By: Tara Vantimmeren
Imagine “recycling” an 8,076-ft-long bridge that carries 50,000 cars and two dozen trains a day over the Mississippi River. That’s essentially what is happening in New Orleans with the retrofitting of the Huey P. Long Bridge.
Louisianians have been making do with two 9-ft lanes in each direction on the bridge since 1935. “It was designed for Model A Fords,” said Danny Johnson, owner of ATR, a Chicago Pneumatic tool dealer in Harahan, La. Traffic on U.S. 90 zips along until it reaches the Huey Long bottleneck.
Carrying the load
Massman had to drill 20,000 holes—16,000 15?8-in. holes 15 in. deep to install the epoxy-anchored rebar and another 4,000 1¼-in. holes, also 15 in. deep, to anchor threaded rod for form ties.
“We used Chicago Pneumatic drills to install epoxy-anchored reinforcing steel into the existing piers to tie the new concrete into the existing concrete, allowing the structure to act as one member,” said Scharmer.
The Massman crew is using CP 0032 (Circle 900) and CP 0022 (Circle 901) sinker drills and CP 0014 rotary drills (Circle 902) for the pier work and used CP 4181 rivet busters (Circle 903) and CP 4123 chipping hammers (Circle 904) before that for demolition. The sinker drills have a multiposition throttle to make starting holes easier and an air-inlet swivel to improve maneuverability.
Firm foundation
Instead of undertaking a more costly project, the New Orleans Public Belt Railroad (NOPB), the bridge’s owner and operator, is widening it—recycling it, in a sense. The project will expand the bridge to three 11-ft lanes each way and a total width of 86 ft, compared with the old 36-ft deck. The original piers must be built up with additional concrete and anchor points for trusses to support the 50-ft wider, cantilevered deck.
Paul Scharmer is the project manager with Massman Construction Co. in charge of widening the main bridge substructure. In April 2006, Massman began enlarging the five main piers by drilling in dowels, adding epoxy and attaching rebar to the existing piers, then pouring concrete to expand the cross-stream width of each pier by 2.5 ft and the upstream-downstream dimensions by up to 10 ft.
“The substructure project is unique in the way the main piers are being encased, widened and strengthened,” said Scharmer, “All the additions to the main bridge are setting on the original foundations.”
—Information provided by Chicago Pneumatic
