• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.117-124
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• 2006

The effects of binder content and recycling mixed waste plastics(PA) content on the workability, work life and hardening shrinkage of fresh polymer concrete using mixed waste plastics are examined. As a result, the workability of the polymer concretes using mixed waste plastics tend to improve with increasing binder content, PA content and filler content. The work life of the polymer concretes using mixed waste plastics is shortened with an increase in the initiator content and curing temperature. The length change of the polymer concretes using mixed waste plastics tend to increased with Increasing binder content and PA content. The result of the present research is expected to make a contribution to the recycling of final mixed waste plastics and the continuing efforts for the development of use of the recycled products are thought to expand the horizon for the recycling of the final mixed waste plastics.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.1
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• pp.55-63
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• 2020

PURPOSE: This study examined the effects of handgrip exercise, which was started two weeks after surgery for shoulder rotator cuff repair, on the extent of muscle activation around the shoulder and the cross-sectional area of the supraspinatus muscle. METHODS: Among patients diagnosed with rotator cuff rupture by an orthopedic surgeon and rotator cuff repair was performed using an arthroscope, 28 were selected as subjects. These subjects were allocated randomly to the experimental group and control group with 14 subjects in each group. An electromyogram was measured as a measure of the extent of muscle activation around the shoulder for a total of six times (%RVC). The cross-sectional area of the supraspinatus muscle was measured before and after the rotator cuff repair by magnetic resonance imaging. RESULTS: The extent of muscle activation in accordance with time in both the experimental group and control group displayed significant differences in various muscles including the anterior deltoid, pectoralis major, upper trapezius and infraspinatus muscle(p<.05). A significant difference in the variation of the cross-sectional area of the supraspinatus muscle was observed between the experimental group and the control group(p<.05). CONCLUSION: Handgrip exercise helps rehabilitate the shoulder joint at the acute stage after rotator cuff repair when assertive exercise therapy cannot be applied.

• Clinics in Shoulder and Elbow
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• v.5 no.1
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• pp.47-54
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• 2002

Purpose : We evaluated clinical result of arthroscopic and open Bankart repair in anterior shoulder instability to identify factors iuluencing operative result and prognosis. Materials & Methods . We reviewed 24 patients of anterior shoulder instability treated with arthroscopic Bankart repair in 16 cases and open Bankart repair in 8 cases. Average age was 26 years old and involved in dominant arm in 15 cases. Patients were suffered instability for 3.1 years before operation and mean follow-up was 2 year 9 months ( 1 you 9 months -4year 10 months). Results : Post operative pain was subsided in 2 weeks in arthroscopic surgery and 3 weeks in open surgery. The final range of motion after arthroscopic repair were flekion in 168" , external rotation in 54" , and internal rotation in 79, and after open repair 168" ,49" , and 78 respectively. In arthroscopic surgery,2 cases (13%) were redislocated, and 4 cases(25%) showed mild instability. In open case,1 case (11%) showed mild instability. According to function- al result by Rowe grading scale, satisfactory results were 12case (76%) in arthroscopic repair and 7 cases (88%) in open cases. Conclusions Both arthroscopic or open Bankart could get good results in the treatment of anterior instability of shoulder. In arthroscopic repair, perioperative morbidity was lower than open repair, but it needs careful rehabilitation program to prevent redislocation and to return to sports activity.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.545-548
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• 1999

The purpose of this study is application of strengthening technique of R/C concrete bridge by standardization of repair and rehabilitation. For that, experiment to bridge is necessary, and through the experiment, this study can identify the efficiency o applied method and analysis of design parameters with can't get in the laboratory experiment. This study will prove the structural behavior of R/C type girder bridge which is deteriorated but repaired and rehabilitation from standardized strengthening method with fiber plastic.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.813-818
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• 1999

The construction of large scale civil and building structures which form the base of social economy has been grown greatly. As the increasing of aged and deteriorated structures, it is necessary to evaluate the safety of those structures. The deterioration, safety evaluation, repair and rehabilitation are important problems in the construction area that every country faces. This paper presents the general information on how to conduct a data analysis of long-term monitoring system and evaluate the characteristics of surveying methods.

• Journal of Korean Association for Spatial Structures
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• v.23 no.2
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• pp.79-90
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• 2023

Existing reinforced concrete (RC) frame buildings have seismic vulnerabilities because of seismically deficient details. In particular, since cumulative damage caused by successive earthquakes causes serious damage, repair/retrofit rehabilitation studies for successive earthquakes are needed. This study investigates the repair effect of fiber-reinforced polymer jacketing system for the seismically-vulnerable building structures under successive earthquakes. The repair modeling method developed and validated from the previous study was implemented to the building models. Additionally, the main parameters of the FRP jacketing system were selected as the number of FRP layers associated with the confinement effects and the installation location. To define the repair effects of the FRP jacketing system with the main parameters, this study conducted nonlinear time-history analyses for the building structural models with the various repairing scenarios. Based on this investigation, the repair effects of the damaged building structures were significantly affected by the damage levels induced from the mainshocks regardless of the retrofit scenarios.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.248-258
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• 2020

This study proposed a breakdown structure for maintenance and management technologies under the concept of comprehensive asset management at the life cycle level of infrastructure based on benchmarking with other developed countries. For this purpose, a comparative case study was performed to review and analyze the existing definitions and hierarchies for infrastructure maintenance, repair, and rehabilitation (MR&R) systems under major industrialized countries and South Korea. In accordance with the ratio of maintenance costs to GDP, the U.S., U.K, and Japan were selected to review their systems. The classifications and definitions of MR&R technologies under the laws were analyzed. The result showed that most developed countries differentiate maintenance and repair from improvement and constitute a system centered on preventive maintenance activities. On the other hand, Korea's system for facility management is not definitely classified and still focused on reactive structures, which need to be improved. In this study, as proposed, a breakdown structure established the concept of Maintenance and Management, Maintenance & Repair, and Performance Improvement. Consequently, this study could be used as the basis for the implementation of preventive MR&R activities and reasonable resource allocations from an asset management point of view.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.79-88
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• 2002

Purpose: In this prospective, randomized study, we compared the results of early motion versus conventional immobilization after the arthroscopic Bankart repair. Materilal and Methods : We performed an arthroscopic Bankart repair using suture anchors in 62 patients with traumatic anterior shoulder instability and randomized them into two groups; Group 1 (n=28; mean age, 28 years) underwent three-week of immobilization and conventional rehabilitation program, while Group 2 (n=34; mean age, 29 years) underwent an accelerated rehabilitation program with staged range of motion and strengthening exercises starting from the immediate postoperative day. Selected patients were non-athletes with a classic Bankart lesion and a robust labrum. Analysis of outcome included pain scores (6-week and follow-up: 31(9 months), range of motion, return to activity, recurrence, patients’ satisfaction with each program, and shoulder scores (ASES, UCLA, and Rowe). Results : The recurrent rate was not different between the two groups (2 anterior apprehension from each group) (p=0.842). Patients with accelerated rehabilitation resumed functional range-of-motion faster and returned earlier to the functional level of activity (p<0.05). Accelerated rehabilitation decreased postoperative pain and more patients were satisfied with this program (p<0.05). No differences were found between the two groups at the follow-up with regards to the shoulder scores, return to activity, pain score, and the range-of-motion. Conclusions : Early mobilization after arthroscopic Bankart repair does not increase the recurrence rate in selected patients. Although the final outcomes are similar in both groups, the accelerated rehabilitation program promotes functional recovery and reduces postoperative pain, which enables patients an early institution of desired activities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.577-585
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• 2024

Infrastructure plays a crucial role in the industrial development and economic growth of a nation. However, recently, domestic infrastructure has been causing not only safety risks due to aging but also social and economic inefficiencies, increasing the need for maintenance. In particular, the deterioration rate of bridges is serious, so application of appropriate repair and rehabilitation methods and estimation of its quantity are required. In this study, frequently applied repair methods for bridges using data from the Facility Integrated Management System (FMS) were identified. the empirical correlation between damage volume and the repair volume was analyzed using Bridge Management System (BMS) data. The result of the analysis showed that the ratio of the repair volume to the damage volume was 1.0. The guideline, on the other hand, suggest 1.5 the ratio of the repair volume to the damage volume. Although the guidelines differently present more conservative figures considering safety, this study is significant in that it presents a practical ratio through data analysis results. This results can be used to develop a model that can calculate the amount of repair and rehabilitation of various facilities in the future.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.723-736
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• 2019

The efficacy of a technique for the rehabilitation and strengthening of RC beam-column connections damaged due to cyclic loading was investigated. The repair mainly uses epoxy resin infused under pressure into the damaged region to retrieved back the lost capacity and then strengthening using fiber reinforced polymer (FRP) sheets for capacity enhancement. Three common types of reduced scale RC exterior beam-column connections namely (a) beam-column connection with beam weak in flexure (BWF) (b) beam-column connections with beam weak in shear (BWS) and (c) beam-column connections with column weak in shear (CWS) subjected to reversed cyclic loading were considered for the experimental investigation. The rehabilitated and strengthened specimens were also subjected to similar cyclic displacement. Important parameters related to seismic capacity such as strength, stiffness degradation, energy dissipation, and ductility were evaluated. The rehabilitated connections exhibited equal or better performance and hence the adopted rehabilitation strategies could be considered as satisfactory. Confinement of damaged region using FRP sheet significantly enhanced the seismic capacity of the connections.