• Advances in concrete construction
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• v.9 no.5
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• pp.511-527
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• 2020

The main aim of the current research is to investigate the flexural behavior of the reinforced concrete (RC) slabs strengthened with strain hardening cementitious composites (SHCC) experimentally and numerically. Seven RC slabs were prepared and tested under four-points loading test. One un-strengthened slab considered as control specimen while six RC slabs were strengthened with reinforced SHCC layers. The SHCC layers had different reinforcement ratios and different thicknesses. The results showed that the proposed strengthening techniques significantly increased the ultimate failure load and the ductility index up to 25% and 22%, respectively, compared to the control RC slab. Moreover, a three dimensional (3D) finite element model was proposed to analyze the strengthened RC slabs. It was found that the results of the proposed numerical model well agreed with the experimental responses. The validated numerical model used to study many parameters of the SHCC layer such as the reinforcement ratios and the different thicknesses. In addition, steel connectors were suggested to adjoin the concrete/SHCC interface to enhance the flexural performance of the strengthened RC slabs. It was noticed that using the SHCC layer with thickness over 40 mm changed the failure mode from the concrete cover separation to the SHCC layer debonding. Also, the steel connectors prevented the debonding failure pattern and enhanced both the ultimate failure load and the ductility index. Furthermore, a theoretical equation was proposed to predict the ultimate load of the tested RC slabs. The theoretical and experimental ultimate loads are seen to be in fairly good agreement.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.98-106
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• 2008

The strengthening in terms of efficiency, easy, economics is very popular method when it is applied to a damaged structures. The purpose of this study develops anchorage system that supports enough strengthening effect without any damage. In addition it is checked whether the method can be conveniently applied to structures. To verify strengthening effect a flexural experiments were performed. Four concrete beams were constructed and tested. Deflections, strains and modes of failure were recorded to examine strengthen of beams. Comparing crack load of each experimental data, yielding load, ultimate load, ductility index, and tendon stress were analyzed.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.3
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• pp.129-139
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• 2020

Objectives The purpose of this study was to compare the effect of supine JS cervical therapy and muscle release/strengthening technique in patients with acute neck pain caused by traffic accidents. Methods We studied 42 patients with acute neck pain caused by traffic accidents from July 1, 2019 to November 30, 2019. The study was conducted as a retrospective study which analyzes the patient's medical records. 21 patients (group A) had received supine JS cervical therapy and 21 patients (group B) had received muscle release/strengthening technique. We used the neck disability index (NDI) and visual analog scale (VAS) to evaluate improvements in symptoms and pain, and used the five point Likert scale to evaluate patient's satisfaction with chuna manual therapy. In each group, we compared the NDI and VAS of hospitalization day to those of 5 days later. Then we compared the NDI, VAS variation and five point Likert scale between the groups. Statistical analysis was conducted using the IBM SPSS for windows 25.0. Result Both group A and group B showed a statistically significant decrease in the NDI and VAS on the 5th day of hospitalization. In group A, there was a statistically significant decrease in the NDI compared to group B. The VAS and Five Point Likert Scale decrease was greater in group A than in group B, but the difference was not statistically significant. Conclusion We found that using supine JS cervical therapy may be more effective than muscle release/strengthening technique in acute stage after traffic accidents.

• Earthquakes and Structures
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• v.26 no.2
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• pp.131-147
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• 2024

Damage caused by an earthquake depends on not just the intensity of an earthquake but also the region-specific construction practices. Past earthquakes in Asian countries have highlighted inadequate construction practices, which caused huge life and property losses, indicating the severe need to strengthen existing structures. Strengthening activities shall be proposed as per the proposed weighting factors, first at the higher weighted members to increase the capacity of the building immediately and thereafter, the other members. Through this study on gravity load-designed (GLD) buildings, relative weights are assigned to each storey and exterior and interior columns within a storey based on their contribution to the energy dissipation capacity of the building. The numerical study is conducted on mid-rise archetype GLD buildings, i.e., 4, 6, 8, and 10 stories with variable storey heights, in the high seismic zones. Non-linear static analysis is performed to compute weights based on energy dissipation capacities. The results obtained are verified with the non-linear time history analysis of 4 GLD buildings. It was observed that exterior columns have higher weightage in the energy dissipation capacity of the building than interior columns up to a certain building height. The damage in stories is distributed in a convex to concave parabolic shape from bottom to top as building height increases, and the maxima location of the parabola shifts from bottom to middle stories. Relative weighting factors are assigned as per the damage contribution. And the sequence for strengthening activities is proposed as per the computed weighting factors in descending order for regular RCC buildings. Therefore, proposals made in the study would increase the efficacy of strengthening activities.

• Physical Therapy Korea
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• v.7 no.1
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• pp.32-37
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• 2000

The purpose of this study is to determine the effects of exercise training on the strength and balance ability of the elderly. The results of this study are: 1) After 8 weeks exercise training, knee muscle strength showed a significant increment. 2) After exercise training, forward functional reach and balance index of KAT 2000 showed a significant increment. Results indicate that strengthening exercise can result in improved muscle strength and balance in the elderly. Further studies are required to show long-term effects of exercise training on the elderly.

• Steel and Composite Structures
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• v.41 no.6
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• pp.851-860
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• 2021

In this paper, a new approach of interface stress analysis in steel beam strengthened by porous FGM (Functionally Graded Materials) is presented to calculate the shear stress in the hybrid steel beam and loaded by a uniformly distributed load. The results show that there exists a high concentration of shear stress at the ends of the imperfect FGM, which might result in premature failure of the strengthening scheme at these locations. A parametric study has been conducted to investigate the sensitivity of interface behavior to parameters such as the rigidity of FGM plate (degree of homogeneity), the porosity index of FGM and the thickness of adhesive all were found to have a marked effect on the magnitude of maximum shear stress in the FGM member. we can conclude that the new approach is general in nature and may be applicable to all kinds of materials.

• The Journal of Korean Physical Therapy
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• v.32 no.3
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• pp.163-167
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• 2020

Purpose: Unilateral strength training effects on contralateral sides have been demonstrated in previous studies for lower extremity exercise, upper extremity exercise, and unilateral surface electrical stimulation. This study was performed to investigate the effects of unilateral ankle training on muscle strength and the balance of contralateral lower extremity in healthy adults. Methods: Thirty healthy subjects were randomized equally to a training or a control group. Those in the training group received unilateral ankle isokinetic strengthening training of the dominant leg (right side) for 4 weeks. Contralateral single-limb balance, including Anterio-Posterior Stability Index (APSI), Medio-Lateral Stability Index (MLSI) and Overall Stability Index (OSI), was assessed before and after intervention. Results: Comparison of pre- and post-test data revealed significant improvements in ipsi- and contralateral ankle strengths, and significant improvement in contralateral single limb balance. Conclusion: These results have practical implications because they demonstrate that unilateral ankle isokinetic exercise improves ankle muscle strength and balance ability of contralateral lower extremity.

• Fire Science and Engineering
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• v.30 no.1
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• pp.81-85
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• 2016

Reasonable disaster prevention signs play an important role in guiding evacuation. Through the field investigation on disaster prevention signs in shelters and surrounding areas in Beijing, some problems were found in the using of sign system. Based on the principle of integrated design, evacuation and rescue requirements, it is necesssary to make further study on aspects such as, design of function, systematic consideration, humanization design, as well as the internationalization using. This paper presents an evaluation index system for disaster prevention signs. Such a system is very important for strengthening the independent guiding function of sign systems and improving evacuation efficiency. An effective connection could be realized between the internal environment of buildings, evacuation routes, and emergencey shelters.

• The Journal of Korean Physical Therapy
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• v.29 no.1
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• pp.1-6
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• 2017

Purpose: This study aimed to demonstrate reduction in stroke symptoms by analyzing the changes in respiratory function and activities of daily living (ADL) after respiratory muscle strengthening exercise in patients who had a stroke and thereby, propose an efficient exercise method. Methods: Twenty patients with hemiplegic stroke were divided into two groups, with 10 patients in each. The control group (CG) received the traditional exercise therapy, and the experimental group (EG) received the traditional exercise therapy combined with expiratory muscle strengthening training. The training continued for 6 weeks, 5 days a week. Forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV1) were measured with a spirometer, $SpO_2$ was measured with a pulse oximeter, and ADL were assessed by using the modified Barthel index (MBI). A paired t test was applied to compare the differences before and after the intervention, and an independent t test was used to compare the differences between the groups. The level of statistical significance was set as ${\alpha}=0.05$. Results: The changes in the FVC and FEV1 values within the group showed significant differences only in the EG (p<0.01). The between-group difference was statistically significant only for FVC and FEV1 in the EG (p<0.01). The changes in $SpO_2$ and MBI within the group showed significant differences only in the EG and CG (p<0.01). Between-group differences were statistically significant only for $SpO_2$ and MBI in the EG (p<0.05). Conclusion: The interventions with active patient involvement and combined breathing exercises had a positive impact on all the functions investigated in this study.

• Physical Therapy Korea
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• v.22 no.1
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• pp.58-68
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• 2015

This study aimed to determine the effect of lower trapezius muscle strengthening exercises on pain, neck disability index (NDI), cervical range of motion (ROM), and lower trapezius muscle strength in patients with unilateral neck pain. Following baseline measurements, the subjects (N=40) with unilateral neck pain were randomized into one of two 5 weeks exercise intervention groups: a experimental group (EG, $n_1=20$) that received strength training of the lower trapezius muscles or a control group (CG, $n_2=20$) that received routine physical therapy program. Each group participated in the intervention for 30 minutes, 3 times a week, for 5 weeks. All participants performed 2 repetitions of each intervention per day. The numeric pain rating scale for pain, NDI, ROM, and lower trapezius strength were recorded both pre- and post-intervention for both groups. Paired t-tests were used to determine significant changes post-intervention compared with pre-intervention and independent t-tests were used to analyze differences in the dependent variables between the 2 groups. After the 5-weeks intervention, both groups experienced significantly decreased pain and disability level (p<.05) and significantly increased cervical flexion, extension, lateral flexion, and rotation ROM (p<.05). The EG that received strength training of the lower trapezius muscles showed greater improvements in pain and functional disability level, cervical rotation, and lower trapezius strength than the CG (p<.05). These results suggest that a lower trapezius strengthening exercises reduce neck pain and neck disability level and enhance cervical ROM and lower trapezius strength level in patients with unilateral neck pain.