Photo By Mark Rankin | An aerial view of the auxililary lock (right) and the main lock (left) as work...... read more read more
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FLORENCE, Ala. – The Wilson Navigational Lock is dry for five weeks while maintenance crews dewater, inspect and repair underwater components.
U.S. Army Corps of Engineers Nashville District employees dewatered the 51-year-old lock this week and are closely inspecting the lower lock miter gates, culvert valves and all other areas of the lower lock chamber that are normally underwater.
Cofferdams were set at both ends of the lock to prevent water from entering into the chamber and various pumps are used to help remove any small leakage.
According to Gerald Choat, lockmaster at the Wilson Lock, crews from the Corps, Tennessee Valley Authority and contractors began work May 5 and have a three phase plan that will allow the scheduled maintenance to be completed by June 10.
Mike Morrison, TVA Dam Safety, said TVA is also is drilling and working below the lower miter gates to install a vertical sock seal.
“This is an extreme collaboration between the Corps and TVA,” said Morrison. “We are going to great lengths to help each other make the repairs, and get the lock running again.”
Choate said the primary phase of work includes drilling and installing horizontal post tension bars, rebuilding the miter gates strut arms, working on the land miter gate-low speed gearbox, replacing the gudgeon pin and bushing, and repairing any cracks on broken welds on the river miter gates. He said the valve sector gears and the bushings, grease seals, sector gear pins are being replaced along with the bushings in the lower land miter gate sector gear.
In phase two TVA is performing minor grouting inside the lock chamber bedrock and the exhaust discharge area. The team will drill 54 vertical strand post tension cables and secure them into the bedrock. Then in phase three, TVA will place 140 yards of concrete to stabilize the lock wall.
Choat said secondary work includes adding a tow haulage unit, extending handrails and replacing a large pin at the top of the gate once the lock can be filled with water.
The U.S. Army Corps of Engineers operates, maintains and performs routine maintenance upgrades on the locks on a three-year cycle.
“The project is going well; however, we have a 63 hour backlog of barges waiting and that can be frustrating for a shipment trying to reach a destination by a deadline,” said Choat.
He said it usually takes a 15-barge tow nearly three hours to lock through Wilson Dam but using the auxiliary lock that number has moved to nearly 16 hours.
“The main lock holds nine barges at a time and the old two stage auxiliary lock handles only one barge passing through at a time which adds a delay,” Choate said.
The main lock at Wilson is 110-feet wide and 600-feet long. With a maximum lift of 100 feet, it is the highest single lift lock east of the Rockies. An auxiliary lock has two 60-feet wide by 300-foot long chambers that operate in tandem.
“Wilson is the highest single lift lock can east of the rocky mountains with a normal lift of between 93 and 100 feet and the workload can add strain to many of its moving parts,” said Choat.
The currently drained Wilson Lock is located in the northwest corner of Alabama and is one of 10 locks on the Tennessee River that are operated as a system of locks, which together makes it possible for recreational boaters to have freedom of movement and for commerce traffic to deliver goods and services across the region.
Corps employees operate and maintain TVA’s 10 locks on the Tennessee River. The Corps maintains 1,175 navigable river miles on the Cumberland and Tennessee Rivers.
Wilson Lock is located at 704 South Wilson Dam Road and at Tennessee River mile 259.4. The original project was completed by the Nashville District in 1927. In 1959, the Tennessee Valley Authority completed the main single-lift lock to replace the old and inadequate double-lift lockage system. It began operating Nov. 10, 1959.
Choat said the smaller auxiliary lock remains open to all navigation traffic and tours are planning to resume the Friday, Saturday, Sunday and federal holiday tours June 19, 2015. Questions about lock tours can be addressed at 256-764-5223.
(The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on the district’s website at www.lrn.usace.army.mil, on Facebook at http://www.facebook.com/nashvillecorps and on Twitter at http://www.twitter.com/nashvillecorps.)
| Date Taken: | 05.20.2015 |
| Date Posted: | 06.03.2015 04:18 |
| Story ID: | 165298 |
| Location: | FLORENCE, SOUTH CAROLINA, US |
| Web Views: | 144 |
| Downloads: | 0 |
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