Dilation behavior of normal strength concrete confined by FRP wire jackets

Nguyen, Hoan D.,Choi, Eunsoo,Park, Kyoungsoo Elsevier 2018 Construction & building materials Vol.190 No.-

<P><B>Abstract</B></P> <P>The introduction of confining pressure is an effective method to improve both ductility and strength of concrete. To confine concrete, recently, fiber reinforced polymer (FRP) wire has been employed because of several advantages, such as corrosion resistance, cost-effectiveness, and the ability to control the tightness of jackets during the installation process. In addition to experimental researches, confinement models need to be studied; in which, a factor affects directly to the accuracy of the models is dilation. This study aimed to investigate dilation behaviors and the effects of FRP wire jackets confinement on concrete. For this purpose, the uniaxial compression tests were conducted on twelve specimens by changing the number of FRP wire layers and the compressive strength of concrete. Experimental results illustrated that the FRP wire jackets provided higher confinement effects on concrete than FRP sheets. The dilation developed through three stages of compressive behaviors of confined concrete, i.e., the elastic, hardening, and damaged stages. Moreover, the test results indicated that the effects of the stiffness ratio for FRP wire jackets were different from these for FRP sheets. Additionally, to estimate the lateral-axial strain relation of concrete confined by FRP wire jackets, a dilation model was developed on the basis of a secant dilation ratio, which is the percentage of the lateral strain to axial strain. The experimental results and the model estimation demonstrated in a good agreement.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The dilation ratio of concrete confined by FRP wire jackets is investigated. </LI> <LI> The FRP wire confinement is more effective than the FRP sheet confinement. </LI> <LI> The stiffness ratio of the FRP jackets affects behaviors of confined concrete. </LI> <LI> The proposed dilation model describes three stages of dilation behavior. </LI> <LI> The proposed model well captures behaviors of concrete confined by FRP wire jackets. </LI> </UL> </P>

A Study on Safety of Environmental Cleaners` Noctilucent Jackets

( Boo Ja Shim ) 한국패션비즈니스학회 2006 패션 비즈니스 Vol.10 No.3

This research chose 135 environmental cleaners in Busan Metropolitan City as subjects. First, the reality of wearing their safety jackets was investigated. Next, visual evaluation of the reflexive function of the current safety jackets was made. Then, based on the above results and the subsequent improvement proposal, the final product, the research costume, was made. 1. Based on the investigation of the wearing reality of safety jackets and the visual evaluation results of the reflexive function, an improvement proposal was made. As cleaners are usually seen sidewise on the roads and lateral luminosity is rather low, this aspect was compensated on the part of a jacket. Also, the reflexive belt used the diagram of △ to improve visual effects. 2. As the lower body held the accident frequency of 45.0%, the sides of pants had the reflexive belt to increase visibility. 3. In consideration of the mutual effects between the background cloth and general reflexive width, the same width (5cm) of the reflexive belt as that of Type A was adopted.

구명조끼 착용 제도화에 관한 국민의식 연구 : 연안해역 활동을 중심으로

하신영,김보영,국승기 한국해양경찰학회 2021 한국해양경찰학회보 Vol.11 No.1

본 연구에서는 구명조끼 착용 제도화에 관한 국민의식을 연구하기 위한 이론연구 를 바탕으로 대국민 설문조사를 실시하였다. 본 설문조사는 유관기관, 관련 학회, 관 련 단체, 일반 국민을 대상으로 885부의 응답 건수를 받았으며, 변수는 연안해역의 이용실태, 관련 제도에 대한 이해도, 구명조끼 필요성에 대한 인식, 구명조끼 착용 법제화에 대한 의견 총 4가지로 구성되어있다. 응답자 중 과반수 이상이 사고가 나지 않을 것이라고 믿어 구명조끼를 착용하지 않은 상태로 바닷가를 이용하고 있었으며, 관련 제도에 대한 이해도가 높을수록 구명 조끼 착용 법제화에 대한 동의정도도 높게 나타났다. 응답자들은 구명조끼가 안전을 위해 필요하다고 인지하고 있었으며, 구명조끼 착용이 필요한 장소는 방파제(테트라 포드 포함), 활동은 수영과 낚시 시 구명조끼 착용이 제도화 되어야 한다고 응답했다. 연안사고 발생원인은 부주의에 의한 사고가 가장 많은 것으로 보아 사고의 경각 심을 일깨워줄 수단이 필요하며, 현재 낚시배·레저보트 승선자가 구명조끼를 의무적 으로 착용해야 하는 것처럼 향후 방파제에서의 낚시, 해수욕장에서의 수영 등 단계 적으로 구명조끼 착용 의무화 범위를 늘려가는 방안을 수립할 필요가 있다. In this study, a public survey was conducted based on a theoretical study to study public awareness about the legislation of wearing life jackets. This survey obtained 885 responses from related organizations, academic societies, organizations, and from the general public. The variables consist of four categories: the actual condition of coastal use, the degree of understanding of related systems, the perception of the need for a life jacket, and the opinion on the legalization of the life jacket. More than half of the respondents were using the beach without wearing life Jackets, believing that there would be no accidents, and higher the understanding of the related system, the higher the agreement on legislation to wear life jacket. Respondents were aware that life jackets were necessary for safety, and in their opinion, places it was mostly needed was breakwater (including Tetrapod), and said that wearing life jacket should be legislated for swimming and fishing. The cause of the highest nimber of coastal accidents was carelessness, so it is necessary to have a mean to alert people about accidents, and just as fishing boats and leisure boats are required to wear life Jacket, it is necessary to establish a plan to gradually increase the scope of wearing life Jacket in activities such as fishing and swimming in the future.

New technique for strengthening reinforced concrete beams with composite bonding steel plates

Su-hang Yang,Shuang-Yin Cao,Rui-nan Gu 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.3

Composite bonding steel plate (CBSP) is a newly developed type of structure strengthened technique applicable to the existing RC beam. This composite structure is applicable to strengthening the existing beam bearing high load. The strengthened beam consists of two layers of epoxy bonding prestressed steel plates and the RC beam sandwiched in between. The bonding enclosed and prestressed U-shaped steel jackets are applied at the beam sides. This technique is adopted in case of structures with high longitudinal reinforcing bar ratio and impracticable unloading. The prestress can be generated on the strengthening steel plates and jackets by using the CBSP technique before loading. The test results of full-scale CBSP strengthened beams show that the strength and stiffness are enhanced without reduction of their ductility. It is demonstrated that the strain hysteresis effect can be effectively overcome after prestressing on the steel plates by using such technique. The applied plates and jackets can jointly behave together with the existing beam under the action of epoxy bonding and the mechanical anchorage of the steel jackets. The simplified formulas are proposed to calculate the prestress and the ultimate capacities of strengthened beams. The accuracy of formulas was verified with the experimental results.

Damage detection of reinforced concrete columns retrofitted with FRP jackets by using PZT sensors

Tzoura, Efi A.,Triantafillou, Thanasis C.,Providakis, Costas,Tsantilis, Aristomenis,Papanicolaou, Corina G.,Karabalis, Dimitris L. Techno-Press 2015 Structural monitoring and maintenance Vol.2 No.2

In this paper lead zirconate titanate transducers (PZT) are employed for damage detection of four reinforced concrete (RC) column specimens retrofitted with carbon fiber reinforced polymer (CFRP) jackets. A major disadvantage of FRP jacketing in RC members is the inability to inspect visually if the concrete substrate is damaged and in such case to estimate the extent of damage. The parameter measured during uniaxial compression tests at random times for known strain values is the real part of the complex number of the Electromechanical Admittance (Conductance) of the sensors, obtained by a PXI platform. The transducers are placed in specific positions along the height of the columns for detecting the damage in different positions and carrying out conclusions for the variation of the Conductance in relation to the position the failure occurred. The quantification of the damage at the concrete substrate is achieved with the use of the root-mean-square-deviation (RMSD) index, which is evaluated for the corresponding strain values. The experimental results provide evidence that PZT transducers are sensitive to damage detection from an early stage of the experiment and that the use of PZT sensors for monitoring and detecting the damage of FRP-retrofitted reinforced concrete members, by using the Electromechanical Admittance (EMA) approach, can be a highly promising method.

Comparisons: women’s garments manufacturing cost survey between Korea and China

김명옥,이연희,Lilian Parreiras Martins,Yingyu Wen 한국의류학회 2016 Fashion and Textiles Vol.3 No.1

This study aims to survey general information from garment factories in South Korea and China, representing, respectively, a developed country and a developing country. Additionally, within the same two countries, the study surveys garment manufacturing costs, from low to high, for a both a “basic” as well as for a “detailed” blouse, pants, and jacket (total of six items), with a goal of determining of an estimation of manufacturing cost in 2018. The results showed that there were meaningful differences between South Korea and China, as expected. Significant differences were shown in the number of employees, monthly wages, effecting factors on the lowest cost price period for a year; garment manufacturing time, and manufacturing costs of basic designs and detailed designs of blouse, pants, and jacket. The results of garments cost were significantly different consistent with the quality, from low cost to high cost, and quantities, from 500 pieces or less to above 10,000 pieces. The overall cost difference between two counties was about 2.6–3.5 times greater (Korea to China). Examining the same item, the difference was larger in low quality and small or large quantity rather than high quality and medium quantity. Interestingly, pants and jackets showed the largest cost difference at quantities above 10,000 pieces. Also, for 2018 there were differences in the estimated costs between both countries. The estimated cost differences were increasing from 2013 giving the implication that future manufacturing cost could increase between Korea and China.

현대 아웃도어웨어 디자인 개발에 관한 연구 -방한재킷을 중심으로-

한상경 ( Sanggyung Han ),김영선 ( Yonson Kim ) 복식문화학회 2016 服飾文化硏究 Vol.24 No.1

Despite both domestic and overseas markets are depressed due to the global financial crisis - the apparel industry is no exception, the market for the outdoor wears including the hiking ones has been recording a high growth rate, making the outdoor wear a high growth industry. The purpose of this study was to provide some basic data useful to our outdoor businesses to help them respond to consumers` needs in the rapidly growing outdoor markets. For silhouettes, the point was given primarily to the oblique cutting to have it follow the human body curves and thereby, look natural and slim. Another point was given to the color schemes along the cutting lines, so that an effect of optical illusion could be created to make the wears look slim making use of lines and colors. On the other hand, in consideration of the rapidly changing weather conditions during hiking, the details were designed practically by setting appropriate hip lengths, using attachable/detachable hoods as well as applying the Velcro & rubber band-type set-in sleeves for the tail edges. As discussed above, the researcher analyzed the design elements for the outdoor wears and developed some sensuous designs meeting consumers` needs to help our outdoor wear businesses to expand their target base, while awakening them of the importance of the outdoor fashion.

An innovative solution for strengthening of old R/C structures and for improving the FRP strengthening method

Tsonos, Alexander G. Techno-Press 2014 Structural monitoring and maintenance Vol.1 No.3

In this study a new innovative method of earthquake-resistant strengthening of reinforced concrete structures is presented for the first time. Strengthening according to this new method consists of the construction of steel fiber ultra-high-strength concrete jackets without conventional reinforcement which is usually applied in the construction of conventional reinforced concrete jackets. An innovative solution is proposed also for the first time that ensures a satisfactory seismic performance of existing reinforced concrete structures, strengthened by using composite materials. The weak point of the use of such materials in repairing and strengthening of old R/C structures is the area of beam-column joints. According to the proposed solution, the joints can be strengthened with a steel fiber ultra-high-strength concrete jacket, while strengthening of columns can be achieved by using CFRPs. The experimental results showed that the performance of the subassemblage strengthened with the proposed mixed solution was much better than that of the subassemblage retrofitted completely with CFRPs.

한국 역대 대통령의 시대별 재킷 스타일 연구

서한상,오순 한국디자인트렌드학회 2018 한국디자인포럼 Vol.23 No.3

Background The purpose of this study is to analyze the changes of men 's jacket design, trend of epidemic trend analysis and elements of design by analyzing and comparing with modern styles based on the jackets of the former presidents. Methods As a theoretical review of the literature data, the analysis of the jacket style of the past is reviewed based on the concept of suits, components of jacket design, changes in men's jackets based on the trend analysis and comparisons of various periods, and the significance of composition. Results The Korean jackets maintain their own detail and silhouette at least for 5 years and 20 years at the most. However, unlike women's doubles, there is a gradual change in the form of silhouette and detail. Conclusion Historical studies of the style of jackets from former Korean presidents have led to predictions of changes in men's jacket styles and hopefully this study will lead to the development of creative designs in the men's fashion industry. 연구배경 본 연구의 목적은 시대별 유행 분석의 흐름과 디자인의 구성요소를 파악하고 역대 대통령들의 재킷을 분석하여 시대별 남성 재킷 스타일과 현대 스타일과의 비교를 통해 현대 남성 재킷 스타일의 변화 양상을 제시하는 데 그 목적이 있다. 연구방법 문헌자료를 통한 이론적 고찰로써 정장의 개념, 재킷 디자인의 구성요소, 시대별 재킷 유행 분석에 따른 남성복의 변화와 복식사적 의의를 바탕으로 연구하여 시대별 재킷 유행 분석을 고찰하고 역대 대통령들의 재킷 스타일을 비교, 분석한다. 연구결과 한국 재킷 스타일의 시대별 변화 양상은 짧게는 5년, 길게는 20년까지 디테일과 실루엣을 유지하고 있다. 여성 복식과 달리 점진적으로 실루엣과 디테일의 형태가 변화되는 양상이 나타났다. 결론 한국 역대 대통령의 재킷의 스타일을 시대별로 연구한 결과 현대 남성 재킷 스타일의 변화 양상을 예측할 수 있으며, 본 연구가 남성복 패션업계에 창의적인 디자인 개발에 선행 연구 자료로서 도움이 되길 기대한다.

제품의 신장특성을 고려한 네오프렌 소재의 3D 라이프자켓 설계

이희란,김소영,홍경희,Lee, Heeran,Kim, Soyoung,Hong, Kyounghi 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.3

As people spend more time on water leisure activities, the importance of safe and comfortable life jackets that fit the wearer is being emphasized. If a life jacket is designed using neoprene, which lacks elasticity, the coverage ratio may be low considering consumer size; therefore, various sizes of life jackets should be produced to fit the human body to maintain comfort and function. In this research, the method of designing a comfortable life jacket with an extended extension ratio and optimal grading rule was investigated to minimize the size category. In addition, Ziegert and Keil's method was modified and applied to investigate the stretch characteristics of thick neoprene and double jersey materials and those of the end product. According to the observed extension value of neoprene and double jersey, they were allocated the patterns of a life jacket to cover wider ranges of human body sizes. The results showed that extension properties of materials and products measured using Ziegert and Keil's experimental condition matched satisfactorily to the actual wear condition of the product made of stretch fabric. Grading rules were suggested according to the extension properties of the life jacket and clothing pressure as well as the Size Korea database.