As a result of poor-quality sealing, moisture and deicing agents had penetrated into the prestressed hollow-core slabs of the top floor of an uncovered parking deck. The slabs showed especially severe chloride-induced damage in the support regions near the joints. Owing to the damage, the theoretical shear capacity according to the technical approval of these slabs was highly questionable. The influence of the damage on the shear capacity of the slabs with different levels of damage was determined with the help of an experimental in situ loading test. Based on the results, the number of slabs that had to be replaced or repaired could be reduced. For the experimental investigation of the shear capacity of the hollow-core slabs, a combination of photogrammetry, acoustic emission analysis, and curvature measurement for each section was used to determine the initial shear damage on a very low level during the test. The comparison of the results of the different measuring techniques allowed the damage processes to be clearly identified and significantly increased the quality of information about the structural condition of the slabs during the experimental investigation.