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        검색결과 4

        1.
        2018.05 구독 인증기관·개인회원 무료
        The current construction and maintenance guidelines applied to airport pavement in Korea are those of the International Civil Aviation Organization (ICAO), the International Air Transport Association (IATA), and the Federal Aviation Administration (FAA). In order to consider local conditions of airports in Korea, more specific details should be addressed in those guidelines. For example, the design and construction for pavements at airports in Korea follow the specifications of materials for general roads or foreign airport pavement guidelines, as there is no design manual or guideline for the granular base and subbase materials for airport pavement in Korea. In such circumstances, the likelihood of premature failure or accelerated damage increases, as the loading from airplanes is not fully taken into account or the local environmental characteristics are not considered. In addition, concerns in public facility drainage systems have been rising recently in line with the increase in the frequency and scale, caused by the global abnormal-temperature phenomenon, of localized torrential rain and snow. For airport runways, measures to maintain swift drainage systems are especially necessary to ensure safety and prevent flight delays. In this study, the appropriate moisture content and pavement method are analyzed by applying porous concrete developed for a cement-treated base course for securing permeability of airport pavement at an actual construction site. In addition, on-site construction testing was performed to determine the appropriate compaction method and the curing method to minimize cracking by using a compaction facility. To determine the optimal moisture content, a quality-control was performed by measuring the moisture content of porous concrete produced at a batch plant. For this purpose, a speed moisture test (ASTM D 4944) was performed on site because the unit-water content of the porous concrete affects its compaction and finishing. Before compaction, a grader was used to remove fragments on the subbase and then a tandem roller was used to level and compact. After compaction, the porous cement-treated base course, called porous concrete, was placed using an asphalt finisher. The mechanical properties and durability of the porous cement-treated base course with a variation of a degree of compaction: noncompaction, tandem roller moved back and forth once, three times, and five times. The pavement was covered with vinyl according to the curing guidelines suggested by the Korea Expressway Corporation’s highway construction specifications, to prevent evaporation from porous concrete that has relatively low moisture content. After curing, the core was collected to analyze the compressive strength, permeability coefficient, porosity, and freeze–thaw resistance characteristics.
        2.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The occurrence of unexpected disasters, including fire events, increases as the road network becomes complicated and traffic volume increases. When a fire event occurs on and under bridges, the damage extensively influences direct damage to structures, vehicles, and human life and secondary socioeconomic issues owing to traffic blockage. This study investigated potential fire-hazard risks on bridges of the Korean national route roadMETHODS: The investigation was conducted using field investigation and analysis with satellite pictures and road views from commercial websites and the Bridge Management System (BMS). From the filed investigation, various potential fire resources were identified. The satellite pictures and road views were helpful in measuring and recognizing conditions underneath bridges, stowage areas, etc.RESULTS : There are various potential fire resources underneath bridges such as piled agricultural products, parked petroleum tanks, construction equipment, and attached high-voltage cables. A total of 94.6% of bridges have underneath clearances of less than 15 m. A bridge underneath volume that can stow a potential fire hazard resource was 7,332 m3 on average, and most bridges have about 4,000 m3 of space. Based on the BMS data, the amounts of PSC and steel girders were 29% and 25%, respectively.CONCLUSIONS : It was found that the amount of stowed potential fire hazard resources was proportional to the underneath space of bridges. Most bridges have less than 15 m of vertical clearance that can be considered as a critical value for a bridge fire. The fire risk investigation results should be helpful for developing bridge fire-protection tools.
        4,200원
        4.
        2017.03 KCI 등재 서비스 종료(열람 제한)
        In this study, It was purpose to provide preliminary data for extension of the applicability of deep corrugated steel plate composite members by steel grade and shear reinforcement method. From the result of flexural test on deep corrugated plates composite members using GR40 and SS590, positive moment capacity was increased about 28% by SS590 steel. But to change steel grade was proved to have insignificant effects for increasement of negative moment capacity. In the moment test result of same overlapping length, Increasement rate of positive and negative moment capacity was not significantly improved by increasing the number of bolt. It was estimated to be due to the characteristics of bolt connection such as distance between centers of bolts, edge distance of bolt. In the test result on the spacing of shear reinforcement, positive moment capacity was increased and deformation of negative moment was reduced as the distance decrease. In the test result on the shape of shear reinforcement, positive and negative moment resistance was increased about 2% ~ 7% by U shaped shear reinforcement. In conclusion It was estimated that moment capacity of deep corrugated steel plate composite members are depend on steel grade of deep corrugated steel plate, spacing of shear reinforcement and reinforcing bar.