PARAMETRIC ANALYSIS OF THE DYNAMIC AMPLIF ICATION FACTOR OF LOADS FORSIMPLE-SPAN REINFORCED-CONCRETE BRIDGES

It is generally accepted that several parameters influence the dynamic amplification of a bridge response, such as the dynamic characteristi cs of both the vehicles and the bridge, the initial loading conditions , the surface profile of the pavement, etc. The objective of this pape r is to use a tridimensional finite element model (vehicle and bridge) to investigate the effect of some significant factors such as the bri dge geometry, the type of measures that form the basis for computing t he dynamic amplification factor (DAF), the loading conditions, and the velocity of trucks, on the DAF applied to static loadings. We limited ourselves to the study of 20 to 32 m simple span reinforced concrete bridges. The simulations show that the DAF proposed in the standards C alcul des ponts routes (CAN/CSA-S6-88), Ontario Highway Bridge Design Code, and Canadian Highway Bridge Design Code is not always safe for c alculating the stresses in the type of bridges investigated herein and that it decreases for high loads and velocities. Using two DAFs, one for bending and the other for shear and bearings, would certainly be m ore adequate for the design and assessment of bridges.