An independent life cycle analysis and assessment (LCA) study of bridges has concluded that steel remains the best material for road crossings. Undertaken by Beco (part of the Ernst & Young group), the ‘Comparative Life Cycle Analysis of Bridges’ study showed that steel outperforms other materials in both performance and sustainability. The study was carried out by Beco on behalf of the Dutch government.
The study found that steel road bridges are more than twice as sustainable as bridges constructed with composite materials. Compared to concrete bridges, steel also performs very well.
“This study is important because it is one of the first to use LCA to determine the lifetime impact of materials in civil engineering projects,” explains Patrick Le Pense, Manager of Business Development Construction and Infrastructure for ArcelorMittal Europe – Flat Products. “It reflects a growing interest in LCA and shows how it can be applied to public projects.”
Steel’s main advantages come from its strength-to-weight ratio and recyclability. Due to the high strength of steel, a steel bridge can be significantly lighter than structures made from other materials. The steel can also be fully recycled at the end of the bridge’s life. The new steel that is produced will have the same (or higher) properties as the recycled steel.
The main goal of the Beco study was to compare the sustainability of bridges made from four different materials: steel, concrete, composite plastic, and wood. Two types of bridges were studied: a bicycle bridge with a free span of 14 metres and a 24-metre road bridge. Wood outperformed steel in the bicycle bridge category, mainly because its low load weight means that lighter foundations can be used to support the bridge structure.
The findings of this life cycle study are very significant for designers and architects, construction companies, and government bodies who are responsible for developing cost-effective and sustainable infrastructure.
Copyright pictures: Gilles Martin - Infosteel