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M4 Junctions 3 to 12 upgrade to smart motorway: structures

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08 September 2020

This event has now ended


The M4 is the main strategic route between London, the West of England and Wales, carrying on average 130,000 vehicles per day and is prone to congestion.

For the M4 Smart Motorway Project (M4 SMP) there will be “All Lane Running” between junctions 3 and 12; the hard shoulder will be converted to a traffic lane, so that there are four lanes available for use by road users. This is the longest smart motorway project in England to date at 51km (32 miles).

To accommodate the new smart motorway 11 bridges carrying local traffic over the motorway will need demolition and replacement. Where the motorway passes over the River Thames at Bray it is being widened to support the new smart motorway.

This talk broadly outlines the M4 smart motorway project, however, it concentrates primarily on the structural aspects of the 11 over bridges and the Thames Bridge at Bray. The talk outlines the planning of the scheme, the assessment of the existing structures, the options considered and the chosen designs. The session also outlines the construction that has occurred to date in demolition and rebuilding of the over bridges and the construction of Bray Bridge.


Dr David Collings BSc PhD CEng FICE

Dr David Collings BSc PhD CEng FICE


technical director

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Dr David Collings BSc PhD CEng FICE

Dr Collings is a highly accomplished engineer with wide-ranging experience of major bridge, highway, railway, water and power infrastructure projects in the UK and overseas.

Recently he has been assisting the development of ARCADIS major bridge capability and in particular its drive for more sustainable and buildable structures. David has been involved in various assessments, designs and reviews for the M4 SMP structures.

For more information please contact:

Rose Creasey