• Applied Chemistry for Engineering
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• v.18 no.2
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• pp.126-129
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• 2007

In order to ruduce traffic-jam, it is requested to extend road. As a result, the construction of tunnels is inevitable considering our mountatinous topography. In tunnel construction work, major contamination materials occur from rock drilling, blasting rock, rock transporting, and short-creat. After rock blasting, a very high concentration of particles over $5000{\mu}g/m^3$ is maintained for 4 h when air is supplied by pans, by which the construction work has to be delayed at least 30 min. Although dry dust collectors are used, the effective operation time span is limited to 3 h. In this work, the behavior of particles in air and use of particle removal instruments are investigated. As a result, it was important to compare efficiencies of dry and hydro dust collectors.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.3
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• pp.79-88
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• 2003

For the construction of PC bridge piers the implementation of 1992 seismic provisions, longitudinal steels were practically lap-spliced in the plastic hinge region. Experimental investigation was conducted ductility of evaluate the seismic earthquake-experienced reinforced concrete columns with 2,5 aspect ratio. Six test specimens were mode with test parameters: confinement ratios, lap splices, and retrofitting FRP materials. They were damaged under series of artificial earthquakes that could be compatible in Korean peninsula. Directly after the pseudo-dynamic test, damaged columns were retested under inelastic reversal cyclic loading simultaneously under a constant axial load, P＝0.1f$\_$ck/A$\_$g/. Residual seismic performance of damaged columns was evaluated and compared to that of the corresponding original columns. Test results show that PC bridge piers with lap-spliced longitudinal steels appeared to fail at low ductility. This was due to the debonding of the lap splice, which resulted from insufficient development of the longitudinal steels. The specimens externally wrapped with composite FRP straps in the potential plastic hinge region indicated significant improvement both in flexural strength and displacement ductility.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.25-32
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• 2019

In many mass-consumption gas facilities, natural gas is not supplied through the pipeline of the gas corporation. LNG is supplied from the gas corporation through the tank lorry to be vaporized. In order to prevent human or property damage due to gas leakage at these facilities, a study was conducted to analyze the concentration of odorant injected at the initial and consumption points. An analysis was performed to confirm the change in odorant concentration according to the pipe position in the gas facility when a constant flow rate flowed. For this study the gas samples were taken with aluminium cylinders(4.5 L) which were created a vacuum at the pressure regulator in which the odorants was injected and the points using the gas. Odorant levels of the samples were analyzed by Gas chromatography(Main Body : Agilent 7890A, Detector : ANTEC 7090).We suggest that the small facilities using LNG need to make the management system by the types of facilities for maintaining the odorization system.

• Journal of the Korean Geosynthetics Society
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• v.4 no.4
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• pp.47-56
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• 2005

With the need of efficient site use retaining walls have frequently used. Of them dry cast modular block wall(MBW), in which geogrid and concrete block are used is getting popular because of its simplicity and economical efficiency of construction. However, since this method is based on the theory of earth pressure, sands with good quality should be used. In contrast, reinforced soil slope(RSS) that the slope is less than $70^{\circ}$ can use wider range of soil than MBW. A hybrid reinforced geo-structure might be a good alternative in view of overcoming difficulty obtaining soils with good quality as well as maximizing the efficiency of site use. This method is composed of reinforced block wall and reinforced soil slope. In this method, reinforced block wall is constructed up to a certain height vertically at ground boundary first. Reinforced soil slope is then constructed on the block wall subsequently. This paper introduces several technical points that should be taken into account in design and construction.

• Korean Journal of Construction Engineering and Management
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• v.12 no.3
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• pp.53-61
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• 2011

After several collapse accidents of large structures in the early 1990s in Korea, the government enacted a law that architectural, engineering and construction firms are obliged to have insurance for projects over a certain size. Particularly, with regard to insurance in design and construction supervision works (i.e. engineering insurance), although several operation-based problems were pointed out from practitioners, still little research has been done on analyzing current regnlartory and operational state and suggesting policy alternatives. Hence, this study applies Delphi technique to solicit current operational problems and propose a series of improvements on engineering insurance based on interview surveys targeting major market participants: municipalities, engineering firms, and insurance companies. Key findings culminate in adopting guarantee limits based on credit evaluation, abrogating joint surety, covering a loss of life, increasing insurance entrance fee, extending time covered, and etc. Reaching a consensus on the proposed alternatives between the market participants will form the foundation for sound developments of construction design and engineering industry.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.75-83
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• 2018

In study, Structural stability was considered when applying the high strength strut method with improved general strut method. considered whether there is sufficient stiffness to so as not buckling to the maximum hypothetical earth pressure. also structure stability of the strut component was reviewed. The high strength strut method is a technique used in place of the general strut method. high strength prefabricated Strut method is a technique that has bolt holes drilled in the upper flange at regular intervals. As a result of the buckling analysis, it was considered that the safety factor increased by about 5 %. also Since the stress generated is below the allowable stress, it is judged that structural stability of the strut is ensured. In particular, the safety factor of axial compressive stress increases about 16 % with use of high strength steel when applying the high strength prefabricated strut method. the high strength strut method is construction method may shorten the construction period and there is no expense to purchase additional materials.

• Fire Science and Engineering
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• v.25 no.4
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• pp.22-27
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• 2011

Fire resistance ceiling system is the structure of which the ceiling installed under the slave of the structure has the fire resistance performance. Because of having the fire resistance performance, fire resistive coatings on steel beams can be reduced and large span structures can be constructed. So, it have advantages of convenience for construction, shorten for construction time and cost reducing. In foreign country, it is general that one system consisting of slave and ceiling is constructed as a fire resistance system. But in Korea, there are no fire resistance ceiling systems thus economical efficiency due to being high-rise and light-weight of structures is not secured. Therefore research and development of nominal fire resistance ceiling systems is necessary. On this study, fire resistances of standard non-loadbearing ceiling systems were assessed and basic informations for developing the fire resistance non-loadbearing ceiling systems were presented.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.132-141
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• 2010

Recently dredged material generation has a tendency to increase since harbor construction are under progress. In this study, an experiment had been carried out which replacement of dredged material of Busan and Ulsan port as concrete mixing material. For this experiment, physical and chemical test of dredged material was carried out, and compressive strength test of mortal specimen with dredged material in scale, as aggregate replacement, was carried out. Compressive strength of Busan and Ulsan was both increased when the ratio of mixing materials was 10%. Compressive strength of Dredged material from Busan with about 70% of mineral silt showed increse when the ratio of aggregate replacement in 30%. In addition, in the result of the ICP test, both dredged materials satisfied the waste's marine discharge treatment and soil contamination concern and measures criterion on that using dredged material as a concrete material can influence on application of concrete positively.

• Journal of the Korean Geosynthetics Society
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• v.11 no.2
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• pp.49-54
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• 2012

The final consolidation settlement is important factor in soft ground improvement because of settlement management and completion time. The compression index, which is slope of primary consolidation curve, is commonly used for the calculation of final consolidation settlement in clay layer. The existing final consolidation settlement is calculated in total consolidation layer that is assumed as one layer. This paper describes analysis result of the acquired settlement, when the consolidation layer is divided as several layer. The consolidation settlement increased according to increase of the divided layer and then it is converged. This result was unrelated to surcharge load. The division effect of layer is very high when the surcharge load is less than the consolidation layer thickness. The division effect of layer is 1.2 to 1.4 in the general surcharge load, and this value can be apply as safety factor in the calculation of final consolidation settlement.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.181-189
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• 2017

The purpose of this research is to set a standard for deciding competitive marketing prices of new supplying apartment houses and to analyze decision factors in sale price of supplying apartment houses with Analytic Hierarchy Process; the resulted model does not use the method that joins the land cost and the cost of construction together, but the method that compares the sales prices of surrounding apartments. This research tries to set a standard for decision of the prices of newly supplying apartment houses by classifying the determinants into the $1^{st}$ step(4 factors), the $2^{nd}$ step(9 factors), and the $3^{rd}$ step(25 factors). According to the process, the relative importance of decision factors in the sale prices is determined and this should be used as the index of sale prices for newly supplying apartment houses when the houses are provided. In addition, through the $2^{nd}$ step including 9 factors, the comparative model for sale prices is defined and the model is presented to be applied in the real business. Subsequent study additionally considering the factors apart from marketing which tries to find a generalized standard needs to be conducted.