A Comparative Life Cycle Assessment of Load-Bearing Structural Systems for Multi-Storey Buildings: Steel vs. Reinforced Concrete

The construction sector plays a pivotal role in global decarbonization efforts, requiring robust methodologies to assess and reduce environmental impacts across the building life cycle. In this context, this study presents a comparative Life Cycle Assessment (LCA) of load-bearing structural systems for multi-storey buildings, focusing on steel and reinforced concrete solutions. The analysis is based on a real case study: a 14-storey building located in Pisa, Italy, ensuring identical boundary conditions in terms of geometry, function, and location. Adopting a cradle-to-grave approach in accordance with EN 15978 and ISO 14040–44 standards, the study evaluates embodied carbon and Global Warming Potential (GWP) over a 50-year reference period. The methodology analysis focuses on the preliminary parametric assessments to testify the critical role of early-stage LCA in guiding design decisions and identifying environmental hotspots. Results show that the steel structural solution achieves a significantly lower carbon footprint compared to reinforced concrete, with reductions in CO2 emissions, mainly due to lower material intensity and higher recyclability. The findings highlight the importance of material selection and circularity strategies in achieving low-carbon buildings. This research provides practical insights for designers, stakeholders, and policymakers aiming to support sustainable construction and accelerate the transition toward a decarbonized built environment.