Lyminster Bypass Bridges

About the project

Enable Infrastructure (formerly BCM Construction) were responsible for constructing two new concrete bridges – one over road and one over rail – for the A284 Lyminster Bypass scheme. The scheme provides a 1.8km bypass for the village of Lyminster in West Sussex and includes new carriageways, pedestrian facilities, street lighting, signs and white-lining.  

One of the two bridges crosses Toddington Lane and the other crosses the up & down Brighton lines at a point between Toddington level crossing and Lyminster level crossing. For both bridges, the activities related to this package of work included: excavation to formation level, construction of the base and subsequent backfill, construction of abutment and wing walls; lifting of beams; construction of bridge decks and ancillary works.  

The project was delivered successfully in accordance with the programme of works from our client, Breheny Group, with only minimal snagging required and no defects reported. Breheny Group commended us on the quality of finish.

The challenge

Key challenge was availability of access: as Enable Infrastructure was not the principal contractor, we could not book additional possessions to complete our works. Instead, we had to work in possessions already booked, operating through liaison with Network Rail Asset Protection and Optimisation (ASPRO) teams. 

The solution

Making full use of our very extensive rail experience and mature risk assessment process, we took steps to limit works ‘on or near the line’ and were able to keep the requirement for additional possessions to a minimum.  

Specifically, Enable Infrastructure:  

• Undertook detailed planning to create ‘High Street’ working environments for the early stages of the works through fencing off Network Rail property, so that we could complete excavation, abutments and bearing pads without the need to close the railway, allowing passenger services to be kept running. 
• Agreed with the Network Rail ASPRO team Any Line Open (ALO) plans for all plant, with ALO alarms set to prevent intrusion on to the railway. 
• Created a ‘High Street’ environment in which all the reinforcement and formwork for the deck pour could be completed following the installation of the bridge beams, permanent formwork and edge protection. 

The deliverables

Enabling works  

• Installation of temporary fencing, removal of vegetation along railway cutting, stripping topsoil, installation of temporary welfare, creation of temporary access road. 

Toddington Lane road bridge 

• Excavation and muck away of spoil  
• Abutment bases: prep & pour blinding, formwork, steelwork, concrete pour, curing & striking, backfill 
• Abutment wing walls: steel fixing, wall formwork, concrete pour, curing & striking  
• Bearing pads: steel fixing, bearing pad formwork, concrete pour & curing, bearing installation 
• Bridge deck: delivery & placement of bridge beams, Permadec installation, steel fixing, form & pour bridge deck, parapet installation  
• Other works including drainage, soakaways and waterproofing.  

Brighton Line rail bridge 

• Excavation, abutment bases, abutment wing walls & bearing pads – as above 
• Bridge deck: delivery of bridge beams, Beams & permanent formwork & edge protection installed over rail possession with 800T crane, formwork, reinforcement and pour bridge diaphragm. Parapet copings installed over rail possession. Bridge deck poured over rail possession. Edge protection removed over rail possession 
• Other works including drainage, soakaways and waterproofing.  

Demobilisation works 

• Remediation works for welfare area, removal of fencing & edge protection, new Network Rail fencing, handback documentation.