• Journal of the Korea Concrete Institute
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• v.29 no.4
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• pp.345-351
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• 2017

This study evaluated the effectiveness of V-shaped ties as an alternative to the supplementary crossties specified in ACI 318-14 on the flexural ductility of reinforced concrete columns. From column specimens tested under constant axial loads and reversed cyclic lateral loads, the mode of failure and lateral load-lateral displacement relationship were measured according to the variation of the applied axial load levels. After the columns reached the peak lateral load capacity, the $90^{\circ}$ hooks of the crossties gradually opened, which eventually caused premature buckling of the longitudinal reinforcement and severe crushing of the core concrete, whereas no V-ties were extracted from the core concrete until the column failure. As a result, the cumulative work damage indicators up to 80% of the peak lateral load for V-tie columns under the axial load level of 0.2, 0.4, and 0.55 was as much as 2.4, 2.3, and 5.2 times higher, respectively, than those of the companion crosstie columns. The superiority of the V-ties to the conventional crossties in enhancing the flexural ductility of columns became more prominent as the axial load level increases.

• Journal of Korea Water Resources Association
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• v.50 no.4
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• pp.223-232
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• 2017

The ability to defend against floods in urban areas was weakened, because the increase in the impervious rate of urban areas due to urbanization and industrialization and the increase in the localized torrential rainfall due to abnormal climate. In order to reduce flood damage in urban areas, various runoff reduction facilities such as detention ponds and infiltration facilities were installed. However, in the case of domestic metropolitan cities, it is difficult to secure land for the installation of storm water reduction facilities and secure the budget for improving the aged pipelines. Therefore, it is necessary to design a storage system (called the detention pond in trunk sewer) that linked the existing drainage system to improve the flood control capacity of the urban area and reduce the budget. In this study, to analyze the effect of reducing runoff amounts according to the volume of the detention pond in trunk sewer, three kinds of virtual watershed (longitudinal, middle, concentration shape) were assumed and the detention pond in trunk sewer was installed at an arbitrary location in the watershed. The volume of the detention pond in trunk sewer was set to 6 cases ($1,000m^3$, $3,000m^3$, $5,000m^3$, $10,000m^3$, $20,000m^3$, $30,000m^3$), and the installation location of the detention pond in trunk sewer was varied to 20%, 40%, 60%, and 80% of the detention pond upstream area to the total watershed area (DUAR). Also, using the results of this study, a graph of the relationship and relational equation between the volume of the detention pond in trunk sewer and the installation location is presented.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.535-546
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• 2010

Recently, the probability of collision accident between vehicles or vessels and infrastructures are increasing at alarming rate. Particularly, collision impact load can be detrimental to sub-structures such as piers and columns. The damaged pier from an impact load of a vehicle or a vessel can lead to member damages, which make the member more vulnerable to impact load due to other accidents which. In extreme case, may cause structural collapse. Therefore, in this study, the vehicle impact load on concrete compression member was considered to assess the quantitative design resistance capacity to improve, the existing design method and to setup the new damage assessment method. The case study was carried out using the LS-DYNA, an explicit finite element analysis program. The parameters for the case study were cross-section variation of pier, impact load angle, permanent axial load and axial load ratio, concrete strength, longitudinal and lateral rebar ratios, and slenderness ratio. Using the analysis results, the performance based resistance capacity evaluation method for impact load using satisfaction curve was developed using Bayesian probabilistic method, which can be applied to reinforced concrete column design for impact loads.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.820-831
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• 2020

Fumigation treatment is mainly used on dead trees affected by the oak wilt disease to prevent the spread of damage. To verify the possibility of intensive use of the damaged Mongolian Oak wood treated by the fumigation treatment, we performed the compression and bending performance evaluation of the fumigation treated wood. The fumigation was done with Nemasect (Metam-sodium) for about 9 months. The dry longitudinal compressive strength of the fumigation treated oak wilt-diseased wood at the ambient temperature and humidity, and the compressive modulus of elasticity were measured to be 58.87MPa, and 5.66GPa, which were similar to the non-treated wood. The strength performance of mature wood of fumigation treated wood was 16% higher than that of juvenile wood. The compression fracture of the non-treated oak wood showed various shapes, however, most of the fumigation treated wood showed shear-type fracture shape. The bending strength of the fumigate treated wood was measured to be 157.43MPa, which was 8% higher than that of the non-treated wood, and the bending modulus of elasticity was measured to be 16.38GPa, which was 16% lower than that of the non-treated wood. However, it was confirmed that the coefficient of variation for the bending strength performance value of the fumigation treated wood was lower than that of the non-treated wood.

• Archives of Plastic Surgery
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• v.37 no.2
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• pp.122-128
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• 2010

Purpose: Many descriptions of the digital arterial anatomy including skin territory of the finger have been published. Relatively few studies on venous architecture of the finger have been performed in this area, in part, attributable to the technical difficulties encountered in dissecting small vessels. The purpose of this study is to present the precise microsurgical anatomy of the vein related to the digital artery and venae comitantes of the components. Methods: Arterial and venous anatomy of their relation to the fingers were examined in 38 specimens of two fresh cadavers and 36 clinical cases. All specimens were evaluated grossly, surgical microscopically, or / and light microscopically to observe the three & two-dimensional structure of the artery and joining vein, evidence of the venae comitantes, and venous valve. Results: No longitudinal venae comitantes along the digital artery were found in any specimens. The size of the venae comitantes of each digital artery was much smaller than other vein, but always existed any level of digital artery. One or two venae comitantes in the digital artery ran spiral, oblique, helical, fibrillar, or irregular branched shape. The authors also found the vein of the finger, that had bicuspid valves, but not in venae comitantes. Conclusion: Recently, venous outflow problem rather than arterial circulation is the most common cause tissue failure after microvascular surgery in the hand. Sometimes, if it is not recognized early, there is an increased risk of tissue damage and loss. The authors concluded that this study presents a useful knowledge for the characterization of the venous structure and evidence for venae comitantes like a venule in the digital artery at varying levels of the finger.

• Journal of the Korean Arthroscopy Society
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• v.6 no.2
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• pp.156-160
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• 2002

Purpose : To evaluate the results and usefulness of meniscal repair using meniscal arrows with ACL reconstruction. Material and Methods : Among cases of the simultaneous meniscal arrow fixation and ACL recontruction performed between May, 1997 and September, 2000, 17 cases could be evaluated. The average follow-up were 18.5 months. Twelve cases were medial meniscus, 5 cases, lateral meniscus. All cases were longitudinal tear. Meniscal tear were seen at red-red zone in 13 cases, red-white zone in 5 cases. The results were analyzed by pain, joint line tenderness, locking, McMurray test, the Marshall knee scoring scale and complications. Results : Postoperatively two patients had mild joint line tenderness without pain on joint motion or weight bearing. No patient had locking or positive McMurray test. At last follow-up, 15 cases $(88\%)$ were 'excellent' or 'good' according to the Marshall knee score scale. There were two complications which are soft tissue irritation sign on active knee motion and a femoral chondral injury due to protruded T-shaped head of meniscus arrow. Conclusion : Meniscus arrow can be one of the options in repairing the associated meniscus tear, especially the posterior horn of medial meniscus, during ACL reconstruction. However, surgeons using meniscus arrow should be aware of its potential complications such as pain due to soft tissue irritation and chondral damage of the femoral condyle.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.165-170
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• 1981

Recently an unknown microbial desease and some parasitic crustaceans are prevailing in the sea-weed farms of Uudaria pinnatifida along the south-eastern coast of Korea.(1) Green spots probably caused by the microbial pathogens were found on the fronds of Undaira Pinnatifide. Particularly they were densely distributed on the distal half of the fronds. The tissues of the green spot area rot off, and small holes with green colored margin are formed. The holes at the distal part of the fronds are enlarged and they finally coalesced each other. Then this process accelerates decaying of the distal ends of the fronds.. The fronds growing in the central part of the farms are usually severely damaged, whereas in the marginal area of the farm toward the open sea side the damage is less serious. An examination revealed that the deseased fronds bore a number of viable bacteria, $6.8\times10^5\;to\;1.2\times10^6$ per gram at $15^{\circ}C$, whereas the healthy fronds $1.1\times10^4$. Twenty-six kinds of colonies, 247 strains of bacteria, were isolated from deseased fronds, belonging to Moraxella, Achromobacter, Vibrio, Flavobacterium, Acinetobacter, Pseudomonas, etc. (2) Pinholes occurred in one series on the frond. They were probably caused by a harpacticoid copepod, Thalestris sp. Seven years ago when the disease was first found to occur the copepod was observed on the fronds from March of the year. Recently, however, they have been found as early as December of the previous year. (3) A gammarid amphipod, Ceinina iaponica, invades the pith of the midrib through holdfast of thalli. This rarely causes the longitudinal seperation of the entire frond through the midrib as they bore a tunnel in the pith. Sometimes holdfasts of tile heavy damaged thalli make the frond departed from the substrate.

• Journal of Korean Foot and Ankle Society
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• v.2 no.2
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• pp.88-92
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• 1998

The course of the sural nerve in the calf has been well documented, but there is a general lack of information concerning the distal course of the nerve. The purpose of this study was to describe the distal course of the sural nerve and its surgical implications. Seven fresh amputated specimens were dissected to show the anatomy of the sural nerve in the foot and ankle. At the level of about 10cm proximal to the plantar surface, the sural nerve coursed anteriorly and inferiorly away from the Achilles tendon. 2 to 4 lateral calcaneal branches arose. The first branch of the lateral calcaneal branches coursed along the lateral border of the Achilles tendon, and it arose at 8cm proximal to the plantar surface in 2 specimens, 12cm proximal to the plantar surface in 4 specimens, and at 12cm proximal to the plantar surface in one specimen. The main nerve trunk continued distally plantar to the peroneal tendons and divided into two terminal branches and crossed peroneus longus tendon at the level of the inferior border of the calcaneo-cuboid joint, at about 3cm(range, $2.5\sim3.0$)cm from the plantar surface. In conclusion, a longitudinal incision lateral to the Achilles tendon would cross the path of the sural nerve at about 10cm proximal to the plantar surface. When the first branch of them arise more than 10cm above the plantar surface, a logitudinal incision lateral to the Achilles tendon may be made without damage. The other lateral calcaneal branches will be cut when we make transverse incision paralled to the plantar surface. The terminal branch also may be in danger by the same transverse incision.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.451-458
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• 2008

The near-fault ground motion (NFGM) is characterized by a single long period velocity pulse of large magnitude. NFGM's have been observed in recent strong earthquakes, Izmit Turkey (1999), Kobe Japan (1995), Northridge USA (1994), etc. These strong earthquakes have caused considerable damage to infrastructures because the epicenter was close to the urban area, called as NFGM. Extensive research for the near-fault ground motion (NFGM) have been carried out in strong seismic region, but limited research have been done for NFGM in low or moderate seismic regions because of very few records. The purpose of this study is to investigate and analyze the effect of near-fault ground motions on reinforced concrete (RC) bridge piers with lap-spliced longitudinal reinforcing steels. The seismic performance of four RC bridge piers under near-fault ground motions was investigated on the shake table. In addition, a RC bridge pier is subjected to pseudo-dynamic loadings. Test results showed that large residual displacements were observed in RC bridge piers under NFGM. RC specimens on the shake table failed at relatively low displacement ductility, compared with the displacement ductility of RC bridge pier subjected to pseudo-dynamic loadings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.1-8
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• 2018

FRP is a new material that is light, has high strength and high durability, and is emerging as a third construction material inside and outside of countries. However, very few studies have been done on curved FRP construction materials that can be used for tunnels or arched bridges. Because a small composite panel specimen is smaller than a full-size specimen, it can be used in a variety of experiments under different conditions. Therefore, in this study, experiments were performed on a void section, a solid section, a connected solid section, and a sand-coating solid section. The results of the experiment show that the connection of composite curved panels with longitudinal connections provides almost equivalent performance to that of a single panel. However, it is necessary to strengthen the connections, since the connections that are most susceptible to damage will break first.