Incrementos dinámicos en puentes de carretera

Impact factors in highway bridges

Fifteen prestressed concrete highway bridges with different typologies have been tested in order to obtain impact factors as well as others magnitudes related with the dynamic response of the structures: frecuencies, mode shapes and damping values. The bridge decks were grouped in precasted double T beams, precasted open box beams, constant depth slabs and box or Pi sections. Controlled passing of a lorry was the usual excitation method and accelerations and displacements were the magnitudes recorder for the experimental structure behaviour analysis. Prior to the tests, the dynamic response of the decks were calculated with a FEM numerical program. The calculated and measure frecuency values were similar and ranged from 1.5 Hz to 5.4 Hz. Damping, evaluated by the logaritmic decrement values, was between 0.04 and 0.17.