The new Craigellachie Bridge was constructed in 1972 by Miller Construction Northern Limited. It carries the A941 over the River Spey between Aviemore and Elgin.
To ensure the continued operation of the bridge, AMCOGiffen were commissioned by Moray Council to replace the original mechanical bearings and expansion joints and resurface the road.
MHB Consultants were employed by AMCOGiffen as the independent checkers of Ekspan’s temporary works jacking design to facilitate the bearing works. We also acted as designers and checkers of the permanent steelwork strengthening of the existing box girder diaphragms at the jacking locations to enable the works.
Site inspections were carried out to ensure that the current condition of the bridge was suitable for the jacking loads as well as determining the exact arrangement of bearings, bolts and stiffening steelwork throughout the jacking area.
By developing a scheme to jack the deck directly from the existing pier-heads, the need to build trestles in the river and strengthening the box girders away from the existing supports was avoided.
To enable operation of the bridge during the works, a jacking sequence was developed, in cooperation with Ekspan, that kept bearing pressures on the pier-head at an allowable level for the existing concrete. Given the limited space available and the historic nature of the pier concrete, this involved coordination with traffic management during the resurfacing works.
Our works started in August 2019 and finished January.