Strengthening of R/C beams with high-performance jackets

The possibility of strengthening RC elements for increasing the bearing capacity is an important issue in the retrofitting field. In RC existing structures, made in the ’60s and ’70s, bending and shear reinforcements are often not sufficient to satisfy the prescription of current codes. Hence, in the retrofitting of these structures it is often necessary to increase their bearing capacity. A possible use of low thickness high performance jackets for flexure and shear strengthening purposes is analyzed herein. The jackets are made with a high performance fiber reinforced concrete, with or without an additional 2 mm diameter steel-wire mesh. Two different high performance concrete are investigated: a concrete with a self levelling rheology, that can be cast with reduced thickness, and a thixotropic material that can be placed without moulds. In order to verify the effectiveness of the proposed solution, different jackets were used for reinforcing two different type of beams: a 2.85 m long beams, without stirrups, for shear strengthening and 4.55 m beams, with a low reinforcement percentage, for bending strengthening. The elements were tested up to failure and the comparison between the obtained results is presented herein.