Frictional resistance analysis on prestressed curved channel under cosine distribution assumption of contact pressure

Referring to the design of prestressed concrete structures with curved channel, the formula of prestressed loss due to friction resistance recommended by Bridge Rules was questioned in this paper. Some conflicts in application of the formula show that uniform distribution assumption of contact pressure was incorrect and the formula had some limitations. A cosine distribution hypothesis of contact positive pressure was proposed in the paper based on the elastic contact theory. The expressions of positive pressure and frictional resistance for any curved channel were derived. The comparison between the calculated results and the current method recommended by Bridge Specifications show that the frictional resistance under non-uniform distribution of positive pressure is less than under the uniform distribution.