The Sakonnet River Bridge (Rhode Island Bridge No. 250) carries Rhode Island State Route 24 over the Sakonnet River between the towns of Portsmouth and Tiverton, Rhode Island. It is a major infrastructural component ofthe regional highway system in the Narragansett Bay area, and is significant for its associations with the history of state and regional transportation. Planning for the bridge began in 1945 and the as-built design was developed by 1947. Construction ofthe bridge began in 1954, and it officially opened for traffic on September 25, 1956. It is Rhode Island's fourth longest bridge in terms of overall and main-span length. It is a 2,982.5 ft long, steel structure incorporating 27 spans of varying design. Its most prominent and distinctive feature is the three-span, continuous Pratt truss structure over the river. The central span of this component is a 375 ft long truss with 65 ft of vertical clearance above the water. This unit was designed to include a prominent arch, resulting in an aesthetically pleasing solution that also provides required clearance for marine navigation.
The Sakonnet River Bridge was exceptionally large and complicated enough to require the design and engineering expertise of noted engineering firms. It was designed in 1946 by the J.E. Greiner Company, a leading East Coast bridge and highway engineering firm. The Sakonnet River Bridge occupies a unique place in Rhode Island bridge design. It is a highly evolved example of the continuous truss-type highway bridge and demonstrates the refinement ofthe type in its economic use ofmaterials and unusual solution to clearance requirements and aesthetic considerations. It belongs to a generation of Post World War II, elegant, slender, steel arch truss bridges designed at the end ofthe era in which firms like Greiner were still concerned about aesthetics, and a point in the science of bridge engineering that allowed great economy of materials. The Sakonnet River Bridge is the only bridge in Rhode Island that incorporates this type of continuous truss as an engineering solution.
Author: Matthew A. Kierstead, Industrial Historian, PAL, Pawtucket, RI 02860
Scope and Contents: The records consist of one copy of the historic bridge documentation (text and photos on archival quality materials) prepared by the PAL project team for the Rhode Island Department of Transportation. Even though the Sakonnet River Bridge No. 250 would not be eligible for listing in the National Historic Register of Places until 2006 (at which time it will have met the age requirement of 50 years), the RI Department of Transportation and the Federal Highway Administration have reached concurrence with the RI Historical Preservation & Heritage Commission to prepare a Rhode Island Historical Resources Archive documentation on the structure. The documentation has been generated to partially satisy a future mitigation plan in the event that the bridge undergoes a major rehabilitation or requires replacement.