g. Transport of the AVLB system (Class 60/Class 70 Bridges) for Air, Rail, Sea and Highway
Mode of Transportation.
Introduction. The Class 60 and Class 70 bridges look almost the same, but there are some
differences that change their physical configuration. The Class 70 differences include the
overall weight, overall width, the redesign of the center hinges, the wider and thicker flange of
the main aluminum angles, in the bottom chords, and the creation of quarter-sections (fixing
the center and end panels together as one unit) instead of having separate panels (center and
end or ramp) as with the Class 60 bridge. These changes have resulted in a slightly heavier and
wider Class 70 bridge, i.e., the weight is approximately 30,000 lbs (15 tons) or about 700 lbs
heavier than the Class 60 bridge, and the width at the bottom flange of the main aluminum
angles; is 3.5 inches wider (the Class 60 bridge being 13.2 feet wide.
Since the Class 60 bridge has never been provided with proper lifting point; for the lift of the
whole scissored (folded) bridge, the Class 70 bridge will have lift points so that the folded
bridge can be safely lifted for easy loading aboard transport means at the loading dock using a
standard equal-length four-legged sling. Lifting points for the lift of the folded bridge will also
be provided for the Class 60 bridges when they are turned in to the depot for repair or overhaul.
Both bridges will use the same type lifting points designed to replace the eight side tiedowns
located at the ends along the outboard girders of the bridge.
In the past, the folded Class 60 bridge has been lifted using the tiedowns and many were
broken requiring replacement at the depot. Lift points have been designed for use on both the
Class 60 and Class 70 bridges so the folded bridge can be properly and safely lifted aboard
appropriate means of transport.
In addition, since the Class 70 bridge sections have been formed from the individual center and
end panels, a two-legged sling of unequal legs will be used for moving the Class 70 bridge's
quarter-sections. These sections weigh approximately 6000 lbs each and will have the
capability of being lifted individually from the outboard side. When using this method, the two
lifting points located at the farthest ends of the section are used, NOT the middle two lift points
on the side. The Class 60 bridge center and end panels will only be lifted through their deck by
use of the 2-legged sling currently in the BII. This sling will not be used to lift these panels
from their sides.
The following addresses the four primary modes of transport in relation to deploying the Class
60 or Class 70 bridge components:
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