• Archives of Plastic Surgery
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• 제46권3호
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• pp.228-234
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• 2019

Background The management of flexor tendon injuries has evolved in recent years through industrial improvements in suture materials, refinements of repair methods, and early rehabilitation protocols. However, there is no consensus on the ideal suture material and technique. This study was conducted to compare the tensile strength, repair time, and characteristics of 4-strand cruciate, modified Kessler, and 4-strand horizontal intrafiber barbed sutures for flexor tenorrhaphy with a 12-mm suture purchase length in an animal model. Methods The right third deep flexors of 60 adult Leghorn chicken feet were isolated and repaired with a 12-mm suture purchase length. The tendons were randomly assigned to three groups of equal number (n=20 each). Groups 1 and 2 received 4-strand cruciate and modified Kessler repair with conventional suture materials, respectively. A 4-strand horizontal intrafiber barbed suture technique was used in group 3. The repaired tendons were biomechanically tested for tensile strength, 2-mm gap resistance, and mode of failure. Repair times were also recorded. Results The maximum tensile strength until failure was $44.6{\pm}4.3N$ in group 1, $35.7{\pm}5.2N$ in group 2, and $56.7{\pm}17.3N$ in group 3. The barbed sutures were superior to the other sutures in terms of the load needed for 2-mm gap formation (P<0.05). Furthermore, the barbed sutures showed the shortest repair time (P<0.05). Conclusions This study found that 4-strand horizontal intrafiber barbed suture repair with a 12-mm purchase length in a chicken flexor tendon injury model showed promising biomechanical properties and took less time to perform than other options.

• Computers and Concrete
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• 제7권3호
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• pp.249-269
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• 2010

Managing and reusing knowledge in engineering and construction sectors can lead to greater competitive advantage, improved designs, and more effective management of constructed facilities. The use of Information Technology (IT) in design and construction can exploit strategic opportunities for new ways of integration, sharing and facilitating information and knowledge in any field of engineering. The integrating of separate areas of IT can be used to bring a group of experts and specialists in any field of engineering closer together by allowing them to communicate and exchange information and expertise that facilitate knowledge capture, sharing, and reuse. A lack of an advisory management system and a need to marshal all available data in a common format has indicated the need for an integrated engineering computing environment to investigate concrete repair problems. The research described in this paper is based upon an evaluation management system (EMS) which comprising a database management system (REPCON) alongside visualisation technologies and evaluation system (ECON) is developed to produce an innovative platform which will facilitate and encourage the development of knowledge in educational, evolution and evaluation modes of concrete repair. This allows us to create assessment procedures that will allow the current condition of the concrete structure and its components to be expressed numerically using a confidence level (CL) so as to take the best course of action in the repair and maintenance management. The explained rating system, which is related to structural integrity and serviceability of the structure, allows the confidence level to be determined by visual inspection and the descriptive information and pictures taken from an available REPair of CONcrete (REPCON) database.

• Earthquakes and Structures
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• 제14권5호
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• pp.379-388
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• 2018

This study aims to identify the effect of both longitudinal reinforcement details and damage level on making a decision of repairing pre-damaged bridge columns using basalt fiber reinforced polymer (BFRP) jackets. Two RC bridge columns with improper details of the longitudinal and/or transverse reinforcement were tested under the effect of a constant axial load and increasing lateral cyclic loading. Test results showed that the lap-splice column exhibited an inferior performance where it showed rapid degradation of strength before achieving the theoretical strength and its deformation capacity was limited; however, quick restoration is possible through a suitable rehabilitation technique. On the other hand, expensive repair or even complete replacement could be the decision for the column with the confinement failure mode. After that, a rehabilitation technique using external BFRP jacket was adopted. Performance-based design details guaranteeing the enhancement in the inelastic performance of both damaged columns were addressed and defined. Test results of the repaired columns confirmed that both reparability and the required repairing time of damage structures are dependent on the reinforcement details at the plastic hinge zone. Furthermore, lap-splice of longitudinal reinforcement could be applied as a key design-tool controlling reparability and restorability of RC structures after massive actions.

• Smart Structures and Systems
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• 제2권4호
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• pp.305-312
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• 2006

In the case of hospital buildings, where seismic design requirements are very high, existing structuresand especially those attacked by past earthquakes, appear, often, unable to fulfil the necessary safety prerequisites. In this paper, the retrofitting of hospital buildings is investigated, using alternative methods of repair and strengthening. Analysis of an existing hospital building in Patras, Greece, is performed. The load-bearing system is a reinforced concrete system. Two solutions are proposed: strengthening using concrete jackets around column and beam elements and application of viscoelastic dampers for the increase of the stability of the structure. Adequate finite element models are constructed for each case and conclusions are drawn on the efficiency of each rehabilitation method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.491-496
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• 2001

In recent years, the research and development about the new material proceed rapidly and actively in the building industry. As building structures become bigger, higher and more specialized, so does the demand for material with higher strength. In the future, we will need to research repair and rehabilitation to make high strength concrete mixed steel fibrous building safe. The carbon fiber reinforced plastic bonding method is widely used in reinforcing the existing concrete structure among the various methods. The repair of initiate loaded reinforced high-strength concrete beams mixed steel fibrous with epoxy bonded Carbon Fiber Sheets(CFS) was investigated experimentally. The CFS thickness and length were varied to assess the peel failure at the curtailment of CFS, The behaviour of the repaired beams was represented by load-longitudinal steel strain relation and failure modes were discussed. The test results indicate that CFS is very effective for strengthening the demand beams and controlling deflections of reinforced high strength concrete beams mixed steel fibrous happen diagonal crack, the increase in the number of CFS layers over two layers didn't effect the increase in the strength of beams.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.541-546
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• 2000

Recently, there have been increased mush concerns about repair and rehabilitation works for aged concrete structures to keep up with rapid economic growth in Korea since the early 1970's. In particular, it is believed in these days that there are significantly increasing number of aged concrete bridge slabs, which are strongly needed to construct and rehabilitate by innovative construction method. The objective of this research is to develop the new construction method of concrete slab in bridge structure, which can contribute to minimize the traffic congestion during the repair and rehabilitation works of aged concrete slab, and can also sufficiently assure the quality through the minimization of in-situ works at the site. I-beams with punch holes, which are substituted instead of main reinforcing steels in concrete slabs, will be manufactured in accordance with the specification in the factory, and will be preassembled into the panel. After erecting the preassembled panels in the site, concrete will be poured into the slab panel. This test is to investigate physical properties of I-Beam with punch holes itself, and then to investigate structural properties of assembled I-Beam panels through static and fatigue test, of which can be utilized for the development of new construction method of concrete slab in bridge structure.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.979-984
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• 2001

The Sang-Jin bridge constructed by the Free Cantilever Method in 1985 is 4-span concrete rahmen bridge with a hinge at midspan. Due to the effect of creep, shrinkage of concrete and relaxation of tendon, the Sang-Jin bridge exposed the excessive displacement at midspan with the passage of time. In order to improve the load-carrying-capacity and durability of the bridge, needs to repair and rehabilitate the structure emerged. New rehabilitation methods were applied such as external prestressing of concrete box, application of pier pre-camber and steel truss jacking. Structural analysis and several tests including static load test, dynamic load test and ambient vibration test were executed to verify the improvement. The test result showed that the displacement of the midspan was improved by 10mm and it was verified that the stiffness of the bridge was increased. Totally, the load-carrying-capacity of Sang-Jin bridge was increased at least 1.56times which was attributed to the new rehabilitation method.

• 한국강구조학회 논문집
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• 제9권3호통권32호
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• pp.363-375
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• 1997

절취된 세로보를 갖는 강철도교량의 바닥판에서의 피로거동 및 손상시 보수 보강의 효과를 연구하기 위해 8개 대형시험체에 대한 모형시험을 수행하였다. 실교량을 대상으로 실동응력을 측정하여 기본 응력범위 빈도히스토그램을 작성하고 이에 의한 변동응력의 등가응력범위를 산출하였다. 이 등가응력범위를 기준으로 피로시험의 응력변동범위의 크기를 조정하면서 정적 및 피로시험을 보강전과 보수 보강후로 구분하여 실시하였다. 정적시험에 의하면 재하하중의 크기가 등가실동응력 수준인 시험체의 경우에서 이미 허용응력과 비슷한 응력을 나타내므로서 피로균열의 발생조건을 충족하고 있었다. 손상된 시험체에 대해 다양한 보수 및 보강을 실시하여, 각각의 결과를 비교검토하였다. 그 결과 보수효과는 stop hole을 천공하고 고장력볼트를 체결한 경우에 피로균열성장의 지체효과가 뚜렷하게 나타났다. 한편 보강효과는 휨의 지배를 받는 세로보의 경우 인장측 플랜지의 보강이 효과적이며, 복부의 보강은 보강방법으로 적절하지 않음을 알 수 있었다. 또한 직각절취된 세로보의 피로설계등급은 우리나라 시방서 피로설계규정의 E등급에 해당한다는 것을 확인할 수 있었다.

• 구강회복응용과학지
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• 제22권3호
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• pp.211-220
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• 2006

Need of porcelain-repair system is largely demanding as dental porcelain restorations are increased in clinical dentistry. This study investigated shear bond strength of commercial porcelain-repair systems on dental porcelain and their reliability. Experimental groups were as follows; Group A Super Bond C&B, Group B Porcelain repair kit, Group C Ceramic repair, and Group D Spectrum system as a control. Porcelain disks were fired and embedded in epoxy resin. Porcelain surface were ground using 220 grit SiC disk, then cleaned in ultrasonic bath. Then porcelain specimens were treated with each repair system. A clear polystyrene cylinder 3.5 mm in internal diameter was filled with composite resin. Then the resin cylinder was polymerized with a visible light curing unit. Thirty one specimens at each group were prepared and stored at $37^{\circ}C$ distilled water for 48 h. Specimens were tested in an Instron testing machine according to ISO TR 11405. Mean shear bond strength and standard deviation of each group was $15.7{\pm}4.1MPa$ (Group A), $12.8{\pm}4.9MPa$ (Group B), $7.2{\pm}3.0MPa$ (Group C) and $9.6{\pm}2.2MPa$ (Group D). ANOVA and Tukey HSD post-hoc test showed that there were significant differences between groups (p<0.05). Data of bond strength were analyzed with two-parameter Weibull distribution. Confidence interval of Weibull modulus (m-parameter) at 95% of Group A (3.5-6.3) and Group D (3.6-6.0) were significantly higher than Group B (2.2-3.7) and Group C (2.0-3.4). There was little correlation between mean shear bond strength and Weibull modulus. Results indicated that acid-etching of porcelain surface increased porcelain-resin shear bonding strength.

• Clinics in Shoulder and Elbow
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• 제9권1호
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• pp.27-33
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• 2006

Purpose: To investigate early complications after repair of massive rotator cuff tears and to find out factors that compromise the results. Materials and Methods: Fourteen patients who had two or more cuff tendons involved were included. All patients were operated by open acromioplasty and rotator cuff repair. At 3 months after operation, we investigated whether there were any early complications or not. We used ASES scoring system for preoperative and follow up evaluation. In addition, various preoperative factors, such as duration of symptom, degree of tendon retraction, degree of fatty degeneration, and acromio-humeral distance, were compared between the complicated patients and non-complicated patients. Results: At 3 months after operation, the ASES score and pain were improved in any degree in all patients. But 5 patients complained persisting pain, and three of them showed major complications such as re-rupture of rotator cuff or deltoid rupture. But no preoperative factors in complicated patients were significantly different from those in non-complicated patients. Conclusion: None of the preoperative factors were related to the complications. There was a tendency of overestimation of fatty degeneration in MRI. Some factors in surgical technique and rehabilitation were highly suspected to be related to the complications.