Design and Construction of Newport Bridge

The east passage crossing of Narragansett Bay was forestalled by U.S. Naval operations until 1964, when a suitable site became available with the requirement that minimum clearances of 1600 ft horizontal and 205 ft vertical were maintained. This condition, plus esthetic requirements, demanded a suspension bridge. A central gorge in the alinement necessitated pile driving at great depths (100 ft and 140 ft) for the minimum span length. However, a longer main span length was found more expensive. Rock was located at minus 220 ft for the west tower pier and minus 432 ft for the east, and modified Potomac-type footings were selected. Pile cutoff was accomplished using a saturation diving unit. Footing forms were designed with variable buoyancy for controlled lowering. Of the remaining piers, some were constructed on piles or in the dry; and others on caissons drilled into rock, the technique used for the west anchorage. Significant features of the bridge superstructure include shop-fabricated parallel-wire cables, a unique cable anchorage, plastic rather than wire cable wrapping, and a new concrete deck curing-protective compound.