Notes: 1. The following conditions will reduce the ratings from those given above. Thebridge commander must monitor bow and roadway freeboard as well as trimto ensure that safe crossing conditions are maintained in the followingconditions:TM 5-5420-278-100036 000036 00-3BRIDGE OPERATION (Contd)(a) Rough, choppy, or turbulent water in current speeds above 4 feet/sec (1.2meters/sec) will reduce ratings from those given in the preceding chart.(b) Shallow fast water of less than 6 ft 7 in (2.0 m) water depth combined withcurrent speeds above 4 feet/sec (1.2 meters/sec) will reduce the ratings fromthose given the preceding chart.(c) Accumulations of snow, mud, or ice will reduce the ratings from those givenabove.2. Bridge commander must observe leading edge of bridge and decrease crossingrating (Normal to Caution to Risk) or halt operations, as necessary, ifcontinuous water is coming over bow dam.3. These ratings apply for a bridge held in place with Mk I/II bridge erection boatsBEBs). The number of bays that boats are to be spaced apart is based on thecurrent speed and is as follows:Note: If the bridge is to remain in place for long periods or time, an anchoragesystem shall also be used.4. Vehicle spacing:Normal and two-lane (each lane): 100 ft (30 m) front to backCaution:170 ft (52 m) front to backRisk:Only one vehicle on bridge at a timeCURRENT SPEEDNUMBER OF BAYS PER MK I/II BEB0.0–5.0 feet/sec (0.0–1.5 meters/sec)45.0–8.0 feet/sec (1.5–2.4 meters/sec)38.0–9.0 feet/sec (2.4–2.7 meters/sec)29.0–10.0 feet/sec (2.7–3.0 meters/sec)Anchorage system necessaryTable 4. Improved Ribbon Bridge Operation BEB Spacing.
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
