Two contractor teams are pitching competing portable bridges to the U.S. Army
during ongoing tests at Aberdeen Proving Ground, Md. They are vying for an upcoming
contract award to build several dozen bridges-which must be capable of spanning
gaps of 150 feet and sturdy enough to sustain a 70-ton tank moving at high speed.
The Army's inventory of bridges includes so-called assault front-line systems,
which are launched from a tank, and tactical bridges-deployed by specialized
engineer units-that facilitate the passage of tracked and wheeled vehicles.
Typically, the tactical bridge units are farther to the rear in the brigade
or corps area.
There are two assault bridges currently in use: the armored vehicle launched
bridge (AVLB) and the Wolverine heavy assault bridge. Tactical bridges include
1970s systems such as the ribbon bridge, which floats in water, and the medium
girder bridge, designed to become a fixed structure. The Army now is seeking
to replace both tactical bridges.
Age and Labor
New bridges are needed, officials said, not only because of aging inventory
of existing systems, but also in response to the Army's desire to cut back on
the manual labor associated with bridge installation and maintenance.
"The ribbon bridge and the medium girder bridge are getting old and are
particularly labor intensive to erect," said James Sutton, project manager
for heavy tactical vehicles at the Army's Tank-automotive and Armaments Command,
Warren, Mich.
In an interview, he explained the Army recently reorganized and created a multi-role
bridge company-which replaces two engineer companies-and will be capable of
deploying both floating and fixed bridges. "The Army is in the process
of activating those companies," Sutton said. The units, under the plan,
will be equipped with new bridges. The fixed bridge is called the heavy dry
support bridge (HDSB) and the floating system is called improved ribbon bridge
(IRB). Either bridge can be transported on one common vehicle.
Four of the companies will be active Army units-two in the United States, one
in Korea and one in Germany. The remaining 12 to 16 will be part of the National
Guard and Army Reserve.
"The new bridges will support the heaviest loads we have in the Army,"
Sutton said. That means they must hold up a trailer truck carrying a 70-ton
Abrams tank. Existing bridges, which can bear 60-ton loads, can, if needed,
allow crossing of a 70-ton tank. "But they have to do it cautiously and
go very slowly," Sutton added. "These new bridges will accept the
loads at normal speeds."
The Army plans to award production contracts on both the HDSB and the IRB in
fiscal year 2000. The service allocated $14 million this year for tactical bridges.
The goal is to procure about 100 HDSBs beginning in 2002. That would include
four bridges for each of the 16 to 20 multi-bridge companies as well as additional
systems for training. The Army also will buy about 200 meters of the IRB bridge
for each company.
Two industry teams received development contracts three years ago for the HDSB
bridge. Both now are in contention for the production award and have turned
over their prototypes for testing by Army officials at Aberdeen. The demonstrations
are scheduled to continue through November.
One of the competitors is a St. Louis-based firm called Systems & Electronics
Inc. (SEI), teamed with the Swedish firm Kockums Naval Systems, in pursuit of
the HDSB award. The other contractor in the competition is Williams Fairey Engineering,
a British company.
SEI's version of HDSB is a modification of an existing system in production
for the Swedish Army, said Robert Whaley, a company executive. He explained
the bridge is designed to deploy in 90 minutes or less with a crew of up to
14. "The program has completed prototype manufacturing, static load testing,
and contractor system testing," Whaley said. The HDSB's launching platform
is a crane.
While Williams Fairey's HDSB bridge is made of aluminum, SEI's is built with
Swedish steel. The Army did not specify one or the other, said Sutton. "We
will consider any material," he asserted.
Work Sharing
SEI also is participating in the IRB program. For this effort, it partnered
with a German firm, MAN Technologie. According to Whaley, SEI produced the launch
vehicles for an earlier Army IRB program, which lost its funding several years
ago. This time, a work-sharing agreement has been negotiated, he said, and SEI
would build much of the bridge in its West Plains, Mo., facility.
The IRB, he added, can be employed either as a full span, floating bridge or
configured into rafts to ferry vehicles and equipment across water. It also
must be compatible with the Army's current ribbon bridge and bridge erection
boats.
Whaley said the current acquisition plan calls for several five-year procurements.
"The first multi-year contract for HDSB is planned for 27 systems with
a 50 percent option and a current funding line of $131.5 million."
The IRB is procured by sections composed of interior bays and ramp bays. The
plan for the first multi-year production of IRB also has a 50 percent option,
he said, and the quantities are 226 interior bays and 92 ramp bays. The program's
five-year budget is $41 million. The IRB can be used in the form of rafts or
bridges of varying lengths, Whaley noted. One IRB kit is made up of 15 interior
bays and 6 ramp sections. Small rafts can be used as tug boats to hold it against
the water current.
Continuous crossing of vehicles and equipment is enabled by coupling the individual
ferries together so that they form a floating bridge. The launching time for
the 138-foot bridge is approximately 30 minutes, with a crew of four.
The program currently is not going to go through a competitive prototype phase
because that "essentially was done about eight years ago," Whaley
added. "The IRB production contract will be awarded without any preliminary
hardware testing."
The Army, meanwhile, is moving forward with efforts to upgrade its assault
bridges, which support tanks, artillery and infantry on the battlefield. The
Wolverine is expected to replace existing armored vehicle launch bridges (AVLB).
Wolverine's prime contractor is General Dynamics Land Systems, Sterling Heights,
Mich.
The system is based on a M1A2 Abrams chassis with a heavy assault bridge built
by MAN Technologie. The aluminum bridge spans about 85 feet and supports 70-ton
loads. It can be deployed in about five minutes and retrieved in less than 10
minutes, according to the manufacturer. It is operated by a two-person crew-a
driver and a commander who have dual controls to operate the bridge.
The Wolverine is scheduled to begin full-rate production for 465 vehicles in
2001 at a rate of 24 to 36 units annually. In the long term, the Army wants
to replace most of its AVLB bridges, which are launched from older M60 or M48
tank chassis.
During bridge deployment operations, the Wolverine drives to the edge of a
gap and deploys a spade, located in the front of the vehicle, into the ground
to give the vehicle the necessary stability to launch the bridge. The front
portion of the bridge slides forward out from underneath the rear portion of
the bridge; the rear portion of the bridge drops in line with the forward section
and the two are then locked together. The entire bridge slides farther forward,
and a hydraulic arm lowers it into place.
The planned allocation is 36 for each Army heavy division. The Army Tank-automotive
and Armaments Command awarded General Dynamics Land Systems a $106 million low-rate
initial production multi-year contract to build 29 Wolverines. Deliveries of
this batch already are under way and will continue through December 2001.