<p>In the off-site construction of steel composite girder bridges, there is a growing need for non-interference interface connections to address various issues arising from conflicts between prefabricated components. This study examines a connection type for prefabricated steel composite girders that allows for efficient assembly without interference between the prefabricated deck panels and the steel girders. This is achieved by mechanically injecting non-shrink grout through continuous channels. The enhanced workability and flow of non-shrink grout are particularly beneficial for hydraulic injection grouting, enabling faster filling and reducing the risk of voids that could compromise the system's flexural capacity. To evaluate the impact of this connection type and injection grouting on structural performance, a full-scale girder designed according to AASHTO LRFD specifications was tested up to the plastic moment capacity range, demonstrating flexural ductility. Then, based on verified numerical models, a series of finite element analyses were conducted as part of parametric studies to investigate the bending and shear performance of prefabricated composite bridge systems, including variations in the material properties of non-shrink grout for hydraulic injections. The comparative studies revealed that prefabricated steel composite girders with the non-interference interface connection can achieve an equivalent full composite capacity. These findings confirm the applicability of the proposed design procedure for prefabricated steel composite girders in bridge construction.</p>