Sometimes, Technical Capability on its Own Isn’t Enough

When it comes to significant highways maintenance projects such as replacing a road bridge, technical capability may not be the critical success factor. That’s not to say it isn’t important, but the process of designing and building bridges to meet a defined performance specification is well understood.

Technical capability can help identify ways to do things more efficiently. Experience can identify small improvements in performance and delivery. But sometimes bigger performance changes are called for. Technical expertise has to be combined with more creative solutions to provide the answer.

Reducing Disruption

Proven solutions may meet the technical requirements but may also mean an unacceptable level of disruption to road users and communities. Replacing a twin road bridge over a busy section of motorway, such as the Romsey Bridge over the M27, is a case in point.

We knew how to demolish old bridges safely. We knew how to install a new bridge. The question was how to achieve this in a series of tightly controlled weekend closures so that the motorway was guaranteed to be open as normal by early Monday morning.

To find a better solution we looked to our rail expertise, where work commonly has to be completed within tight possession periods. We adopted the ‘Delivery Work Within Possession (DWWP)’ approach to ensure complex demolition and installation work could be completed within limited motorway closure periods. Having an integrated infrastructure team helps with this type of cross-fertilisation of ideas.

Pre-Assembly Saves Onsite Effort

To guarantee the timings we maximised the use of pre-assembled components that could be quickly installed on-site. We also worked with a specialist demolition contractor to change the method of removing the old bridge from ‘slice and lift’ to progressive disintegration.

The benefits of thinking creatively soon became apparent. Work to demolish the first section of the bridge was completed early, with the motorway opened 16 hours ahead of schedule. Work to install the first span of the new bridge in summer 2019 was completed 36 hours ahead of schedule.

These successes were not just the result of technical competence. They came from applying creative thought to identify the most efficient and reliable methods that could be employed to guarantee the result.