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Armored Vehicle-Launched Bridge (AVLB)
Mobile armored forces are confronted with obstacles, manmade and natural features, that threaten forward progress, including craters, anti-tank ditches, blown bridges, railroad cuts, canals, rivers and ravines. The Armored Vehicle Launched Bridge (AVLB) moves with the armored force to provide an immediate solution to overcome the obstacles.
Armored Vehicle-Launched Bridge (AVLB) History
Beginning in the 1950s, the standard US military Armored Vehicle-Launched Bridge (AVLB) was based on the M48A2. This AVLB used an M48 tank with its turret removed for the chassis, fitted with a launching system for the scissors bridge carried on top. This AVLB was designed by the US Army Engineer Research & Development Laboratories at Ft. Belvoir, VA. After the 1959 end of production of the M48, the chassis of the similar M60 MBT was used, with the first units produced in 1963.
Armored Vehicle-Launched Bridge (AVLB) Description
The Armored Vehicle Launched Bridge (AVLB) is an aluminum alloy folding bridge carried by a tank chassis, first fielded in the early 1960s as the Army's standard heavy assault bridge. Both the M60A1 tank and M48A5 tank chassis (minus turret) have been used as the carrier. The AVLB scissor bridge is unfolded across the gap using hydraulic power provided by the launcher vehicle to actuate a hydraulic cylinder inside the bridge structure. The power and traction of the vehicle also made it an excellent tank retriever, when not being used in its primary bridging role. The AVLB can launch its bridge without exposing the crew of two to enemy fire. After assault force vehicles have passed over the bridge, the AVLB can cross over, pick up the bridge on the far bank and continue along in support of assault forces.
There are two bridge configurations that can be carried on the same chassis. The Military Load Classification (MLC) 60 bridge has sufficient capacity to support the M48 and M60 families of armored vehicles. The MLC 70 bridge supports the heavier M1 Abrams family of armored vehicles.
The formal nomenclature is BRIDGE, ARMORED-VEHICLE LAUNCHED: SCISSORING TYPE. The Class 60 AVLB is identified by NSN 5420-00-522-9599. For the Class 70 AVLB, the NSN is 5420-01-390-3933.
The Operator's and Maintenance manual for all models of the AVLB is TM 5-5420-203-14. The manuals TM 5-5420-202-xx (where the xx represents the maintenance level) are for the M60A1 Chassis modified for the MLC 60 AVLB (NSN 5420-00-889-2020)
AVLB Weight, Loading and Usable Span Characteristics
The MLC 60 Armored Vehicle Launched Bridge is rated for normal crossings of 60 tons (MLC 60) over a maximum gap of 60 feet and a vehicle speed of 25 mph. MLC 61-64 loads at 8 mph are classified as caution crossings, and MLC 65-75 at 3 mph are classified as risk crossings for the same gap distance. The fielding of the M1A1 Abrams Main Battle Tank with the T-158 track resulted in a load classification of MLC 68, a risk category for crossing the AVLB. The upgraded AVLB has a capacity of MLC 70 to accommodate the M1A1 Abrams.
AVLB Usable Span with Prepared Abutments:
AVLB Usable Span with Unprepared Abutments:
The MLC 60 bridge weighs 29,300 lbs while the MLC 70 bridge weighs 30,000 lbs. Weight of vehicle and bridge is 63 tons. When deployed, the overall length is 63 ft.
Relatively small numbers of the AVLB were produced, used by the Army and USMC at least until FY2009. By then, the AVLB system launch vehicles (the M60 or M48 series tanks) were obsolete, increasingly difficult to maintain, and could not keep pace with modern armored maneuver forces that had to wait for the slow AVLB to be brought forward. For these reasons, the M104 Wolverine Heavy Assault Bridge superseded the AVLB.