Flexural Design and Analysis of Composite Beams with Inverted-T Steel Girder with Ultrahigh Performance Concrete Slab

This study intends to improve the efficiency of the composite beam combining a slab made of steel fiber-reinforced ultrahigh performance concrete (UHPC) and a steel girder without top flange. To that goal, the experiment is conducted on 24 composite beams fabricated with varying compressive strength of UHPC, steel fiber content, stud spacing, and slab thickness to evaluate the behavior of the studs and the flexural behavior of the composite beam combining the UHPC slab and the inverted-T steel girder. The experimental results show the test members developed sufficient ductile behavior with respect to the slip limit of 6 mm stipulated in Eurocode-4 and regardless of the considered test variables. The experimental ultimate horizontal shear force is seen to be clearly larger than the static strengths of the stud predicted by Eurocode-4 and AASHTO-LRFD. Improved design formulae for the composite beam shall be derived to reflect the UHPC slab thickness.