MnDOT is in the initial phases of designing and constructing a pair of side-by-side bridges on I-35, one with GFRP and the other with conventional steel deck reinforcement. 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 them. Thus, the main goals of the proposed project are to: (1) collect the behavior information and response characteristics of the two bridge structures under service loads, (2) examine the short and long-term durability of the two bridge decks, and (3) assess the impact of using non-conventional, corrosion-resistant deck reinforcement on maintenance needs and life-cycle cost. The outcome of this project will also contribute to develop procedures, approaches, and details that would ensure that bridges have service lives beyond 100 years. This is in direct alignment with the implementation of SHRP2 Project R19A to design the bridges for service life. The Iowa Department of Transportation is currently embarking on a similar effort – also on I-35 – in which one bridge is being designed and constructed conventionally and one following the recommendations of the R19A implementation effort. This unique opportunity affords the chance for neighboring states to compare so-called service life designs on different portions of a very important national corridor.