Along the years, researchers have made efforts in the sense of quantifying structural performance and damage in function of vibration measurements, [1] and [2]. Similarly the present work investigates a vibration based criteria for bridge structures as a basis to evaluate damage in existing bridges. With this purpose, a bridge data base collected during field tests accomplished in Brazilian bridges was used. The results show a clear correlation between the damage index and the intensity of bridge vibration. As a final result, from the observed correlations, limits of acceleration are proposed to be considered in existing bridges to certify a correct long-term condition. A critical approach of current Brazilian Standard (NBR-15307 2005) which suggests damage estimation in function of bridge vibration is also carried out.