Scour Assessments for Rail & Highways Bridges
As flooding events become more prevalent, railways and highways bridges over rivers have become more vulnerable to collapse through the scouring away of their foundations. This leads to instability of the superstructure and the outcome is the type of failure we saw at Feltham Railway Bridge in 2009, six separate road bridges in Cumbria also in 2009 and Tadcaster in 2015. Thankfully there have no associated fatalities since Glanryhd in 1987.
Scour at bridge sites is typically classified as constriction scour and local scour. The former occurs across the cross-section of the bed on account of increased flow velocities associated with narrowing of the channel at the bridge site. Local scour is brought about by the increased velocities and vortices at abutments and piers. Debris struck at a crossing can exacerbate the effect by further constricting the channel.
HRS Services can help:
- HRS can provide level 1 scour assessments to BD97/12 by surveying the riverbed, foundations and any existing protection measures and undertaking a preliminary risk rating
- Depending on the outcome of the level 1 assessment, HRS can also proceed to a level 2 assessment involving the calculation of flow depths and velocities under flood conditions resulting in the assignment of a Scour Risk Rating and recommendations for management measures
- HRS can remove the debris deposited during flood events, including when the river is in spate
HRS has undertaken inspections on trunk road structures for clients the UK’s leading contractors and consultants and numerous local authorities.
Since 1990 HRS has inspected over 1,000 structures on live railways and 3,000 disused rail structures.