Performance-driven choice of steel vs aluminum curtain walls: A scenario-based comparison

Curtain wall systems play a key role in the aesthetic of modern buildings, serving as a bridge between architectural look and engineering requirements. This study presents a comparative engineering evaluation of steel and aluminum curtain wall systems using a novel Performance Index (PI) framework. The study integrates qualitative SWOT analysis and parametric analysis to support context-specific material selection for projects with seismic, fire-rated, or sustainability priorities. The PI model quantifies compromise across key criteria such as strength, fire resistance, environmental impact, aesthetics, and cost. Results show that steel excels in structurally demanding and fire-critical applications, while aluminum offers superior corrosion resistance, aesthetic flexibility, and environmental advantages. The extended PI model further demonstrates that aluminum becomes competitive in visually expressive and sustainability-driven designs. Ultimately, this framework empowers engineers and architects to make smarter, context-sensitive decisions when selecting curtain wall materials, balancing safety, sustainability, and design intent.