding of the yield stress by sliding. A normally bolted high-tension bolt joint and deduction of bolt tension were also analyzed with the finite element analysis of bridge-sliding behavior.

• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.597-608
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• 2011

It has been often noted as a problem that as there are no objective and clear criteria for the repair cost estimate of persistent defects, when a claim arises in relation to an apartment construction, significantly different amounts of compensation may be given for similar defects based on the experience and tendencies of the construction experts asked to make a judgment. For this reason, this research aims to present defect managers with a more reasonable and objective estimation criteria and a system to determine the repair cost of defects based on an analysis of relevant factors. The research findings show that the historical cost system is applied first, and then a standard of estimation is used to estimate the cost for the items that are not included in the historical cost system. The criteria for the repair cost for each defect is as follows: the repair cost for defects arising from a regulation violation is determined by calculating the reconstruction cost of the parts in question after demolishing them; the repair cost for progressive defects is determined based on a contribution ratio proportional to the age of the building; the repair cost for repetitive defects is calculated by considering an alternative to maximize the intended function of the defective parts; and the repair cost for value depreciation defects is determined based on the ratio of the warranty period to the lapsed years. However, repair cost estimation for dual value depreciation defects should be studied in future research.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.80-84
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• 2008

We constructed the null mutants of fission yeast Schizosaccharomyces pombe spDbp5 gene that is homologous to DEAD-box RNA helicase DBP5 in budding yeast Saccharomyces cerevisiae, which plays important roles in mRNA export out of nucleus. A null mutant in an $h^+/h^+$ diploid strain was constructed by replacing the spDbp5-coding region with an $ura4^+$ gene using one-step gene disruption method. Tetrad analysis showed that the spDbp5 is essential for vegetative growth. The haploid spDbp5 null mutants harboring pREP81X-spDbp5 plasmid showed extensive $poly(A)^+$ RNA accumulation in the nucleus and decrease in the cytoplasm after repression of spDbp5 expression. These results suggest that spDbp5 is also involved in mRNA export from the nucleus.