QC ice accretion and FRB joint replacement

Overview

This is a joint presentation describing the review that has been carried out to examine ways to mitigate against the impact on users of ice forming on the cables and other elements of the M90 Queensferry Crossing structure. The other part of the presentation will cover the project to replace the expansion joints on the Forth Road Bridge which lies adjacent to the Queensferry Crossing.

The M90 Queensferry Crossing is a multi-span bridge with an overall length of 2.6km between the north and south abutments. The cable stayed section has two main spans of 650m each between three towers.

Since 2019 the Queesferry Crossing has closed to traffic on three occasions due to falling ice which had accreted to the structure. BEAR Scotland Ltd who manage and operate the bridge, was asked by Transport Scotland to review, and as necessary, trial and test, available passive and reactive techniques and technologies which may mitigate the problem. The presentation will provide some background to the issue and provide an update on this review.

When the 1,006m-long Forth Road Suspension Bridge opened in 1964 it carried some of the largest expansion joints of their type anywhere in the world and, by the early part of this century, these needed replacement. The presentation will describe the procurement and construction process for the new joints, as designed by Atkins. Tenders were issued in 2017 for a works contract which was subsequently awarded to American Bridge international. Works to replace the joints commenced in 2018, with Amey acting on behalf of Transport Scotland as part of a contract to operate and maintain the bridge. BEAR Scotland Ltd subsequently took over the operation and maintenance of the bridge in August 2020.