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Seismic Resistance of Slab-Column Connections in Existing Non-Ductile Flat-Plate Buildings

A.J. Durrani and Y.Du

NCEER-92-0010 | 5/18/1992 | 108 pages

About the Report:

TOC: The table of contents is provided.

Keywords: Flat-Plate Buildings, Stiffness Degradation, Spandrel Beams, Shear Strength, Slab Column Connections, Moment Transfer Capacity, Nonductile Reinforced Concrete Buildings, Experimental Tests, Lateral Drift, Seismic Loads, Reinforcement, Punching Failure, and Detailing.

Abstract: An experimental investigation was conducted to evaluate the seismic resistance of slab-column connections in existing non-ductile flat-plate buildings. The test subassemblies were designed and detailed in accordance with the building codes of the late forties and fifties. Each subassembly consisted of two exterior and one interior connection and was subjected to several cycles of increasing lateral displacements. The test variables included the slab reinforcing detail, intensity of the gravity load applied to the slab, and the presence of a spandrel beam. Rapid stiffness degradation, significant reduction in deformation capacity under increased gravity load, and limited moment-transfer capacity of connections were observed to be the main response characteristics of the non-ductile slab-column connections subjected to earthquake-type loading. The mode of failure and deformation capacity of the connections was observed to depend greatly on intensity of the gravity load on the slab. At lower gravity load, the response of connections was dominated by flexural yielding of the slab. As the gravity load was increased, the interior connections punched at significantly smaller lateral drift. Provided the gravity shear is kept within a certain maximum limit, the test results suggest that the rapid degradation of the lateral stiffness and the lack of protection against progressive collapse resulting from punching of connections may be the two most critical factors affecting the response of non-ductile flat-plate buildings during moderate earthquakes