Using data obtained from the dynamic load testing of bridges a method was developed to evaluate level of the dynamic performance without performing a dynamic load test. In this method a dynamic index of the bridge is calculated. Dynamic index allows to evaluate the dynamic performance level of existing and new structures taking into account such bridge parameters as span length / height ratio, natural frequency, vibration damping coefficient, relative deflection and international roughness index IRI. Dynamic index method can be used by bridge owners and maintainers to determine the dynamic potential of a particular bridge.

The maximum allowable values of the dynamic amplification factor for standard prestressed concrete beam bridges were determined. These values were calculated for maximum allowed traffic load in Latvia. The obtained results can be used for the safety assessment of existing and reconstructed reinforced concrete beam bridges.