Thousand Islands International Bridges — Alexandria Bay, NY & Ontario, Canada
Client
- Thousand Islands Bridge Authority
Project Value 
Duration of Service: 88 Years
Market
Bridge, Transportation
Services
Design, Engineering
Parsons, through its legacy firm Steinman, is the original designer of the entire Thousand Islands International Crossing, which was opened to traffic in 1938. The crossing includes two suspension bridges, an arch span, truss spans, and many spans of steel girder viaducts. These structures connect New York and Ontario, Canada.
Since its completion, we have provided continuous engineering services to the Thousand Islands Bridge Authority, including annual and special inspections, structural steel strengthening, and load rating.
Comprehensive Bridge Rehabilitation
Our work on the Thousand Islands Bridges has included major rehabilitation projects, such as the complete deck replacement and widening of the Canada Crossing and U.S. Crossing. As the final design consultant, we oversaw the installation of a new widened deck, new steel rail barriers, and a reconfigured floor framing system. This project also involved complex construction load and sequence evaluations. Additionally, we designed a new suspended span center-tie for each of the two suspension spans.
Ongoing Inspections And Unique Operations
Our team travels to the Thousand Islands region every year to perform inspections. This work includes detailed main cable interior inspections, assessments of the stay cable systems, and underwater inspections. A recent project involved a unique operation to remove and replace a fully loaded suspender cables. While the bridge remained open to traffic, our team provided engineering oversight for this complex task using Parsons-designed jacking frames. It demonstrated our commitment to innovative and safe project execution. The old suspenders have undergone ultimate strength testing as part of an ongoing asset management program.
