Replacement of the existing steel vertical-lift bridge carrying US Route 1 Bypass over the Piscataqau River while maintain this critical link between Portsmouth, NH and Kittery, Maine required close collaboration between design, construction and the New Hampshire and Maine Departments of Transportation. To maximize the benefits of an integrated project team, Cianbro Corporation was selected to lead New England first
CM/GC alternative delivery bridge project.
To construct the new Sarah Mildred Long Bridge replacement structure, which included a 2,800-foot concrete vertical-lift bridge constructed at a higher elevation than the existing bridge, a longer 300 foot lift span, with a vehicular structure stacked over a railroad level, Cianbro retained Case Foundation – A Keller Company of Berwyn, Pennsylvania to install a total of 29 ten (10) foot diameter drilled shafts, having 9.5 foot diameter rock sockets, extending approximately 110 feet below working elevation. Cianbro engaged GTR to provide drilled shaft fabrication and testing consultation in advance of drilling. As part of the CM/GC team, GTR perform Cross-hole Sonic Logging, reporting and consulting on all drilled shafts. For select shafts, GTR performed Crosshole Tomography (CT), as well as, additional non-destructive testing of drilled shafts using the Sonic Echo Method (SEM) using both the PET system and the NDE 360 system.
