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Experimental and analytical studies on the hysteretic behavior of reinforced concrete rectangular and T-beams

Ma, Shao-yeh Marshall; Bertero, Vitelmo V.; Popov, Egor P.

UCB/EERC-76/02, Earthquake Engineering Research Center, University of California, Berkeley, 1976-05, 260 pages (515/M15/1976)

This report describes an experimental and analytical program carried out for investigating the inelastic behavior of critical regions that may develop in a beam near its connection with the column of a reinforced concrete ductile moment-resisting space frame when subjected to severe earthquake excitations. In the experimental program, a series of nine cantilever beams, representing half-scale models of the lower story girder of a 20-story ductile moment-resisting reinforced concrete office building, were designed according to present seismic codes. These beams were designed in order to study the effects of (1) the slab by testing T-beams with a top slab width equal to the effective width specified by the ACI 318-71 Code; (2) relative amounts of top and bottom reinforcement by varying the amounts of bottom reinforcement; (3) supplementary ties by providing hairpin ties around the main bars not restrained by the corners of stirrup ties; (4) the high shear force by varying the shear-span ratio; and (5) loading histories by testing some beams under loading reversals inducing a gradually increased deformation, and others under monotonic loadings to large deformations in one direction. The significance of the experimental results in relation to the seismic design of the reinforced concrete critical region is discussed. Analytical studies were carried out to gain a better understanding of the flexure, shear, and bond-resisting mechanisms in the reinforced concrete critical regions subjected to inelastic load reversals.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-76-02.pdf (12 MB)