Issued as Part of the Tenth Progress Report of the Highway Bridge Impact Investigation

The results of an analytical investigation are presented to illustrate the nature of the dynamic effects produced by moving vehicles in highway bridges of the cantilever type. In the analysis the bridge is represented by a beam with distributed flexibility and seven concentrated point masses, and the vehicle is represented by a smoothly moving, single-axle, sprung load. The parameters investigated include the speed of the vehicle, the stiffness of the vehicle suspension in comparison to the stiffness of the bridge, and the limiting interleaf friction in the springs of the vehicle. It is shown that cantilever bridges are more susceptible to vibration than continuous bridges of the same general proportions.The Division of Highways. State of Illinois.The U.S. Department of Commerce. Bureau of Public Roads