돼지고기 수출상의 문제점과 대응방안

이수헌,Lee, Su-Heon 대한양돈협회 1987 養豚 Vol.9 No.11

외부 포스트텐션 콘크리트 보의 전단강도

이수헌,강현구,신경재 한국공간구조학회 2015 한국공간구조학회지 Vol.15 No.1

This paper shows the test results of continuous reinforced concrete beams with external post-tensioning rods. Six three-span beams were prepared and tested to fail. Three beams were designed to have flexure-dominating behavior and the others to have shear-critical behavior. In each group, one beam without external post-tensioning rods was designated as a control beam and two beams had the external post-tensioning rods of 18 mm or 22 mm diameter. External post-tensioning rods were installed within an interior span of 6000 mm. They show V-shaped configuration because two anchorages were located at the top of interior supports and a saddle pin at mid-span was installed at the bottom of the beam. Test results show that the load and shear capacities of strengthened beams were increased when compared with the control beam. Additionally, the measured shear strength was compared with the strength predicted by ACI 318-11 code equations. The detailed ACI 318-11 equation predicted the measured shear strength and failure location of the continuous beam reasonably well.

시설 및 노지재배 고추의 바이러스병 발생과 분포

이수헌,이재봉,문제선,최홍수,이기운,박진우,김상목,이준성 한국식물병리학회 2004 식물병연구 Vol.10 No.4

Behavior of Plate-to-Circular Hollow Section Joints of 600 MPa High-Strength Steel

이수헌,Kyung-Jae Shin,이희두,Woo-Bum Kim,양재근 한국강구조학회 2012 International Journal of Steel Structures Vol.12 No.4

While the recent high demand for high rise buildings has led to the development of high-performance and high-strength steels, the requirements for structural-performance steel for such buildings have been raised as engineers recognized the potential wreak damage that an earthquake could cause on a tall building. Many studies on high-strength steels have explored such requirements, but appropriate design equations are needed for the case of hollow structural section (HSS) due to the design equations that limit the maximum yield stress up to 360MPa in the design codes (AISC, 2011; KBC, 2009). This study investigated the behavior of 600MPa plate-to-circular hollow section joints subjected to applied moment and shear force by experiment and finite element analysis (FEA), and the results are compared with current design equations. The nominal strength of AISC (2005) (or KBC (2009)) overestimated the tested strength in the range between 105% and 137%. It is found that the nominal strength equation of AISC (2011) is reasonably revised in comparison to those of other design codes.

한우개량의 효율적 추진방안

이수헌 한국종축개량협회 1996 種畜改良 Vol.18 No.1

고온에 노출된 H-형강 압축재의 유한요소해석

이수헌,이희두,최준호,신경재 한국화재소방학회 2016 한국화재소방학회논문지 Vol.30 No.5

Steel is a structural material that is inherently noncombustible. On the other hand, it has high thermal conductivity andthe strength and stiffness of the material are reduced significantly when exposed to fire or high temperatures. Because theyield strength and modulus of elasticity of steel are reduced by 70% at 350 oC and less than 50% at 600 oC, the load-carryingcapacity of steel structure at high temperature rapidly lose. To be accepted as a fire-resisting construction, the firetest should be performed at the certificate authority. On the other hand, the fire test on a full-scale structure is limited bytime, space, and high-cost. The analytical method was verified by a comparison with the fire test of H-section columnsunder compression and thermal analysis based on a finite element method using the ABAQUS program, and the numericalanalysis method reported in this study was suggested as a complement of an actual fire test. 구조재료 중에서 강재는 불연성 재료이지만 열전도가 높고, 온도상승에 의하여 강성의 저하가 높은 편이다. 일반적으로 강재의 항복강도 및 탄성계수는 350 oC에서 70%, 600 oC에서 50% 이하로 감소하기 때문에 고온에서의 철골구조의재하능력은 급격히 감소하게 된다. 통상 내화구조로 인정받기 위해서는 공인기관으로부터의 품질시험을 거쳐야 한다. 하지만, 실물내화실험은 공간과 시간의 제약, 고비용의 문제점을 안고 있으므로, 본 연구에서는 ABAQUS 프로그램의 유한요소법을 이용한 열해석을 수행하여 압축을 받는 H-형강기둥의 내화실험과의 비교로 해석모델의 신뢰성을 입증하고,실물실험의 보완책으로의 가능성을 제시한다.

포스트텐션 콘크리트 보에서 비부착 외부강봉의 응력

이수헌,강현구,신경재,Lee, Swoo-Heon,Kang, Thomas H.K.,Shin, Kyung-Jae 한국공간구조학회 2015 한국공간구조학회지 Vol.15 No.1

This paper shows the simplified equation to predict the ultimate moment capacity and corresponding rod stress in reinforced concrete beam with external post-tensioning rods. Because the stress of external post-tensioning rod depends on the beam deflection, the previous analytical model for post-tensioned beams requires a tedious iteration process. Also, the stress equations in ACI code or other researchers' models are suitable only for internal tendons in concrete beams. In this study, given the lack of analytical approaches to predict the nominal stress of the external unbonded rod, a simple and robust equation has been proposed for externally post-tensioned concrete beams. It is concluded that the proposed equation predicted the stress of external steel rods in post-tensioned concrete beams reasonably well.

Relationship Between Endplate Defects, Modic Change, Facet Joint Degeneration, and Disc Degeneration of Cervical Spine

이수헌,손동욱,이준석,성순기,이상원,송근성 대한척추신경외과학회 2020 Neurospine Vol.17 No.2

Objective: The ‘‘disc degeneration precedes facet joint osteoarthritis’’ hypothesis and multidimensional analysis were actively discussed in lumbar spine. However, in cervical spine degeneration, the multifactorial analyzes of disc degeneration (DD), Modic changes (Mcs), facet degeneration, and endplate degeneration (ED) is still limited. In this cross-sectional study, we aimed to analyze the prevalence and interrelationship of cervical DD parameters. Methods: We retrospectively recruited 62 patients aged between 60 and 70 years. The disc height, segmental angle, ossified posterior longitudinal ligament (OPLL), ED, facet joint degeneration (FD), uncovertebral joint degeneration (UD), DD, spinal stenosis (SS), Mc, and cord signal change (CS) were evaluated using a previously well-known grading system. Results: The prevalence of cervical degenerative parameters were DD (grade 1, 1.2%; grade 2, 13.3%; grade 3, 54.8%; grade 4, 19.0%; grade 5, 11.7%), OPLL (26.2%), SS (grade 0, 7.7%; grade 1, 42.3%; grade 2, 26.2%; grade 3, 23.8%), UD (39.1%), ED (normal, 69.0%; focal defect, 9.7%; corner defect, 11.7%; erosion, 6.9%; sclerosis, 2.8%), and FD (normal, 48.8%; narrowing, 27.0%; hypertrophied, 24.2%). The interrelationship of degenerative parameters showed close relation between UD, SS, DD, OPLL, Mc. ED, and CS has partial relation with degenerative finding. FD only has relation with UD, and Mc. Conclusion: Our results may indicate that FD is a degeneration that occurs independently, rather than as a result of other degenerative factors.

화재손상을 입은 철근콘크리트 보에서 외적 포스트텐셔닝 강봉의 전단 보강

이수헌 대한건축학회 2023 대한건축학회논문집 Vol.39 No.1

The purpose of this study is to discuss the applicability, strengthening effect and improvements when an externally post-tensioned steel rodsystem is applied to a fire-damaged reinforced concrete (RC) beam. A total of twelve specimens were prepared in three groups and tested tofail. Group one was not heated, and group two and group three were heated to 700℃ and 1,000℃, respectively. In each group, one beamwithout externally post-tensioned steel rods was designated as a control beam and three beams had the externally post-tensioned steel rods of18 mm, 22 mm or 28 mm in diameter. The initial effective tension of about 2,000 was applied to the steel rods. Test results indicated thatthis can be applied to fire-damaged RC because externally post-tensioning increased the load-carrying capacity by more than 67%. However,additional reinforcement is required in the part where the deviator and anchorage are installed since the concrete surface is weakened bymoisture evaporation at high temperatures. 이 연구는 화재손상을 입은 철근콘크리트 보에 외적 포스트텐셔닝 강봉을 적용하였을 때 적용 가능성과 보강 효과, 개선점 등을 논한다. 총 12개의 실험체가 3개의 실험군으로 구성되었고 파괴 시까지 실험하였다. 실험군 #1은 고온에 노출하지 않았고, 실험군 #2와 #3은 각각 700℃, 1,000℃에 노출하였다. 각 실험군은 포스트텐셔닝 강봉으로 보강하지 않은 기본 실험체 1개, 18mm, 22mm, 28mm 강봉으로 보강한 3개의 실험체로 디자인되었다. 강봉에는 초기 긴장력 약 2000με이 도입되었다. 실험결과를 보면, 포스트텐셔닝 강봉 보강법은 67% 이상의 강도 보강 효과를 보였기 때문에 그 보강 효과를 입증하였다. 하지만 고온에 콘크리트 표면의 손상이 발생하였기에 데비에이터와 정착구 부근에는 추가 보강이 이루어져야 할 것으로 판단한다.

잉여원유 상황 개선 기미가 보이지 않고 있다.

이수헌 한국낙농육우협회 2002 낙농·육우 Vol.22 No.11