ICE member Kerry Evans is project managing the remedial work currently being carried out on the Menai Suspension Bridge in Wales. Her team is providing a behind-the-scenes look at the works in this new blog series, and in the first post, she explains the benefits of bringing a contractor in early.
The Menai Suspension Bridge is more than a magnificent structure. It’s an icon of civil engineering history, and to those who work on it, cross it and live within its shadow, it’s their personal piece of history, too.
Work is now underway to carry out remedial works on the Thomas Telford-designed bridge, which opened in 1826 and is the second oldest operational vehicular suspension bridge in the world.
Almost 200 years later, I’m the custodian for a short window of the bridge's lifetime, and it's already taught me how getting the right people in the right place, at the right time, is vital for good project management.
Identifying the defects and the solutions
A principal inspection was undertaken in 2020 of the Menai Suspension Bridge and two ‘types’ of high category defects were identified: the footway panels and the hangers.
Following a procurement exercise, WSP were brought on board and Sam Dorgan, the lead design engineer for WSP, has been the driving force. Very quickly we carried out further inspections and tests on the hangers and determined that cleaning and repainting would address the defects, and this work is scheduled in March/April 2021 when the weather is a little warmer.
Related links
- Going the extra mile to extend the lifespan of the Menai Suspension Bridge Luke Fisher, sector lead for Bridges & Structures at Spencer Group, provides a fascinating overview of the project.
- Restoring Thomas Telford’s iconic Menai Suspension Bridge: a graduate’s story Sam Dorgan, graduate engineer, had to learn quickly as he took over the reins of the remedial work on the Menai Bridge.
What are the real challenges of the footway replacement work?
The project has been an interesting process for me and I’ve been quite reflective over how it’s developed, specifically as I had been subconsciously aware over the years of this tipping point in the design process where the ‘unknowns’ sit entirely under the banner “it depends what the contractor wants to do”.
This milestone was very evident for the footway replacement scheme. The footways are not necessarily anything super technical that require hours and hours of attention, or BIM models.
As I, and the former General Manager of the Design Build Finance and Operate (DBFO), John Gardner (recently retired), had seen it, the complication was access, safe methods of working and protecting the environment.
The difficulties of working with a listed construction
The known constraints, apart from access, was the listing of the bridge and that what we put back must look the same. Added to that, there were significant challenges to achieve a 50-year design life with such a shallow panel.
Steel panels were removed as an option, as their appearance was not in keeping with the structure and we considered that it was unlikely to achieve approved listed building consent.
Why we got a contractor involved early
We hit the ‘tipping point’ in early August 2020, when all our discussions started with “The contractor should tell us….” From that point, we all agreed that the project needed a competent, experienced contractor to report the pros and cons of the remaining options.
I was aware that a footway replacement project was being undertaken on the Erskine Bridge over the River Clyde in west central Scotland, and so contacted its contractor, The Spencer Group. Very quickly, by way of a fixed cost piece of work, they provided us with a report that demonstrated the best option for safety, buildability and achieving the project goals.
Although it was “early contractor involvement”, it was not our intention to go down that path initially.
I'll be honest here and admit that there's a general nervousness about involving a contractor too early - perhaps related to escalating costs, perhaps bias on the project direction. But our experiences in the project team were nothing short of positive and exactly what the project needed (and ourselves).
Being open and listening to the advice of those that know more than yourself is an invaluable trait that every project manager should practise – we, none of us, can know it all.
Choosing safety over deadlines
In late August, the final design for pre-cast panels had been submitted to the technical approval authority in line with the DBFO contract requirements, and though we had hoped to start on site in September, getting the construction phasing and preparation right was more important than rushing for a deadline. Under no circumstances did any of us want to cut corners, knowing our decisions would have a direct impact on operatives working on ropes above the Menai Strait.
For the remainder of this blog series I've asked for Luke Fisher, the project manager at The Spencer Group and its site supervisor Tom Inglis to contribute. Also Sam Dorgan will also write a piece relating to the design development and his experience as a graduate working on this project. WSP site supervisor Graham Wilkinson will also contribute a post.
Work on the bridge is estimated to take 23 weeks.
