Behavior of Composite Beams Using Lightweight Concrete Slabs Reinforced With GFRP Bars

This study examines the structural performance and sustainability aspects of steel–concrete composite beams utilizing lightweight concrete (LWC) slabs reinforced with glass fiber‐reinforced polymer (GFRP) bars. A total of six beams were tested under four‐point bending, comparing normal concrete (NC) slabs against lightweight slabs reinforced with different ratios of steel and GFRP reinforcement. The investigation focused on mid‐span deflection, stress distribution, crack development, and failure modes. Results demonstrated that beams with NC slabs exhibited higher ultimate load capacities; however, the GFRP‐reinforced LWC slabs showed better crack width control, contributing significantly to enhanced durability. Interestingly, despite the lower elastic modulus of GFRP bars, the stiffness of lightweight slabs fully reinforced with GFRP bars was comparable to steel‐reinforced counterparts. Numerical simulations validated by experimental results highlighted the potential of GFRP reinforcement in sustainable composite beam designs, particularly suitable for structures exposed to aggressive environmental conditions, thus supporting the broader goals of sustainability in construction. Based on the identified comparative advantages, a proposal for the full‐scale application of composite steel beams with LWC slabs will be presented. Subsequently, a comparative analysis will be conducted to further demonstrate the feasibility and applicability of this structural solution.