Highway 417 Westbound was tendered by Ontario Ministry of Transportation (MTO) in 2004. It was the 2nd alternate bid with Life cycle cost adjustment factors and concrete pavement is the lowest bid. The 2 westbound lanes were constructed in 2004/2005. The concrete slab is 200 mm thick and built with slipform paver equipped with automated dowel-bar and tie-bar inserters. During construction, the alignments of dowel bars were found to be not in accordance with MTO’s specification. Significant numbers of dowel bars were replaced with dowel-bar retrofit technique.
First MIT (Magnetic Imaging Tools) scan was deployed to identify misaligned dowel bar locations, then these bars were cut and adjacent slots were cut for new dowel bars. In some transverse joints, only a few bars were replaced but there were instances where the dowel bars were replaced for the entire joint. Figure 9 shows pictures depicting the installation process. As of today, the retrofit appears to work with minimal problems.