The usage of prestressed concrete hollow slabs is widespread in the construction of small and medium-sized span highway bridges in China. However, due to increased load requirements, several hollow slab bridges built in China during the early stages fail to meet the new regulations" shear bearing capacity requirements. Nevertheless, these hollow slabs continue to function adequately under existing vehicle loads. Consequently, it becomes essential to conduct an in-depth investigation into the shear bearing capacity of these slabs. This study focuses on analyzing the shear bearing capacity by performing tests on five 16m-span hollow slabs that were dismantled during a renovation and expansion project. Out of the tested slabs, three top slabs were cast-in-place with a 15cm concrete structural layer. Various parameters such as load displacement curve, web concrete strain, cracking load, crack development patterns, failure mode, and ultimate load of the hollow slabs were determined. The experimental findings reveal that the 16m hollow slabs exhibit diagonal cracks and shear compression failure. Additionally, the cracking load of the 16m hollow slabs increases by 32% and the shear bearing capacity increases by 22% when a 15cm concrete structural layer is added to the top plate. Comparing the experimental results with the calculation results specified in the standards highlights the overly conservative nature of the current calculation method for the shear bearing capacity of hollow slabs.