• Journal of Korea Port Economic Association
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• v.32 no.3
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• pp.95-108
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• 2016

China has recently advocated a national strategy called "One Belt One Road" and transferred to execution to refine it into detailed action plans and has continued to fix the complement. However, the Korean Peninsula, including the North Korea remains could not be included at all in the Chinese development policy and framework in terms of the International Logistics. Currently it is raised between Korea-China rail ferry system again and that is when we need to make effective policy development on international multimodal transport system in Northeast Asia. This paper introduces the K-LB (Korea LandBridge) as its execution plan and conducted a feasibility study on this. K-LB consists of a Korea-Russian train ferry system based in Pohang Yeongil New Port(light-wing) and a Korea-China train ferry system based in Saemangeum New Port(left-wing). These two wings are linked to the existing rail system in Korea. This study is convinced that the K-LB is an effective international logistics system in the current terms and conditions and also demonstrated that it is feasible to introduce th K-LB on the peninsula. More strictly speaking, through a linear programming under objective function that minimize the transport cost quantified prior to demonstrate the feasibility, the available ranges and conditions for the transportation costs that are ensured the effectiveness of the K-LB are presented as results. According to the results, if the transport cost of K-LB is cheaper about 34.5% than that of sea transport such as container transport, the object goods may be transported by K-LB on this route. It means that the K-LB system has a competitive advantage due to more rapid customs clearance as well as omitted loading and unloading procedures over container transportation system. It also noted that the threshold level may not be large. Therefore, K-LB has competitive enough to prove its introduction in the Northeast Asian logistics system.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.661-670
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• 2016

In 2000, post-construction evaluation was introduced for the purposes to evaluate demand, cost, and construction period of public construction projects and to reduce errors of public order agencies. However, pricing guide of post-construction evaluation has not been established, which becomes a cause of quality degradation of post-construction service and conflict occurrence. This study suggests the pricing guide in the form of percentage of construction cost method and cost plus fee method based on data of post-construction evaluation. This study investigates the construction costs and service costs for post-construction evaluation and conducts the comparative analysis of 'percentage of construction cost method' and 'cost plus fee method.' The analysis result shows 'cost plus fee method' is more accuracy than 'percentage of construction cost method.' In particular, cost plus fee method includes various correction coefficients, such as distance, area, and integration, in order to reflect the project characteristics of each infrastructure, and suggests linear construction (roads, railways), nonlinear construction I (housing and industry complex), and nonlinear construction II (airports, seaports, dams, water and sewage).

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.211-224
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• 2018

It is important to design tunnel support system considering the various loads acting on the tunnel because they have a direct impact on the stability of tunnels. In Korea, standardized support patterns are defined based on the rock mass classification system depending on the project, and it is stated that it should be modified appropriately considering the behavior of tunnel during construction. In this study, the tunnel support pattern optimization method is suggested based on the convergence-confinement method, earth pressure, axial force of rock bolt, and moment acting on the shotcrete. The length and spacing of the rock bolts and the thickness of the shotcrete were optimized by using the differential evolution algorithm (DEA) and the results were compared to the standard support pattern III for railway tunnel. Rock bolt length can be reduced and the installation interval can be widened for shallow tunnel. As the depth of tunnel increases, the thickness of shotcrete increases linearly. Therefore, the thickness of shotcrete should be thicker than the standard support pattern as the depth of tunnel increases to secure the stability of tunnel.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.5
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• pp.397-403
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• 2016

During the rapid economic growth in Korea since the 1970s, many underground facilities were constructed such as under passes and railways. Seismic design has been mandated in 1988, but the structures built before 1988 were not reflected on the seismic design. Accordingly, these underground structures require effective seismic reinforcing methods to ensure safety when the earthquake happens. By these reasons, in this study, using the proposed pre-flexed members, RC box structure was analyzed for seismic reinforcement of the corner. This method is based on a principle that enlarging the resistance against the external force by installing the pre-flexed member to the box structure corner. To evaluate validity, a newly developed member with CornerSafe was compared with traditional type reinforcement using experiments and finite element analysis. In finite element mode, nonlinearity of steel was modeled based on J2 plasticity model and concrete was based on CEB FIP MODEL CODE 1990. Also, composite ratios of box and pre-flexed member were computed for design application. The reinforcement and box structure were analyzed under the bond condition completely attached by the tie, and the results of experiment and finite element analysis were same in the force-displacement curve.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.31-40
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• 2012

The irregularity of railway track affects not only the comfort of ride such as noise or vibration but also the safety of train operation. For this reason, it is an interesting research area to design a reliable and sustainable railway track system and to analyze the train movement mechanism based on systematic approaches considering reasons of track irregularity possible in a specific local environment. Irregularity data inspected by EM-120, an railway inspection system in Korea includes unavoidable incomplete and erratic information, so it is encountered lots of problem to analyse those data without appropriate pre-data-refining processes. In this research, for the efficient management and maintenance of railway system, progress rate of standard deviation of irregularity is quantified. During the computation, some important components of railways such as rail joint, ballast, roadbed, and fastener have been considered. Probabilistic distributions of irregularity growth with respect to time are computed to predict the remaining service life of railway track and to be adapted for the safety assessment.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.467-467
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• 2016

암거는 일반적으로 용수나 배수용의 수로가 도로, 철도, 제방 등의 아래에 매설 된 수로를 지칭한다. 이러한 암거는 산업발전으로 사회기반시설의 신설 및 확충, 재정비 등으로 많이 활용되고 있다. 최근 들어 기후로 인한 재해가 급증하면서 이러한 시설물에 대한 안정성 및 관리에 대한 관심이 높아지고 있는 것이 현실이다. 특히 소하천은 집수면적 및 유로연장이 짧고 하상경사가 급하기 때문에 홍수에 취약하다. 즉, 빨라진 유속으로 인해 구조물 주변의 세굴에 의한 유실, 토사유출로 인한 하상퇴적, 부유물로 인한 차단으로 인해 통수에 지장을 받아 피해가 발생하게 된다. 이러한 암거시설물 피해는 2차 피해로 이어질 수 있으며 사회기반시설 파괴로 도시기능이 마비되고 인근 주변지역에 침수로 인한 재산 및 인명피해까지 발생시킬 수 있는 피해 잠재능력을 보유하고 있다. 그러나 피해에 대한 예방대책은 유지관리를 통해 지속적으로 관리하는 것이 대부분의 지침 등에 소개된 내용들이다. 본 연구에서는 암거를 대상으로 암거의 폐색으로 인해 암거주변에서 변화되는 흐름특성을 축소모형을 통해 검토하고자 하였다. 암거 축소모형실험은 1.5m 폭을 갖는 직선수로에서 수행하였으며, 암거모형은 도로암거표준도(2008)를 참조하여 $3m{\times}3m$ 수로암거를 대상으로 1/10 축소모형을 제작하였다. 암거유입부 퇴적으로 인한 암거의 차단률(차단면적/암거단면적)은 차단이 발생하지 않는 0% 조건에서부터 10%, 20%, 30%, 40%, 50% 조건에 대해 실험을 수행하였다. 실험결과 차단에 따른 암거 상류단의 수위는 차단이 없는 암거의 경우에 비해 차단율이 높아질수록 암거유입부 수위는 20.4% ~ 82.7% 상승하는 것으로 나타났다. 암거의 차단률이 40% 이상일 경우 높아진 수위로 인해 암거통로의 윗상면부까지 다다르고 있으며 50%일 경우 암거를 통과하는 흐름이 자유수면흐름이 아닌 오리피스 흐름이 발생하는 것으로 나타났다. 암거유입부 차단으로 인한 암거주변의 최대유속은 암거 직하류부에서 주로 발생하여 암거 유출부에서의 최대유속은 차단율이 증가할수록 선형적으로 증가하는 것으로 나타났으며 암거 유출부에서의 유속은 차단전의 조건(0%) 대비 4.2% ~ 35.5% 까지 상승하는 것으로 나타났다. 이와 같은 결과를 토대로 고려하였을 때 대부분 산지부에서 설치되는 암거의 경우 유속이 불가피하게 증가하게 됨으로 유속에 따른 유속조절방안(차단 및 우회시설) 및 세굴대책을 세워야 할 것으로 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.65-77
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• 2008

The effects of climatic changes owing to urbanization, geographical and topographical conditions on annual and monthly FAO Penman-Monteith (FAO P-M) reference evapotranspiration, and energy and aerodynamic terms of FAO P-M reference evapotranspiration were studied. In this study, 21 climatological stations were selected. The statistical methods applied for trend analysis are Spearman rank test, Sen's test, linear regression analysis and analysis of actual variation ratio. Furthermore, the cluster analysis was applied to cluster 21 study stations by considering the geographical and topographical characteristics of study area. The study results indicate that urbanization affects the trend and amount of FAO P-M reference evapotranspiration, energy term and aerodynamic term; however, the result of Sen's test indicates that urbanization does not significantly affect the magnitude of trend (Sen's slope). The energy term increased at study stations located in coastal area; however, decreased at study stations located in inland area. The topographical slope of study area did not significantly influence on the trend of energy term. The aerodynamic term increased in both coastal area and inland area, indicating much significantly increasing trend in inland area, and it was also affected by the topographical slope of the study area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.965-976
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• 2006

A realistic lifetime seismic-reliability based approach is unavoidable to perform Life-Cycle Cost (LCC)-effective optimum design, maintenance, and retrofitting of structures against seismic risk. So far, though a number of researchers have proposed the LCC-based seismic design and retrofitting methodologies, most researchers have only focused on the methodological point. Accordingly, in most works, they have not been quantitatively considered critical factors such as the effects of seismic retrofit, maintenance, and environmental stressors on lifetime seismic reliability assessment of deteriorating structures. Thus, in this study, a systemic lifetime seismic reliability analysis methodology is proposed and a program HPYER-DRAIN2DX-DS is developed to perform the desired lifetime seismic reliability analysis. To demonstrate the applicability of the program, it is applied to an example bridge with or without seismic retrofit and maintenance strategies. From the numerical investigation, it may be positively stated that HYPER-DRAIN2DX-DS can be utilized as a useful numerical tool for LCC-effective optimum seismic design, maintenance, and retrofitting of bridges.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.517-528
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• 2007

Domestic or international existing researches regarding rail damage factors are focused on laying, vehicle conditions, driving speed and driving habits and overlook characteristics of track structure (elasticity, maintenance etc). Also in ballast track, as there is no special lateral spring stiffness of track also called as ballast lateral resistance in concrete track, generally, existing study shows concrete track has 2 time shorter life cycle for rail replacement than ballast track due to abrasion. As a result of domestic concrete track design and operation performance review, concrete track elasticity is lower than track elasticity of ballast track resulting higher damage on rail and tracks. Generally, concrete track has advantage in track elasticity adjustment than ballast track and in case of Europe, in concrete track design, it is recommended to have same or higher performance range of vertical elastic stiffness of ballast track but domestically or internationally review on lateral spring stiffness of track is very minimal. Therefore, through analysis of service line track on site measurement and analysis on performance of maintenance, in this research, dynamic characteristic behaviors of commonly used ballast and concrete track are studied to infer elasticity of service line track and experimentally prove effects of track lateral spring stiffness that influence curved rail damage as well as correlation between track elasticity by track system and rail damage to propose importance of appropriate elastic stiffness level for concrete and ballast track.

• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.15-22
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• 2002

Transportation project appraisal should be precise in order to increase the social welfare and efficiency, and it has been evaluated by only a single criterion analysis such as benefit/cost analysis. However, this method cannot assess some qualitative items, and cannot get a proper solution for the clash of interests among various groups. Therefore, the multi-criteria analysis, which can control these problems, is needed, and then Saaty has developed one of these methods, AHP(Analytic Hierarchy Process) method. In AHP, the project is evaluated through weighted score of the criteria and the alternatives, which is surveyed by a questionnaire of specialists. It is based on some strict suppositions such as reciprocal comparison, homogeneity, expectation, independence relationship between multi-criteria, but supposing that each criterion has independence relation with others is too difficult in two reasons. First, in real situation, there cannot be perfect independence relationship between standards. Second, individuals, even though they are specialists of that area, do not feel the degree of independence relation as same as others. This paper develops a modified AHP method for solving this dependence relationship between multi-criteria. First of all. in this method, the degree of dependence relationship between multi-criteria that the specialist feels is surveyed and included to the weighted score of multi-criteria This study supposes three methods to implement this idea. The first model products the degree of dependence relationship in the first step for calculating the weighted score, and the others adjust the result of weighted score from the basic AHP method to the dependence relationship. One of the second methods distributes the cross weighted score to each standard by constant ratio, and the other splits them using Fuzzy measure such as Bel and Pl. Finally, in order to validate these methods, this paper applies them to evaluate the alternatives which can control public resentments against Korean rail path in a city area.