Federal Highway Administration State Planning and Research Funding
Iowa Department of Transportation
Brent Pharesbphares@iastate.edu email >
Bridge Research Engineer
About the research
Increasing the cost-effective life of our nation’s bridges (sometimes known as the service life) is a very high national infrastructure priority. In fact, a recent Second Strategic Highway Research Program (SHRP2) Project (R19A) was specifically dedicated to developing tools for designing bridges to meet specifiable service-life design criteria. More specifically, Project R19A was intended to develop procedures, approaches, and details that would ensure that bridges have service lives beyond 100 years.
There is a current effort being undertaken by the National Academies to implement certain components of the R19A project report. As has historically been the case, the Iowa Department of Transportation (DOT) is playing a leading role in the implementation of R19A by actively demonstrating the integration of the recommendations in typical bridge replacement projects. (Examples of other Iowa DOT demonstrations of life-increasing design details include implementing jointless bridge configurations and the use/development of a low-slump/high density deck overlay concrete.)
The Iowa DOT is currently involved in two projects to integrate the results of R19A. In one project, the Iowa DOT utilized A1010 steel for the exterior girders of a bridge over I-29 in Woodbury County, Iowa. The second project is a unique endeavor by the Iowa DOT to design and construct side-by-side bridges on I-35 near Ames, Iowa. One bridge was designed using current practices, procedures, and details while the other will be designed using service life design procedures. Because these two bridges will be exposed to the same environmental conditions, very similar traffic, and will be constructed within the same timeframe, a unique opportunity exists to identify and evaluate differences in performance between the two bridges.
The goals of this work are as follows:
- Collect behavior information for two uniquely designed bridges (the second implementation mentioned above) and compare the impact of using service life design procedures
- Collect information needed to complete service life designs of other bridges