Caunton are helping with the upgrading of one of the oldest tramways in the world. The Blackpool tramway runs 11 miles from Blackpool to Fleetwood. It is the only first generation tramways that are still in operation in the UK and over 6,500,000 people travel on it each year.

Caunton are working on a new depot to house the new Supertrams after the tramway’s upgrade. The depot is estimated to cost £20million to build and will be able to house 20 new Supertrams, though only 16 have been ordered initially.

Caunton are supplying and erecting over 400te of steelwork for the structure for main contractor Volker Fitzpatrick.

The photograph shows the structure under construction- about 50% complete in fact. The building comprises four high level roof units and four low level roof units. Each high level unit alternates with a low level one - working down the building. A high level unit in plan is 66 metre span and 12 metre wide. The low level units are the same. The photograph shows the stage at which the steelwork framing for three high level and two low level units is erected, and ahead of the sheeting and cladding operations.

The overall roof, both at high and low levels, is supported by rafters which in the main are curved in elevation; they are in fact curved in the same plane but comprise two distinct curves. These curves are in two opposite directions in order to create the appearance of a flowing wave effect. This of course is imaginatively designed, in order to reflect the proximity of the sea.

The rafters, for both high and low level units, span directly between similar columns. The high level rafter comprises a single universal beam (albeit spliced) – the profile is a concave curve meeting a convex one. The low level comprises also a single universal beam (similarly spliced) – but the profile in this case comprises in the first place a straight section, before meeting first a concave profile and finally a convex. (Numerically - the radii of curvature for high level are 100 metres and 115 metres and the low level 200m and 75 m.) The vertical space created where the high level meets the low level will be clad with glazing on the south facing side, and sheeting on the north facing side.

Manufacture of the rafters of course required highly sophisticated modelling, engineering and fabrication techniques. These Caunton Engineering have developed most successfully over the years.

The depot should be ready for Easter 2012 when the newly upgraded tramways will open.