It is well recognised that the carbon costs of construction and building operations form a large part of the world’s overall carbon footprint. Those who are now designing, building and reimagining structures are, therefore, vital in achieving the national and international sustainability goals.  

As civil engineers, we can play a key role in uncovering opportunities for reuse and recycling, as well as efficiency of build and maximisation of space, in both new and refurbished structures. One such method that we are focusing on is a more wide-spread adoption of the circular economy that enables achievement of both commercial and sustainable objectives.  

The challenge we face and the circular economy response 

Independent non-profit Architecture 2030 estimates that 42% of the world’s carbon emissions are caused by construction and subsequent building operations, so more sustainable designs and construction methods are vital. One of the ways used to illustrate the new thinking required is the concept of the circular economy, adopted by member organisations like the Institution of Civil Engineers (ICE) and the Institution of Structural Engineers (IStructE). 

The circular economy is defined by ICE as “a system in which products and assets are used, repaired, transformed and reused indefinitely”, emphasising that the concept involves not only recycling but the “reuse of manufactured goods and assets in the most complete form in which they can continue to be useful.” 

The adoption of sustainable construction 

WCS has long been a passionate advocate of sustainability in construction, something validated by our recent Environmental, Social and Governance Leader award. “Nothing matters more than creating a more sustainable model for future generations to build on,” says WCS Engineering Manager Natalja Petkune. 

Natalja, who earnt Associate status with IStructE in December 2023, is more than well placed to talk about the role of civil engineering in delivering a more sustainable future. At the institution’s Young Engineers Conference 2023, she co-chaired a workshop on Pathways to Positive Change and the circular economy, and she serves on more than one IStructE panel and is a member of the IStructE Surrey Regional committee. 

Professional bodies are championing sustainability  

“Organisations like IStructE are playing a really positive role in the shift to the circular economy,” adds Natalja. “Their publications are a great resource, with specific case-study examples of how structures and materials can be reused. But they aren’t just looking for better academic understanding, they are also looking to encourage greater adoption of practical, appliable skills and recently changed the tests and core objectives of the Initial Professional Development path for engineers seeking chartered status. Knowledge and experience in areas such as carbon calculations are now much more central to what younger engineers will need to master.” 

Considering sustainability at an early stage is vital 

If carbon costs are assessed alongside financial costs at the feasibility assessment stage, the potential for a sustainable solution emerging is maximised. On every project, our engineers are able to complete carbon cost calculations at this stage to help further decision-making throughout the project team.  

“On some projects, our calculations mean we are able to challenge the assumed scope,” comments Natalja. “For example, when working on structures such as substations, with which we are very familiar, we might be able to propose smaller structures than assumed because of efficiency of space use, or the strengthening of something existing instead of the creation of a whole new building.” 

Specific ways to drive sustainable construction  

Continued use of existing structures might require measures to extend asset life or strengthen assets in place. Formal verification of compliance is vital, of course, and underpins all of our work. 

“If we are considering an approach such as reuse of reclaimed materials within a new structure, we have access to a materials database which we can use to assess whether reuse is compliant,” continues Natalja. “Of course, it’s better not to decommission at all. In one of the cases, my colleague Konstantina Vasilopoulou was able to win acceptance of an option of strengthening an existing bridge rather than building a new one when we undertook an optioneering study for one client. On another project, we are designing a new foundation for an existing Glass Fibre Reinforced Polymer enclosure, so it can be used as housing for a new transformer.” Other options for achieving sustainable design include crushing reclaimed concrete and reusing it as road surfacing material.  

Carbon costs can also be reduced by specifying more sustainable materials. The WCS team recently visited Aggregate Industries to assess their ECOpact sustainable concrete, which uses cement alternative technologies such as alkali activators. 

Culture and values lie at the heart of sustainable construction 

For sustainable outcomes to be driven strongly, the partners working on projects do need to prioritise this area. Natalja oversees CPD at WCS, and recently organised a lunch and learn session, with her colleagues benefitting from an IStructE online course on embodied carbon. 

She continues: “Our graduate engineers are very motivated in this area, in part perhaps because their education emphasises it more strongly than for older colleagues. In terms of external drivers, limiting carbon cost is sometimes a tender consideration. In other cases, architect partners may champion the issue. I was fortunate recently to attend an architectural Open Day at the Black & White Building, a highly sustainable new timber-frame structure that has won a number of awards. It was great to learn how each component of the building was designed as efficiently as possible.” 

There is a belief that sustainable methods can have a cost premium, and in some cases that is the case, however this isn’t always the case with reuse, particularly when you consider the total cost rather than individual element costs. Clients, as well as the various partners involved in a project, must further their understanding of what is achievable if we are to prioritise the issue so gains can be made. Many obstacles stand in the way of the global acceptance of sustainable construction solutions, but vital advances can be won if all parties pull together to ensure a more sustainable future for coming generations. 

If sustainability is central to your project, please contact the WCS team today