Integral abutment bridges (IABs) have no joint across the length of bridge and are therefore also known as jointless bridges. IABs have many advantages, such as structural integrity, efficiency, and stability. More importantly, IABs have proven to be have both low maintenance and construction costs. However, due to the restraints at both ends of the girder due to the absence of a gap (joint), special design considerations are required. For example, while replacing the deck slabs to extend the service life of the IAB, the buckling strength of the steel girder without a deck slab could be much smaller than the case with deck slab in place. With no deck slab, the addition of thermal expansion in the steel girders generates passive earth pressure from the abutment and if the applied axial force is greater than the buckling strength of the steel girders, buckling failure can occur. In this study, numerical simulations were performed to estimate the buckling strength of typical steel girders in IABs. The effects of girder length, the width of flange and thickness of flange, imperfection due to fabrication and construction errors on the buckling strengths of multiple and single girders in IABs are studied. The effect of girder spacing, span length ratio (for a three span girder) and self-weight effects on the buckling strength are also studied. For estimation of the reaction force of the abutment generated by the passive earth pressure of the soil, BA 42/96 (2003), PennDOT DM4 (2015) and the LTI proposed equations (2009) were used and the results obtained are compared with the buckling strength of the steel girders. Using the selected design equations and the results obtained from the numerical analysis, equations for preventing the buckling failure of steel girders during deck replacement for maintenance are presented.
Journal of the Korean Society of Manufacturing Process Engineers
/
v.2
no.4
/
pp.53-60
/
2003
Large sized marine structures are used under corrosion environment of seawater and applied by severe service loading such as an ocean current, a billow and a tempest. Marine structures are usually constructed by lots of thick wall steel pipes joining welded joints. The thickness of such as steel pipes is usually more than 40mm. The such as steels are called "Thermo-Mechanical Control Process steel (TMCP steel)" strengthened by a heat treatment in process of steel manufactures. The failure, especially crack initiation, of marine structures was starting at weld joints under service condition. Then they should be designed by basis of the fatigue strength under seawater corrosion environment of weld joints. To clarity the fatigue crack initiation behavior is important more than to clarify the crack propagation behavior on the strength design of marine structures, because it is very difficult to find out the crack initiation and propagation phenomena and then even if it will be able to find out, it is considered that the refit of the damaged parts of welded joints have a technical difficulty under the sea. Therefore, it is most important to clarify the corrosion fatigue crack initiation behavior under the seawater condition. But, there is one big difficulty to make a test for thick plate specimen, for example thicker than 40mm. Because, it is need large capacity loading apparatus to test such as thick plate specimen. In this research, the new configuration specimen for fatigue crack initiation tests was proposed. Using this new specimen, it is easy to carry out the fatigue clack initiation tests with relatively low cyclic loading and to observe a fatigue crack initiation behavior.
Kim, Seog-ku;Jeong, Jang-sik;Kwak, Phill-jae;Choi, Jun-hyang;Lee, Hyun-dong;Lee, Tae-yoon
Journal of Korean Society on Water Environment
/
v.20
no.2
/
pp.163-169
/
2004
Feasibility of using PE sheet laminated CSP(Corrugated steel pipe) to sewers were tested via corrosion and abrasion tests for PE sheet laminated CSP; 1) corrosion test for PE film and PE coated plate, 2) corrosion test for joint of PE sheet laminated CSP, 3) corrosion test for outside of PE sheet laminated CSP, and 4) abrasion test for inside of PE sheet laminated CSP. The results for the corrosion and abrasion tests are as follows. 1. Results for corrosion tests on PE films and zinc coated steel plates that were coated with PE films show that the surfaces of both PE were not changed compared to those of original PE samples. Furthermore, PE films maintained strong adhesion on the steel plates even though they were exposed to sewage and seawater provided cutting planes of the steel plates were treated with molding. But, results for corrosion tests on the spots that were previously cut off by a knife and a cutting planes of the steel plates were treated without molding show that steel plates have been corroded if they were exposed to sewage and seawater. 2. Results for corrosion tests on joints of PE sheet laminated corrugated steel using sewage show that gathering rust was observed at cutting plane of PE sheet laminated corrugated steel after 180 days, but PE film was not flaked off. However, PE film at cutting plane was flaked off when PE sheet laminated corrugated steel was exposed to seawater. Furthermore, flaking process was severely progressed at lockseam points of which the surfaces were not smooth. 3. Results for laying PE sheet laminated corrugated steel under the ground show that the surface of untouched PE film was almost identical to that of original PE film. However, the spots that were previously cut off by a knife and a cutting plane of PE sheet laminated corrugated steel have flaked off. 4. As a result of abrasion tests conducted with PE sheet laminated corrugated steel and sand, brilliance and thickness of PE was not greatly changed under the severe abrasion conditions. Therefore, the durability of PE sheet laminated corrugated steel for abrasion was determined to be good.
Experimental tests and theoretical methods of the analysis of the concrete shrinkage behaviors of steel-concrete composite girders are described herein. Steel-concrete composite test specimens were fabricated in the laboratory, and long-term behaviors such as deflections, curvatures, and strains were measured for one year. Test results were compared to the analytical results obtained by using the age-adjusted effective modulus method (AEMM). In addition, composite girders have been analyzed to investigate the effects of several parameters on the concrete shrinkage behaviors. From the long-term test results, it could be used to validate AEMM for the evaluation of the shrinkage behavior of composite girders. Because the shrinkage of the reinforced concrete slab in composite girders may lead to large tensile stresses in the concrete section, the transverse cracking of the slab could occur both in the positive and negative regions. Therefore, if the cracking of concrete would be ignored,it might lead to an overestimation of the stresses of the steel section of composite girders. Based on this research, it is proposed that the effect of transverse concrete cracking on the shrinkage behavior of steel-concrete composite bridges be considered.
There have been 20 cases of trade disputes related to zeroing in WTO. In these day, it was judged that the use of zeroing in the calculation of dumping margin is against ADA. Recently, WTO decided in favor of Korea in regards to Korea's stainless steel products on January, 2011. There finally was a high possibility of zeroing being changed. In December 2010, the American government announced it would revise zeroing system through an federal register. Many researchers, such as Linsey and Ikenson(2000), William W. Nye(2009) already clarified through empirical analysis that no use of zeroing leads to a large decline in the margin of dumping. If zeroing is abolished in the future, the margin of dumping imposed on Korea's stainless steel will drop sharply. According to this empirical study, the margin of dumping in 6 stainless steel among 12 products commodities subject to Anti Dumping regulation from US reduced below de-minimis or 3%. These stainless steel is likely to be excluded from the Anti Dumping regulation through review investigation and Korea's export of steel to America is expected to be increased steeply in the future.
Journal of Advanced Marine Engineering and Technology
/
v.31
no.6
/
pp.753-760
/
2007
For protection of the cylinder wall of the ball mill for grinding raw ore. the inner side of the cylinder is covered with rubber liner. The rubber is easily worn down because the rubber relatively soft compared with raw ore. So the rubber liner in the ball mill cylinder must be replaced almost every year and the cost for replacing rubber liner formidable. In this paper, for reducing or excluding the cost of replacing rubber liner the basalt liner is designed. The basalt materials are generally harder than raw ore and the basalt liner in the ball mill does not wear down and so it can be used almost permanently. The concave surfaces are made on the liner of the ball mill and the liner in the cylinder wall plays also the role of raising the steel balls mixed in the raw ore. The section profiles of the concave surface have an important effect on the performance of the ball mill. The deep concave grooves raise the steel balls to high levels and give the large potential energy to the steel balls impacting to the raw ore. But if the concave grooves are too deep. the steel balls raised too high by the concave grooves fly along the parabolic path and reach to the other side of cylinder wall and so the steel balls do not play the roles of grinding the raw ore. The forces acting to a steel ball in a concave groove of the cylinder liner are also analyzed in this paper. The formulas calculating the height and the impact point of the steel ball are introduced and presented. Based to these formulas, the optimum section profiles of the basalt liner are presented.
Lee, Song Kwon;Lee, Young Sei;Kim, Young Su;Kim, Yong Lae
Journal of Korean Society of Occupational and Environmental Hygiene
/
v.4
no.1
/
pp.117-126
/
1994
Some of the important and vital roles performed by the Health Care Center of Pohang Iron & Steel Co., Ltd.(POSCO) are the periodic monitoring of the work sites as well as regular medical check-ups for each workers to ensure both pleasant and safe working conditions and to protect employees' health. Pohang Steel Works, which has 42 plants, 26 facilities and 12,000 employees, has an annual crude steel production capacity of 9,670,000 using 24,500,000 ton of raw materials. We have measured lots of areal and personal working environment according to Occupational Safety and Health Law semiannually. All data collected on industrial hygiene is stored and managed by personal computer. The developed of a computerized industrial hygiene control system linked to the company's main computer system will provide efficient evaluation of the working environment as well as critical informations on employees' health. Development of this system had begun in May, 1992 and was completed in March, 1994. The computerized industrial hygiene control system can; 1. store industrial hygiene data, providing key pertinent to the diagnosis of occupational related illnesses, and if necessary, the basis for improving the working environment, 2. decide type and time of medical examination of each work for exposure to specific agents, and supply proper protection periodically, 3. prevent occupational related illnesses through evaluation of environmental and biological monitoring, and performance of epidemiological surveillance, 4. facilitate proper job placement through linking of industrial hygiene control and personnel information systems, 5. monitor job processes. levels of chemical agents used, and new agents introduced, 6. and increase productivity by saving time resulting from the implementation of the computerized sysyte,
Journal of the Korea institute for structural maintenance and inspection
/
v.12
no.5
/
pp.81-90
/
2008
This paper concerns the flexural capacity of reinforced concrete beams with ultra-high performance cementitious composites(UHPCC). It was investigated if the existing equations to estimate the flexural capacity of reinforced fiberous concrete beams are applicable with the experiments including lightly reinforced concrete beams. The reinforcing effect when the steel fiber reinforced concrete was used in beams was also estimated. The results showed that the equation to predict the flexural capacity of reinforced steel fiber concrete by ACI 544 committee didn't have a good agreement with the test results and underestimated the flexural capacity in especially lightly reinforced beams with under 1.5% reinforcement ratio. the enhancement of flexural capacity was quite considerable in lightly reinforced beams when the steel fiber reinforced concrete was used. A equation to predict the reinforcing effect of steel fiber in reinforced steel fiber beams was developed. the equation was proposed as a function of both the characteristics of steel fiber and reinforcement ratio.
In this research, the gene expression programming (GEP) technique was employed to provide a new model for predicting the maximum loading capacity of concrete-encased steel (CES) columns. This model was developed based on 96 CES column specimens available in the literature. The six main parameters used in the model were the compressive strength of concrete (fc), yield stress of structural steel (fys), yield stress of steel rebar (fyr), and cross-sectional areas of concrete, structural steel, and steel rebar (Ac, As and Ar respectively). The performance of the prediction model for the ultimate load-carrying capacity was investigated using different statistical indicators such as root mean square error (RMSE), correlation coefficient (R), mean absolute error (MAE), and relative square error (RSE), the corresponding values of which for the proposed model were 620.28, 0.99, 411.8, and 0.01, respectively. Here, the predictions of the model and those of available codes including ACI ITG, AS 3600, CSA-A23, EN 1994, JGJ 138, and NZS 3101 were compared for further model assessment. The obtained results showed that the proposed model had the highest correlation with the experimental data and the lowest error. In addition, to see if the developed model matched engineering realities and corresponded to the previously developed models, a parametric study and sensitivity analysis were carried out. The sensitivity analysis results indicated that the concrete cross-sectional area (Ac) has the greatest effect on the model, while parameter (fyr) has a negligible effect.
Resistance spot welding has been widely used in the sheet metal joining processes because of its high productivity and convenience. Recently, automobile industries are trying to replace partly steel sheets with aluminum alloy sheets. Among currently produced aluminum alloys, Al alloy sheets of Al-Mg-Si(6000 series) are being tested. Especially, 6000 series are the most probable substitute in view of strength and weldability. In this paper, an attempt was made to apply resistance spot welding to joining of dissimilar sheet metals (KS6383+SCPZn or KS6383+SHCP). An effort was made to balance heating rate in the Al alloy with that in the steel sheets by increasing electrode tip diameter. Although resistance spot welding of Al alloy sheet and sheet metals does not produce desirable nugget, it proved to have reasonable strength if optimal weld condition is found by tensile-shear strength and fatigue life test. Since spot weld joints in automobile are always experiencing repeated load, spot welding methodology proposed in this paper is found to be not suitable to automobile body manufacturing.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.