ABSTRACT
A conventional RC flat-plate system consists of RC slab with uniform thickness supported directly on RC columns without using beams or drop panels. Due to the low construction cost associated with simple formwork and simple arrangement of slab flexural reinforcement, flat-plate systems are widely used for residential and office buildings. An additional advantage of flat-plate systems is the reduced story heights that lead to increased number of stories for a given building height. Flat-plate systems, however, are not effective to resist earthquake-induced lateral deformation due to the low rotational stiffness built into the slab-column connections. Consequently, a separate lateral load resisting system such as reinforced concrete shear walls or perimeter moment frames must be used in conjunction with flat-plates to control lateral deformations. Under seismic loading, the lateral story drift causes significantly concentrated bending moment and vertical shear in RC slab in the vicinity of the column. The stress and strain concentration may result in a brittle premature punching shear failure of the slab due to diagonal tension cracking. The lateral deformation capacity of RC slab-column connections under seismic loading has been experimentally investigated by Hawkins et al. (1974), Morrison et al. (1983), Pan and Moehle (1989, 1992), Durrani et al. (1995), and Tian et al. (2008) among many others.
