EQUIVALENT FRAME ANALYSIS OF FLAT-PLATE BUILDINGS FOR SEISMIC LOADING

An equivalent frame approach is presented for nonlinear seismic analysis of reinforced-concrete flat plate buildings. The approach employs a parametric hysteretic model and is based on the effective slab-width concept. Unlike in the previous equivalent frame approaches, the proposed method targets both the moment-transfer capacity as well as stiffness of the interior and exterior slab-column connections. The hysteretic parameters and the effective slab width factors are determined from results of laboratory tests on slab-column connections for the class of flat plate buildings constructed prior to the 1960s with reinforcing detail typical of gravity load design. The validity of the approach is justified by comparing the calculated and the measured responses of two-bay flat plate subassemblies tested under earthquake-type loading. With the proposed equivalent frame approach, the response of flat plate buildings for seismic loading could be predicted more realistically over a wide range of lateral drift levels.