2025 ACEC-NH & NHDOT Technical Exchange Conference

Session 1A: Lyme-Thetford Bridge - Lessons Learned
Speaker: Jeff Potter, NHDOT
- This session highlights the rehabilitation process for the Lyme-Thetford bridge with highlights on the public outreach, painting process, conditions after grit blasting of the 1937 structure, repairs to the truss members, and lessons learned in the process. The presentation will also give a quick overview of the cofferdam utilized to repair the pier which was floated into place and attached to the pier.

Session 1B: Innovative Combination of Prefabricated Bridge Elements and Conventional Construction Provides Economical Solution for Aging Infrastructure
Speakers: Sam White, McFarland Johnson; Jim Bowles, NHDOT
- Within a six-week roadway closure, this project replaced the superstructure and rehabilitated the foundations on the bridge carrying NH 113A over the Swift River in Tamworth, NH. The long detour (25 miles) warranted accelerated construction; however, low roadway user numbers did not support the added expense of fully committing to an Accelerated Bridge Construction (ABC) approach. The solution for this project was an ABC “lite” approach that economically blended the use of Prefabricated Bridge Elements (PBEs) with conventional construction techniques. Attendees of this presentation will benefit by learning how techniques traditionally reserved for ABC can be applied on routine projects to improve project delivery. 

Session 6A: FE Everett Turnpike Projects Update from Nashua to Bedford
Speakers: Wendy Johnson, NHDOT; Greg Tedeschi, NHDOT; Sam Newson, NHDOT
- This presentation will provide an update on the design and construction of several construction projects on the FE Everett Turnpike between Nashua and Bedford. The presentation will focus on design/construction work that has occurred to date, and active design/construction efforts for the Nashua-Merrimack-Bedford 13761 series of projects. A brief presentation highlighting the Bedford 16100 All Electronic Tolling (AET) conversion project will also be included.

Session 6B: The First Turbine Interchange
Speaker: Smith Siromaskul, HDR
- This presentation will discuss the development and design of the world’s first signalized turbine interchange located just outside of Daytona Beach.  Learn about the selection of this interchange concept from the perspective of different modes and stakeholders looking at traffic volumes, land use, cost, pedestrian safety, and future flexibility. Additionally, pros and cons will be compared against other innovative and traditional interchange types.  This presentation covers the basics of the system turbine interchange and its evolution into a service interchange.  This presentation will cover the basics of a signalized turbine interchange and the contexts in which one would work best.

Session 10A: Fern Hollow Bridge Emergency Replacement Project Pittsburgh, PA
Speaker: Jason Fuller, HDR
- January 2022 the Fern Hollow Bridge collapsed. This critical NHS route is a diversion route for I-376, with 100,000+ vpd. Immediately, PennDOT, the City of Pittsburgh and FHWA used an emergency declaration to hire HDR to design and Swank Construction to construct the project using a design-build process. Instantly it was clear that schedule and budget were critical to implementing the project. Early coordination with the agencies, contractor and designer was critical. The permanent bridge was reopened to traffic in under 11 months, in December 2022. This could only be accomplished by the collaboration that the emergency design-build process provided.

Session 10B: Madawaska-Edmundson International Bridge Replacement
Speakers: Josh Olund, HNTB
- The international bridge spanning from Madawaska, Maine to Edmundston, New Brunswick, Canada serves as the sole link between a close-knit, mixed-national community. When inspection of this critical structure’s load capacity called for all truck traffic to travel through the next border crossing—approximately 20 miles away—MaineDOT and other stakeholders recognized the need for an alternative plan.

Within four years, working alongside countless stakeholders, HNTB evaluated and designed a six-span, steel girder replacement bridge that reaches an overall length of 1,828 feet and is a landmark for the community. The four-girder-designed system supports two lanes of traffic, six-foot shoulders for multimodal traffic and a six-foot sidewalk for pedestrians.

Session 14A: Dummer-Cambridge-Errol 16304B (NH 16) Design and Construction
Speaker: Tim Dunn, NHDOT; Chuck Flanders, NHDOT
- The Dummer-Cambridge-Errol 16304B project reconstructs one mile of NH Route 16 in Cambridge, NH. The project is the second of four planned in Thirteen Mile Woods, from Dummer to Errol, that when complete would allow the road to not require load posting in the spring. The project was complicated by the proximity of the Androscoggin River to the east and extensive wetlands and multiple conservation easements to the west along with challenging construction conditions. All aspects of the project’s development will be discussed from design and mitigation to ROW acquisition and construction.

Session 14B: Milford 101 Safety Improvements 13692D
Speakers: Jason Ayotte, NHDOT
- Coming Soon!