Tom Duffy chews on his fourth coffee stirrer of the hour as he monitors the readings from 10 enormous strand jacks on screen. The straw's predecessors lay in a pile at his feet, and a room full of colleagues keeps watch on the pile's growth to judge how the risky process is going.
"You can tell how well the lift is coming along by counting the number of straws he's chewed up," says one of Duffy's teammates, Bruce Bennett.
By "lift," Bennett means the maneuvering of a 3,500-ton concrete foundation shell being lowered to the bed of the Ohio River. It will become part of the foundation and outer surface of the $2.1-billion Olmsted Locks and Dam project, near Paducah, Ky.
Everyone looks to Duffy because he plays a critical role in making sure the shell gets to where it is going in one piece. He is the technical representative from Dorman Long, Northamptonshire, U.K., supplier of custom-made, 1,000-tonne strand jacks that are placing the dam's dozen tainter-gate foundation shells, six pier shells that hold the gates and another dozen navigable-pass foundation shells.
"When strand-jacking or heavy lifting gets exciting, you don't want to be there," says Duffy.
The 2,596-ft-long dam, which crosses the river between Illinois and Kentucky, has had its share of excitement as the team pushes to replace two failing locks built in the 1920s. The work is being done with the world's biggest strand jacks and gantry cranes, claims Bennett, executive project director for the general contractor, a joint venture of URS Corp., San Francisco, and Alberici Constructors, St. Louis.
The 125-ft x 116-ft concrete shells, which will form a stilling basin and foundation for the tainter gates, are placed with a 1-in. tolerance on piles 60 ft below the river's surface, lowered from the world's biggest catamaran-barge, says Bennett. Flowing up to six feet per second, the river's current complicates the operation.
"When we started this project, many seasoned veterans stated that this method of construction, to the tolerances required, could not be done," says Mark Rawlinson, project engineer for URS.
The Olmsted Locks and Dam replacement project broke ground in 1996 and originally was scheduled to finish in 2008 at a cost of $775 million, circa-1988 dollars. The U.S. Army Corps of Engineers, which is splitting the total cost of the project with the Inland Waterways Trust Fund—currently is evaluating the $2.1-billion budget.
The lengthy construction time is attributed to funding delays, floods and events, such as Hurricane Katrina, that caused the cost of construction materials to inflate, says William Gilmour, the Corps' resident engineer. The new 2016 completion date for Olmsted is funding- and weather-dependent, he adds. "Mother Nature controls the schedule," says Gilmour.
In the 1950s, the Corps began replacing the Ohio River's 52 locks and dams with 20 larger locks to accommodate increasing traffic and larger barges. Olmsted is the last of these replacement locks.
Each year, 90 million tons of goods worth over $17 billion pass through the two locks Olmsted will replace. The locks are well past their design life and in fragile condition—in fact, it takes two teams, each working full time, to keep them cobbled together.
"It will be a blessing when Olmsted is finished," says Randy Robertson, a Corps lockmaster at one of the locks. Robertson uses a steam-powered barge and crane to keep the old dam operational.
Several contractors worked on past phases of the Olmsted project, but after no contractors would bid the dam-phase contract in 2002, the Corps switched to a "cost-reimbursable contract," in which change orders allow the contractor to increase or decrease the fee pool. "We pay what it costs," says Gilmour.