• Journal of the military operations research society of Korea
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• v.36 no.1
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• pp.91-102
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• 2010

Doubler repair is one of the frequently applied methods to repair cracks which occur at the structure of aircraft weapon systems. The requirement of the doubler repair for some of aging aircraft has increased more recently. However very few researches have been conducted until now. In this paper, the effect of the various doubler repair methods was evaluated. Especially, the relationship between the array of revet and the effect of stress concentration was investigated. To calculate variation of the stress with different repair methods, commercial FEA program was utilized. As a result, it was shown that the main factor for the variation of stress is pitch and number of revet line. Furthermore the optimized array of revet for the specific geometries of doubler was suggested.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.4
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• pp.284-291
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• 2013

Purpose: This study compared fracture strength and fracture modes between metal wire reinforcement and glass fiber reinforcement in repaired maxillary complete denture. Materials and methods: In this study, fracture was reproduced on center of maxillary complete dentures and the denture was repaired with auto-polymerizing resin. The experimental groups (n = 10) were subjected to the following condition: without reinforcing material (control group), reinforcing with metal wire (W group), reinforcing with glass fiber pre-impregnated with light-curing resin (SES MESH, INNO Dental Co., Yeoncheon, Korea, G group). The fracture strength and fracture modes of a maxillary complete denture were tested using Instron test machine (Instron Co., Canton, MA, USA) at a 5.0 mm/min crosshead speed. The flexure load was applied to center of denture with a 20 mm diameter ball attachment. When fracture occurred, the fracture mode was classified based on fracture lines. The Kruskal-wallis test and the Mann-whitney U test were performed to identify statistical differences at ${\alpha}=.05$. Results: W group showed the highest value of fracture strength, there was no significant difference (P>.05) between control group and G group. Control group and W group showed anteroposterior fracture mainly, group W showed adhesive fracture of denture base and reinforcing material. Conclusion: In limitation of this study, the glass fiber did not improve the fracture strength of repaired maxillary complete denture, and adhesive failure was occurred along the lines of glass fiber.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.106-114
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• 2009

The basis principle of conservation about deterioration and corrosion of cultural assets building is the archetype maintenance, and should not make a factitious damage mistake by repair. Accordingly, conservation processing method using synthetic resins is embossed. The purpose of this paper is about flexural capacity of rectangular section wood using synthetic resins, the 11 specimens are manufactured and made an experiment about reinforcement length, ratio, material strength, direction of synthetic resins as variable. The results of this paper has shown that flexural reinforcement of wood by synthetic resins are efficient and found the possibility of using.

• Journal of Korean Association for Spatial Structures
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• v.9 no.3
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• pp.93-100
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• 2009

As interest in latest cultural heritance is increased, an importance about conservation of dilapidated cultural building asset is risen. Most of cultural building asset used wood by main material and conservation repair about corrosion and damage by deterioration of these cultural building asset considers cultural value of member and the basis principle is the archetype maintenance. Accordingly, conservation processing method that use synthetic is embossed. This paper experimented with reinforcement sectional area ratio, direction of section, length, strength of synthetic resins as variable and manufactures total 14 specimens as experimental study about compression reinforcement performance of circular section wood that strengthen by synthetic resins. The result of this paper has shown that adequate strengthen is more efficient than new member and the most important authenticity in strengthen and repair of cultural heritance can be ensured.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1377-1387
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• 2013

Most embankment of the reservoirs (99.1 %) have been constructed in the earth filled type in Korea because the construction of this type is less expensive and simpler than others such as concrete one. However, it has to be reinforced the slope to prevent the breach due to overtopping or piping under unexpected flood conditions. This study has been analyzed the retardation effect using three types (L, T, $L^*$ shape) of stiffener in order to reinforce embankment when they are collapsed by overtopping flow. Experimental results showed that L-type stiffener is the most effective in delaying the breaching of embankment and reducing the soil erosion when compared with others. The reinforced embankment breaching showed that time delay was occurred about 1.73 to 2.29 times and the peak flowrate was reduced compared to non-stiffener embankments due to energy dissipation by collision and less soil erosion. The embankment breaching mostly leads to major damages because of the lack of repair time. Thus, since these stiffeners can resist the rapid breach, it would be possible to earn the time to emergency repair and lifesaving, as well as reduction of damages of embankment in downward region with decreasing peak flowrate. Results from this study would be used for the basis when establishing the emergency action plan for the reservoirs on the verge of hazard.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.159-164
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• 2017

This paper presents the results of an investigation into the thermo-hydromechanical response of weathered granite soil. The effect of forced change temperature and relative humidity at the soil layer boundaries were monitored during heating. A series of load settlement test were performed on layers of compacted, unsatureated weathered granite soil with geosynthetic embedded at mid height before and after application of heat exchanger to the base of the soil layers. The results from this study indicated the potential for using embedded heat exchangers for the mechanical improvement of geotechnical systems incorporating weathered granite soil.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.5
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• pp.869-886
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• 2018

Rockbolt is one of the most common supports used to reinforce discontinuous rock during underground excavation. Extra drain pipes are installed to improve excavation workability and the anchorage of rockbolts in water bearing ground. The drain pipe is effective in improving the workability by providing drainage path, but it is difficult to expect the reinforcement effect, increasing disturbance of the discontinuous rock mass and the construction cost. To solve this problem, dual purpose rockbolt (DPR) has been developed for the reinforcement of rock and the drainage of ground water. DPR was able to improve the mechanical and hydraulic stability of the rocks quickly and economically. Two kinds of DPRs using FRP (Fiber Reinforced Plastic) and steel were investigated for the mechanical and hydraulic performance. Also, the workability and stability of DPR were analyzed.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.4
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• pp.8-20
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• 2023

Although the landscape architectural facilities need to be repaired according to historical and authentic techniques, the repair criteria of the standard specification for repairing cultural heritages still remain at a theoretical level, and there are little research analyzing detailed techniques from specific cases. This study discussed the repair techniques based on historical facts, around terraced flower beds, ponds, waterways and pavement in the government-managed spaces in the Joseon Dynasty. It analyzed the materials and finish of stone wall elements, the structural reinforcement and backfill materials, and topsoil surface protection measures, and drew out stones for foundation reinforcement, plastering material for agglutination, and stone processing techniques for the terraced flower beds. It examined the materials and structures of the rock revetment, foundation reinforcement and waterproofing techniques and drew out the outstanding characteristics of the foundation work, the recycle of used elements and the management of water quality, for the ponds. It primarily investigated the materials, foundation reinforcement and waterproofing techniques and discovered the repair techniques such as cover stone finishing methods, foundation and backfill materials, and flow reduction methods, for the waterways. Finally, it provided actual cases of the foundation composition, auxiliary materials and tools, and the use of cyperaceae and highlighted the existence of professional craftsmen called Bangjeonjang(方磚匠), for the pavement. This study is expected to be a staring point for discovering the repair techniques for landscape architectural facilities and used as basic data for revising specifications in the future.

• Korean Journal of Heritage: History & Science
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• v.48 no.4
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• pp.110-125
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• 2015

This study is objected to investigate the repairing method and the modification period of rafters via the transformation traces left in the superciliums, where repair process takes places frequently. This is the basic research of analyzing the architectural features of Deokkeori, one of the additional-rafter methods. Deokkeori method can be described as using Deokdori in the top section of Hayeon, and placement of Sangyeon above it. This method was started to be used since middle of the Joseon dynasty period(middle 18th Century) and mainly used at 19th Century to resist the transformation caused by repairing. It had been gradually developed from non-application stage to application stage including additional usage of complement. The architectural features of Deokkeori can be categorized into four. First, the usage of Deokdori to connect Sangyeon to the top section of Hayeon. It reduct the direct connection between Sangyoen and Hayeon, therefore give constructive benefits and prevent the downfall of the eaves by increasing the power which pressing the top section of Hayeon. Second, it gives the autonomy to the inside structure of ceiling by comprising it. By using Deokdori, the limit of top section's longitude was eliminated while also simplify the upper section by blocking the inside structures with ceiling. In addition, the complements occasionally seen in several buildings increase the power which pressing Hayeon. Third, the ceiling's slope has been changed to be concerned with Sangyeon, instead of Hayeon which was highly related with it before. The last factor is the thickness of rafters which used in Deokkeori. The diameter is thiner in Sangyeon than Hayeon.

• Composites Research
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• v.32 no.1
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• pp.37-44
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• 2019

The reinforcement effect of micro-bolt for a bonded scarf joint was investigated. Three scarf ratios of 1/10, 1/20, and 1/30 were considered to examine the effect of scarf patch configuration on joint strength. To maintain the same density of micro-bolt, 16, 32, and 48 bolts were installed in the scarf joint specimens with scarf ratios of 1/10, 1/20, and 1/30, respectively. Tests were also carried out on the joints that are bonded with only adhesive and that are fastened with only micro-bolts to obtain reference values. The average failure loads of the adhesive joints with scarf ratios of 1/10, 1/20, and 1/30 were 29.7, 39.6, and 44.8 kN, respectively. In case of micro-bolt reinforcement, the failure loads at the same scarf ratios were 28.4, 37.2, and 40.1 kN, respectively, which corresponds to 96, 94, and 90% of the pure adhesive joint failure loads. In the case of using only micro-bolts, the failure loads were only 13-25% of the average failure loads of pure adhesive joints. Fatigue test was also conducted for the joints with scarf ratio of 1/10. The results show that the fatigue strength of hybrid joints using both adhesive and microbolts together slightly increased compared to the fatigue strength of adhesive joint, but the rate of increase was small to 2-3%. Through this study, it was confirmed that the reinforcement effect of micro-bolt is negligible in the scarf joints where shear stress is dominating the failure, unlike in the structure where peel stress is dominant.