This paper analyzed design bearing capacities of pile foundations strengthened by pre-loading method for vertical expansion. The bearing capacities were investigated for two different pre-loading strategies: (1) after partial removals of structural/non-structural elements (e.g. finish, masonry wall etc.); and (2) after vertical expansions. Based on the numerical studies, more than 60% of the existing piles exceeded the design bearing capacities due to the difference of pre-loading strategies, which should be considered in structural design.

본 연구는 철근콘크리트 보에 대해 선가력 후 보강재료별로 보강 효과를 파악하기 위하여 휨 실험한 결과, 다음과 같은 결론을 얻었다. 실험결과, CB 보강 실험체가 콘크리트 내부에 매입되어 일체 거동함으로써 휨내력 향상 및 연성능력 면에서 가장 우수한 것으로 나타났으며, 섬유계 보강재인 CFS와 GFS 보강 실험체 또한 우수한 내력을 가지는 것으로 나타났다. GSP 보강실험체의 경우 다른 보강 실험체에 비해 보강재 자체의 내력은 큰데 반해 콘크리트와 부착성이 떨어져 상대적으로 낮은 보강효과를 보였으며 실제 구조체에서는 콘크리트와 부착성이 개선 되어 보다 큰 보강효과를 발휘할 것으로 사료된다.

This study was conducted to analyze the operating conditions of predenitrification process to improve the treatment efficiency in low organic loading sewage plant in use today, and to investigate the treatment efficiency of pilot plant added night soil as well as the nitrogen removal characteristics of pilot plant added carbon sources. In the operation under the condition of BOD5 sludge load 0.03-0.28kg BOD5/kg VSS/d and oxic ammoniac nitrogen sludge load 0.02-0.24 kgNH4+-N/kg MLVSS/d, nitrification efficiency is higher than 95%. In order to achieve 70% nitrogen removal at the T-N sludge loading 0.06kg T-N/kg VSS․d and the SRT 6~11 days, optimum operating factors were revealed to CODcr/T-N ratio 9, recycle ratio 2.6, and denitrification volume ratio 0.33. At this time, denitrification capacity was approximately 0.09 kg NO3--N/kg CODcr; specific nitrification rate was 3.4mg NH4+-N/g MLVSS/hr; and specific denitrification rate was 4.8mg NO3--N/g MLVSS/hr.