Improved Design and Construction Procedures Improve Seismic Resistance of Bridges

Bridges with revised recommendations (Left) I-65 over SR 25 (Right) US 231 over AEP Railroad Spur

In 2008, Robert Frosch, Michael Kreger, and Aaron Talbott completed "SPR-2867: Earthquake Resistance of Integral Abutment Bridges." The project examined the response of integral abutment bridges to seismic loading. The project combined the results of field, analytical, and laboratory investigations to evaluate allowable bridge lengths based on seismic performance.

Based on the project results, design and detailing recommendations were developed to enhance the seismic performance of integral abutment bridges both in Indiana and across the country. The research determined that INDOT integral abutment bridge details with slight modifications are sufficient to provide seismic resistance for bridges up to 500 ft in length. Integral abutment bridges, however, can be used for lengths up to 1000 ft when confining reinforcement is provided around the pile head. Construction details were also recommended for proper connection of the pile to the abutment. "This research is one of the most significant projects that I have been a part of in my years at INDOT. We can now easily and with little effort build our way out of seismic risk as we replace older structures," stated Randy Strain, INDOT, Structural Services.

The INDOT Design Manual (Chapters 403 and 409) has been revised based on these recommendations. Through incorporation of the research findings, integral bridges across the state can be constructed with inherent seismic resistance even when design does not specifically require seismic resistance. This increased resistance not only provides enhanced safety to the traveling public in the event of a seismic event, it also allows for the preservation of transportation routes which are essential for emergency response, public welfare, and economic security.

More Information | In addition to the JTRP technical report on this project, several other JTRP projects on integral abutment bridges have been conducted which serve as the basis of changes made to the INDOT Bridge Design Manual for this bridge design type. Hyperlinks to this as well as the other publications are listed below:

• Frosch, R. J., V. Chovichien, K. Durbin, and D. Fedroff. Jointless and Smoother Bridges: Behavior and Design of Piles. Publication FHWA/IN/JTRP-2004/24. Joint Transportation Research Program, Indiana Department of Transportation and Purdue University, West Lafayette, Indiana, 2006. DOI: 10.5703/1288284313379.

• Frosch, R. J., M. E. Kreger, and A. M. Talbott. Earthquake Resistance of Integral Abutment Bridges. Publication FHWA/IN/JTRP-2008/11. Joint Transportation Research Program, Indiana Department of Transportation and Purdue University, West Lafayette, Indiana, 2009. DOI: 10.5703/1288284313448.

• Frosch, R. J., and M. D. Lovell. Long-Term Behavior of Integral Abutment Bridges. Publication FHWA/IN/JTRP-2011/16. Joint Transportation Research Program, Indiana Department of Transportation and Purdue University, West Lafayette, Indiana, 2011. DOI: 10.5703/1288284314640.