비선형 해석 모델특성이 곡선 프리스트레스트 콘크리트 사장교의 풍하중에 의한 정적 휨거동에 미치는 영향

Abstract

A parametric study for the effects of nonlinear analysis model characteristics on the prediction of the static flexural behavior of the curved prestressed concrete(PSC) cable-stayed bridge under the wind load is presented. To account for the time-dependent effects of materials at each erection step of the PSC bridge, creep, shrinkage and aging of concrete and the relaxation of tendons and cables are considered. Various case analyses regarding not only the effects of material nonlinearities including nonlinear stress-strain relations of materials, tension crack and tension stiffening effects of concrete but also geometric nonlinearities including geometric stiffness matrix of frame elements and large defflection effect on the static flexural behavior of segmentally erected curved PSC cable-stayed bridge under the wind load are carried out. The numerical results on this bridge show that nonlinear analysis considering the effects of material and geometric nonlinearities is necessary in order to accurately predict the cracking of concrete of the girder section and the excessive deflection of the bridge deck under the static wind load. Tension stiffening effect of concrete and the effect of geometric stiffness matrix due to the axial forces of frame elements are found to have little effect in predicting the static wind load behavior of this bridge. Also the flexural behavior of this bridge under the static wind load is found to be the most disadvantageous just before the closure step of the deck. Finally, the effect of geometric nonlinearities due to large deflections and the change of the topology of the bridge on the flexural behavior of this bridge under the static wind load is found not to be negligible in the erection steps of the bridge decks.