Spectra performed a hands-on inspection of the Barnhart Island Bridge over the south channel of the St. Lawrence River. The bridge is a three-span modified Warren through-truss with a segmentally straight parabolic shape upper chord. The structure has a center span of 508 feet 6 inches and the two ends spans are each 282 feet 6 inches for a total length of approximately 1076 feet. The bridge has a width of 46 feet center to the center of the trusses with a five foot clear sidewalk on the outside of the west truss.
The inspection consisted of a hands-on inspection of all truss members, floorbeams, stringers, and supporting members. Spectra inspected the abutments and piers including a diving inspection and bathometric survey. Spectra determined the most appropriate methods for necessary repairs and included appropriate sketches and magnitude construction cost estimates.
Spectra conducted the Barnhart Island Bridge Biennial Inspection in 1995, 1999, 2001, 2003, 2005, 2007, 2009, and 2015.