Longitudinal Reduction Factor Study In Highway Bridge Design

The standard vehicle loads is major basis in the design of highway and bridge,impacting on the structure security and economy. As the development of thetransportation demand and automotive industry, the overload is more and more serious.Many bridges were damaged by overload trucks in recent years, and caused wideattention. And super-large bridge of crossing the river and the sea are being constructed.The new design load model and standards should be adjusted to the long-span Bridgesdesign load model. In order to do some research on the actual vehicle loads of recentyears and offer basis for the highway bridge longitudinal discount factor standarddepending on the western traffic science and technological project ‘Research on thedesign load and safety judge load of bridges’, using the vehicle load data provided byinterested divisions, this paper did some research as follows:①The comparison of home and abroad vehicle loads;The design vehicle load is simulative load all over the world, but it fits in with theflow, traffic volume and the development of the traffic.②Research on probabilistic model of highway bridge vehicle loads and vehiclesspacing;The result indicates that vehicle loads in different area can describe by weightedsum of several normal distributions. Lognormal distribution can serve as vehiclesspacing probability model. Vehicle load and vehicles spacing standard values during thereference period is determined.③Research on effects caused by vehicle loads;The actual vehicle load in different loading bridge and different span of virtualbridge, and the vehicle load effect value is determined.④Long-span bridges longitudinal reduction coefficient sure;The effects of value is compared between the actual load and the current teamregulate standard vehicle load.And the dimensionless ratio is got. Standard vehicle loadlongitudinal discount formula and suggested value is presented.