Low Carbon Pathways for Structural Design

To avoid an increase in greenhouse gas emissions, a depletion of resources, and waste accumulation, structural engineers have a major role to play in low carbon structural design. For example, cement- based materials represent one-third of all materials extracted each year [1]. This paper offers three pathways for lowering the embodied carbon of building structures – the emissions related to material extraction, production, transport, construction, maintenance and demolition – through the lens of three case studies of building structures in Switzerland. The first pathway focuses on the structural scale by reducing material intensities in terms of material use per unit of floor area. The second pathway focuses on the material scale by lowering the impact of the materials themselves through the choices of the materials typically used in structures. The third pathway focuses on potential changes to current construction practices by (re-)introducing reuse strategies in the building sector. A simplified version of Life Cycle Assessment (LCA) is used to evaluate each Swiss case study compared to current practice. The material quantities are collected from literature, architectural drawings, Bill of Quantities (BoQ), and Building Information Models (BIM). This research illustrates the challenges and opportunities of three pathways for low carbon structural design: the optimization of material efficiency, the use of low- carbon materials, and the reuse of structural elements from other demolition sites.