Skip to content
ICE Community blog

Restoring Thomas Telford’s iconic Menai Suspension Bridge: a graduate’s story

19 May 2021

Circumstances meant Sam Dorgan, an ICE Wales Cymru graduate member, had to learn the ropes quickly as he took over the reins of the remedial work on this iconic structure. 

Restoring Thomas Telford’s iconic Menai Suspension Bridge: a graduate’s story
The Menai Suspension Bridge. Anglesey, North Wales

The Menai Suspension Bridge is a structure of major historical significance; the initial construction works started over 200 years ago. It's a real honour to contribute to the successful delivery of the remedial works to Thomas Telford’s iconic structure.

The project has allowed me to nurture professional relationships with the client and the contractor. It has also accelerated my own personal development as a bridge engineer in terms of technical capabilities, project management and commercial awareness.

As a graduate engineer on this project

At the inception stage of the project, former colleague Huw James and I developed the conceptual proposals for the footway slab replacements to present to the client. This optioneering process allowed us to identify the most suitable and practical solutions for the footways.

Having worked closely with Huw on previous schemes, we knew we were a very effective team; Huw was a great driving force for the development of the initial proposals. We quickly established a trusted relationship with Kerry Evans, DBFO Operations Manager for UK Highways A55 Ltd, which set in motion the development of the final proposal for the restoration works.

During the initial phase of the project, the Cardiff Bridges team learnt, with great sadness, that Huw had to take long-term sickness leave and soon after passed away. This came as a shock to me and the whole team. Huw was not only a well-respected bridge engineer, but also an admired and cherished member of our team.

I started to take the reins and lead the design development of the remedial works in Huw’s absence, due to my specific project knowledge and previous client interaction. Needless to say, I had big shoes to fill.

As I took on more and more responsibility, there was certainly a steep learning curve as a graduate engineer to understand all the requirements and processes that this project demanded, due to the significance of the structure and the environment within which it is set.

WSP conducted an optioneering exercise for the panels early in the project; steel panels were considered, along with cast in situ options using Glass Reinforced Plastic (GRP) or pre cast panels.
WSP conducted an optioneering exercise for the panels early in the project; steel panels were considered, along with cast in situ options using Glass Reinforced Plastic (GRP) or pre cast panels.

However, I received a great deal of support from several colleagues in my team along the way, which made the many challenges much less daunting! There were a couple of moments during the development of the project where I felt slightly overwhelmed with the magnitude of the task I was presented with. Positive and encouraging feedback from our client, Kerry Evans , allowed me to feel empowered and more confident about the quality of my work and designs. It's without doubt, that a little feedback and encouragement from time to time goes a long way!

From concept design to construction

Having received all of the structural records and previous health and safety files from the client, we quickly realised that the archive drawings were missing critical dimensional details for us to be able to produce conceptual drawings.

We arranged a site visit to acquire these missing details, which would then allow us to propose our three feasible concept designs for the slabs that collectively comprise the approach span footways. The existing slabs are reinforced concrete, but it was unclear from the record drawings if these are cast in-situ or precast elements. So, in short, our concepts were:

  • a stiffened steel deck plate;
  • a cast in-situ concrete option which utilised glass reinforced plastic (GRP ) permanent formwork. GRP panels can be used as permanent formwork, for the decks of bridges, spanning between the main precast concrete beams; and
  • a precast reinforced concrete option.

Due to the structure’s Grade I listing, it was imperative that any designs did not alter the aesthetics of the bridge. Through evolving discussions with the client, we narrowed our options down to the cast in-situ concrete design with GRP permanent formwork and the precast reinforced concrete design.

At this point we decided to establish an early contractor involvement (ECI) process as we wanted to move forward with the most practical and buildable solution. Particular constraints on-site, such as a limited bearing lengths, tight geometry and environmental sensitivities meant that getting a contractor’s perspective on buildability would be invaluable at this stage. The early involvement of Spencer Group gave us assurances that allowed us to develop the detailed design of the precast concrete slabs.

Spencer Group reviewed our two outstanding proposals, recommending that precast reinforced concrete slabs would be preferable and outlined a bespoke temporary works design to suit.

In January 2021, the construction phase for the replacement scheme begun. My involvement in the project continued with regular team meetings, addressing a number of technical queries from the Spencer Group’s on-site team and generally coordinating activities. I was fortunate to attend the site and see our designs being constructed which was a great full-circle moment.

Works are now complete on the western elevation of the bridge and works have already began on the east side which will draw the scheme to a close, when finished.

A career in civil/structural engineering? Absolutely!

The process of leading the design development of this scheme over the past year has made me realise how rewarding and enjoyable a career in civil engineering can be. My experiences as a graduate with WSP have been hugely varied across different sectors. I would encourage anyone thinking of pursuing of a career in engineering to consider a civil or structural path.

The effects of climate change have brought about initiatives such as net zero and future ready, driving change in industries globally. So, the prospect of engineering a better world for the future is exciting for me and I’m sure I share this passion with countless other people too.

If my story has inspired you to take up a career in civil engineering visit How to become a civil engineer.

Related links

  • Sam Dorgan, Graduate Engineer, WSP at WSP