Iowa ABC Connections Iowa ABC Connections Iowa ABC Connections

Research Project


Iowa ABC Connections


Principal investigators: Brent Phares, 515-294-5879, (project list), Iowa State University

Co-principal investigators:

Project status


Start date: 04/01/13
End date: 06/30/15


Report: June 2015, Iowa ABC Connections 2.27 mb (*pdf)

Related publications: Iowa ABC Connections 622.45 kb *pdf June 2015

*To read pdf files, you may need to download the free Adobe Acrobat Reader.


Sponsor(s): Federal Highway Administration State Planning and Research Funding
Iowa Department of Transportation

About the research


For several years the Iowa Department of Transportation (DOT), Iowa State University, the Federal Highway Administration, and several Iowa counties have been working to develop accelerated bridge construction (ABC) concepts, details, and processes. Throughout this development, much has been learned and has resulted in Iowa being viewed as a national leader in the area of ABC. However, at this time, the Office of Bridges and Structures does not have a complete set of working standards nor design examples to accompany ABC portions of the bridge design manual (now called the Load and Resistance Factor Design/LRFD Bridge Design Manual).

During the fall of 2013, the Iowa DOT constructed a bridge on IA 92 in Cass County using an ABC technique known as slide-in bridge construction. During the design of the Cass County Bridge, several questions were raised about the performance of critical design and construction details: the pile-to-pile cap connection and the polytetrafluoroethylene (PTFE) coated bearing pads on which the bridge would slide.

The timing of this specific need and the initiation of this project offered a unique opportunity to provide significant short- and long-term value to the Office of Bridges and Structures. Several full-scale laboratory tests, which included several variations of the pile-to-pile cap connection and bearing pad slides, were completed. These tests proved that the connection was capable of achieving the desired capacity and that the expected coefficient of friction of the bearing pads was reasonably low.

Finally, a design tool was developed for the Office of Bridges and Structures to be used on future projects that might benefit from a precast pile cap.

2711 S. Loop Drive, Suite 4700, Ames, Iowa 50010-8664
Phone: 515-294-9501 ~ Fax: 515-294-0467
The Bridge Engineering Center is administered by Iowa State University's Institute for Transportation.

Bridge Engineering Center logo

Timber Bridge Program Structural Health Monitoring Current Projects Completed Projects About BEC Staff Students Related Links

Iowa State University logo and link