Verrazano-Narrow Bridge: Design of Superstructure

The 4,260-ft-long center span of the Verrazano-Narrows Bridge is the longest built to date (1966). The two sidespans are 1,215 ft each. The bridge carries twelve lanes of traffic on two decks. Each deck contains two three-lane roadways 37 ft-0in. wide, flanked by steel curbs, safety walks, and parapets. The pavement consists of concrete-filled steel grids with integrally placed concrete wearing surface. The members of the deck framing (stiffening trusses, vierendeel frame floor trusses, stringers, and lateral bracing) form an integrated continuous tubular structure of full length for each span. Its great vertical, lateral, and torsional rigidity permitted a relatively shallow depth of suspended structure. The deck structure is carried by four, 36-in.-diameter cables, each composed of 61 strands of 428 wires. The strands are anchored by eyebar chains flamecut from manganese vanadium steel. The two steel towers are 693 ft high. Aerodynamic behavior of the suspended structure was checked by comparative section model tests that led to development of a torsional stiffness index.