Steel and the circular economy: design for deconstruction and reuse

by Ricardo Pimentel & Dr. Michael Sansom

There is growing pressure on the construction industry to be more resource efficient, reduce waste and to lower embodied carbon impacts. More recently, circular economy concepts are being promoted, particularly at the EU level, with a roadmap developed to support a shift towards a resource efficient, low carbon European economy.

A circular economy is an alternative to a traditional linear economy (often described as a take, make, use, dispose economy) in which we keep resources in use for as long as possible, extracting the maximum value from them while in use, and then recover and regenerate products and materials at the end of each service life. Central to the concept of the circular economy is the EU waste hierarchy.

The environmental advantages of re-using structural steel are considerable, compared to the common practice of recycling by re-melting scrap. There are also potential cost savings compared to the use of new steel. However, there are many barriers to the wider uptake of steel reuse including the cost and availability of reclaimed sections, uncertainty about the properties of reclaimed steel, and the longer procurement and construction programmes involved.

Structural steel sections are inert, robust and dimensionally stable elements that are generally bolted together to form structural assemblies. As such, they are seen as an obvious candidate for reclamation and reuse as opposed to the current common practice of recycling by remelting.

Over recent years, SCI (Steel Construction Institute) has conducted several studies into the reuse of structural steel. Through this work we have identified two distinct scenarios for which different measures and solutions are required:

1. Deconstruction and reuse of existing/reclaimed steel-framed buildings – for which sampling and testing to determine material properties is important

2. Design for deconstruction and reuse of new steel-framed buildings – for which the development of new demountable systems and the use of BIM is key.

Reuse of existing/reclaimed structural steel

Design for future deconstruction and reuse

Ricardo Pimentel & Dr. Michael Sansom of SCI will be presenting at this year’s BILT Europe in Edinburgh on the 10-12 October on SCI’s recent work on steel reuse, particularly on two, current EU-funded, collaborative research projects that focus on two specific issues:

• REDUCE – which focusses on the development of demountable composite flooring systems
• PROGRESS – which is focussed on the deconstruction and reuse of single-storey, steel-framed buildings which are seen as the easiest structures to deconstruct and reuse.

Both projects also consider key aspects of environmental and economic assessment and the role of BIM in supporting future deconstruction and reuse. In addition, we will present a new SCI protocol for testing, assessing and designing new structures using reclaimed structural steel.

Case study using reclaimed steel (UK)

Lab tests dismountable floor system (NL)

BIM has the potential to facilitate the future deconstruction and reuse of structural steel by providing traceability and the relevant material properties necessary for their reuse. Steelwork contractors have used software for many years to efficiently manage all aspects of their design and manufacturing activities. Providing as-built, structural steelwork files containing all necessary properties including the steel grade, sub-grade, section size, test certificates, etc. is a simple, low cost exercise. The challenges are more likely to be around forward compatibility of the models, digital record and traceability, intellectual property, security, etc. Done correctly, BIM models can avoid the cost of sampling and testing steelwork prior to reusing it.

The level of information needed (LOIN) to allow for future reuse will be discussed in the session. Practical examples about how to efficiently specify relevant material and structural design data in the BIM model will be presented, using tools such as Excel, Dynamo, Robot and Revit.

The research projects REDUCE and PROGRESS are collaborative, EU programmes funded by the RFCS (Research found for Coal and Steel). REDUCE (Reuse and Demountability using Steel Structures and the Circular Economy) is coordinated by SCI and the partners include the Technical University of Delft, Tata Steel, University of Bradford, University of Luxembourg, AEC3, Bouwen met Staal and Lindab.

PROGRESS (Provisions for Greater Reuse of Steel Structures) is coordinated by VTT and the partners include SCI, Polytechnical University of Timisoara, RWTH Aachen University, ECCS – European Convention for Constructional Steelwork and Ruukki.