VIBRATION OF ROAD BRIDGES UNDER MOVING VEHICLES: A COMPARATIVE STUDY BETWEEN SINGLE CONTACT POINT AND TWO CONTACT POINT MODELS

The study of dynamic response of bridges under the action of moving vehicles provides a tool for structural designing as well as damage identification. Bridge-vehicle interaction is generally modelled through single contact point for mathematical simplicity, although the interaction actually takes place through front and rear wheels. In the present work, dynamic deflection of the bridge modelled through two contact points is investigated for a range of vehicle velocity and wheel to wheel distance. It is observed that for wheelbase to bridge span ratio greater than a certain limit, two contact point model gives significantly different results particularly at higher velocity range. The results, presented in terms of non-dimensional parameters, can be used as a design monograph for any bridge-vehicle-velocity combination.