The Tamar suspension bridge in the South West of England was constructed in the early 1960’s by Cleveland Bridge & Engineering Company. It has a main span of 335m and two side spans of 114m and was the longest bridge in the UK when it was opened in April 1962. In the late 1990’s Cleveland Bridge were also awarded the contract to strengthen and widen the bridge. DLT were responsible for value engineering of the permanent works and conceptual and detailed design of all erection and demolition methods and related temporary works.
The bridge was widened from 3 lanes to 5 lanes by the addition of one lane cantilevers on either side of the existing deck. Major strengthening and replacement works were carried out on the suspended superstructure and approach spans. This included the addition of eighteen new stay cables to the suspended spans, replacement of the original deck steelwork in the approach spans, replacement of the concrete deck in the suspended spans and the erection of new deck cantilever steelwork.
A major constraint on the construction process was the requirement to keep the bridge open to traffic throughout the works, which raised complex engineering and safety issues. The upgraded bridge was completed in 2001.