Title:
Seismic Resistance of Reinforced Concrete Frame Structures Designed Only for Gravity Loads: Experimental Performance of Subassemblages
Author(s):
Luis E. Aycardi, John B. Mander, and Andrei M. Reinhorn
Publication:
Structural Journal
Volume:
91
Issue:
5
Appears on pages(s):
552-563
Keywords:
beams (supports); columns (supports); joints (junctions); earthquake-resistant structures; lap connections; loads (forces); shear properties; structural design; Structural Research
DOI:
10.14359/4170
Date:
9/1/1994
Abstract:
The behavior of gravity load-designed reinforced concrete members under simulated seismic loading was investigated experimentally. Four column specimens, loaded with low and high levels of axial forces, with and without lap splices, representing interior and exterior columns at floor slab and beam soffit levels, were examined under reversed cyclic loading at increasing drift amplitudes until failure. The failure of all columns was flexurally dominated, resulting from either of the following: concrete crushing and buckling of the longitudinal steel in the case of columns with high axial load; or low-cycle fatigue of the longitudinal bars in columns with low levels of axial load. All columns were capable of sustaining at least two cycles of loading at a 4 percent drift angle. In addition, two specimens at one-third scale that model typical exterior and interior slab-beam-column subassemblages, of a prototype building frame designed and detailed only for gravity loads, were subjected to axial load and reversed cyclic lateral displacements. The exterior subassemblage experienced a weak beam-strong column failure mechanism, whereas the interior subassemblage developed a weak column-strong beam mechanism. This paper presents important experimental results and attempts to model analytically the seismic behavior and parameters that govern the seismic response. Conclusions are drawn on how individual detailing deficiencies can affect the seismic response and failure mechanism of a structural frame as a whole.