January 17, 2013
ANNISTON ARMY DEPOT, Ala. -- It often takes years to construct the bridges most people travel over daily - from the initial planning to the time the first vehicle crosses its span. On the battlefield, however, Soldiers cannot wait that long to traverse obstacles.
That is where the military's vehicle-launched bridges, including the Army's Armored Vehicle Launched Bridge, come in.
An AVLB is comprised of a M60 tank chassis, which is used as a base, and bridge panels that extend more than 60 feet across rivers or other obstacles. The vehicle is overhauled and repaired by Anniston Army Depot.
The restoration process for each bridge begins at disassembly. Because of the way AVLB bridge panels are extended, disassembly cannot be performed in most buildings on the installation.
"Up until April 2012, when the employees received a shed to work in, most of the disassembly work was done outside in all sorts of weather conditions," said Patti Sparks, process optimization manager for the depot's Manufacturing, Cleaning and Finishing Value Stream.
Sparks said disassembly is an interesting process to watch because it is very hands-on.
"The employees take hammer drills to remove the old hardware and they spray a solution on each component to check for cracks," said Sparks. "It isn't a high-tech job, but it is extremely important for the engineers who deploy these bridges in the field."
As each part is removed from the bridge, it is examined for defects and to ensure it is in good working condition. Then, each part is sent to support shops throughout the depot's Nichols Industrial Complex to be cleaned and, if needed, repaired.
"After sandblasting, components go through our ultrasound testing bay to check the rivets for cracking," said Charles Hanner, a heavy mobile equipment mechanic.
Each rivet is coated with an ultrasound-conductive gel then tested for structural integrity. Rivets failing the test are replaced and the bridge panel is then sent to the repair bay where any remaining defects are mended.
From there, components go to the shop's plumbing bay where hydraulic systems used to extend and retract the bridge panels are tested and repaired.
Once all panel components are returned to proper working condition, they are painted, reassembled and reattached to the M60 chassis, ready for deployment wherever needed.