• Journal of the Korean Society of Hazard Mitigation
• /
• v.6 no.4 s.23
• /
• pp.49-56
• /
• 2006

The rainfall runoff is drained through sewerage outlet at urban area. But, there is no guideline or standard to install sewerage outlet, so the sewerage outlet are designed or installed by discretion of engineers or constructors. In this paper, for the sake of supporting basic data to design, it would be suggested a guideline for less influenced to flow at the channel flow condition through hydraulic experiment by variation of lateral inflow discharge, sewerage outlet projecting part, sewerage outlet direction and position. Through 10 cases of experiments, it would be less influenced two sewerage outlet at up and down stream than one installed at up or down stream even though the same discharge. And installed conditions which are installed angle and protecting part will be influenced to increase water depth and to decrease velocity at upstream. So when sewerage outlet is installed, it would be try to find a installing way to be less influence with more careful.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.3A
• /
• pp.139-148
• /
• 2012

Circular concrete-filled tubes (CFTs) are composite members, which consists of a steel tube and concrete infill. CFTs have been used as building columns and bridge piers due to several advantages such as their strength-to-size efficiency and facilitation of rapid construction. Extensive experimental studies about CFT have been conducted for past decades. However experimental results alone are not sufficient to support the engineering of these components. Complementary advanced numerical models are needed to simulate the behavior of CFT to extend the experimental research and develop predictive tools required for design and evaluation of structural systems. In this study, a finite element modeling technique for CFT was developed. The confinement effects, and behavior of CFT subjected various types of loading predicted by the proposed finite element model for CFT were verified by comparing with test results.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.4
• /
• pp.637-645
• /
• 2017

Jeju Island is composed of irregular volcanic rock layers formed by several volcanic activities. Since structure such as the offshore wind turbine has to support considerably large over turning moment due to long distance from foundation to load point and relatively large horizontal load. Pile foundations are needed to economically support such structure even in the case of rock layer. Therefore, in this study, mechanical performances are estimated by mixing ratio of water, cement, and sand to figure out optimal mixing ration of filling material for pile penetrated to rocky layers, and outcomes of this study are compared and analyzed with results of other researches. In the same conditions, mechanical performances of the mortar (S/(S+C)=20~40%) are better than those of cement paste and soil cement. On the basis of major outcome of this study, appropriate range of mixing and a strengthening model are suggested.

• Magazine of the Korea Concrete Institute
• /
• v.9 no.2
• /
• pp.167-177
• /
• 1997

In thtx design of ductile moment -1csist1ng frnmcls (DMRFs) f'ollow~ng the. stlong columnweakbeam design philosophy, it is desirable that the joint and column remain essentiallyelastic in order to insure proper energy dissipation and lateral stability of the structure.Thv joint has been identifid as the "weak link: in DMRFs because any stiffness orstrength deterioration in this region can lead to substantial drifts and the possibility ofcollapse due to t'-delta effects. h3oreove1.. the tngintw is faced with the difficult task ofdetailing an element whose size is determined by theframing members, but \vhich mustresist a set of loads very different from those used in the design of the beams and columns.Four 3 -scale beam-column-slab joint assemblies were designed according to existing cod\ulcornerrequirements of' ACI 318-89. representing perimeter joints of DMRFs with reinforced highstrength concrete. The influence on aseismic behavior of beam-column joints due tomonolithic slab, has been investigated.lab, has been investigated.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.21-24
• /
• 2008

This research verifies efficiency of Beam-Slab connection with Precast Prestressed Concrete Slab System of WAffle Shape(WAS) which solves problems of double-T system(DTS). Specimen is produced in Precast Concrete factories and is made in a way that WAS is layed across inverted T beam(ITB) and then it is filled with packing. After casting topping concrete into the specimen, curing is carried out. Variable are width of shear key and packing. The analysis is carried out in comparison between displacement and strength of Beam-Slab connection of specimen. The variable is not a effect in joint efficiency. Consequently, it may plans at the minimum with of shear key that packing is easy, will not affect strength.

• Journal of the Korean GEO-environmental Society
• /
• v.16 no.8
• /
• pp.45-49
• /
• 2015

Using 2D numerical analysis that covers the largest section of the dam body, a process is generally performed when evaluating its stability against seepage. The quantity of seepage is first obtained by assuming that its bottom topography is in the simple form of a rectangle, it is then calculated by reflecting its sectional shape during this process of analyzing the seepage quantity. Considering that various forms of dams are being constructed on various types of ground, thanks to more recent technological advances, it is judged more appropriate to draw a conclusion by means of the results on reflecting the realistic shape and topographical conditions of the dam body through 3D numerical analysis. Therefore, this study intends to present a method designed to carry out safety management by evaluating the correct quantity of water leakage that passes only through the dam body, having excluded other factors that include the amount of rainfall through the 3D FEM analysis.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.573-576
• /
• 2008

When the concrete structures are in contact with seawater, concentration of chloride for estimating chloride diffusion coefficient can be defined as the chloride concentration of sea water. However, in case the concrete structures, constructed in the seashore, aren't directly in contact with seawater, it is difficult to establish the interface concentration of chloride. In addition, marine concrete structures are greatly affected by salt attack such as rebar corrosion, among the cause of salt attack, airborne chlorides is primary factor. Therefore, in this study, salt attack environment by airborne chlorides was investigated in terms of a seasonal distribution at 72 spots, 27 areas in the East, West, South coast for 3 years from July '03 to June '06. Results indicated that in the East and South coast, the amount of the airborne chlorides is comparatively higher in summer, in the West coast, higher in winter according to the seasonal wind.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.345-348
• /
• 2008

Recently, demand is caused that new building environment of value added rising demand on the lines of becoming bigger, manhattanize of structure and becoming high standard of structure in a construction site and influx of advanced foreign nation technique. To satisfy these requirements for alternative, structures applied to the PSC, PC is increasing. Double Tee Slab is possible for long length structure and applied to the method of construction. When assembling Double Tee Slab produced by the factory in the field, becamed carry-out topping concrete in upper, but occurred crack to slab line. There is no structural problem to crack occurred in upper, waterproof in maintenance and repair of structure due to a conservative cause several problems.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.997-1000
• /
• 2008

Strength development of concrete subjected to cold weather is generally delayed due to its low temperature. In case of soil nailing method, it is necessary to apply the shotcrete. However, the shotcrete placement under low temperature experiences retardation of strength development due to delayed hydration reaction. Therefore, in this paper, the use of fine particle cement which is produced through particle classification in cement manufacturing process, is discussed to enhance the strength development of the shotcrete under low temperature. According to the results, the concrete containing 100% of fine particle cement had excellent strength development even at $-9^{\circ}C$ of temperature and at 5days, it reached design strength with PE film curing. It is thought that more than 70% of fine particle cement can secure required strength of the shotcrete even at low temperature condition.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.437-440
• /
• 2008

This study enforced to produce the planting concrete block which could be applied to various slopes economically. First of all, the physical properties was investigated with the various types of aggregate and aggregate ratio of the paste for the lead to mixture proportion of the planting concrete. As a result, the orchid stone as aggregate and 30% of aggregate ratio of the paste were used as the basic mixture proportion considering 20${\sim}$30% of maintained void ratio for the growth of plant, over 20% of capillary suction for holding water, and 3MPa as the minimum strength. For the result of the test to the new planting block which was quite different from existing planting concrete block, it could complement the problems and be possible to produce effectively and economically because various slopes like $40^{\circ}{\sim}75^{\circ}$, continual produce by extrusion, and pumping out were possible were possible.