Kincraig to Dalraddy

A9 Dualling: Kincraig to Dalraddy

overcoming poor ground conditions was key for this PROJECT'S SUCCESS

This project involved the construction of a dual carriageway along the section of existing trunk road between Kincraig and Dalraddy, as part of an overall systematic upgrade of the A9 dualling separating Perth and Inverness in Scotland.

ByrneLooby was commissioned by the design and build contractor to act as the temporary works designer for online widening of approximately 8km of the A9. The specific remit for the temporary works solutions involved the demolition of six underpasses, beneath the existing road, followed by reconstruction of new structures to accommodate the upgraded dual carriageway.

A major constraint on the project was the requirement for the existing road, a single carriageway, to remain open to traffic at all times. Costly lane closures required the design solution to minimise lane closure in order to keep the project cost down.

ByrneLooby devised a solution which involved complicated sequential temporary works, comprising combinations of reinforced earth, soil nailing and bored pile anchored retaining walls to maintain traffic flow, whilst the bridges were demolished, extended and improved and the carriageway widened, all within a tightly constrained work site.

Unforeseen conditions arose during the works that could potentially have incurred additional project cost. However ByrneLooby worked quickly to assimilate the issues by developing a redesign and providing an alternative cost effective temporary works solution.


“As part of the design team for the A9 dualling, I was involved in the design of a number of earth retaining structures. This project was particularly challenging because the Perth to Inverness carriageway could not be closed during the works, consequently, the design solution we produced had to cater for this requirement. One of the most enjoyable aspects of this project was working within a multidisciplinary environment and being able to offer the contactor robust, practicable design solutions, while minimising disturbance to the carriageway.”

Eugene, Graduate Engineer


Project Photos