The Tay Bridge carries two lanes of dual carriageway which forms the A92, linking Dundee to Newport over the Firth of Tay, Scotland. Each two-lane carriageway is 6.7m wide with a raised central cycle/walkway of width 2.4m between guardrails and consists of twin steel box girders acting compositely with reinforced concrete cantilever decks.
The bridge has 43 spans in total, supported by 42 piers culminating in an overall length of 2.25km. The contract comprised the replacement of all bridge bearings, located on the top of 74 columns with 676 bearings removed and subsequently replaced with 296 new bearings.
This was achieved by temporarily supporting the structure and removing the top section of the pier, enabling the necessary bearings to be extracted and replaced; achieved whilst maintaining the operation of the bridge traffic system, a key engineering challenge for this project.
Project elements and Work scope included:
- Traffic Management on the Southbound carriageway.
- Blast cleaning existing steelwork to remove paint, and the application of a Protective Treatment system.
- Procurement of the new replacement bearings, the removal of existing bearings and the installation of the replacement bearings.
- To install permanent Strengthening internally within the box girder, by installing structural stiffeners and concrete locally to the proposed jacking points.
- The jacking up and down of the bridge to allow the removal and replacement of the bridge bearings.
- The removal of the pier tops to allow the removal and replacement of bearings (Hydro-demolition) and the subsequent re-instatement of the pier tops.