A93 Craighall Gorge

On the southern fringes of Scotland’s Cairngorms, the A93 Perth to Braemar road runs through the twisting and steeply wooded Craighall Gorge, a mile or so north of Blairgowrie.

The need to carry out improvement works to the section of the A93 between Craighall Bridge and Middle Mause Farm was first identified in 1985 when a Bailey-type bridge was used to replace a collapsed section of the existing retaining wall. Although installed as a temporary structure, this still carried over 3000 vehicle movements per day, to and from the Highlands.

Recently, engineering assessments of the area concluded that the slopes were not sufficiently stable to support new carriageway construction and the site was also too restricted to accommodate the works whilst keeping the existing road open to traffic. The Environment Services of Perth and Kinross therefore proposed that a completely new road be built to by-pass the bridge and on their instruction, Consulting Engineers Mouchel of Dundee, designed a 2.4km long single carriageway road running to the east of the gorge and broadly parallel to the existing route but at a higher level.

At the southern end of the works where the low-level old and higher-level new carriageways join up, Mouchel conceived a 130 m-long reinforced earth wall which would create a smooth transition from old to new.