Kessock Bridge– Rail Assessment

The Kessock Bridge is a cable-stayed bridge located in Inverness Scotland. The bridge has a total length of 1,056 metres (3,465 ft) with a main span of 240 metres (787 ft). The bridge carries the A9 trunk road north from Inverness to the Black Isle, connecting the Southernmost crossings to the rest of Scotland. This has contributed significantly to the growth of the city of Inverness and has transformed road transport in the Highlands.

The £5.1m projects involved carrying out a structural assessment of the existing maintenance gantry rails to demonstrate it had adequate strength and remaining life to operate the new maintenance gantry. CaSE designed the temporary works, jacking equipment, and new permanent works steelwork for C Spencer to carry out the operations. CaSE also assessed the original gantry rails which are welded to the main structure of the bridge in accordance with Highways Scotland regulations, determining the strength and remaining fatigue life. CaSE specified inspection, measurement, and testing required and incorporated the as-built data in the assessment.

In order to operate the new gantry, the existing tuned mass dampers currently installed below the orthotropic deck needed to be lifted above the envelope required for the gantry to pass. CaSE designed the temporary works, jacking equipment, and new permanent works steelwork for Spencer to carry out the operations.

CaSE Scope & Specialist Inputs:

  • Inspection, measurement, and testing.
  • Incorporated the as-built data in the assessment.
  • Designed an elevated steel frame mimicking a section of the gantry rails which was used to test the new gantry at a site near the bridge prior to installation.
  • Developed the construction scheme and associated temporary works design to remove the existing gantry and install the new gantry adjacent to the north abutment.

Independent CAT 3 Check of Web Deck System on approach viaducts

  • Inspection Specification
  • Assessment of Rail Capacity (Finite element / manual assessment)
  • Remedial Specification

Staff

  • Gerard Kiely
  • Richard Lamb
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Client

Bear Scotland/Spencer Group

Contractor

C Spencer Ltd

Project Duration

June – August 2018

Sector

Road/Bridge