Scottish Water

Conditions Of Contract
NEC Option A

78 weeks

Contract Value


The pipe-bridge over the main A81 Glasgow to Aberfoyle road at Ballat is a substantial structure on the 42km long Katrine Aqueduct, which transfers the main raw water supply for the City of Glasgow from Loch Katrine in the Trossachs to Milngavie Water Treatment Works.

Severe structural damage resulted from the impact of a high vehicle attempting to drive under the open-structured steel pipe bridge, which resulted in a lengthy closure of the main road to enable a detailed assessment of the damage and a complex repair and reinstatement to be undertaken, whilst ensuring the security of supply was maintained.


Following emergency mobilisation, temporary supports were installed together with other measures to maintain the integrity of the structure to enable a detailed investigation and the development of a permanent repair to the main elements of which included; masonry abutment repair & block replacement; complex steel beam & bracer pipeline top supports; monolithic reinforced concrete sill, padstone and pipe-end anchor walls; pipe section replacement; collision protection beam installation; and an advanced warning system was also incorporated to reduce the risk of future incidents.

An advanced warning system incorporating conventional signage, physical height restrictors and illuminating warnings were also incorporated to reduce the risk of future incidents, with the work subject to meticulous planning and careful execution throughout to ensure the critical water supply was maintained.

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