• Earthquakes and Structures
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• v.7 no.5
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• pp.705-718
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• 2014

This paper presents an analytical model for determining the transverse reinforcement required for reinforced concrete exterior beam-column joints subjected to reversed cyclic loading. Although the joint aspect ratio can affect joint shear strength, current design codes do not consider its effects in calculating joint shear strength and the necessary amount of transverse reinforcement. This study re-evaluated previous exterior beam-column joint tests collected from 11 references and showed that the joint shear strength decreases as the joint aspect ratio increases. An analytical model was developed, to quantify the transverse reinforcement required to secure safe load flows in exterior beam-column joints. Comparisons with a database of exterior beam-column joint tests from published literature validated the model. The required sectional ratios of horizontal transverse reinforcement calculated by the proposed model were compared with those specified in ACI 352R-02. More transverse reinforcement is required as the joint aspect ratio increases, or as the ratio of vertical reinforcement decreases; however, ACI 352R-02 specifies a constant transverse reinforcement, regardless of the joint aspect ratio. This reevaluation of test data and the results of the analytical model demonstrate a need for new criteria that take the effects of joint aspect ratio into account in exterior joint design.

• The Journal of Korean Physical Therapy
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• v.17 no.3
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• pp.285-295
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• 2005

The purpose of this study was to evaluate effects of sacroiliac joint mobilization and lumbopelvic stabilizing exercises on the equilibrium ability. The subjects were consisted of ninety healthy adult two decade(43 females. 47 males; mean aged 22.1) from 20 to 29. All subjects randomly assigned to the control group, sacroiliac joint mobilization group, lumbopelvic stabilizing exercises group. Lumbopelvic stabilizing exercises group received lumbopelvic stabilizing exercises for 30 minutes, sacroiliac joint mobilization group received sacroiliac joint mobilization for 2-3 minutes per day and three times a week during 3 weeks period. Active balancer(SAKAI EAB-100) was used to measure equilibrium ability. All measurements of each subjects were measured at pre-experiment, after 10 days, and post-experiment. The results of this study were summarized as follows: 1. The WPL of control group, sacroiliac joint mobilization group, lumbopelvic stabilizing exercises group was no significantly differences at pre-experiment(p>.05), but significantly reduced after 10 days and post-experiment(p<.05). The results of analyzed effects of WPL was significantly reduced between experiment type of control group, sacroiliac joint mobilization group, lumbopelvic stabilizing exercises group according to pre-experiment, after 10 days, and post-experiment(p<.05). 2. The RA of control group, sacroiliac joint mobilization group, lumbopelvic stabilizing exercises group was no significantly differences at pre-experiment(p>.05), but significantly reduced after 10 days, and post-experiment(p<.05). The results of analyzed effects of RA was significantly reduced between experiment type of control group, sacroiliac joint mobilization group, lumbopelvic stabilizing exercises group according to pre-experiment, after 10 days, and post-experiment(p<.05). Conclusionally these data suggest that a 3-week SI joint mobilization and lumbopelvic stabilizing exercises improved equilibrium. Additional randomized controlled trials to more fully investigate treatment effects and factors that may mediate these effects are needed.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.11 no.1
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• pp.29-36
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• 2005

The purpose of this study was to evaluate change of path length center of body on sacroiliac joint mobilization. The subjects were consisted of sixty healthy adult two decade(28 females. 32 males; mean aged 22.2) from 20 to 29. All subjects randomly assigned to the control group, sacroiliac joint mobilization group. sacroiliac joint mobilization group received sacroiliac joint mobilization for 2-3 minutes per day and three times a week during 3 weeks period. The study carried out to determine the change of path length center of body on sacroiliiac joint mobilization from July 1, 2004 through september 30, 2004. Active balancer(SAKAI EAB-100) was used to measure equilibrium ability. All measurements of each subjects were measured at pre-experiment and post-experiment. The results of this study were summarized as follows: 1. The WPL of control group, sacroiliac joint mobilization group was no significantly differences at pre-experiment but significantly reduced post-experiment(p<.05). The results of analyzed effects of WPL was significantly reduced between experiment type of control group, sacroiliac joint mobilization group according to pre-experiment and post-experiment(p<.05). 2. The UPL of control group, sacroiliac joint mobilization group was no significantly differences at pre-experiment but significantly reduced post-experiment(p<.05). The results of analyzed effects of UPL was significantly reduced between experiment type of control group, sacroiliac joint mobilization group according to pre-experiment and post-experiment(p<.05). Conclusionally these data suggest that a 3-week S-I joint mobilization improved equilibrium. Additional randomized controlled trials to more fully investigate treatment effects and factors that may mediate these effects are needed.

• Structural Engineering and Mechanics
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• v.52 no.2
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• pp.427-443
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• 2014

This paper presents detailed analysis of the internal forces of interior beam-column joints of reinforced concrete (RC) frames under seismic action, identifies critical joint sections, proposes consistent definitions of average joint shear stress and average joint shear strain, derives formulas for calculating average joint shear and joint torque, and reports simplified analysis of the effects of joint shear and torque on the flexural strengths of critical joint sections. Numerical results of internal joint forces and flexural strengths of critical joint sections are presented for a pair of concentric and eccentric interior connections extracted from a seismically designed RC frame. The results indicate that effects of joint shear and torque may reduce the column-to-beam flexural strength ratios to below unity and lead to "joint-yielding mechanism" for seismically designed interior connections. The information presented in this paper aims to provide some new insight into the seismic behavior of interior beam-column joints and form a preliminary basis for analyzing the complicated interaction of internal joint forces.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.92-101
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• 1997

In this paper, modeling methods for 2D joints are proposed. Earlier methods for modeling 2D joints that use geometric relationships may not consider irregularities or dynamic effects of joints. In any case, it is important to consider irregularities or dynamic effects. To consider those, methods that use dynamic contacts are proposed. With the method, 2D joints that have irregularities or dynamic effects amy be model- ed and analyzed. 2D joints that are developed are revolute, translational, gear and point-follower joint.

• Proceedings of the ESK Conference
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• 1994.04a
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• pp.115-123
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• 1994

A man model can be used as an effective tool to design ergomonically sound products and workplaces, and subsequently evaluate them properly. For a man model to be truly useful, it must be integrated with a posture prediction model which should be capable of representing the human arm reach posture in the context of equipments and workspaces. Since the human movement possesses redundant degrees of freedom, accurate representation or prediction of human movemtn was known to be a difficult problem. To solve this redundancy problem, the psychophysical cost function can predict the arm reach posture accurately. But the joint discomfort that human feels at the joint can not be predicted since the effects of external factors on the joint discomfort is not known. In this study a psychophysical experi- ment using the magnitude estimation technique was performed to evaluate the effects of external factors such as joint, joint angle and Perceived Exertion Ratio on the joint discomfort. Results showed that the joint discomfort increased as the Perceived Exertion Ratio increased, but the relation is not linear and was affected not only by the joint but also by the joint angle for the same Perceived Exertion Ratio. The interaction effect of the joint and the joint angle was also significant. From the results it is needed to develope the cost function which can predict the joint discomfort considering the joint, joint angle and external load.

• PNF and Movement
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• v.16 no.1
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• pp.51-58
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• 2018

Purpose: The aim of the present study was to investigate the effects of proprioceptive neuromuscular facilitation (PNF) and taping interventions on balance ability, joint position sense, and ankle joint strength. Methods: Thirty subjects who had experienced an ankle sprain within the previous 3 months participated in this study. The subjects were randomly assigned to a PNF group (n=15) or a taping group (n=15). Before and after the interventions, ankle dorsi-flexion and plantar-flexion strength, joint position error, and total center of pressure movements in one leg while in a standing position were measured. Results: Regardless of the group allocation, ankle dorsi-flexion and plantar-flexion strength significantly improved after the interventions (p<0.05). Compared to preintervention measurements, joint position errors were significantly reduced postintervention (p<0.05). The PNF intervention significantly decreased the total lateral movement of the center of pressure in the one leg standing condition (p<0.05). Conclusion: Both PNF and taping interventions improved joint position sense and ankle joint strength. In common with the findings of a previous study, the PNF intervention improved balance ability. Further study is required to investigate the effects of various PNF and taping interventions on ankle performance in subjects with chronic ankle sprains.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.4
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• pp.509-514
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• 2012

PURPOSE: This study aims to compare the effects of upper backbone joint mobilization and self-stretching exercise in the patients with chronic neck pain. METHODS: Thirty seven patients with chronic neck pain were divides into self stretching group(SSG, n=18) and mobilization group(MG, n=19). To assess the degree of neck pain, the visual analog scale (VAS) was utilized, and to measure the joint range of motion at the flexion-extension, it was compared and analyzed by using the cervical range of motion (CROM) device. RESULTS: The joint range of motion and visual analog scale of SSG and MG showed significant effects on both groups. In the comparison of groups, there was no significant difference, but it indicated effects on improving the pain and the range of joint motion in MG. CONCLUSION: According to the analysis, not only self-stretching exercise intervening for direct treatment but also upper backbone joint mobilization intervening for indirect treatment are effective to improve the pain and the range of motion.

• Journal of the Korea Safety Management & Science
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• v.25 no.2
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• pp.107-111
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• 2023

This study aims to empirically investigate effects of motion repetition and external load according to joint motion on discomfort through an experiment. Eighteen college students (female: 9; male: 9) participated in an experiment measuring perceived discomfort using the Borg CR10. Joint(wrist, elbow, shoulder and trunk) motion, its repetition and external load were adopted as independent variables. The results showed that all three independent variables were statistically significant on discomfort. Participants' sex also significantly affected discomfort obtained in the experiment. While the interactions of joint motion and repetition, and joint motion and external load were not significant at α = 0.05, that of motion repetition and external load was significant. Based on the experimental results, four regression equations by the joints involved were presented, which could be used as a tool for evaluating postural loads by the joints. It may be postulated that based on the results of this study, scoring systems of RULA and REBA, and those of OWAS and REBA underestimates effects of motion repetition and external load, respectively. It is expected that the results of this study will be used as a basic data for developing an observational method properly reflecting the effects of motion repetition and external load.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1174-1179
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• 2004

Field tests were conducted to investigate effects of a rail joint on the dynamic behavior of railway bridge. A four-span simpled supported plate girder bridge which has a rail joint on the third span was selected for tests. At the operating train loading, the induced vibration of the first and third span has been examined. The dynamic magnification ratio was used for quantitative analysis of impact effects caused by rail joint. The result of tests show that dynamic behavior of railway bridge picked up considerably due to a rail joint.