M4 Blagrove Railway Bridge

CRL carry out difficult project under possesions

The M4 Blagrove Railway Bridge, which carries the M4 Motorway over the London to South Wales railway Line (Great Western Railway) and is located approximately 1.2km to the west of Junction 16, was constructed in 1970 for Highways England Agent Skanska Infrastructure Services. 

CRL tendered for, and was awarded the contract to carry out the concrete repairs and cathodic protection works to the bridge in January 2017.

CRL carried out ECI works initially with Skansks to develop the logistics for access, welfare and storage as the works needed to be undertaken under possession at night and access was only available via the M4 near the Swindon junction 16. A temporary support structure was erected that provided a platform to place the welfare, storage and plant, so that these facilities would be in place at the start of each shift. One side was scaffolded with a protection screen. A scaffold staircase provided access from the road down the embankment to the bridge by the rail lines and tower access was used to access one side and the soffit repairs. This tower had to be erected and dismantled for each shift/possesion.

Major repair areas were cut out using hydrodemolition and then sprayed back. Smaller repairs were cut out by hand and made good with hand placed materials.

The following works were carried out;

• • Movement and positioning of scaffold access equipment on abutments,
  • Concrete repairs to soffit, beams and abutments,
  • Installation of galvanic anodes,
  • Replacement of mastic joints on wingwall movement joints, and
  • Application of anti-graffiti coating on abutments and wingwalls.

The works were all undertaken during night possesions and for multiple stakeholders, namely  Highways England, Swindon Borough Councils and Network Rail (NWR).