Steel in the Deconstruction Industry: From Recycling to Reuse

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As global warming continues to have a negative impact on the world there is a rising pressure for decarbonisation, especially in industries which contribute high levels of emissions. Steel production produces 4% of global CO2 emissions, with half of these emissions being attributed to the construction industry. Although the recycling of steel has led to a reduction in emissions from the steel industry further measures are needed, one such measure is the reuse of steel. Through the reuse of steel, the high temperature (high energy and high carbon) processes used for both virgin and recycled steel can be avoided, cutting carbon emissions.Currently identified barriers to using reused structural steel are a lack of supply chain integration, cost certainty and stock availability. In order to overcome such barriers this project will aim to establish untapped sources of steel, make reused components more accessible to designers and determine the most appropriate end-use for reused components. Environmental, economic and engineering considerations will be incorporated through a cross-discipline approach. As there are so many factors which impact both the barriers and goals mentioned in the previous paragraph, the demolition industries transition from steel recycling, to selling steel for reuse will be used as a focal point. This will be analysed through reviewing current literature, perspectives from industry and case studies. The project will compare the shift of the demolition industry over the past 40 years, from an overreliance on haulage to landfill, to the prominence of material sorting and recycling today, and extrapolate this transformation to modern steel reuse. A secondary goal is to study the current practices followed in other countries and organisations which have increased their acquisition, sale and use of reusable structural steel. This secondary goal will be especially important for factoring in the differences between recycling and reuse, there are many varieties of steel which can be recycled, but reuse is currently heavily limited. There are so many different structures which steel can be used to form: Vierendeel girders, lattice beams, compound columns, web beams, multi-chord frame-like columns etc. All these structures must be joined together by a combination of bolts, screws, rivets and welds and in many cases treated with metallic coatings and/or a paint system. All these factors have an impact on the feasibility of reuse which should be accounted for.To measure the success of different factors in these studies, a measurable metric will be used to represent "success", such as the cost implications incurred to a demolition contractor by a change in policy, as a metric of incentive. Any successful change to the industry will then be analysed to understand the reduction in the embodied carbon of projects it created. although there will be limits to measuring metrics in such a way. The process of isolating different possible causes and linking them to a measurable outcome will be particularly important, as in any real-world situation there are several changing factors which exist within a wider context, all of which could impact any metric under investigation.