EFFECTS OF VEHICLE SUSPENSION DESIGN ON DYNAMICS OF HIGHWAY BRIDGES

The effects of heavy vehicles with leaf-spring and air-spring suspensi ons on the dynamic response of short-span highway bridges are consider ed in this paper. The dynamic bridge responses are calculated by model ing the bridge and vehicle separately and combining the models with an iterative procedure. The bridge model is obtained by combining mode s hapes with dynamic wheel loads in a convolution integral. This bridge calculation procedure is validated by experiments on two highway bridg es. The validated, nonlinear vehicle models consist of a leaf-sprung, four-axle articulated vehicle, and a similar vehicle fitted with air s uspensions and hydraulic dampers. These two vehicle models are combine d with three different bridge models to predict dynamic bridge respons es. Two surface profiles are used on each bridge: a step up at the ent rance, and a pseudo-random profile. Dynamic response increments are us ed to compare the effects of the two vehicles on bridges. The air-susp ended vehicle is found to cause significantly lower dynamic bridge res ponses than the leaf-sprung suspended vehicle.