해상송전철탑 구조물의 주기점검을 통한 경년열화 변화특성

이호범,장일영 한국구조물진단유지관리공학회 2012 한국구조물진단유지관리공학회 논문집 Vol.16 No.4

해상송전철탑 구조물에 있어서 구조 및 재료 손상에 대해 주기적으로 안전점검을 실시하고, 그 결과를 이용한 수명관리(life management)의 시행은 적극 추천되는 일이다. 본 연구에서는 영흥도 시화호 내에 있는 총 6개의 해상송전철탑에 대해서 강재부재에 대해 3가지, 콘크리트 기초에 대해 5가지, 해수 중 강관파일 및 해수 자체에 대해 4가지 형태의 열화점검을 각각 수행하였다. 강재에 대한 점검 항목들은 외관조사, 부재두께, 도막상태 등에 대한 것이고, 콘크리트 기초에 있어서는 균열형상, 압축강도, 중성화깊이, 염화물 함유량 등에 대한 항목, 그리고 해중 강관파일에 있어서의 전위 및 양극조사에 따른 부식정도, 동영상 촬영 및 해수의 수질환경성 평가 등에 대한 항목이다. 이와 같은 정기적 열화점검은 연속 3년 동안 매년 10월경에 동일위치에 대해 평가하였다. 결과적으로 본 연구에서는 이러한 자료를 체계적으로 활용함으로써 해상송전철탑 안전성 유지관리에 유익하게 적용될 수 있는 새로운 열화지표를 개발하였다. In electric power transmission tower structures on offshore, implementation of life management using the event data of regular safety inspections for structural and material damages is strongly recommended. In this study, six tower structures in Sihwa Lake around Yeoungheung island were target bodies for the safety inspections. safety inspections for deterioration about each of six towers were performed about three items for steel member, five items for concrete foundation, and four items for steel-pipe pile in seawater and seawater itself. Safety inspections for steel members included the visual observations of surface appearances, the measurements of member thicknesses, and the checks of painting states. Also safety inspections for concrete foundations comprised the estimation of crack features, the evaluation of non-destructive compression strengths, and the measurements of neutralization depths and chlorides contents. For steel-pipe piles in seawater the inspections comprised the surveys of corrosion states in accordance with potential levels tests and anode tests, the analyses of photos taken on surfaces of the piles as well as the evaluation of seawater quality. A set of deterioration inspections was performed at the same positions around october of each year for three consecutive years. As a result in this study, Newly developed deterioration indexes have been applied profitably to maintain structural safety for electric power transmission towers by utilizing these event data systematically.

반도체 정밀 생산기기 방$\cdot$제진을 위한 미진동 Design Guide Line 해석

이호범 한국공기청정협회 1999 空氣淸淨技術 Vol.12 No.1

흉요추부 골다공성 압박 골절과 동반된 천골 기능부전 골절 - 동반 빈도와 고위험 인자에 대해-

이호범,유찬종,이상구,김우경,박찬우,홍지명 대한척추신경외과학회 2009 Neurospine Vol.6 No.2

Objective: The sacral insufficiency fractures (SIFs) are not uncommon and usually occur in osteoporotic bone with minimal or unremembered trauma. Especially, if they are accompanied by osteoporotic compression fracture of the thoracolumbar spine, SIFs can be usually overlooked due to subtle clinical symptoms and signs coupled with radiographic findings. The review aims to be raising awareness of the incidence & risk factors of the SIFs. Methods: We retrospectively reviewed the 252 patients who were admitted at our hospital due to osteoporotic compression fracture of the thoracolumbar spine with minimal or unremembered trauma for 5 years. We assessed the incidence of the SIF being accompanied by osteoporotic compression fracture of the thoracolumbar spine and the effects according to sex, age, probable risk factors (diabetes mellitus & arterial hypertension), the location of fracture and the severity of osteoporosis. Results: 252 patients, including 36 men (14.3%) and 216 women (85.7%) were involved in this study and the osteoporotic compression fractures were located at thoracic (36 cases), thoracolumbar junction (180 cases), lumbar spine (36 cases). There are 18 cases (the incidence: 7.1%), including 2 men (5.5%) and 16 women (7.4%) in which the SIF was accompanied by osteoporotic compression fracture of the thoracolumbar spine. The effects according to sex, age, probable risk factors, the location of fracture and the severity of osteoporosis were not statistically different in both groups (group with SIF and group without SIF). Conclusion: The clinicians need to consider the possibility of SIF in patients of osteoporotic compression fracture of the thoracolumbar spine. Objective: The sacral insufficiency fractures (SIFs) are not uncommon and usually occur in osteoporotic bone with minimal or unremembered trauma. Especially, if they are accompanied by osteoporotic compression fracture of the thoracolumbar spine, SIFs can be usually overlooked due to subtle clinical symptoms and signs coupled with radiographic findings. The review aims to be raising awareness of the incidence & risk factors of the SIFs. Methods: We retrospectively reviewed the 252 patients who were admitted at our hospital due to osteoporotic compression fracture of the thoracolumbar spine with minimal or unremembered trauma for 5 years. We assessed the incidence of the SIF being accompanied by osteoporotic compression fracture of the thoracolumbar spine and the effects according to sex, age, probable risk factors (diabetes mellitus & arterial hypertension), the location of fracture and the severity of osteoporosis. Results: 252 patients, including 36 men (14.3%) and 216 women (85.7%) were involved in this study and the osteoporotic compression fractures were located at thoracic (36 cases), thoracolumbar junction (180 cases), lumbar spine (36 cases). There are 18 cases (the incidence: 7.1%), including 2 men (5.5%) and 16 women (7.4%) in which the SIF was accompanied by osteoporotic compression fracture of the thoracolumbar spine. The effects according to sex, age, probable risk factors, the location of fracture and the severity of osteoporosis were not statistically different in both groups (group with SIF and group without SIF). Conclusion: The clinicians need to consider the possibility of SIF in patients of osteoporotic compression fracture of the thoracolumbar spine.

추간반 및 후관절의 퇴행 정도를 이용한 요추 불안정 판단의 임상적 유용성

이호범,박찬우,이상구,김우경,유찬종 대한척추신경외과학회 2009 Neurospine Vol.6 No.3

Objective: Treatment for symptomatic lumbar stenosis is usually surgical decompression and additional global fusion is recommended for patients with segmental instability. The aim of this article is to evaluate that degeneration degree of the disc and facet joint could be the indicator of judgment for segmental instability. Methods: We retrospectively reviewed 84 patients who underwent surgical treatment for lumbar spinal stenosis. Patients in Group 1 (30 patients) with radiological instability underwent decompression with global fusion, patients in Group 2 (54 patients) without radiological instability underwent decompression with global fusion or decompression only according to the existence and nonexistence of clinical instability. Magnetic resonance images were used to assess the disc degeneration from Grade I (normal) to Grade V (advanced) and the facet joints degeneration from Grade 0 (normal) to Grade 3 (advanced). All patients were checked with the simple X-ray stress view and evaluated. Results: Severity of the disc degeneration had no significant association with the segmental instability, and no correlation with the facet joint degeneration. Severity of facet joint degeneration had significant correlation with the radiological instability. The segmental instability was increased with increasing severity of facet joint degeneration, especially translation. There was a significant association between facet joint degeneration and clinical instability. The facet joint degeneration was increased in patients with clinical instability. Conclusion: Our results suggest that the facet joint degeneration may be the useful indicator of judgment for segmental instability Objective: Treatment for symptomatic lumbar stenosis is usually surgical decompression and additional global fusion is recommended for patients with segmental instability. The aim of this article is to evaluate that degeneration degree of the disc and facet joint could be the indicator of judgment for segmental instability. Methods: We retrospectively reviewed 84 patients who underwent surgical treatment for lumbar spinal stenosis. Patients in Group 1 (30 patients) with radiological instability underwent decompression with global fusion, patients in Group 2 (54 patients) without radiological instability underwent decompression with global fusion or decompression only according to the existence and nonexistence of clinical instability. Magnetic resonance images were used to assess the disc degeneration from Grade I (normal) to Grade V (advanced) and the facet joints degeneration from Grade 0 (normal) to Grade 3 (advanced). All patients were checked with the simple X-ray stress view and evaluated. Results: Severity of the disc degeneration had no significant association with the segmental instability, and no correlation with the facet joint degeneration. Severity of facet joint degeneration had significant correlation with the radiological instability. The segmental instability was increased with increasing severity of facet joint degeneration, especially translation. There was a significant association between facet joint degeneration and clinical instability. The facet joint degeneration was increased in patients with clinical instability. Conclusion: Our results suggest that the facet joint degeneration may be the useful indicator of judgment for segmental instability

자기공명영상의 image scale 재설정에 따른 최적의 영상신호 표준화

이호범,최관우,손순룡 한국콘텐츠학회 2017 한국콘텐츠학회논문지 Vol.17 No.12

In this study, we tried to improve the reproducibility of signal intensity by applying DOTS method. The study was conducted on 30 patients who had undergone hepatic screening because of poor reproducibility and decreased signal intensity. The images were acquired before and after injection of contrast media and then post - processed by DOTS methods. Signal intensity was compared and evaluated. The results showed that the signal intensity of the images was 183.3% (1038.0 ± 70.7 before application, 2940.7 ± 179.6 after application) and 1118.4% (444.1 ± 92.4, 5410.5 ± 168.4 after application). This is a significant improvement in the fact that the reproducibility of MRI) was changed by the DOTS method, which is a post-processing method. 본 연구는 자기공명검사 시 재현성이 달라져 신호강도가 저하되는 문제점을 후처리 기법인 DOTS 기법을 적용함으로써 개선하고자 하였다. 연구방법은 재현성이 떨어져 신호강도 저하가 가장 빈번하게 발생하는 간 검사를 시행한 30명을 대상으로 하였으며, 조영제 주입 전․후 영상을 획득한 다음 DOTS 기법으로 영상을 후처리하여 적용 여부에 따른 영상의 신호강도를 비교 평가하였다. 연구결과 영상의 신호강도는 DOTS 기법을 적용한 경우가 적용하지 않은 경우보다 조영제 주입 전에는 183.3%(적용 전 1038.0±70.7, 적용 후 2940.7±179.6), 주입 후에는 1118.4%(444.1±92.4, 적용 후 5410.5±168.4) 유의하게 증가하였다. 이는 후처리 기법인 DOTS 기법을 통해 영상척도의 기준을 재설정하여 개선한 것으로써 자기공명검사 시 재현성이 달라져 신호강도가 저하되는 문제를 근본적으로 해결하였다는 데 의의가 있다.

실험적 응력해석의 IITC 방식에 의한 콘크리트 구조물 잔류응력 평가

이호범,한상희,장일영,Lee, Ho Beom,Han, Sang Hee,Jang, Il Young 대한토목학회 2014 대한토목학회논문집 Vol.34 No.2

The carrying capacity of existing concrete structures is evaluated by the measured data from displacement and strain gauges for given loads and the results of numerical analysis that are compared with the measured ones. Consequently, this process could be accomplished in doing the direct measurement of residual stress on existing concrete. This study is concerned with the development of IITC (Instrumented Indentation Technique for Concrete) system which is based on the experimental stress analysis technique using non-destructive test method to evaluate the residual stress of concrete structures depending on the types of applied loadings in analysing indentation load - indentation depth curve derived experimentally on concrete surface. As a result, in this paper, almost all of systematized H/W and S/W were newly developed to estimate the residual stresses of concrete structures. Thus, the creation of new experimental equations for deriving residual stresses and automatical calculations of residual stresses using the empirical formula can lead to evaluate the structural resistances conveniently in the structures from construction phase to maintenance stage.

기초침하에 의해 손상된 송전철탑 구조물의 구조성능개선

이호범,박종권,김일수,장일영,송재호 한국구조물진단유지관리공학회 2013 한국구조물진단유지관리공학회 논문집 Vol.17 No.2

일반적으로 송전철탑 부재들의 보강은 적절한 그라우팅재를 활용한 인젝션과 구조 보강재 부착을 이용한 단면 확장에 따른 강성보강 방식을 주로 사용한다. 이와 같은 그라우팅 인젝션 및 단면보완은 주로 축력능력을 확장시키는 데에 의미를 갖는다. 그렇지만 보다 안정적 상태를 유지케 할 수 있는 보강방안이 적극 요구되는데 그 방법은 좌굴에 의해 손상을 받은 부재를 원상태의 길이로 환원시키고, 또한 내부적 보강효과를 동시에 갖는 새로운 부재로 교체하는 것이다. 본 연구에서는 기초침하로 구조적 손상을 받은 송전철탑의 손상회복을 위한 실증적 과정으로 우선 현장에서의 손상도 확인점검과 손상상태 및 회복상태에 대한 수치 해석적 결과를 도출하였고, 새롭게 고안한 잭킹시스템을 이용하여 보강된 부재를 교체하는 과업을 수행하였다. 이 결과는 송전철탑 유지관리의 차원상승 효과를 갖게 한다. Generally the capacities of electric power transmission tower's members are improved by increasing their stiffness nature through injection of grout or attachment of other structural stiffeners. Those are for upgrading their axial strength by fulfillment of proper materials into pipe members, increment of member dimension by addition of section, or a combination of the two. However the use of innovative and unusual procedures would be positively recommended for getting more stable state. It is that buckled members are replaced with lengthened and strengthened members. In providing the structural restoration procedures for the existing electric power transform tower whose main members have been damaged due to unequal foundation settlement, structural damage inspection works and numerical analyses for the damaged one and the restored one were done in detail at first. secondarily member-exchanging works using a newly-generated jacking system and strengthened members were achieved. This figures are to point clearly to inherent advantages attending the management of the towers.

구조물에 대한 진동 및 진동제어 방법에 관한 해석

이호범 한국공기청정협회 1996 空氣淸淨技術 Vol.9 No.2

반도체공장 클린룸 구조에서의 미진동 연구

이호범 한국공기청정협회 1992 空氣淸淨技術 Vol.5 No.2

자기공명영상에서 표준화된 ACR 팬텀 영상을 통한 상용화된 딥러닝 기법 평가

이호범,장지성 대한자기공명기술학회 2022 대한자기공명기술학회지 Vol.32 No.3

Compared to existing imaging equipment, MR images exhibit a relatively large difference in reproducibility according to hydrogen density in the human body. It is therefore extremely important for the DL algorithm to demonstrate this in clinical practice and supplement it when a problem is found. Therefore, this study evaluated the changes before and after application of the DL algorithm by implementing the method now clinically applied to image quality standards using the MR phantom of the American College of Radiology (ACR) recommended by special medical equipment. The results revealed that aspects of the resolution-related image quality, such as high illuminance spatial resolution, improved resolution, and location accuracy were statistically different from the previous DL algorithm before application. There was no difference between images in the intensity of the DL algorithm. These results meet the evaluation criteria of ACR Phantom applied to the special medical equipment image quality management regulations, but the existence of statistical differences before and after application of the DL algorithm suggest other related research tools will be needed in the future.