Claire Smith, NCE editor
NCE is continuing to mark its 50th anniversary at its live events this year, with keynotes that look back over the last 50 years and others that look forward to the next 50. The insight into the challenges ahead has been fascinating but one point that has stood out for me was about legacy and was made by UK Bridges Group chair Hazel McDonald, who is also the chief bridge engineer at Transport Scotland.
McDonald spoke about the next 50 years at NCE’s Future of Bridges event and said that one of the biggest challenges we face as engineers is to ensure we avoid leaving a negative legacy for the next generation of engineers. She explained that the bridge sector has the “challenge of dealing with the ‘bright ideas’ put into practice in the last 50 years that have created vulnerable details”.
To illustrate the issue, she pointed to high alumina cement structures, electro-slag welding and metal fatigue that are likely to present the industry with issues around bridge performance. She urged bridge engineers to take care when specifying new materials and solutions in the future to ensure they are not storing up further problems for the sector.
But I think that warning should be broader. As we seek to drive up productivity and efficiency and meet the carbon net zero challenge, there is a push to find innovative solutions and materials to meet these demands.
Many new techniques and innovations may prove to be the answers we are looking for but we must ask difficult questions now to avoid a negative legacy
Many new techniques and innovations may prove to be the answers we are looking for but we must ask difficult questions now to avoid the negative legacy McDonald warns of. Earlier this year, Heathrow’s sustainability strategy was described as risky as it relied too much on undeveloped technology. There is the potential that such technology and new materials will not deliver the carbon reductions anticipated and could fail to live up to performance expectations.
In this month’s issue we take a look at whether including waste material in asphalt is really a positive step or whether it is storing up challenges for the future.
To understand the pros and cons, and what needs to come next to ensure a positive legacy result, I encourage you to read the article on page 40 and – even if you do not work in the roads sector – consider whether the questions asked can be applied to your work.
Understanding the whole life impact of a project is an essential part of considering the effect the materials used will have on that impact. I saw that in action during my site visit to the Southsea Coastal Scheme for the article in this month’s Future of Floods focus. There the project team is working to balance the embedded carbon cost of the new sea defences, which are predominantly based on new concrete structures and imported rock armouring, with the finished project’s 100 year design life.
Our overview for the floods focus looks at how the drive towards resilience means that hard civil engineering solutions are no longer the first stop for the Environment Agency, although nature based alternatives and managed retreat are not possible everywhere.
That is very much the case in Southsea – a defence failure and a tidal surge could make the second floor student flat I once lived in become a waterside residence rather than being half a mile from the sea. With another 9,999 homes also at risk, along with 700 businesses, the need for hard defences there is real but it does not mean that any concrete will do. At Southsea, the project team has decided against using fibre reinforced concrete, despite the performance benefits. This is due to the risk of the fibres being released into the marine environment as the new structures age. So, while there is a need for rapid change in the way we work, we must ensure that we take a paced approach and do not race to the wrong decisions.
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