This research presents results of the structural analytical behavior of diaphragms built with precast slabs supported on reinforced concrete walls. The current analysis approach that some designers propose for this type of construction, supposes the implementation of a rigid diaphragm model provided by the slab connections, stipulated in the construction regulations. However, given the loss of continuity between the slab panels in these prefabricated systems and the adoption of spaced connections, some differential displacements are released inside these diaphragms, which leads to a loss of their rigidity and changes in the behavior of the structural seismic resistance system. Two buildings were analyzed in this research, whose geometric characteristics were: length/width ratio of 1.5 and 2; with 5 stories high. The modeled structural system was reinforced concrete walls and the diaphragm consisted of precast slab panels hoisted in situ, joined by spaced connections. A chronological-spatial analysis was performed with acceleration records of scaled earthquakes; with the purpose of evaluating the behavior of the structure and checking the floor displacements throughout the building. With calculated displacement at various points of the diaphragm, flexibility indices and floor accelerations were determined. From these results, it was possible to establish whether the behavior of these diaphragms is rigid or flexible.