• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.854-859
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• 2009

Multiple people using places are being managed to prevent disasters by the special law for safety supervising of multiple people using spots. The KESCO is managing the places through intensification of inspection. Perfect safety is not insured by frequencyinspections because disaster symptoms in electrical facilities include invisible faults. Especially, entertainment spots, such as entertainment bars and karaoke bars, are different from other multiple people using places, and active reaction to prevent electrical fires is impossible. Therefore, special protection plans to prevent electrical disasters are needed. In this paper, equipments of entertainment spots were researched, and their electrical characteristics were analyzed. The function for detecting aloose terminal, which is one of the main causes of electrical fires, was developed.

• Structural Engineering and Mechanics
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• v.61 no.4
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• pp.551-561
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• 2017

As FGM (functionally graded material) bars which vibrate in axial or longitudinal direction have great potential for applications in diverse engineering fields, developing a reliable mathematical model that provides very reliable vibration and wave characteristics of a FGM axial bar, especially at high frequencies, has been an important research issue during last decades. Thus, as an extension of the previous works (Hong et al. 2014, Hong and Lee 2015) on three-layered FGM axial bars (hereafter called FGM bars), an enhanced spectral element model is proposed for a FGM bar model in which axial and radial displacements in the radial direction are treated more realistic by representing the inner FGM layer by multiple sub-layers. The accuracy and performance of the proposed enhanced spectral element model is evaluated by comparison with the solutions obtained by using the commercial finite element package ANSYS. The proposed enhanced spectral element model is also evaluated by comparison with the author's previous spectral element model. In addition, the effects of Poisson's ratio on the dynamics and wave characteristics in example FGM bars are numerically investigated.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.4
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• pp.285-291
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• 2011

In this study the mechanical performance of the new wave dissipating block is evaluated through experiment and numerical analysis. Also, by selecting adequate reinforcement, the improvement of the structural performance is examined. The reinforcement is designed by predicting the amount of tensile force and the location where the tensile stress develops in the new wave dissipating block through numerical analysis. The new wave dissipating block is reinforced with the ordinary steel bars and the fiber reinforced plastic(FRP) bars which have advantages in ocean environment in terms of corrosion and fatigue. The test result shows that the fracture resistance of the un-reinforced concrete block is 350 kN which is about 6.2 times that of the weight of the block. All the test blocks which are reinforced by either steel of FRP bars show strength capacity of over 900 kN which is the maximum load of the test equipment. Although the single reinforcement with larger-diameter bars has advantage in terms of construction convenience, it is recommended to use multiple number of smaller-diameter bars in order to reduce the crack width.

• Journal of Trauma and Injury
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• v.19 no.2
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• pp.183-187
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• 2006

An increase has been see in fall injuries at construction sites and in penetrating injuries by iron bars or pipes associated with the fall. In particular, a thoraco-abdominal penetrating injury had the worse prognosis, and multiple organ injury occurred because of blunt trauma associated with fall. Iron bars were the most common penetrating materials, and pipe penetrating injuries were uncommon. However, because the diameter of the pipes were large than those of the bars, penetrating injuries associated with pipes were more often fatal. A secondary thoraco-abdominal injury worsened the prognosis. We reported a case of a 33-year-old man with a thoraco-abdominal trauma secondary to a penetrating injury with a scaffolding pipe following a fall.

• Computers and Concrete
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• v.23 no.1
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• pp.49-60
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• 2019

In recent years, multiple experimental studies have been performed on using fiber reinforced polymer (FRP) bars in reinforced concrete (RC) structural members. FRP bars provide a new type of reinforcement that avoids the corrosion of traditional steel reinforcement. In this study, predicting the shear strength of RC beams with FRP longitudinal bars using artificial neural networks (ANNs) is investigated as a different approach from the current specific codes. An ANN model was developed using the experimental data of 104 FRP-RC specimens from an existing database in the literature. Seven different input parameters affecting the shear strength of FRP bar reinforced RC beams were selected to create the ANN structure. The most convenient ANN algorithm was determined as traingdx. The results from current codes (ACI440.1R-15 and JSCE) and existing literature in predicting the shear strength of FRP-RC beams were investigated using the identical test data. The study shows that the ANN model produces acceptable predictions for the ultimate shear strength of FRP-RC beams (maximum $R^2{\approx}0.97$). Additionally, the ANN model provides more accurate predictions for the shear capacity than the other computed methods in the ACI440.1R-15, JSCE codes and existing literature for considering different performance parameters.

• Journal of the Korean Society of Safety
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• v.21 no.2 s.74
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• pp.29-34
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• 2006

It is revealed that these are correlated with the height of chamber deciding the turbulence extent. In the first experiment, It was examined about the effects of different multiple obstacles such as circular, triangular and square things with the rig that the dimension of original experimental rig was $700{\times}700{\times}200mm{\wedge}3$. Then the heights of chamber were increased from 200 to 1000mm. The dimensions of each obstacle were $70{\times}700{\times}{\wedge}2$ and rectangular vent area were $210{\times}700{\times}{\wedge}2$. In the second one, we performed to see the effects of locations of different multiple obstacles in 200, 500 and 800mm height from the bottom. The results are : The multiple triangular obstacles caused the highest overpressure while the lowest one was the multiple circle bars. Then, the triangular bars caused the highest flame acceleration while the circular obstacles was lowest too. The results showed that the critical height was 800mm due to the formation of turbulence. And the lesser $Av/V^{2/3}$ were small, the more pressure and pressure acceleration rate were increased.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1370-1376
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• 2009

Reinforcing steel works should be carefully controlled by the construction manager considering the severe fluctuation of the price of reinforcing steel bars and for the safety of structure in building constructions. In particular, preparing rebar placing drawings needs more effort and time than before because of the emergence of higher and more complicated buildings. Moreover, the experience of field engineers or foremen (fabricators or detailers) in preparing placing drawings gives rise to the differences in fabricated bar type and quantity of bars used. To address these problems, this study proposed the support system in preparing placing drawings for reinforcing steel works efficiency. In the near future, if this system can be made available on the web, multiple end-users will be able to share the result; the efficiency of rebar supply chain management will also be improved.

• Journal of the Korea Concrete Institute
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• v.15 no.4
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• pp.615-622
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• 2003

The purpose of this study is to propose the more reasonable equation of bond strength of grout-filled splice sleeve. To accomplish this objective, total 60 full-sized specimens were tested under monotonic loading. The experimental variables are compressive strength of mortar, embedment length and size of reinforcing bars. Following conclusions are obtained; 1) If the adequacy of existing equations which estimate the bond strength of grout-filled splice sleeve are investigated, they underestimate the bond strength of grout-filled splice sleeve by 8-18%. Also the existing equations have a tendency to underestimate with decrease in the embedment length of reinforcing bars. 2) From the test result of bond failure, the equation which estimates the confining pressure of grout-filled splice sleeve was proposed by making multiple regression analyses of which independent variables are embedment length of reinforcing bars and compressive strength of mortar. This equation predicted the measured bond capacity of this test more accurately than existing equations and eliminated the deviation according to the embedment length of reinforcing bars.

• Journal of Korea Water Resources Association
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• v.46 no.9
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• pp.909-919
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• 2013

This study examines the hydraulic characteristics, the channel changes, the behavior of bars, and bank stability by means of laboratory experiments. Three sets of laboratory experiments are conducted to elucidate the influence of riparian vegetation of the channels with erodible banks. Flow velocity is decreased in the vegetated zone, the mobility of lower channels is decreased. The double Fourier analysis of the bed waves shows that 1-1 mode (alternate bar) is dominant at the initial stage of the channel development. As time increases, 2-2 and 2-3 modes (central or multiple bars) are dominant due to the increased width to depth ratio. As the vegetation density is increased, the number of bars are increased, bank stability increases. The variation of sediment discharges is affected by vegetation density. The braided intensity is decreased with vegetation density. As the vegetation density is increased, the correlation coefficient of bed topography and bed relief index is increased.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.13-16
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• 2008

In a tension-controlled section, all steel tension reinforcement is assumed to yield at ultimate when using the strength design method to calculate the nominal flexural strength of members with steel reinforcement arranged in multiple layers. Therefore, the tension force is assumed to act at the centroid of the reinforcement with a magnitude equal to the area of tension reinforcement times the yield strength of steel. Because FRP materials have no plastic region, the stress in each reinforcement layer will vary depending on its distance from the neutral axis. Similarly, if different types of FRP bars are used to reinforce the same member, the stress level in each bar type will vary, and the member will show different behavior from our expectation. In this study, six high-strength concrete beam specimens reinforced with conventional steels, CFRP bars, and GFRP bars as flexural reinforcements were constructed and tested. The members reinforced with hybrid reinforcements showed higher stiffness, smaller crack width, and better ductility than the members reinforced with single type of FRP bars.