Structural Steel and the Circular Economy (Steel for Life PDF)

Industry CPD Supplied and sponsored by Steel for Life Supplied and sponsored by Industry CPD Structural steel and the circular economy This CPD module, Continuing...

Industry CPD Supplied and sponsored by Steel for Life Supplied and sponsored by Industry CPD Structural steel and the circular economy This CPD module, Continuing professional development (CPD) ensures you remain sponsored by Steel for competent in your profession. Chartered, Associate and Technician members of the Institution must complete a specified amount each year. Life, examines a number All CPD undertaken must be reported to the Institution annually. Reading of steel’s credentials and refl ecting on this article by correctly answering the questions at the specifically on its ability to end is advocated to be: be reused, recycled and multi-cycled, its structural 1 hour of verifiable CPD efficiency as a construction material, and its alignment and application to circular economy principles. The construction industry continues to set itself ambitious targets for reducing its carbon footprint and environmental impact as a sector; key to this approach is the adoption and implementation of circular economy principles. A circular economy aims to design out waste and pollution, maximise the service life of products and materials and avoid sending materials to landfill after their first-life use. It signals an end to the ‘take-make-dispose’ attitudes that have contributed to the climate emergency. Circular economy principles Client demand, as well as legislation, are key drivers of the increasing focus on the circular economy; one in which resources including construction materials are used long enough to ensure the maximum societal value is gained from them. At the end of the useful service life éFIGURE 1: Forth Rail Bridge (1890) – example of durable steel structure of a building or other structure, products and materials used in the original construction, and construction include crushing concrete to combination of strength, recyclability, availability, those added to accommodate changing uses, produce aggregates for fill and chipping timber versatility and a ordability makes it unique. will be recovered and regenerated by being to produce chipboard. Although landfill is Maintaining products at their highest utility recycled and/or reused. avoided, production of new concrete and timber and value for as long as possible is a key Another distinction to be understood is is not avoided. component of the circular economy, as the that there are di erent types of recycling that longer a product lasts, the less raw materials deliver di erent circular economy benefits. With How steel enables the circular will need to be sourced and processed and less true, or closed-loop, recycling, products are economy waste generated. recycled into new products with exactly the Steel has excellent circular economy credentials: Steel-framed buildings are adaptable same material properties. An example would be it is valued as a strong, durable (Figure 1), and fl exible assets a business can invest in. reprocessing steel through a steelworks, which versatile material that provides structural framing The steel frame itself can be easily adapted could be called upcycling. systems that are lightweight, fl exible and (Figure 2), with parts added or taken away, On the other hand, downcycling describes adaptable, as well as reusable. and its light weight means that extra fl oors can the process of converting materials into Its high strength-to-weight ratio means often be added without overloading existing materials of lesser quality and reduced other sustainability benefits can be created, foundations, as frequently seen in inner-city functionality. Examples of downcycling in such as lighter and smaller foundations. Steel’s projects. This can add many years to the useful 26 March 2021 | thestructuralengineer.org CPD_TSE MAR 2021_The Structural Engineer.indd 26 17/02/2021 11:19  Supplied and sponsored by Steel for Life Industry CPD îFIGURE 2: Redevelopment of life of a building. former Royal Mail sorting office Steel structures are commonly used to made use of significant elements renovate buildings, e.g. behind retained of its existing frame facades. This allows the historic value, character and resources of the facade to be retained, and the building structure can be reconfigured to create open, fl exible internal spaces that meet modern client requirements and maximise net lettable fl oor area. Circular Economy Action Plan The EU has adopted a Circular Economy Action Plan1, one of the main strands of the European Green Deal, the EU’s new agenda for sustainable growth. It refers to the Levels study2, which recommends the whole-life carbon approach, i.e. including building end-of-life impacts (Module C) and benefits from reuse and recycling (Module D). The Action Plan incorporates initiatives throughout the lifecycle of products, targeting their design, promoting circular economy processes and promoting sustainable consumption, with the aim of ensuring that the resources used are kept in the EU economy for as long as possible. Among other things, the aim is to make we are going to deliver a truly circular, zero- sustainable products the norm in the EU, carbon built environment, then we have to move focusing on the sectors that use most resources and where the potential for circularity up the waste management hierarchy and reuse our buildings and their constituent parts. THE VERSATILITY OF is high, which includes construction and While reducing ‘upfront’ carbon emissions STEEL MEANS THAT IT buildings. is a short-term priority, this has to be achieved CAN BE EASILY Even post-Brexit, such a plan must surely be welcomed and refl ects a growing appreciation in tandem with longer-term, smarter thinking that is compatible with broader sustainable RECYCLED OR here in the UK of the need to include Modules development objectives. REMANUFACTURED C and D as part of a robust, whole-life carbon assessment. Limiting the scope to just Module History of steel recycling A equates a 100% recyclable building to one Since steel was first mass produced in the the price paid for UK scrap structural steel which is 100% landfilled when it is demolished. 1880s, it has always been highly recycled (grade OA) is currently £230–240 per tonne Landfill avoidance through downcycling (Figure 3). This is principally because: Ò| the versatility of steel means that it can be construction materials is unsustainable and if Ò| steel has a relatively high economic value – easily recycled or remanufactured into new applications as demand dictates Ò| steel’s magnetic properties mean that it can îFIGURE 3: There are considerable savings to be efficiently segregated from mixed waste be made from recycling streams. steel as landfill is no longer considered to be an option for construction products Steel is available in thousands of di erent and materials compositions (grades), each tailored to specific applications in sectors as diverse as packaging, engineering, white goods, vehicles and construction. This versatility promotes recycling since steel scrap can be blended, through the recycling process, to produce di erent types of steel (di erent grades and JUANAN BARROS MORENO / SHUTTERSTOCK products) as demand changes. Steel recycling in the construction sector Steel has a unique characteristic as it can be reused and recycled repeatedly without losing its qualities as a building material. All steel used in today’s construction projects has some recycled content. The constructional steelwork used in the UK contains an average of 60% recycled content. Current recovery rates from demolition sites in the UK are 99% for structural steelwork and 96% for all steel construction products. 27 thestructuralengineer.org | March 2021 CPD_TSE MAR 2021_The Structural Engineer.indd 27 17/02/2021 11:19  Industry CPD Supplied and sponsored by Steel for Life îFIGURE 4: Surplus large-diameter steel tubes repurposed for bridge repair at Grinton Moor éFIGURE 1: Comparison of lifecycle assessment scopes and system boundaries CLEVELAND STEEL & TUBES LTD Steel is routinely recovered for recycling, future reuse. Steps that the designer can and a highly sophisticated global infrastructure take to maximise the opportunity for reusing has developed to take advantage of this. THERE IS A GROWING structural steel include: Ò| using bolted connections (Figure 5) Steel reuse TREND TOWARDS in preference to welded joints to allow As well as recycling, there is a growing trend THE REUSE OF the structure to be dismantled during towards the reuse of structural steelwork (Figure 4), as there are significant savings to STRUCTURAL deconstruction Ò| using standard connection details including be made if a new project simply uses steel STEELWORK bolt sizes and the spacing of holes sections obtained from an older demounted or Ò| ensuring easy and permanent access to disassembled structure. situ. This is generally associated with connections Structural steel sections are inherently refurbishment projects and it is currently Ò| where feasible, trying to ensure that the reusable. Reuse, as opposed to the current, the most common way of reusing steel is free from coatings or coverings common practice of recycling structural structural steel in the UK. that will prevent visual assessment of the steel by remelting, o ers significant potential Ò| Relocation reuse involves condition of the steel in terms of resource efficiency and carbon deconstruction of an existing steel frame, Ò| minimising the use of fixings to structural emission savings, which support the which is then transported and re-erected, steel elements that require welding, construction industry’s ambitious carbon generally in its original form, at a di erent drilling holes, or fixing with Hilti nails; using reduction targets as the industry moves location for the same or similar purpose. clamped fittings where possible towards net-zero. Ò| Component reuse involves careful Ò| identifying the origin and properties of Currently, there are many steel-based deconstruction of an existing structure the component, e.g. by bar-coding or temporary works systems which are highly where individual structural steel members e-tagging or stamping and keep an reused; the next step is to develop permanent are reclaimed and used to construct a inventory of products works systems that are similarly reusable. new permanent structure. Ò| considering using long-span beams as Steel reuse generally happens in three main they are more likely to allow fl exibility of use ways: Reuse advice for designers and to be reusable by cutting the beam Ò| In situ reuse sees the structural frame To facilitate greater reuse, it is important to a new length – bearing in mind the reused, with or without alterations, in that designers do what they can to optimise increased steel weight associated with this. 28 March 2021 | thestructuralengineer.org CPD_TSE MAR 2021_The Structural Engineer.indd 28 17/02/2021 11:19  Supplied and sponsored by Steel for Life Industry CPD íFIGURE 5: Reuse advice for designers includes suggestion of using bolted connections in preference to welded joints to allow structure to be dismantled during deconstruction REFERENCES 1) European Union (2020) Circular Economy Action Plan: For a cleaner and more competitive Europe [Online] Available at: https://ec.europa.eu/environment/circular- economy/pdf/new_circular_economy_action_ plan.pdf (Accessed: February 2021) 2) European Commission (s.d.) Level(s): SEVERFIELD European framework for sustainable buildings [Online] Available at: https://ec.europa.eu/ environment/topics/circular-economy/levels_ en (Accessed: February 2021) Questions To claim your CPD certificate, complete the module online by 30 April 2021 at: www.istructe.org/industry-cpd 1. What was the value of 1t of UK structural scrap steel in 4. Which of the following modules should be included as part of a 2020? whole-life approach to carbon assessment? £230–240 Module A (product and construction stages) £105–150 Module C (end-of-life stage) £50–100 Module D (reuse, recovery, recycling) £25–50 All of the above 2. What is the average recycled content of structural steel in 5. In what ways does steel enable a circular economy? (Select all the UK? that apply.) 20% Its strength and durability enable long-lasting structures when well 40% maintained 60% A steel frame is fl exible and can easily be adapted 80% Scrap steel is difficult to recycle or remanufacture Structural steel sections can often be reused in situ or in new or 3. What are the current recovery rates from demolition sites relocated structures in the UK for structural steel? 29% 6. Which of the following can designers do to maximise the 49% opportunity to reuse structural steel? 89% Use bolted connections in preference to welded joints 99% Consider using long spans Use standard connection details All of the above Supplied and sponsored by 29 thestructuralengineer.org | March 2021 CPD_TSE MAR 2021_The Structural Engineer.indd 29 17/02/2021 11:19