Title: Prestressed Concrete Composite Beams Under Repeated Loading

Author(s): H. W. Chung and T. Y. Chung

Publication: Journal Proceedings

Volume: 73

Issue: 5

Appears on pages(s): 291-295

Keywords: beams (supports); bond (concrete to concrete);deflection: failure: fatigue (materials);flanges: joints (junctions); loads (forces);shear connectors: sheer stress: slippage:T-beam; webs (supports).

DOI: 10.14359/11074

Date: 5/1/1976

Abstract:
An experimental investigation was undertaken to study the effects of repeated loading on the horizontal shear connection between the precast concrete web and the cast-in-place concrete flange of a composite beam. The test program included 18 prestressed concrete composite t-beams, the variables being the amount of joint reinforcement and the intensity of the repeated load. The test results indicate that the fatigue strength of the rough bonded interface is not less than 55 percent of the static strength and, under repeated loading, the critical slip is around 0.025 mm (0.001 in.), beyond which the efficancy of the joint rapidly deteriorates. To improve the endurance of the joint, a minimum of 0.3 percent of the joint reinforcement is tentatively recommended. It is shown that any previous repeated load not high enough to cause fatigue failure has no detrimental effect on the horizontal shear esistance of the joint.