This paper presents a strategy for the detection of mechanical damage of a reinforced concrete beam strengthened by Carbon Fiber Reinforced Polymers (CFRP) sheets (TFC ©) based on the joint use of piezoelectric sensors and conventional accelerometers. The beam is subjected to repeat impacts that may represent the action of vehicles on a roadway joint of a bridge, at different levels of damage induce by bending of the reinforced concrete beam. The results show that piezoelectric sensors provide a much wide response those accelerometers allowing a study in the high frequency range (above 2 kHz). The spectral response appears largely affected by mechanical damage on the beam and suggests a possible use for SHM in Civil Engineering structures.