The development of a dynamic amplification estimator for bridges with good road profiles

The paper considers the influence of the surface profile on the dynamic amplification of a simply supported bridge when subject to a quarter-car vehicle model. The effect of the profile irregularities on the bridge dynamic amplification is characterized with a ‘response surface’ giving dynamic amplification due to a ‘unit ramp’ at any location. Even though the dynamic interaction problem is nonlinear, the effects of all ramps which together make up a road profile can be calculated separately and added using the ‘response surface’. This superposition process achieves reasonable accuracy for ‘good’ (moderately smooth) surface profiles. An accurate estimate of dynamic amplification for bridges is demonstrated with a wide range of good profiles.