Stability of Timber Bridges Subject to Scour

Abstract

Because scour is responsible for most disastrous bridge failures, bridge scour monitoring is necessary for the safety of public roads. While much attention is paid to the amount of bridge scour at a foundation, the structural stability implications of the loss of embedment due to scour are not easily assessed. To fill this need, an automated screening tool for the evaluation of timber pile bents was developed. The tool examines five failure modes of timber piles and timber bents: kick-out of a bent due to zero or negligible embedment after scour; pile plunging due to soil failure; pile buckling failure in either the longitudinal or transverse direction; bent pushover failure due to the combined effects of superstructure gravity loading and loading from the lateral debris raft load; and beam-column failure of the upstream pile due to the combined lateral debris raft load and axial gravity loading. The automated screening tool was programmed using Visual Studio 2005 and 2010 software package. A series of forms allow the user to input bent geometry and scour conditions for the bent under assessment, then the program will internally evaluates the structural stability. A printable report is also provided to supply documentation of the stability analyses.