• 한국구조물진단유지관리공학회 논문집
• /
• 제23권3호
• /
• pp.9-16
• /
• 2019

최근 프리캐스트 PSC 거더 형식의 교량이 널리 시공되고 있으며, 거더의 경간과 운송제한을 극복하기 위하여 분절거더의 시공이 증가하고 있다. 분절 공법을 적용한 세그먼트 간의 접합면에는 불연속면이 존재할 수 있으므로 교량의 건전성에 있어 접합부의 일체거동이 매우 중요하다. 분절 접합부는 접합부의 형태, 전단키 유무, 구속력의 크기에 따라 거동차이를 보이기 때문에 이러한 영향인자를 변수로 한 접합부 거동 연구가 필요하다. 본 연구에서는 프리캐스트 PSC 거더교의 접합부 거동을 평가하기 위하여 전단키의 형상, 구속력 도입여부를 변수로 한 전단키 유한요소해석과 축소모형시험을 실시하고, 그 결과를 비교하여 전단키와 구속력 효과를 평가하였으며, 접합부에 1/2~1/3의 돌출높이비를 갖는 전단키를 설치하고 콘크리트 강도의 1/2 수준의 구속력을 도입하는 것이 분절 접합부 거동향상에 효과적이라는 것을 확인하였다. 또한, 분절 공법으로 시공된 실제 프리캐스트 PSC 거더 교량의 재하시험을 실시하고 접합부 세그먼트 간의 처짐차이를 측정하여 분절부 거동을 평가하는 방법을 제안하였다.

• 대한기계학회논문집
• /
• 제15권6호
• /
• pp.1967-1974
• /
• 1991

본 연구에서는 근육수축에 의해 발생되는 각 신체부분의 각가속도의 방향이 다음 두가지 요소의 변화에 따라 어떻게 달라지는가를 중점적으로 살펴보기로 한다` (1) 신체매개변수(body-segmental parameter): 길이, 무게 등, (2) 신체 각 부분의 위치. 이러한 상관관계를 더욱 명확히 이해함으로써, 주어진 운동(given task)을 FES 에 의해 수행하고자 할 때 전기적으로 자극되어야 할 근육을 사전에 선택할 수 있을 것이다.

• Physical Therapy Rehabilitation Science
• /
• 제12권3호
• /
• pp.240-250
• /
• 2023

Objective: The purpose of this study was to characterize the movement of adjacent segments that occurred when posteroanterior joint mobilization was applied to the 3rd lumbar and thereby to provide basic clinical data. Design: Randomized controlled trial design. Methods: While the subjects were receiving posteroanterior joint mobilization of the 3rd lumbar vertebra, LD (lumbar displacement), LID (lumbar intervertebral distance), LIA (lumbar intervertebral angle), and LLA (lumbar lordosis angle) were measured using X-ray, and the data were then analyzed. Changes before and after posteroanterior joint mobilization were analyzed using a paired-sample t-test, and a one-way ANOVA of variance was performed to determine the difference between segmental movements. In addition, Pearson's correlation analysis was performed to determine the correlation between segmental movements. Results: The results revealed that there was a significant change in LD before and after the application of joint mobilization of the 3rd lumbar in all lumbar vertebrae (p<0.000), among which the 2nd lumbar vertebra, an adjacent segment, showed the most significant change. A significant change in LIA angle was observed in all segments (p<0.000), with the most significant change observed between the 2nd and 3rd lumbar vertebrae. There was a significant change in LLA before and after the application of posteroanterior joint mobilization (p<0.000). The correlation analysis showed a high correlation between displacement of the 3rd lumbar vertebra and displacement of all the other lumbar vertebrae. Conclusions: The presence of kinematic movements of the lumbar vertebrae when segmental movements were generated through the application of posteroanterior joint mobilization of the 3rd lumbar vertebra.

• Earthquakes and Structures
• /
• 제17권4호
• /
• pp.411-424
• /
• 2019

In this study, a numerical model of a shield tunnel with an assembled segmental lining was built. The seismic response of the segmental lining of the section of the shield tunnel in Line 1 of the Chengdu Metro is analyzed as it passes through the interface of sand-cobble and mudstone layers. To do so, the node-stress seismic-motion input method was used to input the seismic motion measured during the 2008 Wenchuan earthquake, and the joint openings and dislocations associated with the earthquake action were obtained. With reference to the Ethylene-Propylene-Diene Monomer (EPDM) sealing gaskets used in the shield tunnels in the Chengdu Metro, numerical simulation was applied to analyze the contact pressure along the seepage paths and the waterproof property under different joint openings and dislocations. A laboratory test on the elastic sealing gasket was also conducted to study its waterproof property. The test results accord well with the numerical results and the occurrence of water seepage in the section of the shield tunnel in Line 1 of the Chengdu Metro during the 2008 Wenchuan earthquake was verified. These research results demonstrate the deformation of segmental joint under earthquake, also demonstrate the relationship between segmental joint deformation and waterproof property.

• 한국운동역학회지
• /
• 제16권4호
• /
• pp.105-113
• /
• 2006

The purpose of this study was to analyze the joint torque of triple segmental system in golf driver swing. For this purpose, joint torque were calculated. In order to determine the load on the lumbar region, a triple segmental system was set for wrist, left shoulder and lumbar, torque working on the lumbar region were estimated. For this study, a total of 7 professional golfers were sampled, and then, their driver swings were recorded with two high-speed digital video cameras (180 frames/sec.) to be synthesized into 3-dimensional images and coordinated. Then, Eular's equation was used to produce some kinematic data, which were used to calculate joint torque with Newton's function. All data were calculated using LabVIEW 6.1 graphic program. The results of this study can be summarized as follows; It was found that the joint torque was generated in the direction opposite the target on wrist and shoulder during down swing, while in the direction towards the target on the lumbar region. During impact and release, the torque on the wrist joint was converted from the direction opposite the target to the direction towards the target, while the torque on the lumbar region was generated vice versa. The joints on the club-arm-shoulder were generated in the opposite direction at the beginning of down swing when the torque on the thorax-pelvis began to be generated, and then, the torque on the thorax-pelvis began to lower, while that on the club-arm-shoulder began to increase. Thus, a rapid decrease of the torque on the lumbar region linked to the low trunk acted to increase moment and joint torque on the arm-club region.

• 한국운동역학회지
• /
• 제15권2호
• /
• pp.57-67
• /
• 2005

The purpose of this study was to analyze the kinetic factors of the golf driver swing using the Inverse Dynamics function. For this purpose, joint force were calculated. In order to test the possibility of Inverse Dynamics function(motion-dependent interaction), a triple segmental system was set for wrist, left shoulder and lumbar and joint force working on the anatomical joint region was estimated. For this study, 7 professional golfers were sampled, and then, their driver swings were recorded with two high-speed digital video cameras (180 frames/sec.) to be synthesized into 3-dimensional images and coordinated. Then, Eular's equation was used to produce some kinematic data, which were used to calculate joint force and torque with Newton's function. All data were calculated using LabVIEW 6.1 graphic program. The results of this study can be summarized as follows; It was found that the joint force was generated on wrist, shoulder and lumbar joints in the direction of the target, and that the joint force was stronger in the direction of target immediately before impact. The joint force was generated towards the target to activate the nodes, and then, it was generated in the reverse direction to increase the speed during impact.

• Journal of Korean Neurosurgical Society
• /
• 제45권1호
• /
• pp.24-31
• /
• 2009

Objective : To investigate the effectiveness of radiographic parameters on segmental instability in the lumbar spine using Kinetic magnetic resonance imaging (MRI). Methods : Segmental motion, defined as excessive (more than 3 mm) translational motion from flexion to extension, was investigated in 309 subjects (927 segments) using Kinetic MRI. Radiographic parameters which can help indicate segmental instability include disc degeneration (DD), facet joint osteoarthritis (FJO), and ligament flavum hypertrophy (LFH). These three radiographic parameters were simultaneously evaluated, and the combinations corresponding to significant segmental instability at each level were determined. Results : The overall incidence of segmental instability was 10.5% at L3-L4, 16.5% at L4-L5, and 7.3% at L5-S1. DD and LFH at L3-L4 and FJO and LFH at L4-L5 were individually associated with segmental instability (p<0.05). At L4-L5, the following combinations had a higher incidence of segmental instability (p<0.05) when compared to other segments : (1) Grade IV DD with grade 3 FJO, (2) Grade 2 or 3 FJO with the presence of LFH, and (3) Grade IV DD with the presence of LFH. At L5-S1, the group with Grade III disc and Grade 3 FJO had a higher incidence of segmental instability than the group with Grade I or II DD and Grade 1 FJO. Conclusion : This study showed that the presences of either Grade IV DD or grade 3 FJO with LFH at L4-L5 were good indicators for segmental instability. Therefore, using these parameters simultaneously in patients with segmental instability would be useful for determining candidacy for surgical treatment.

• 한국터널지하공간학회 논문집
• /
• 제17권3호
• /
• pp.363-382
• /
• 2015

본 연구는 수치해석을 통하여 TBM 세그먼트의 분할 수와 인접한 링의 이격각도가 라이닝의 부재력에 어떤 영향을 미치는 살펴보았다. 수치해석은 Midas civil 2012+ 프로그램을 사용하였고, 모델링은 2링빔 스프링 모델을 이용하였다. TBM 세그먼드 부재력은 다양한 요소에 의해 결정된다. 본 논문에서는 세그먼트 분할 수와 분포를 제외한 다른 요소인 이음부 스프링 계수, 지반반력계수를 통제하고 특정한 분할 수와 분할 특성을 통해 case를 선정함으로써 분할 수와 분포와 같은 분할 특성이 부재력에 미치는 영향을 분석하였다. 이로써 TBM 세그먼트 시공 설계시 구조적으로 유리하거나 불리한 이음부 특성을 확인할 수 있다.

• 콘크리트학회논문집
• /
• 제23권2호
• /
• pp.235-244
• /
• 2011

세그멘탈 교량의 파괴는 부적절한 접합에 의해 파괴를 일으키게 되는데 이는 세그멘탈 접합부를 가로지르는 횡방향 텐던의 부식을 야기하게 된다. 이 연구에서는 현장 타설 접합 및 에폭시 접합 조건에 따른 초고성능 프리캐스트 콘크리트 접합부에서의 전단키 거동을 전단 및 극한거동 측면에서 평가하였다. 또한, PC 세그멘탈 교량 접합부의 전단 거동을 파악하기 위하여 전단키 접합부의 전단 거동과 전단강도 특성을 실험적으로 연구하였다. 이 연구를 통하여 접합부 형상에 따른 하중-변위 관계, 균열 거동, 파괴 모드, 전단 강도 등을 구명하고, 접합부의 역학적 거동에 영향을 미치는 여러 인자들에 대해 분석한다. 또한 이로부터 최적의 접합부 형상을 도출하고, 이에 따른 최적의 접합 방식을 검토함으로서 접합부 설계의 지침과 해석의 근거를 제시하도록 한다.

• Physical Therapy Rehabilitation Science
• /
• 제10권4호
• /
• pp.450-456
• /
• 2021

Objective: Studies confirming the lumber spine kinematics of direct or indirect segmental mobility under the application of joint mobilization, which induces passive force on the spine, are insufficient.Therefore, this study aims to obtain the underlying clinical data by identifying direct or indirect segmental mobility produced by Maitland's PA mobilization technique. Design: Randomized controlled trial design. Methods: Thirty subjects with no back pain participated in this study. X-ray testing equipment (SIG-40-525, Ecoray Inc., Korea) was used to verify the segmented movement of their lumbar. Joint mobilization was performed by physiotherapists with more than 10 years of experience in prescription therapy, and radiography was performed once without PA joint mobilization and once without the mobilization for comparing the lumbar vertebrae before and after the mobilization. The radiographs taken were analyzed using the picture archiving and communication system (PACS) program to measure the spinal displacement, intervertebral height, intervertebral angle, and lumbar lordosis angle. Results: Significant differences were observed in the lumbar displacement, intervertebral angle, and lumbar lordosis angle in all lumbar vertebrae before and after the mobilization. The intervertebral height indicated significant differences in all ventral vertebrae and only in L3-L4 and L4-L5 in dorsal vertebrae. Conclusions: This study suggests that the segmental mobility produced through indirect approaches plays an important role in inducing therapeutic effects in patients with back pain.