ARMY TM 5-5420-212-10-1MARINE CORPS TM 08676A-10/1-1(2)A peg-Edge of firm ground on the far bank.(3)AR Gap-The distance measured between the A and A’ pegs. This is the actual gap to be spanned byyour bridge.(4)A’ peg-Edge of firm ground on the near bank.(5)F’ peg-Designates the location of the near bank end of bridge (outer edge of bankseat beam). Thedistance (determined later), from the A’ to F’ peg is the amount of bridge that will bear on the near bank, known as thenear bank bearing. The minimum acceptable near bank bearing is 1.4 m.(6)ex FRB peg-Designates the position of the ex front roller beam (ex FRB). The distance from the A’ pegto the center of the ex FRB can not be less than 0.9 m, and from the ex FRB to the F’ peg can not be less than 0.5 m. Theplacement of the ex FRB is determined by using the length of bridge (L), AR gap, far bank bearing, and bridge overhang(0.5 m) to obtain an X distance (from A’ to CRB). Placement of the ex FRB in this manner will ensure minimum effortduring the jack down operation.(7)CRB peg-Designates the position of the capsill roller beam (CRB). The distance from the A’ peg to thecenter of the CRB must be 2.7 m.(8)FRB peg-Designates the position of the front roller beam (FRB) (measured center to center) must be 9.1m.(9)RRB peg-Designates the location of the rear roller beam (RRB). It is placed 4.6 m from the FRB(measured center to center).(10) O peg-Marks the clear distance behind the capsill roller beam required to construct the bridge. It ispositioned by measuring the R distance, Table 3-31, column (e), behind the CRB peg.g.Calculate bearingThe minimum and maximum bearings for all DS bridges with LRS are shown in the Table 3-32 and on Figure 3-15.3. To calculate the actual locations of the F and F’ pegs, the following procedure is used:Near bank bearing = bridge length (L) - (AR gap + See note below)Where:Bridge length is obtained from column (d) of Table 3-31.The AR gap was measured in the first step of this design procedure.NOTEUse minimum bearing from Table 3-32 for length and bridge being designed.Table 3-32. BearingsMinimumsMaximumNo. of BaysFar BankA to FNear BankA’ to F’Near/FarBanks13, 14,16 thru. 200.6 m1.4 m2.3 m151.1 m1.4 m2.3 m211.14 m1.4 m2.3 m221.6 m1.6 m2.3 m3-43