Effect of Cross Rib Type and Number on Reinforced Concrete Hollow Core Slab Performance

This research explores how the type and number of cross ribs affect the performance of reinforced concrete hollow core slabs under flexural loading. Seven one-way slab specimens with three longitudinal hollow cores were cast and tested, featuring variations in cross rib geometry, ranging from narrow to wide solid ribs, as well as hollow rib configurations, with either one or two ribs per slab. The experimental program focused on key structural behaviors including cracking resistance, ultimate load, deflection, stiffness, ductility, and energy absorption. The results showed that adding cross ribs significantly improved the slabs’ overall performance. In particular, slabs with two wide solid ribs (CR2-N2) demonstrated the highest gains, offering better load capacity, enhanced stiffness, and increased ductility after cracking. Crack patterns also became more distributed and complex in these ribbed slabs, indicating more efficient stress redistribution. Although slabs with hollow ribs showed less dramatic improvements, they still provided practical advantages, such as easier construction and open core space for utilities. These findings underscore the importance of cross rib design in enhancing the structural efficiency and resilience of hollow core slabs