ARMY TM 5-5420-212-10-1
MARINE CORPS TM 08676A-10/1-1
distance the bridge falls in front of the roller beam (0.23 m).
X = (L + 0.23 m) - (AR Gap + 0.4 m)
NOTE
To adhere to minimum/maximum bearing rules without having to dig out or pack up under the end
of bridge, you must ensure that the RB peg Is placed between 0.63 m and 2.33 m from the A’ peg.
(b)
Jack launch. The distance X to the RB peg is calculated by using the position of the A’ peg on the
near bank, bridge length (L), AR Gap, minimum bearing requirement (0.4 m), and the approximate distance required
behind the roller beam (0.23 m) to attach the jacks.
X = (L - 0.23 m) - (AR Gap + 0.4 m)
NOTE
To adhere to minimum/maximum bearing rules without having to dig out or pack up under the end
of bridge, you must ensure that the RB peg Is placed between 0.17 m and 1.87 m from the A’ peg.
(7)
O peg-Marks the clear distance behind the roller beam required to construct the bridge. It is positioned
by measuring the R distance, Table 3-7 or 38, column (f), behind the RB peg
g.
Calculate Bearing
The minimum and maximum bearings for all SS bridges are shown in the Table 3-9 and on Figures 3-7 and 3-8
TABLE 3-9. Bearings
Bearings
Near Bank
Far Bank
Minimum
0.4 m
0.4 m
Maximum
2.1 m
2.1 m
(1)
Push launch. To calculate the actual location of the F’ peg:
X - 0.23 m = Near bank bearing
(2)
Jack launch. To calculate the actual location of the F’ peg:
X + 0.23 m = Near bank bearing
h.
Check bearing
(1)
If the near bank bearing is within the minimum and maximum bearing limits, there is no need to shift the
position of the F and F’ pegs. The position will be as initially determined, F peg 0.4 m from A peg and the F’ peg will be
placed the distance determined as near bank bearing measured from the A’ peg.
(2)
If the near bank bearing is more than the maximum bearing allowable (2.1 m), it will be necessary to
shift bearing.
3-20
