Comparative Case-Study Analysis of Lightweight and Conventional Concrete in Structural Elements of a Multi-Story Building
Abstract This study evaluates the structural implications of adopting lightweight concrete (LC) in multistory buildings, with emphasis on columns – a configuration seldom examined. Three models of the same fourstory building – (i) all conventional concrete (CC), (ii) LC in slabs and beams (CLC), and (iii) LC in slabs, beams, and columns (LC) – were analyzed in AltoQi Eberick V10. Verifications followed NBR 6118 (ABNT 2023a); where NBR 6118 does not prescribe LC material properties, ACI 318-19 (ACI 2019) was used for the elastic modulus and EN 199211 (CEN 2004) for the densitybased tensile adjustment. Results show foundation loads decreased by up to 12.8% and total steel consumption by up to 13.7% with LC, while lateral displacements remained within code limits. Applying LC in columns increased the global instability index to γz = 1.10 yet retained a nonsway classification. The column case clarifies the tradeoff between weight reduction and increased deformability and provides codeanchored guidance for safe adoption in Brazilian practice. Overall, the findings indicate that LC is structurally viable and materially efficient for multistory buildings under NBR-based design, and highlight priorities for detailing and stiffness control when columns are also cast with LC.