IRB BRIDGE
MLC RATINGS
WATER FLOW VELOCITY FEET/SEC (METERS/SEC)
CROSSING
0.0
1-2
3-4
5-6
7-8
9-10
TYPE
(0.3-0.6)
(0.9-1.2)
(1.5-1.8)
(2.1-2.4)
(2.7-3.0)
NORMAL
Track
105
105
105
100
100
55
Wheel
105
105
105
100
100
55
CAUTION
Track
115
115
115
110
110
65
Wheel
115
115
115
110
110
65
RISK
Track
140
140
140
140
125
80
Wheel
140
140
140
140
125
80
TWO-LANE
Track
20
20
20
20
20
0
Wheel
20
20
20
20
20
0
TM 5-5420-278-10
0036 00
0036 00-2
BRIDGE OPERATION (Contd)
Table 2. Improved Ribbon Bridge Length Restrictions.
c. Required Conditions for Bridges
b. Bridge Length Restrictions
NOTE
For moving bodies of water in minimum water depth of
2.6 ft (0.8 m), the bridge length is restricted as follows:
Table 3. Improved Ribbon Bridge Operation MLC Ratings.
INTERIOR BAYS
BRIDGE LENGTH
WATER SPEEDS
Up to 6
175.8 ft (53.60 m)
max. 5 feet/sec (1.5 meters/sec)
Up to 8
219.8 ft (67.01 m)
max. 4.3 feet/sec (1.3 meters/sec)
Up to 10
263.8 ft (80.42 m)
max. 3.6 feet/sec (1.1 meters/sec)
