Laira Bridge refurbishment
Laira Bridge is a disused Victorian, six-span rail bridge constructed in 1887. It last carried a train in 1968. This contract, for Plymouth City Council, was to refurbish the bridge for conversion into a pedestrian and cycle path crossing the River Plym. Laira Bridge now connects existing walking and cycling facilities near The Ride (east of the river) with the Laira Cycleway (west of the river) and forms part of the National Cycle Network Route 27.
Our works included:
- Removal of all previous paint coatings down to bare metal
- Identification of required structural repairs
- Application of a six-coat epoxy paint system to protect the bridge for the next 25 years
- Additional works including a permanent bridge for cyclists
The bridge spans the tidal estuary of the River Plym, so the main challenge to delivering the works was the intertidal zone, which meant that the ten individual piers had to be painted during the low spring tides. The paint had to be fast curing and have the ability to be resistant to salt water. A two-part epoxy paint was selected to meet these requirements. We also used a rapid drying/ hardening concrete with an underwater additive to prevent the migration of cement paste.
Maritime operations also had to be taken into account when planning the works.
Initially, we consulted with local the Harbour Master and the Maritime Management Organisation to develop systems of work which had minimal impact on their operations. We continued regular contact with the Harbour Master and the Marine Management Organisation so that, if large vessels did needed to pass below the bridge, we could be aware of its movements and adjust our programme.
The works included gritblasting lead-based paint. To avoid pollution of the water and contamination of the atmosphere, each span was totally encapsulated in plastic and a large vacuum system installed along the bridge deck to draw lead-based paint flakes and bio-degradable grit to filter skips placed at the end of the bridge. Skips were then taken from site for the paint and blasting grit to be separated, which could then be reused on future projects. The advantage of this encapsulating system allowed painting to be continued in all weather conditions in a controlled environment, meaning the whole scheme was delivered on time.
Additional works required a temporary ramp from the end of the existing bridge to provide access to cyclists back to road level, with plans to replace it with an additional permanent bridge at some point in the future. We suggested building this additional bridge whilst completing the restoration works to eliminate the additional cost associated with the preparation of a further contract and the waste involved in removing the temporary ramps. Through close collaboration on design meetings, our proposal was accepted and the bridge was completed in 2015.
“It really is a privilege to be a part of a project that involves works on an historic structure. Bringing Laira Bridge back to life and protecting pedestrians and cyclists is our main priority. We look forward to seeing it in use on a daily basis in the near future”.
Cris Peck, Site Agent, SWH Civils
“The Laira Rail Bridge scheme has delivered an important part of our east-to-west cycling route and will soon be enhanced by improvements between Saltram and the Plym Valley, thanks to funding from the Department for Transport’s Cycle Ambition Fund.”
“We’ve also brought forward work to provide a new bridge over The Ride as part of this project and, in the longer term, we plan to extend the pedestrian and cycle path further along the old railway alignment to Saltram Meadow and beyond.”
"It’s been great to see so many walkers and cyclists using the new path over Laira Rail Bridge and this extension now takes them safely over to the other side of The Ride. We’d like to thank everyone for their patience while this final phase of the scheme was completed.”
Councillor Mark Coker, Cabinet Member for Strategic Transport and Planning
Client: Plymouth City Council
Contract Value: £3.6m
Year completed: 2015
Dean works as Structures Manager for SWH Civils and is responsible for the planning, resourcing and programming of structures and bridge works for our clientsMeet Dean