• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.640-647
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• 2018

Many harbor structures have been constructed, and some structures are now under construction in Korea, which is a peninsular state and a logistics hub in Northeast Asia. Expansions and extensions of existing harbors are also being planned to meet increasing natural disaster threats. Wave-dissipation concrete blocks are recycled or discarded based on the personal experience of engineers only, and there are no safety checks or criteria. To check the safety of used blocks, material evaluations were done by visual inspection of blocks on the ground and under water and from 20 non-destructive measurements of the rebound hardness test and 3 concrete core samples. Wave-dissipation blocks are sometimes fully or partially damaged in the process of transferring and mounting them or during construction. Therefore, a safety check is essential for recycling blocks with an evaluation of materials while considering the construction phases. To do this, a block was modeled with a 3D finite element method using ADINA, and impact analyses were done according to the transfer, mounting, and construction phases. From the results of the impact analyses and material evaluation, the safety checks and reasonable evaluation of used blocks were examined, and detailed construction methods are proposed. The methods are expected to maximize the reuse of used wave-dissipation blocks from an economical point of view.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.18
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• pp.27-62
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• 2002

The international sale contract is the central contracts in export-import transactions. A good sale contract or set of general conditions of sale will cover all the principal elements of the transaction, so that uncertainties are avoided. The parties' respective duties as concern the payment mechanism, transport contract and insurance responsibilities, inter alia, will all be clearly detailed in the contract. The following key clauses should be included in international contracts of sale and general conditions of sale: ${\bullet}$ preamble ${\bullet}$ identification of parties ${\bullet}$ description of goods ${\bullet}$ price and payment conditions ${\bullet}$ delivery periods and conditions ${\bullet}$ inspection of the goods - obligations and limitations ${\bullet}$ quantity or quality variations in the products delivered ${\bullet}$ reservation of title and passing of property rights ${\bullet}$ transfer of risk - how accomplished ${\bullet}$ seller's warranties and buyer's complaints ${\bullet}$ assignment of rights ${\bullet}$ force majeure clause and hardship clause ${\bullet}$ requirement that amendments and modifications be in writing ${\bullet}$ choice of law ${\bullet}$ choice of dispute resolution mechanism Under most systems of law, a party can be excused from a failure to perform a contract obligation which is caused by the intervention of a totally unforeseeable event, such as the outbreak of war, or an act of God such as an earthquake or hurricane. Under the American commercial code (UCC) the standard for this relief is one of commercial impracticability. In contrast, many civil law jurisdictions apply the term force majeure to this problem. Under CISG, the standard is based on the concept of impediments to performance. Because of the differences between these standards, parties might be well advised to draft their own force majeure, hardship, or excusable delays clause. The ICC publication, "Force Majeure and Hardship" provides a sample force majeure clause which can be incorporated by reference, as well as a hardship clause which must be expressly integrated in the contract. In addition, the ICC Model provides a similar, somewhat more concise formulation of a force majeure clause. When the seller wishes to devise his own excusable delays clause, he will seek to anticipate in its provision such potential difficulties as those related to obtaining government authorisations, changes in customs duties or regulations, drastic fluctuations in labour, materials, energy, or transportation prices, etc.

• Journal of the Korean GEO-environmental Society
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• v.14 no.7
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• pp.39-50
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• 2013

Crib wall is one of the segmental grid retaining walls using headers and stretchers to establish the framework of the wall. In this method, grids formed by the intersection of headers and stretchers are generally filled with the gravel to maintain the weight of the wall. Therefore, the construction can be carried out with higher speed and much economically when compared with the concrete retaining wall. Furthermore, it has high drain capacity, and environmentally friendly aspects also have been pointed out because the possibility of the planting at the front of the wall. However, in the wooden crib wall method, the relative movement between the individual headers and stretchers was generally recognized, and stress redistribution in the gravel filling was also observed when subjected to the external loading and self-weight of filling. In this study, it was analyzed fracture types and causes of wooden crib wall through detailed investigation and analysis of a large crib wall construction site. As a results, it occurred the damage in the members of 5.7% in a total of 2,315 locations and the damage of header occurred in the members of a header 80.2%. The 65.7% of the damaged header are concentrated in the lower part of crib wall. Therefore, it was analyzed the differences of fracture types and causes of wooden crib wall depending on the installation position and the kinds of members. It is considered basically the members of various forms of distortion and the grain affecting.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.235-243
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• 2014

According to the "Safety Evaluation Detailed Instructions (Dam)", precise safety inspection is carried out for dams that exceed a certain scale. However, as the Hydrological Safety Evaluation from various evaluation standards is designed to evaluate the safety of existing dams considering PMF, the evaluation is much less applicable for most agricultural reservoirs. Therefore, the Hydrological Safety Guidelines for agricultural reservoirs are expected to be re-evaluated considering the diverse risk factors with the coefficient model and AHP in this study. The coefficient model has been developed by selecting the hydrological safety superordinate subordinate evaluation factors to reflect diverse risk factors of agricultural reservoirs. After calculating the sum of indicators score for each evaluation factors, validation procedures were performed for the questionnaire which a panel answered. The practical coefficient has eventually been estimated for the hydrological safety evaluation considering the diverse risk factors. The conclusions acquired based on the study done are that both most agricultural reservoirs were classified as flood defense capability is insufficient and agricultural reservoirs which meet embankment-freeboard standards considering PMF was overestimated.

• Land and Housing Review
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• v.8 no.3
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• pp.189-200
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• 2017

The work breakdown structure and the precedence relations by work activity are very important because they are the basic data for estimating the construction duration in the construction work. However, there is no standard to accurately estimate the construction duration since the size of the school facilities construction is smaller than the general construction work. Therefore, some schools are unable to open in March or September and the delay of the construction duration can cause damage to the students. To solve this problem, this study developed a work breakdown structure of school facilities construction work and analyzed the precedence relations by work activities. The work breakdown structure of the school facilities construction is composed of three steps. The operations corresponding to level 1 and level 2 are as follows. (1) 2 preparatory work categories; preparation period and temporary construction. (2) 17 architectural work categories; temporary construction, foundation & pile work, reinforced concrete work, steel roof work, brick work, plaster work, tile work, stone work, waterproof construction, wood work, interior construction, floor work, metal work, roof work, windows construction, glazing work and paint construction. (3) 7 mechanic and fire work categories; outside trunk line work, plumbing work, air-conditioning equipment work, machine room work, city gas plumbing work, sanitation facilities and inspection & test working. (4) 4 civil work categories; wastewater work, drainage work, pavement work and other work. (5) 1 landscaping work categories; planting work. The work breakdown structure was derived from interviews with experts based on the milestones and detailed statements of existing school facilities. The analysis of precedence relations by school facilities work activity utilized PDM(Precedence Diagramming Method)which does not need a dummy and the relations were applied using FS(Finish to Start), FF(Finish to Finish), SS(Start to Start), SF(Start to Finish). The analysis of this study shows that if one work activity is delayed, the entire construction duration may be delayed because the majority of the works are FS relations. Therefore, it is necessary to use the Lag at the appropriate time to estimate the standard construction duration of the school facility construction. Lag is a term used only in the PDM method and it is used to define the relationship between the predecessor and the successor in creating the network milestone. And it means the delay time applied to the two work activities. The results of this study can reasonably estimate the standard construction duration of school facilities and it will contribute to the quality of the school facilities construction.

• Journal of Wetlands Research
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• v.17 no.2
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• pp.130-138
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• 2015

According to the "Safety Evaluation Detailed Instructions (Dam)", a precise safety inspection is carried out for dams that exceed a certain scale. However, as the Hydrological Safety Evaluation from various evaluation standards is designed to evaluate the safety of existing dams considering PMF(Probable Maximum Flood), the evaluation is much less applicable for most agricultural reservoirs. Therefore, the Hydrological Safety Guidelines for agricultural reservoirs are expected to be re-evaluated considering the diverse risk factors with the coefficient model and AHP(Analytic Hierarchy Process) in this study. The coefficient model has been developed by selecting the hydrological safety superordinate subordinate evaluation factors to reflect diverse risk factors of agricultural reservoirs. This study indicated that in the short term, improving the safety check condition evaluation grade will be useful to improve the hydrological safety of the agricultural reservoir because it can be performed immediately.

• Journal of Ocean Engineering and Technology
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• v.30 no.5
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• pp.389-399
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• 2016

This paper presents the explorations of hydrothermal vents located in the Marina Arc and Back Arc Basin using the deep-sea ROV Hemire. These explorations were conducted by KRISO and KIOST to demonstrate the capability of Hemire in various applications for deep-sea scientific research. The missions included the following: (1) to search the reported vents, (2) conduct visual inspections, (3) deploy/recover a sediment trap and bait traps, (4) sample sediment/water/rock, (5) measure the magnetic field at the vent site, and (6) acquire a detailed map using multi-beam sonar near the bottom. We installed three HD cameras for precise visual inspection, a high-temperature thermometer, a three-component magnetometer, and a multi-beam sonar to acquire details of the bottom contour or identify vents in the survey area. The explorations were performed in an expedition from March 23 to April 5, 2016, and the missions were successfully completed. This paper discusses the operational process, navigation, and control of Hemire, as well as the exploration results.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.637-658
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• 2022

TBM tunnel is simple with the iterative process of excavating the ground, building a segment ring-build, and backfilling. Drill & Blast, a conventional tunnel construction method, is more complicated than the TBM tunnel and has some restrictions because it repeats the inspection, drilling, charging, blasting, ventilation, muck treatment, and installation of support materials. However, the preparation work for excavation requires time and cost based on a very detailed plan compared to Drill & Blasting, which reinforces the ground and forms a tunnel after the formation of tunnel portal. This is because the TBM equipment for excavating the target ground determines the success or failure of the construction. If the TBM, an expensive order-made equipment, is incorrectly configured at the assembly stage, it becomes difficult to excavate from the initial stage as well as the main excavation stage. When the assembled shield TBM equipment is dismantled again, and a situation of re-assembly occurs, it is difficult throughout the construction period due to economic loss as well as time. Therefore, in this study, the layout and plan of the site and the assembly process for each major part of the TBM equipment were reviewed for the assembly of slurry shield TBM to construct the largest diameter road tunnel in domestic passing through the Han River and minimized interference with other processes and the efficiency of cutter head assembly and transport were analyzed and improved to suit the site conditions.

• Korean Journal of Construction Engineering and Management
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• v.20 no.3
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• pp.113-121
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• 2019

The death rate of industrial accidents per 10,000 people in Korea is two to three times higher than that of major countries. Falling accidents at the construction site happened to have caused the most deaths. Analysis of existing research and measures by national institutions showed that the industrial accident management concentrated on falling accidents was insufficient and the seasonal safety management measures were not enough. There is thus the need for research that provides detailed and enough information on falling accidents. This study, therefore, aims to overcome the limitations of existing research and safety management accident response using a methodology that provides the necessary information for the prevention of fall accidents by deriving seasonal crash characteristics of the construction site. In order to provide enough information, 387 cases of seasonal construction site falling were collected, which describes the causal relationship of accidents. Text mining using principal component analysis and cluster analysis was carried out. The analysis showed that: In the spring, snowfall and unreasonable operation of equipment including lifts were the major cause. In summer, most accidents were caused by form, insufficient safety inspection, and installation work. In autumn, weather factors such as wind and typhoon were the cause. In winter, material transportation, exterior wall work, and ignore safety precautions were the cause of the crash.

• Journal of the Society of Disaster Information
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• v.18 no.2
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• pp.306-313
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• 2022

Purpose: The purpose of this study is suggested to improve upon current existing methods of ammonia chemical accident prevention and damage reduction. Method: Ammonia is one of the most common toxic substances that causes frequent chemical accidents. And it was selected as leakage materials according to statistics on chemical accident. Based on actual cases of chemical accidents, CARIS modeling was used to compare the damage impact range of Ammonia and HCl and Cl. Also, find out problems with the current systems. Result: As a result of find out the range of accident influence that spreads to the surroundings when an ammonia chemical accident, it was longer than the range of influence of hydrochloric acid and shorter than that of chlorine. In addition, it was found that when chemical accident by ammonia, hydrochloric acid, or chlorine, there are apartments and schools, which can have an effect. Conclusion: It is decided that it is necessary to determine whether or not chemical accident prevention management plans and statistical investigations are submitted for workplaces dealing with ammonia, and detailed guidelines and reviews are necessary. In addition, it is judged that it is necessary to establish a DB for ammonia handling plants, and it is considered that information sharing and joint inspection among related organizations should be pursued.