UFC 3-270-07
12 August 2002
at the other end of the 16.46-meter (54-foot) edge of the same mat using the remaining
joining panel. Hand-tighten these bushings; final tightening will be accomplished later.
2-3.2.12 The second mat is then towed over to the first mat with joining panel
attached. One of the holes near the end of the second mat is aligned with its
counterpart on the joining panel and a top joining bushing is installed.
2-3.2.13 This end connection acts as a pivot point when the second mat is moved into
position so all the remaining holes on the joining panel are in alignment. Install the
remaining top bushing and tighten the entire second mat bushing with an impact
wrench.
2-3.2.14 Revert to the first top joining bushings and tighten them with the impact
wrench. All joining bushings should be tightened and the joined mats are now ready to
be towed over the repaired crater.
2-3.2.15 Before any towing operation can commence, the area between the mat
assembly area and the repaired crater must be completely swept. Any debris that is
picked up under the mat as it is being towed could damage the matting and affect the
smoothness of the repair.
2-3.2.16 When the width of the MAOS permits, the mat should be towed parallel to and
next to the crater. Align the joining panel with the center of the crater. Use a front-end
loader or similar vehicle to tow the mat over the crater with the hinges perpendicular to
the tow direction. Position the mat so the hinges are parallel to the direction of the
MAOS traffic. The mat should not be more than 5 degrees off parallel.
2-3.2.17 With the mat in position over the crater, it must be anchored in place.
Techniques for anchoring the FFM will depend on the type of pavement surface. The
FFMs are predrilled for anchoring bolts. All three anchoring techniques use a 101.6-
millimeter (4-inch) bushing through which the bolt passes to hold down the mat.
2-3.2.17.1 Concrete Pavements. The concrete anchor is normally a rock bolt that is
127 to 152.4 millimeters long and 15.9 to 19.1 millimeters in diameter (5 to 6 inches
long and 0.625 to 0.75 inch in diameter). At each predrilled hole in the leading and
trailing edges of the mat, drill a hole into the pavement corresponding to the diameter of
the bolt being used. Position an anchor bushing in the predrilled hole as a guide for
centering the drill bit. The depth of the hole must be at least 12 millimeters (0.5 inch)
longer than the length of the bolt. Clean out the drill cutting with compressed air and
insert the bolt through the bushing. Stand on the mat and bushings and tighten the bolt
with an impact wrench.
2-3.2.17.2 Asphalt-overlaid Concrete Pavements. Asphalt-overlaid concrete usually
entails using a rock bolt that is 241.3 millimeters long and 15.9 to 19.1 millimeters in
diameter (9.5 inches long and 0.625 to 0.75 inch in diameter). The installation
procedure is the same as those for all-concrete pavements. The key factor in this
installation is to ensure the bolt has been set deep enough into the concrete layer for a
2-17
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