SIMULATION OF THE DYNAMIC-RESPONSE OF CONCRETE BEAMS EXTERNALLY REINFORCED WITH CARBON-FIBER-REINFORCED PLASTIC

Laboratory-scale concrete beams 3 x 3 x 30 in (7.62 x 7.62 x 76.2 cm) in size were impulsively loaded to failure in a drop-weight impact mac hine. The beams had no internal steel reinforcement, but instead were externally reinforced on the bottom or tension side of the beams with one-, two- and three-ply unidirectional carbon-fiber reinforced plasti c (CFRP) panels. In addition, several of the beams were also reinforce d on the sides, as well as the bottom, with three-ply CFRP. The beams were simply supported and loaded at beam midspan, and sustained dynami c loads with amplitudes up to 10 kips (44.5 kN) and durations less tha n 1 ms. Experimental measurements included total load, midspan displac ement and strains, and a high-speed framing camera (10 000 frames s(-1 )) which gave insight into the failure mechanisms. Dynamic beam behavi or was also studied numerically using the finite-element method. The n umerical simulations gave insight into the localized displacement beha vior of the beams when subjected to an intense, impulsive load, as wel l as the phenomenon known as the 'traveling plastic hinge.' Results sh owed that the numerical simulations did very well in predicting the di splacement-time behavior of two beam types studied in detail; a plain concrete beam and a beam reinforced with three-ply CFRP on the bottom. (C) 1997 Elsevier Science Ltd.