EXPERIMENTAL INVESTIGATION ON R.C. BEAMS RETROFITTED IN FLEXURE AND SHEAR BY PRETENSIONED STEEL RIBBONS

The experimental results of three and four point loading tests on reinforced concrete beamsstrengthened by angles and/or pre-stressed stainless steel ribbons (CAM system) are presented. Thestainless steel prestressed ribbons play the role of adjunctive transversal reinforcement as well asconfine the structural element. Six flexural critical beams and nine shear critical beams were tested. Inthe first group four beams were retrofitted with bottom stainless steel angles and transversal ribbons,with two different spacing. In the second group three specimens were retrofitted by wrapping the beamwith the ribbons, while three specimens were strengthned by perforation of the beam beneath the slabheight, and by partially wrapping the beam by inserting the ribbons through the hole, in order tosimulate a strengthening performed without drilling of the slab. The test results prove the effectivenessof the retrofitting system for both the flexural and shear critical beams.