Expansion of sustainability in the ACI 318 building code

Abstract

The American Concrete Institute (ACI) has long recognized the growing importance of accounting for environmental sustainability in the design of concrete structures. As the next version of the ACI 318 Building Code is being developed (ACI 318-25), a new sustainability subcommittee, Subcommittee N, has been formed and tasked with expanding the provisions related to sustainability in the code. This paper reviews the current provisions in the ACI 318 Code that are related to sustainability and explores the possible future expansion of code and commentary language to provide better guidance on sustainable design. Areas of focus for expansion of code language, including definitions of sustainability metrics, as well as the defined baseline for comparison, are discussed. While sustainable design is increasingly being specified in concrete projects, the sustainable properties of concrete are often interrelated with other aspects of design, including resiliency and intended lifespan. Approaches to acknowledging the impacts of life cycle considerations on the sustainability of concrete construction are also explored. Finally, the anticipated timeline for the development of ACI 318 sustainability provisions is described, as well as potential interactions with other code writing organizing that are currently developing sustainability provisions.