Harsh climate conditions, as experienced in Canada, have raised a growing interest in precast construction. Precast concrete hollow core (PCHC) slabs featuring circular or ellipsoidal voids in their sections are structural elements that are precast and transported to the construction sites. Widely employed in multistory long-span structures, these slabs offer advantages such as being lightweight, cost-effective, easy to install, fire-resistant, and possessing superior thermal insulation. Despite their widespread application, current design codes overlook the significant aspect of composite action between steel beams and PCHC slabs. It is advantageous to consider this composite action in the design process, potentially leading to the specification of smaller steel beam sections. Shear studs play a crucial role in facilitating the establishment of composite action, underlining the need for a thorough investigation into their mechanical properties. This study aims to develop a 3D finite element (FE) model based on six full-scale pushout tests. These tests, conducted on full-scale composite beams with 254 mm depth PCHC slabs connected to steel beams via 19 mm diameter shear connectors, serve as the basis for quantifying the composite behavior. The FE model results are accurately calibrated against the experimental findings. Finally, a parametric study investigates the impact of the shear stud diameter and compressive strength of the concrete on shear stud capacity. Finally, the results of this study will provide valuable insights into the composite behavior of the steel beams with PCHC slabs.