Comparison of Aluminum Composite Sandwich and Traditional Reinforced Concrete Slab Frame Systems in Terms of Dynamic and Global Behavior

The high mass of traditional reinforced concrete (RC) slabs significantly increases seismic forces in buildings. While lightweight aluminum foam sandwich (AFS) composite slabs offer radical mass reduction, their global seismic performance and interaction with diaphragm flexibility in RC frames remain underexplored. This study presents a linear elastic comparative analysis of pure RC moment frames (1–6 stories), contrasting traditional slabs with AFS slabs under both rigid and semi-rigid diaphragm assumptions. All models were optimally designed to meet identical Eurocode serviceability and stability limits, ensuring a fair comparison via response spectrum analysis. Results show that AFS slabs reduce total structural weight by 33.5–45.9%. This mass reduction, combined with period elongation in semi-rigid models, substantially decreases elastic seismic demands: story shear forces are reduced by 30.9–45.1% for rigid-diaphragm models and by up to 64.3% for semi-rigid ones, while column axial loads decrease by up to 33.7%. All systems satisfied code drift and stability criteria. It is concluded that AFS slabs can dramatically lower seismic mass and elastic force demands while maintaining serviceability, with semi-rigid action providing additional reductions. These conclusions are derived from linear elastic analysis and are applicable to pure frame systems; nonlinear performance and behavior in dual systems require future investigation.