The M60A1 Armored Vehicle-Launched Bridge (AVLB) is a United States Army and United States Marine Corp engineering vehicle originally put in production in 1987 from a modified, turret-less M60A1 chassis {1}. Quite simply, an AVLB is a mobile bridge placed on a tank. It is used to cross nearly any natural or man-made obstacles including rivers, tank ditches, ravines, and can be extended over numerous kinds of light-weight fences, walls, and barbed wire by simply crushing them when it is extended and lowered. This vehicle can also be modified to carry two Mine Clearing Line Charges (MICLIC). With this modification, the AVLB is then called an Armored Vehicle-Launched MICLIC (AVLM).

When not in use, the bridge is literally folded in half, and mounted on top of the tank body. To extend the nearly 15 ton aluminum alloy bridge for use, two sets of hydraulics are used: one to raise the bridge from the chassis and then lower it to the ground, and another to unfold the structure. Once extended, the bridge can span a gap of 60 ft (~18 meters). An experienced two member crew (a driver and a TC) can properly extend and secure the bridge within 2-5 minutes, and retrieve it in 5-10 minutes. While it is designed to hold a Military Load Class 60 vehicle (~60 tons), it can support up to a Class 70 vehicle (such as the Army's main battle tank, the M1A1 Abrams) if certain "caution crossing" guidelines are followed including:

  • The overweight vehicles must not stop on the bridge. The movement prevents the full weight of the vehicle from occupying a single position which could cause the bridge the buckle.
  • The vehicles must not turn or adjust its alignment on the bridge. The ground guide must have the vehicle lined up properly before it drives on to the bridge. This is important for any tracked vehicle because the method by which these vehicles turn can tear up the metal bridge panels.
  • All center pins must be manually put in place after the bridge is extended to provide additional support and stability. This additional support is needed here since the bridge's center of mass is where the bridge folds when it is stored, and supports the most weight.
  • The maximum gap spanned must be reduced to 15 meters.

Crossing any obstacle over an AVLB can be an unnerving experience since most tanks are as wide (sometimes even slightly wider) than the bridge itself. For this reason, vehicles are nearly always directed by a soldier on the ground, called a ground guide, to ensure they remain centered and safe during the crossing. Once all vehicles in the convoy have passed, the M60A1 chassis drives over its own bridge, turns around, and picks it up from the other side. The vehicle has absolutely no offensive weaponry except for the crews' personal firearms, so they must rely on radio communication.


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Above: image of the AVLB with the bridge partially open

Specifications:

Primary function: Armored vehicle used for launching and retrieving a 60-foot scissors-type bridge. Manufacturer: General Dynamics Land Systems Division Contractor: Anniston Army Depot (ANAD) M60A1 Tank Chassis: Power Plant: 12 cylinder diesel engine - AVOS-1790-20 Power Train: CD-850-6A - 2 speed forward, 1 reverse Weight, Combat Loaded: 56.6 tons (51.33 metric tons) Ground Clearance: 18 inches (.4572 meters) Length: 31 feet (9.44 meters) Width: 12 feet (3.66 meters) Maximum Speed (governed): 30 mph (48.3 kph) Cross Country Speed: 8-12 mph (12.88-19.32 kph) Trench Crossing: 8.5 feet (2.59 meters) Range: 290 miles (464 kilometers) Fuel Capacity: 375 gallons (14.19 hectoliters) Crew: 2 enlisted Introduction Date: February 1987 Unit Replacement Cost: $749,000 Bridge: Length, Extended: 63 feet (19.19 meters) Length, Folded: 32 feet (9.75 meters) Bridge Span: 60 feet (18.28 meters) Width, Overall: 13.1 feet (3.99 meters) Width, Roadway: 12.5 feet (3.81 meters) Width, Treadway: 5.75 feet (1.75 meters) Height, Unfolded: 3.1 feet (.94 meters) Weight: 14.65 tons (13.28 metric tons)

Other Combat Engineering Vehicles


Notes

  • {1} In some cases, the chassis is actually an M48 instead of an M60.

Sources

  • I was an AVLB driver
  • http://globalsecurity.org/military/systems/ground/m60a1-avlb.htm
  • http://www.fas.org/man/dod-101/sys/land/docs/avlb.htm
  • http://www.adtdl.army.mil/cgi-bin/atdl.dll/fm/3-34.2/appc.htm#marker-1041629

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