Nationally there is concern regarding the design, fabrication, and erection of horizontally curved steel girder bridges due to unpredicted girder displacements, fit-up, and locked-in stresses. One reason for the concerns is that up to one-quarter of steel girder bridges are being designed with horizontal curvature. The concerns are significant enough that an NCHRP research problem statement has been developed and given high priority for funding. It is also noted that an urgent need exists to reduce bridge maintenance costs by eliminating or reducing deck joints. This can be achieved by expanding the use of integral abutments to include curved girder bridges.

The long-term objective of this effort is to establish guidelines for the use of integral abutments with curved girder bridges. The project scope will focus on the monitoring and evaluation of constructed bridges that will be documented by reports outlining the findings and recommendations for design policies.

Phase IA includes placing instrumentation on six curved girder bridges in Iowa with integral and semi-integral abutments that will be constructed in 2008. These instrumented bridges will give us a better understanding of the behavior of curved girder integral abutment bridges. In addition to the Iowa bridges identified above, other participating states may also propose additional curved girder integral abutment bridges (outside of Iowa) to be instrumented and monitored in Phase IB. Phase IB will be an extension/expansion of Phase IA where additional bridges (if desired) can be selected by the TAC.

Requested commitment is $7,500 per year for 5 years. The total project budget is estimated at $250,000 to $625,000. With additional participation it is anticipated that further and more in-depth analysis of the project features including a greater level of extrapolation could be made.