HA starts installation of 'superspan' gantries

The Highways Agency (HA) has started the installation of the first ‘superspan’ gantries on the M4/M5 Managed Motorway Scheme. During June, the existing gantries and infrastructure were successfully removed, whilst the new steel gantries were being constructed, fitted-out and tested at a dedicated facility located near junction 17 of the M5, before being delivered to the works site. A total of 33 new overhead gantries, some spanning 50m (164ft) and weighing over 30 tonnes, will be installed along the new Managed Motorway section. A further seven existing gantries are being upgraded to take the new variable message signs (VMS). Information displayed on the gantries will advise drivers when the hard shoulder is open for use by traffic, display variable speed limits to manage traffic flow and reduce congestion, and also provide information on the road conditions.

The M4/M5 Managed Motorway scheme is taking place on the link between the main motorways that link London and the West (M4) and the Midlands and South-West (M5). The scheme will introduce variable mandatory speed limits and allow the hard shoulder to be used as an extra traffic lane during heavy traffic flow. Main construction work started in January 2012, with work due to be completed in spring 2014. Balfour Beatty is the main contractor on the £88.6 million (US$138.6 million) project.

To enable installation of the overhead gantries, there will be a series of week-night closures throughout July. The HA’s senior project manager, Paul Unwin, said, “The new gantries will hold the signs and signals that will convey vital road information to drivers. Their sheer size means that a full motorway closure is essential to give us access for delivery and installation. Closing the motorway also ensures the safety of the travelling public, as road workers with large and heavy equipment complete the task of installing the gantries and associated technology. Although the closures will be in place when there is less traffic, we do advise road users to allow more time for their journeys and to follow the clearly signed diversion routes.”

4 July 2012