Smoothness Provision for Bridge Decks

A contemporary survey of bridge ride quality is described, and use of the survey to support the development of a modern smoothness provision for bridge decks is discussed. The survey found that bridges have an average of 60% more roughness than most mainline highway pavements [as measured by use of the international roughness index (IRI)]. However, a secondary analysis revealed that beam and girder camber can easily contribute more than 1000 mm/km of additional IRI roughness, which suggests that IRI may not be an equitable tool for measurement of the construction quality of bridges. This finding led to an additional analysis that focused on the use of a simulated rolling straightedge as a tool to control smoothness. Ultimately, the study demonstrated how inertial (and high-speed) profiling equipment can be applied to control bridge deck roughness through the use of a simulation that mimics the traditional 3-m straightedge.