Location: Portsmouth, New Hampshire / Kittery, Maine
Client: Maine DOT
H&H is providing design services for the preliminary design, final design, and design support during construction, including providing a preliminary design report, plans, design and design check computations, ratings, specifications, and cost estimates, for the replacement of the Sarah Mildred Long Bridge located on U.S Route 1 Bypass between Kittery, ME, and Portsmouth, NH – a combined highway and railroad movable bridge. H&H is responsible for the movable bridge concept study and report and design for the fender system, lift pier substructure units, lift piers, lift bridge towers and lift span superstructure, operator’s house, mechanical room, electrical room, mechanical operating system and electrical operating system. The upper portion of the bridge provides vehicular and pedestrian access, while the lower portion provides railroad service. The railroad portions of the bridge will be designed in accordance with local, state and AREMA codes and guidelines. This project will be completed with the CMGC process. H&H was involved in selection of a contractor that teamed with the designers to perform constructability and cost reviews.
The concept developed by the design team included many innovations including the first application of pre-cast post-tensioned concrete for the lift span towers, a lift span comprised of steel boxes with an FRP wind fairing, operating machinery located in the tower bases, and a single level 300-foot-long lift span with separate seating locations for the double level highway and rail bridge approaches.
Construction kicked off on January 5th, 2015 and is scheduled to be complete in 2017.