The new Sarah Mildred Long bridge replaces a 65 year old bridge that serves an estimated 14,000 drivers and crucial commercial traffic along the route 1 bypass each day between Kittery, Maine and Portsmouth, New Hampshire. The dual level bridge carries vehicle traffic on the top deck and railroad access to the Portsmouth Naval Shipyard on the lower deck. The main span lift superstructure is designed to carry traffic when set at the top deck level and lowers to carry trains when lowered to the railroad deck level. The main span also lifts to allow large ship access.
The four main span towers are constructed using precast tower segments cast on site by Cianbro.
The vehicle and railroad superstructures are constructed using precast segments fabricated by Unistress Corporation off-site.
Hatcher Technical worked with construction engineer McNary Bergeron and contractor Cianbro Corporation to provide:
- Fully integrated shop drawings for the 4 main span lift towers (88 total segments)
- Fully integrated shop drawings for the precast segmental vehicle bridge superstructure (239 total segments)
- Fully integrated shop drawings for the precast segmental railroad bridge superstructure (139 total segments)
- Fully integrated conflict free 3D models of selected tower and vehicle bridge segments
- Fully integrated shop drawings of CIP elements;
- Main span tower footings
- Machine rooms
- CIP Tower caps
- Shared pier footings and columns