There increasing demand for technologies that are capable of producing heat and electric energy by burning fuels such as solid refuse fuel (SRF) and biomass to mitigate the effects of greenhouse gas emissions from fossil fuels and global warming in the field of thermal power generation. In particular, conversion of SRF into energy (Waste to Energy) is the promising technology with high economic and social benefits. The high temperature corrosion of the heat exchange tube is the most important factor that affects the economic deterioration of a circulating fluidized bed boiler using solid refuse fuel, due to operating time decrease and the periodic shutdown during plant operation. The purpose of this study was to examine the high temperature corrosion characteristics of boiler superheater tubes. The change of corrosion characteristics according to the temperature and alkali chloride salt can be investigated by analyzing the morphology of the surface and the microstructure of specimen cross-section and examining the changes in the physical and chemical properties. The degree of corrosion increased as the temperature increased and the weight of the alkali chloride specimen deposit decreased due to the volatilization of the metal chloride compound above 700°C. Deposits of KCl were found to accelerate corrosion by destroying the oxide layer and forming potassium compounds.

Steel pipe pile, which is used for the base of structures, need the reinforcing head method to prove enough dynamic performance. Currently there are various reinforcing head methods are used, but most of them have problems of structural complications and heavy charges. Thus, this study is to develop a reinforcing head method for steel pipe piles using hook type bending reinforcement, which can fix piles using nuts, and experimentally prove structural performances.

This study was performed to develop a reinforcing head method for steel pipe piles using screw type bending reinforcement, which can fix piles using nuts, and experimentally prove structural performances. In order to do so, steel pipe pile reinforcing head method test specimen using screw bending iron was produced and implemented to vertical tensile test, vertical compression test, and horizontal loading test. As a result, the test showed that it secured 1.28-3.62 times safety factors that are demanded from the design criteria for highway bridge.

본 연구에서는 대직경 고장력볼트 이음부의 안전성 및 경제성을 검토할 목적으로 F10T-M30 대직경 고장력볼트를 사용한 시험편을 대상으로 정적 인장시험을 실시하여 미끄러짐 특성을 평가하였다. 또한 유한요소해석을 실시하고 볼트의 강도등급 및 직경에 따른 소요볼트 개수를 산정하였다. 그 결과 M30 고장력볼트의 평균 미끄러짐 계수는 도로교설계기준의 기준인 0.4를 초과하며, M22 고장력볼트와 동등한 미끄러짐 성능을 확보하는 것으로 나타났다. 또한 고장력볼트의 강도등급 및 직경에 따른 경제성 분석을 실시한 결과, F10T-M22 고장력볼트를 기준으로 하여 F13T-M22 고장력볼트를 적용하면 소요볼트 개수가 21% 감소하며, F10T-M30 고장력볼트를 적용하면 46% 감소하는 것으로 나타나 고장력볼트의 대직경화에 따른 경제성을 확인할 수 있었다.