Seismic Resistance of Reinforced Concrete Frame Structures Designed Only for Gravity Loads - Part II: Experimental Performance of Subassemblages
J.M.Bracci, A.M.Reinhorn, J.B.Mander
University at Buffalo
This report is Part II of a three part series on the evaluation of seismic resistance of reinforced concrete frame structures designed only for gravity loads. It is concerned with the experimental behavior of gravity load designed reinforced concrete columns and subassemblages under reversed cyclic lateral load. The report presents the study of four column specimens (with and without lap splice), and two beam-column (exterior and interior) subassemblages of a one-third scale model of a prototype designed for gravity loads according to ACI 318 non-seismic detailing that were subjected to axial load and cyclic lateral displacements. Column failure was flexurally dominated, resulting either from buckling of the longitudinal steel or from low cycle fatigue of the longitudinal bars. The exterior subassemblage experienced a weak beam-strong column failure mechanism whereas the interior subassemblage developed a weak column-strong beam mechanism. Thus a hybrid mechanism is likely to occur in a complete structural frame. Conclusions are drawn regarding the appropriateness of hoop spacing in the columns, length and location of lap splices, joint reinforcement, equivalent plastic hinge lengths, and desirable failure mechanism for an entire frame. The results presented in this report were used to identify member characteristics to develop analytical models to predict the seismic response of the one-third scale model building.
Reinforced Concrete Frames, Lateral Loads, Low Rise Building, Lightly Reinforced Concrete Buildings, Gravity Load Design, Reinforced Concrete Columns, Reinforcement, Reversed Cyclic Loads, Beam Column Subassemblages, Mathematical Models, Experimental Tests, and Detailing.