Existing Reinforced Concrete (RC) buildings generally are vulnerable to seismic actions worldwide, often exhibiting shear failures, especially in high-seismicity areas, like Italy. According to obsolete technical or seismic codes in force in Italy until ‘80s, columns often have a minimum amount of transverse reinforcement requiring seismic improvements. Different strengthening techniques are nowadays spread in common practice to solve such critical failure typology, by means of FRP wrapping, RC or steel jacketing.

This paper experimentally analyses the effectiveness of pre-stressed stainless steel strips, which are externally applied on shear-critical RC columns to increase shear strength without changing lateral stiffness. Cyclic pseudo-static tests are carried out under increasing top displacement on nominally identical cantilever columns, comparing the as-built condition with different retrofitting layout, also considering different pre-stress levels. Experimental results are described in terms of damage evolution and global response. Local strain measurements on stirrups and external strips are also investigated as a support to assess and improve code-based prescriptions about the design of this retrofitting technique.