• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.40-40
• /
• 2016

우리나라는 산업화시기에 도시지역의 급속한 발달로 불투수면적과 하수보급률이 증가 하였으며, 이로 인해 지하수함량 감소, 용수사용량 증가 및 무분별한 지하수 개발 등은 도시하천의 수질 악화, 유량부족의 문제를 발생시켰다. 또한 1960년대 이후 하천정비사업은 홍수방지 등의 치수 차원에서 주로 정비되어 왔고, 산업화 팽창시기에 도시를 관통하여 흐르는 중소하천은 도시의 과밀화 문제를 해소하는 수단으로서 도로와 주차장등으로 이용되었다. 따라서 수변공간이 가지는 의미와 가치에도 불구하고 우리나라의 경우 수변공간은 치수와 이수 등 기능적인 목적을 위주로 관리되고 사용되어 왔다. 그러나 최근들어 지속가능한 물순환 체계 구축 및 적응 대책 수립을 지원하기 위해 개발사업 추진 시 저영향개발 기법의 적용을 확대하도록 권장하고 있으며, 국가하천 주변의 개발허가를 골자로 하는 "친수구역 활용에 관한 특별법"이 공표되어 수변공간 및 수변도시에 대한 관심이 증가하고 있는 추세이다. 본 연구에서는 도시개발에 따른 수문 및 환경적 영향을 최소화하기 위해 자연상태를 가급적 보존하고 불투수면적을 최대한 줄이며, 분산식 우수배제 방식을 지향하는 저영향개발 기법을 적용하였다. 이를 위해 현재 수변도시로 개발중인 송산그린시티에 저영향개발 기법을 적용하였으며, 기존의 개발 방식과의 비교를 통하여 저영향개발 기법의 효과를 분석하였다.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.4
• /
• pp.569-577
• /
• 2021

CFRP(Carbon Fiber Reinforced Plastic) can maintain the same strength even if the diameter is reduced by about one - third, and the weight is about one - twentieth of that of the deformed reinforcing bars that have been used in the construction industry. In particular, it is resistant to corrosion, which is the weakest part of reinf orcing bars, and there is no concern that it will deteriorate over time, It is light and durable, so transportation costs are low and it is convenient for high-rise buildings. This paper experimentally clarifies the adhesive properties of CFRP and clarifies its behavior. That is, bond strength test was conducted with the directness of CFRP and the strength of concrete as experimental variables, and the bond mechanism was clarified experimentally. Furthermore, based on the experimental results, we constructed the bond stress-slip-strain relationship of CFRP compared to the existing deformed reinforcing bars.

• Journal of the Korean Geotechnical Society
• /
• v.37 no.2
• /
• pp.19-31
• /
• 2021

Micropiles are cast-in-place piles with small diameters. The advantage of micropile is low construction expense and simple procedures, so it is widely applied to existing buildings and structures for the reinforcement of foundation and seismic performances. The base expansion structure has been developed following the original mechanism of horizontal expansion steps under compressive loading. This kind of structure can be installed at the pile end to improve the bearing capacity by tip area enlargement and horizontal force increment to the pile surface area. However, 'Micropile with base expansion structure' cannot be put into practical use, because detailed verification for the developed technique has not been conducted so far. In this research, 3-D numerical analysis was conducted to figure out the bearing mechanism of base expansion micropile and to verify the bearing capacity improvement compared to the general micropiles. 3-D modelling of micropile with base expansion structure was carried out and input parameter was determined. Bearing mechanism induced by base expansion structure was analyzed by lab-scale modelling, and bearing capacity improvement was verified by field-scale analysis.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.283-286
• /
• 2002

Defect problems happening in the course of stressing quantity expansion of residence supply due to lark in maintenance are intensifying insincerity of construction business resulting from the psychological and economic damage, and there are many quarrel between residence suppliers and consumers. Because an apartment house's qualify is decided by various elements from design, to lotting-out, construction, and after-management, it is limited to express house capacity and standard to appraise defect objectively and quantifiably. The bound of defect and the period of guarantee expressed cleary in regulation of apartment house lack in quantifiable concept, and guarantee of defect is composed of a general concept. Therefore the big difference in opinion about defect and the bound of repair makes repair process slow and only to increase social costs. This research will give residence suppliers and consumers a resonable way to solve repair process during tile obliged period of guarantee since moving into from a process which are design, planing, construction, and after management. Furthermore it will present each business and role to conclude defect repair easily, so I planed to promote maintenance after conclusion of defect repair.

• Plant Journal
• /
• v.10 no.4
• /
• pp.35-41
• /
• 2014

The height and capacity of the thermal storage tank can be decided by the altitude and heat load of the heat supply area. Evaporation in heat pipe can be prevented by pressurizing it with the hydraulic head of the thermal storage tank. In addition, it absorbs the expanded volume from the temperature changes and supplies water to the pipelines in case of the shortage of water. One of the most important roles of the thermal storage tank is a stable heat supply facility. It can control the heat demand by accumulating the surplus heat and supplying in changing heat demand time. The purpose of this thesis is to be helpful for the operation and maintenance of the thermal storage tanks. The study has been carried out for 18 thermal storage tanks, which have been used polyurethane foam as insulation, among 27 tanks in district heating plants. The characteristics of the insulation materials, the reasons for the damages of the insulation and how impact the insulation damages to the corrosion of the thermal storage tank have been studied.

• Korean Chemical Engineering Research
• /
• v.47 no.2
• /
• pp.203-207
• /
• 2009

In the NCAs(non-conductive adhesive) for adhesion of Micro Electro Mechanical System(MEMS), there are some problems such as delamination and cracking, because of the differences of CTE(coefficients of thermal expansion) between NCAs and substrates. Addition of inorganic particle or flexibilizer have been performed to solve those problems. In this study, to improve the flexibility of epoxy adhesive, epoxy/siloxane composites were prepared by adding 1, 3, or 5 phr of amino modified siloxane(AMS). Glass transition temperatures(Tg), moduli and CTE of those composites were measured to confirm effects of siloxane on thermal/mechanical properties of siloxane/epoxy-composites. Tg of AMS/epoxy-composites decreased from $134^{\circ}C$ to $122^{\circ}C$ with increasing AMS contents and moduli decreased from 2,425 MPa to 2,143 MPa with increasing AMS contents. But CTE of AMS/epoxy-composites increased from $67ppm/^{\circ}C$ to $71ppm/^{\circ}C$ with increasing AMS contents. In short, the addition of siloxane is effective for enhancing the flexibility of epoxy but leads to the decrease of Tg.

• Journal of the Korean Geotechnical Society
• /
• v.15 no.5
• /
• pp.281-290
• /
• 1999

The coastal area, particularly along the West and South coasts in Korea, is often reclaimed with dredged marine-clay to meet the demand of land capacity. A large number of ground improvement techniques are developed for such a newly formed soft clay deposit. However, the quick lime column method, which is effectively used for the purpose of ground improvement in the other countries, is seldom applied in Korea. This study, therefore, focuses on the development of appropriate soft soil improvement technique by using quick lime column. A model test as well as finite element analysis was conducted to identify the consolidation characteristics around the lime column. Although actual pore water pressure measured from model tests does not coincide with the predictions made by finite element method and Chen ＆ Law's theoretical formula, their trends are quite similar. It is revealed from this study that the pressure caused by the expansion of lime column affects considerably the consolidation characteristics of the surrounding ground.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2003.05a
• /
• pp.45-48
• /
• 2003

The plume interference is a complex phenomenon, consisting of plume-induced boundary layer separation, separated shear layer, multiple shock waves, and their interactions. The base knowledge of plume interference effect on powered missiles and flight vehicles is not yet adequate to get an overall insight of the flow physics in plume-freestream flow field. Computational studies are performed to better understand the flow physics of the plume-induced shock and separation for Simple, Rounded, Porous-extension test model configurations. The present study simulates highly underexpanded exhaust plume effect on missile body at the transoni $c^ersonic speeds. In order to investigate the plume-induced separation phenomenon, Simple, Rounded and Porous-extension plate are attacked to the missile afterbody. The computational result shows that the rounded afterbody and the porous-extension wall attached at the missile base can alleviate the plume-induced shock wave and separation phenomenon and improve the control of the missile body.dy.

• Journal of Navigation and Port Research
• /
• v.26 no.1
• /
• pp.55-65
• /
• 2002

The eighteenth century in Great Britain was the period of transformation, Great Britain externally experienced several wars intermittently mid internally transformed into the industrial country in the course of the 18th century. British shipowners were faced with short of seamen mainly due to several wars and expansion of shipping tonnage British shipowners tried to solve the mooing problem by decreasing the number of seamen from 22-23 sailors per ship of 100 tonnage in 1710's to 5 in 1810 and increasing seamen's wage from shillings per common seaman per month in the 17th century to 25 shillings in the middle of the 18th century and equation omitted during the French Revolutionary and Napoleonic Wars. What caused and resulted by specialized shipowners to cope with changeable market situation with flexibility was decrease of the number of seamen per ship and increase of wage.

• Journal of the Society of Disaster Information
• /
• v.11 no.4
• /
• pp.589-596
• /
• 2015

As urbanization progressed along with quantitative expansion of the construction industry, concrete has developed diversely as a material that is the most extensively used in the construction industry. However, aggregate resources that are an essential element of concrete production are gradually being depleted and the phenomenon of aggregate shortage has been intensifying due to the reinforcement of regulations on environmental issues. Therefore, in the present study, environment friendly mortar was made by replacing aggregate with mud that is dumped when dredging sand is dumped. To identify the dynamic characteristics of the mortar and to identify its fire resistance efficiency, the mortar was heated and its residual compressive strength was measured. In the results, the residual compressive strength values of MM1, MM2, and MM3 were 45%, 95%, and 57.7% respectively and the mix MM2 showed the highest fire resistance efficiency.