河沟头渡槽50m跨预应力引槽箱梁槽身结构设计

The Structural Design of 50 m Span Prestressed Channel Box Beam Aqueduct in the Hegoutou Aqueduct Project

河沟头渡槽是黔中水利枢纽一期工程总干渠上的一座关键建筑物,其引槽为50m跨预应力箱梁结构,采用箱形断面构造及三向预应力体系,具有自重轻、跨度大、承载力高、经济性优、施工简便等特点,使得50m级简支梁式渡槽仍然能保持较强的抗裂能力。结合渡槽自身受力、运行等特点,分别按照公路、水利行业有关规定开展相应计算分析,计算结果表明,在正常使用状况下槽身纵向最小正应力1.151MPa,不考虑竖向预应力钢筋情况下最小主拉应力-0.31MPa,最大正压应力10.09MPa,水荷载导致的槽身下挠12.3mm,纵向预应力钢筋最大永存应力1 207.07MPa,均能很好地满足各自体系的要求。

The Hegoutou Aqueduct is a critical building of the first-phase project of Qianzhong Hydro-junction Project.The channel of the project is a 50m span prestressed box girder structure.By adopting the box section structure and three prestressed systems,incorporating light weight,large-span,high bearing capacity,optimal economy,easy construction and other features,makes even to the simply supported beam aqueduct can keep high seismic performance.Combined aqueduct itself force and operation features,this paper calculates and analyzes,according to the related regulation in road industry and water conservancy industry.The calculation results show that the aqueducfs minimum longitudinal normal stress is 1.151 MPa under service load.At the same time disregarding vertical prestressed forced steel,the minimum principal tensile stress is-0.31 MPa and the maximum vertical prestressed force is 10.09 MPa.The down-warping caused by water load can reach 12.3 mm and the maximum remaining stress of portrait forced steel can achieve 1 207.07 MPa.The requirements of each system could well satisfied.