大跨活性粉末混凝土连续刚构桥的性能研究

Performance Research on Long-Span RPC Concrete Continuous Rigid Frame Bridge

活性粉末混凝土(RPC)在热养护条件下几乎没有收缩,并且在长期荷载作用下的徐变也很小,本文探讨了RPC在大跨梁式桥中应用的可能性.以主梁的应力和结构的刚度为控制目标,拟定了一座主跨为200 m的RPC连续刚构桥,通过与同跨度预应力普通混凝土刚构桥的比较,讨论了不同主梁材料对大跨度连续刚构桥静力性能、稳定性及抗震性能的影响.分析结果表明:由于RPC具有较高的韧性及强度,在不降低结构正常使用性能的前提下,RPC主梁比普通混凝土主梁减轻自重达53%,其主梁截面的几何尺寸往往是由结构的刚度而不是强度控制;同时更轻的结构自重降低了惯性荷载,从而改善了整个结构特别是桥墩的抗震性能;并且桥梁上部结构自重的减轻提高了结构抵抗使用荷载的有效性,增大了桥梁结构的跨径.

Reactive Powder Concrete （RPC） has lower shrinkage and creep under heat curing condition,and this paper studied the feasibility of the RPC application for long-span continuous rigid frame bridge. Taking both the stress of the girder and the stiffness of the structure as control aims, one 200m main-span continuous rigid frame bridge was designed. By comparing ordinary concrete continuous rigid frame bridge with RPC continuous rigid frame bridge, the impacts on static behavior, stability and seismic performance of different girder material were discussed. The results have indicated that, without the reduction of service performance, the dead weight of RPC girder was only 47 96 of ordinary concrete girder, and the geometry size of RPC girder section was decided by the stiffness of the structure instead of the strength of concrete. The structure with lower dead weight decreased the inertia load, which greatly improved the seismic performance of the total structure, especially that of the pier.