Rewatering McAlpine

The U.S. Army Corps of Engineers recently let water flow into the cofferdam protecting its new, 110-foot by 1,200-foot-long concrete lock on the Ohio River at Louisville, marking a major milestone in the $430-million McAlpine Lock Replacement Project. This massive project, taking place at McAlpine Locks, has been ongoing since 1996.

"We are putting water back in the cofferdam," said Col. Raymond (Ray) Midkiff, commander of the Corps' Louisville District, at an Oct. 18 press conference. "It is a very significant stage for the project. To use a football analogy, we're inside the 20-yard line — we're getting close to getting this thing done. We anticipate that we will be at a point where we are locking boats through the new chamber in late 2008 or in early 2009. We're very excited about wrapping this project up."

The new lock, constructed on the Kentucky bank side of the Portland Canal, replaces a 110-foot by 600-foot auxiliary lock (constructed in 1921) and an inactive 56-foot by 360-foot, two-stage lock (dating back to the 1860s), which were demolished early in the project. The replacement lock was built parallel to an existing 110-foot by 1,200-foot lock completed in 1961.

The twin 1,200-foot locks will enable the McAlpine facility to meet projected increases in commercial barge traffic during the next 30 years. On average, more than 50 million tons of freight passes through McAlpine, the top commodity being coal.

Preparatory work for the multiphase McAlpine project began in 1996 with the construction of resident office facilities, followed by a wharf extension and gate storage piers in 1998. First phase construction, involving demolition of the old locks to make room for the second 1,200-foot lock and cofferdam construction, was completed in early 2003.

Then, during mid-2003, TGM Constructors — a construction team composed of Traylor Bros. Inc., Evansville, Ind.; Granite Construction Co., Watsonville, Calif.; and Massman Construction Co., Kansas City, Mo. — proceeded with construction of the new lock, and replacement of the existing swing and bascule bridges over the two McAlpine locks with a two-lane, high-lift, fixed-span concrete bridge to provide continuous access across the national Wildlife Conservation Area on Shippingport Island, the Louisville District Repair Station and to the Louisville Gas & Electric hydroelectric facility.

Corps officials credit TGM Constructors for their "excellent work" at McAlpine. "It's been a marvelous partnership," says Midkiff. "This has been a very safe job — over 2.4 million man-hours have been worked without a lost-time accident. That is an incredible safety record for a project of this magnitude. We have partnered with them every step of the way, and it has been a wonderful experience."

The new McAlpine structure required the placement of 445,000 cubic yards of concrete, including 150,000 cubic yards of roller-compacted concrete. During the project's peak construction years, as many as 360 workers were on-site each day. "Now, we are down to about 50 to 60 people," says David Klinstiver, P.E., resident engineer for the Corps' Louisville District. "So, the amount of activity on the project site has changed drastically. There used to be people and cranes everywhere."

In the current construction phase, crews still need to remove the cofferdam and build approach walls downstream and upstream of the new lock. "It will take a couple of months to remove the cofferdam," Klinstiver says.