Investigation of impact factors for permit vehicles FDOT Contract No. BD543, FSU Project No. 020555 supervisor Prof. Jerzy Wekezer, FAMU-FSU College of Engineering

Aim of project
Bridges are designed for maximum load including dynamic eff ects specifi ed for each structure. However, it is sometimes necessary to move a heavy vehicle across the bridge with loads exceeding those for which the bridge is designed. In such cases, a permit is needed from the owner of the bridge. Such decisions are made quickly and should be supported by a sound analysis to ensure that the bridge is not damaged. The development of such guidelines is the main objective of this study. Two popular heavy vehicles were identified:

A three-axle detachable lowboy trailer and 6-wheel tractor based on Series were selected with a total mass exceeding 60000kg;

A heavy construction crane.

Finite element models of both vehicles are developed and experimental testing of the suspension of the fi rst vehicle was already completed by driving the vehicle with diff erent speeds over speed bumps. Early research results helped to identify specific causes which infl uence dynamic impact factors for bridges. Among them bridge approach depression, speed bumps and other road imperfections were found to be strongly correlated with dynamic impact factors.

Expected results
This research project will provide specifi c information about the magnitude of possible dynamic load produced by permit vehicles on reinforced concrete bridges. Computational mechanics analysis will be backed up by an experimental program in which a reinforced concrete bridge will be loaded dynamically by two actual permit vehicles. Experimental results will be used to validate fi nite element analysis, which in turn will provide thorough and reliable information about possible sources and magnitude of dynamic impact factors.