Pendel bearing replacement at A9 Kessock Bridge, Scotland

The A9 is the primary north–south trunk route in the Scottish Highlands and bypasses the city of Inverness by means of Kessock Bridge, a major cable-stayed structure spanning the Beauly Firth and opened to traffic in 1982. The bridge is a 1052 m long viaduct with a main cable-stayed span of 240 m, 80 m back spans and a number of 64 m and 72 m approach spans. At the ends of the 80 m back spans, four pendel-type bearings were installed to accommodate uplift reaction due to loading on the main span. These pendel bearings became excessively worn over time and required replacement. This paper describes the design and construction issues associated with replacement of these critical structural elements, an operation made more challenging by the very constrained geometry and the need to maintain overall stability of the bridge under operational traffic conditions.