DEADMAN OFFSET ANGLE (O
I )
TYPE OF
ASSEMBLY
CURRENT VELOCITY
TM 5-5420-278-10
0035 00
0035 00-24
BRIDGE ANCHORAGE (Contd)
TOWER-TO-DEADMAN OFFSET
Just as it was necessary to calculate the distance at which to place the tower
upstream from the bridge centerline, it is now necessary to determine the distance
at which to place the deadman upstream from the tower. This distance is called the
tower-to-deadman offset, or O2. To calculate, use the formula:
O2 = (C x O2 ft)
where O2 ft is a factor determined from table 10, and C is the tower-
to-deadman distance (in feet).
A slightly more accurate means of positioning the deadman is to determine the
exact angle at which the deadman should be placed in relation to the tower (refer to
table 11) and place the deadman at the calculated distance (C) along that angle. The
slight difference between the two methods is negligible to the extent that the
difference will not cause the system to fail.
DEADMAN OFFSET FACTOR (O2)
TYPE OF
ASSEMBLY
CURRENT VELOCITY
Table 10. Determination of the Deadman Offset Factor (O2).
3 feet/sec
5 feet/sec
7 feet/sec
9 feet/sec
11 feet/sec
(0.9 meters/sec) (1.5 meters/sec) (2.1 meters/sec) (2.7 meters/sec) (3.4 meters/sec)
Normal
.09
.11
.14
.17
.19
Reinforced
.11
.14
.17
.19
.23
3 feet/sec
5 feet/sec
7 feet/sec
9 feet/sec
11 feet/sec
(0.9 meters/sec) (1.5 meters/sec) (2.1 meters/sec) (2.7 meters/sec) (3.4 meters/sec)
Normal
5°
6.5°
8°
9.5°
11°
Reinforced
6.5°
8°
9.5°
11°
13°
Table 11. Alternate Means of Determining Deadman Offset.