Shear connection requirements for composite cellular beams

Beams with regular circular web openings (cellular beams) are often used in composite construction. Rules for the minimum degree of shear connection in composite beams are presented in Eurocode 4 but were derived for solid web beams in propped construction. This paper investigates the degree of shear connection requirements for composite cellular beams, focusing on the combined effect of using a steel section with regularly spaced, large circular web openings and unpropped construction conditions. The effect of the diameter and the spacing of the openings is also investigated. In order to provide rules for the minimum degree of shear connection in cellular beams, parametric finite element (FE) analyses were carried out for beams in the span range of 9 to 18 m. The results were calibrated against a 15.3 m span composite cellular beam test with a low degree of shear connection. The proposed minimum degree of shear connection requirements for beams with regular circular web openings are presented for both propped and unpropped construction, and for symmetric and asymmetric steel sections. Comparisons are made with equivalent beams with solid webs (no openings) and it is shown that significant relaxation in the codified minimum degree of shear connection to the current version of Eurocode 4 can be justified for composite cellular beams.