Resource expenditure for bridges in Sweden – do we build greener bridges now compared to 50 years ago?

The building and construction sector is responsible for a significant portion of embodied and energy related carbon emissions. Efforts to reduce this are reflected in the need for improved sustainability in the design, construction, and operation of structures such as buildings and bridges. This issue has become more prominent in recent decades due to the ongoing climate crisis. A historical review of developments in bridge design and construction reveals an evolution in procedures, codes, and practices. The aim was often to improve something; reduce costs, reduce conservatism, optimize structural configurations, increase safety, improve durability, etc. Significant developments over the previous half century have included the now ubiquitous use of more advanced computational software and the growth in both size and complexity of design codes. A relevant question concerns how these types of developments have impacted sustainability; do we build greener than 50 years ago? This paper discusses this issue for the case of bridge construction in Sweden, where an increase in material expenditure, costs, and environmental impacts have been observed when comparing newer and older bridges. Case studies of existing bridges are provided as examples highlighting potential driving forces for the observed increases. As it stands, it is unclear whether, and to what degree, these increases are justified. Industry perspectives, obtained from interviews with bridge experts, confirm the observed trend and some of the causes for the increase. Possible strategies for dealing with this problem are discussed, highlighting the need for further action.