|Swing Time. Giant truss is placed on its bearings with help of rising tides and jacks. (Photo above and below courtesy of Kiska Construction Corp/ Brennan Photo)|
The new Third Avenue Bridge, fabricated in Alabama, was floated to the Bronx in July (ENR 7/19 p. 14). It was tethered to temporary posts about 200 ft south of its permanent home while crews with the local office of Kiska Construction Corp. rebuilt three Harlem River piers in an $118-million contract.
The new center pier is about 100 ft x 60 ft with a reinforced concrete cap and is supported by six 10-ft-dia drilled shafts, says Paul Connolly, project manager for Hardesty & Hanover, New York City. The firm provided design and construction support services.
Early on Oct. 29, six tugboats pushed the truss, supported by falsework on two barges, to within 2 in. of the center pier and bearings. Crews worked with the rising tide and hydraulic jacks to position and then set the truss. After positioning, and working with the now falling tide, 480,000 gallons of water was pumped into ballast tanks to sink the barges and bring the truss onto its bearings, says Mehmet Ayverdi, Kiska project manager.
Crews will now pour the concrete deck and complete machinery work to allow the swing span to operate. Along with equivalent potential liquidated damages, Kiska has a $37,500-per-day incentive for opening two lanes of traffic before Nov. 24, and a $25,000-per-day incentive for opening all five lanes before May of next year, with a cap of about $3 million, say project officials.
The 360-ft-long steel bridge replaces a 107-year-old truss that carries some 76,000 daily vehicles from the Bronx to Manhattan. Like its predecessor, the bridge will pivot 90° with at least a 26.5-ft clearance for marine traffic.