• Journal of Korean Society of Steel Construction
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• v.19 no.4
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• pp.413-423
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• 2007

Slimfloor composite-beam systems could considerably reduce the story height of a building if the steel beam would be installed deep into the concrete floor slab. However, as the depth of the steel beam's installation is limited, it cannot cope with the various demands of building systems. To address this problem, a profiled steel beam section that can control the depth of the steel beam's and slabs' installation was developed in this study. Presented herein are the results of an experiment that was conducted focusing on the flexural behavior of the partially connected composite beams with profiled steel beams encased in composite concrete slabs. Five full-scale specimens with different slab types, with or without shear connection and reinforcement bars, were constructed and tested in this study. As a result, the shear bond stress without an additional shear connection was found to be $0.20{\sim}0.76N/mm^2$due to the inherent mechanical and chemical bond stress.

• Archives of Plastic Surgery
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• v.48 no.1
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• pp.3-9
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• 2021

Background For an attractive and natural tip contour in Asian rhinoplasty, insertion of a nasal implant and reinforcement of the cartilaginous framework are essential. However, scar contracture, which often results from augmentation with implant insertion and inadequate soft tissue coverage of the framework, is one of the most common causes of alar retraction. This study reports a novel method of redraping soft tissue along the alar rim to prevent alar retraction in Asians. Methods Twenty young Asian men who underwent primary rhinoplasty with septoplasty were retrospectively reviewed. After the usual rhinoplasty procedures, alar rim redraping was conducted for the soft tissue along the transcolumellar and bilateral infracartilaginous incisions. The longest axis of the nostril (a) and the height of the nostril from that axis (b) were measured in anterior-posterior and lateral views. The preoperative and postoperative ratios (b/a) were analyzed using the paired t-test. Results All 20 patients showed natural contours of the nasal tip, nostrils, and alae after a mean follow-up of 53.6 weeks (range, 52-60 weeks). The ratio of the nostril axes significantly decreased postoperatively in all patients except one, by an average of 11.08%±6.52% in the anterior-posterior view and 17.74%±8.49% in the lateral view (P<0.01). There were no complications, including asymmetry, contracture, subdermal plexus injury, flap congestion, or infection. Conclusions A quantitative analysis of alar retraction by evaluating the ratio of nostril axes showed that alar rim redraping is a simple and effective adjuvant technique for preventing alar retraction in rhinoplasty for young Asian men.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.161-170
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• 2022

The maintenance of bridges installed in rivers is carried out through facility safety inspection and repair & reinforcement procedures according to the results. Many studies have been so far conducted on the safety check of the bridge upperstructure because of the ease of access. However as it is impossible to directly investigate whether the pier foundation installed in the river has been scoured. Management of underwater foundations has remained based on theory. In this study, the scour of the bridge foundation installed in such a river was realized in 3D form by using an echo sounder and VRS. This made it possible to predict the scour pattern through comparison and analysis with the ground height of the riverbed at the time of the bridge installation. Based on these results, if the pier foundation is used as an initial data to determine whether or not local scour is present and to predict long-term scouring, bridge collapse due to foundation scour can be prevented.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.87-95
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• 2007

This study analyzed ground settlement and ground stress depending on tunnel excavation and the ground reinforcing grouting methods for double line road tunnel through deep weathered zone. Diameter of double line road tunnel was approximately 12m and umbrella arch method and side wall reinforcing grouting were applied. The ring-cut split excavation method and CD-cut excavation method for excavation method were applied. Analyses of failure rate and vertical stress ratio show that the tunnel for which the height of the cover (H) was higher than four times the diameter, can be considered a deep tunnel. Comparisons of various excavation and ground reinforcement methods showed that CD-cut method results in lower surface and crown settlement, and lower failure rate than that obtained by Ring-cut split method. In addition, the side wall reinforcing grouting resulted in reduction of tunnel displacement and settlement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6A
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• pp.853-859
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• 2008

As a new system of steel pipe pile cap reinforcement, the application of perforated flat bar bolted to the steel pipe pile head was suggested for the improvement of structural performance of footing structure. This study investigates the structural characteristics of perforated flat bar shear connectors according to shape and diameter of hole, number of rebars passing through the hole and the depth of settlement. The result shows several requirements to ensure sufficient pull-out resistance and ductility such as that the hole diameter excluding diameter of rebar should exceed the size of aggregates; the hole should be perforated with diameter as the half of plate height; and the adequate depth of settlement should be ensured for the optimal performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.177-183
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• 2023

Various failure modes occur in the concrete beams reinforced with GFRP(Glass Fiber Reinforced Plastic) under initial condition and repairing patterns. In this study, the failure behaviors of concrete beams restrengthened with GFRP sheet with slightly higher elastic modulus than concrete were investigated. For the tests, concrete beams with 24 MPa were manufactured, and the effects of initial notch, overlapping, end-strip reinforcement, and fiber anchors were analyzed on failure load. The cases of GFRP overlap around notch and the initial notch showed increasing failure loads similar to those of normal restrengthened case since the epoxy of the saturated GFRP sufficiently repaired the notch area. Compared to the control case without restrengthening of GFRP, the concrete with initial notch showed 0.78 of loading ratio and normal restrengthening showed 4.43~5.61 times of increasing ratio of failure loading, where interface-debonding from flexural crack were mainly observed. The most ideal failure behavior, break of GFRP, was observed when end-strip over 1/3 height from bottom and fiber anchor were installed, which showed increasing failure load over 150 % to normal restrengthening.

• Advances in concrete construction
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• v.16 no.4
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• pp.205-216
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• 2023

Concrete structures may become vulnerable during their lifetime due to several reasons such as degradation of their material properties; design or construction errors; and environmental damage due to earthquake. These structures should be repaired or strengthened to ensure proper performance for the current service load demands. Several methods have been investigated and applied for the strengthening of reinforced concrete (RC) structures using various materials. Fiber reinforced polymer (FRP) reinforcement is one of the most recent type of material for the strengthening purpose of RC structures. The main objective of the present research is to identify the behavior of reinforced concrete slabs strengthened with FRP bars by using near surface mounted (NSM) technique. Validation study is conducted based on the experimental test available in the literature to investigate the accuracy of finite element models using LS-DYNA to present the behavior of the models. A parametric analysis is conducted on the effect of FRP bar diameters, number of grooves, groove intervals as well as width and height of the grooves on the flexural behavior of strengthened reinforced slabs. Performance of strengthening RC slabs with NSM FRP bars was confirmed by comparing the results of strengthening reinforced slabs with control slab. The numerical results of mid-span deflection and stress time histories were reported. According to the numerical analysis results, the model with three grooves, FRP bar diameter of 10 mm and grooves distances of 100 mm is the most ideal and desirable model in this research. The results demonstrated that strengthening of reinforced concrete slabs using FRP by NSM method will have a significant effect on the performance of the slabs.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.2
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• pp.42-54
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• 2014

This study was conducted to identify landscaping elements such as location, situation and feng shui included in the spatiality of Jangseong Pilmaseowon and to interpret aesthetic features of visual-perceptual spatial composition according to its arrangement. As it is shown in 'Pilamseowon', 'Pilbongseowon', and 'Gimhaseoseowon' appearing in antique maps, the awareness considering 'Pilam' as 'Pilbong' and 'Gimhaseo' was revealed. Mountain Pilamsan[Mountain Munpilsan] which is the location of seowon and Pilam(Brush-shaped rock) is the core of establishment of location identity of Pilamseowon and the symbol of Haseo Kim In-hu, which shows that they are deeply related to Ingeoljiryeong(人傑地靈: 'a place derives reflected glory from an illustrious human') based on connection. Pilamseowon shows locational characteristics of living in stream(溪居) facing panoramic 'jeungsan field' without Ansan(案山). Based on the teachings of Neo-Confucianism, Village Maekdong which is the birth place of Haseo, Pilam, seowon geomancy considering the Danbonghamseo-type(丹鳳含書形) geographical shape, formative reflection, Pilmaseowon and structures revealed in building naming more clearly show symbolic landscaping features resulting from 'theory of 'Heaven-Man Unity'(天人合一)' representing the union of nature and haman, than other seowons. The maximization of centrality through connected yards constructed with the 'jeondang hujae(前堂後齋)' arrangement in the order of Whakyeon-lu, Chenogjeol-dang, Jindeak-jae or Sungui-jae, and Woodong-sa is a unique feature of spatial frame of Pilmaseowon. In addition, it reveals the centrality reinforced with 'the move of inner center through arrangement of Kyeongjang-kag and Kyesengbi inside 'YuSik(遊息)' space and religious space' and the landscaping arrangement of Pilmaseowon from installation and device for reinforcement of territoriality. Moreover, it was found that orders and aesthetic features based on Neo-Confucianism were logically realized in the formation of Pilmaseowon with visual and compositional landscaping arrangement such as 'reinforcement of view centrality through composition of windows and doors', 'securement of visual transparency through framing and duplication', and 'realization of hierarchy through height of jaesil toenmaru'. The meaning system and spatial or visual aesthetic features of Pilmaseowon newly arranged and interpreted through landscaping recomposition is not a coincidental but inevitable result. It is another resource basis and an element that can improve the internal exuberance of Pilamseowon. This landscaping reading study is expected to improve the understanding of landscapes of Pilmaseowon and elevate the sensibility of unrevealed cultural landscapes.

• Korean Journal of Environment and Ecology
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• v.21 no.4
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• pp.347-355
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• 2007

Asiatic black Bear(Ursus thibetanus ussuricus) cubs aged one or two were introduced from Russia(Primosky krai) and North Korea for reinforcement of the bear population and they were released to grow wild in Jirisan National Park. We did research on the characteristics of the denning sites of the Asiatic black cubs, which were released before, from Oct. 2004 to Apr. 2006, and the results were as follows: The released bears hibernated in three types of dens,; tree hollows, rock hollows or ground nests. The hibernating sites were dominated by a community of oak trees and its location was at an average of $923{\pm}221m$ height above the sea level ; the average slope incline was $25.9{\pm}7.9^{\circ}$, and the average denning duration was $98{\pm}9$ days. It was analyzed that the cubs' denning site was $2.8{\pm}2.8km$, on an average, far from the release point; $2.0{\pm}0.9km$ far from villages; $1.9{\pm}1.7km$ far from park inspection trails, and $1.9{\pm}1.0km$ on the average far from a driveway. It is assumed that environmental attributes of the denning sites were closely correlated to those of the release points.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.121-128
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• 2005

A RC column-bent pier represents one of the most popular piers used in highway bridges. Seismic performance of reinforced concrete (RC) column-bent piers under bidirectional seismic loadings was experimentally investigated. Six column bent-piers were constructed with two circular supporting columns which were made in 400 mm diameter and 2,000 mm height. One single column specimen was additionally made to comparatively evaluate the seismic response of RC column-bent piers. Test parameters are different transverse reinforcement and loading pattern. These piers were tested under lateral load reversals with the axial load of $0.1 f_{ck}A_g$. Three specimens were subjected to bidirectional lateral load cycles which consisted of two main longitudinal loads and two sub transverse loads in one load cycle. Other three specimens were loaded in the opposite way. Test results indicated that lateral strength and ductility of the latter three specimens were generally bigger than those of the former three specimens. Plastic hinges were formed with the spall of cover concrete and the fracture of the longitudinal reinforcing steels in the bottom plastic hinge of two supporting columns for the former three specimens. Similar behavior was observed in the top and bottom parts of two supporting columns for the latter three specimens.