ARMY TM 5-5420-212-23
MARINE CORPS TM 08676A-23/2
Section II. EQUIPMENT DESCRIPTION AND DATA
EQUIPMENT CHARACTERISTICS, CAPABILITIES AND FEATURES
a. The Medium Girder Bridge (MGB) is a two girder deck bridge. The wide upper surfaces of the girders, and the
deck units laid between them form a roadway 13 ft 2 in (4.0 m) wide. The girders can be constructed in two forms: a
shallow single story construction as shown in Figure 1-1, or a deeper double story construction as shown in Figure 1-2.
The double story can be reinforced by adding components of the Link Reinforcement Set (LRS) as shown in Figure 1-3;
this permits longer Military Load Class (MLC) 70 bridges to be constructed.
FIGURE 1-1 Single story MGB.
b. The two girders are constructed from a number of panels pinned together, and are separated by two bankseat
beams, one pinned to each end of the girders. The roadway is formed by hanging deck units between the girders and
connecting ramps to each end. Curbs and guide markers are placed at the outside edges of the girders to mark the edge
of the bridge. The single story bridge is used for light loads, for example it will carry MLC 70 Tracked (T) up to 32 ft (9.8
m) decreasing to MLC16 at 74 ft (22.6 m).
FIGURE 1-2 Double story MGB
The US junction panel is slightly larger than standard, therefore the bridge lengths quoted below
for double story and link reinforced bridges are "nominal lengths."
c. A double story bridge (DSB) uses all of the parts of a single story bridge (SSB) which are pinned on top of
triangular bottom panels, with junction panels and end taper panels at each end. For example these parts make the
bridge strong enough to carry MLC 70 (T) over a length of 102 ft (31.1 m) decreasing to MLC 16 at 162 ft (49.4 m).