ARMY TM 5-5420-212-10-1
MARINE CORPS TM 08676A-10/1-1
TABLE 5-7. Central and eccentric deflections - Single Story Bridges
SPAN
DEFLECTION
feet (meters)
Inches (mm)
DEAD LOAD
DEAD LOAD
DEAD LOAD
+
+
LIVE LOAD
LIVE LOAD
(CENTRAL)
(ECCENTRIC)
26 (7.9)
1 (25)
2 (51)
1.75 (44)
32 (9.8)
1 (25)
3.25 (83)
3.25 (83)
38 (11.6)
1.5 (38)
4.75 (121)
5.5 (140)
44 (13.4)
2 (51)
5 25 (133)
6 (152)
50 (15.2)
2.75 (70)
7.5 (190)
8.75 (222)
56 (17.1)
3.5 (89)
8.25 (210)
9.5 (241)
62 (18.9)
4.25 (108)
10.5 (267)
12.25 (310)
68 (20.7)
5.75 (146)
12.75 (324)
15 (381)
74 (22.6)
7.25 (184)
16 (406)
19.5 (495)
Tracked vehicle of maximum load class allowed.
5-14
ASSEMBLY
a.
Assembly using a launching nose
With launching noses, an over bridge is built as if it was being put across a gap. The roller beam closest to the
existing bridge must be positioned so that it does not touch the existing span. Also, the roller beam height should be kept
high enough to prevent launching nose or far bank end of bridge from coming into contact with the existing span.
(1)
Set up rear roller beam/forward roller beam clear of the span to be bridged.
(2)
Assemble and launch bridge as though bridging a gap.
b.
Assembly without a launching nose
Without launching noses, an over bridge is built in place over the existing span. Ensure that the existing span is
capable of supporting the weight of the over bridge during construction. The following procedure is for the assembly of a
12 bay bridge; shorter bridges use the same method.
(1)
Position and stack packing (3 in x 8 in x 36 in) on site where far end of bridge will set. Packing must be
stacked a minimum of 6 in (15.2 cm) and can be stacked as high as required by design.
5-42
