UPSTREAM ANCHORAGE SYSTEM
The upstream anchorage system is the system which holds the bridge in position
against the force of the river’s normal current. This system is the bridge’s primary
anchorage system and its design is the most critical. Two types of anchorages can be
used for the purpose of upstream anchorage: shore guys and the overhead cable
system.
Although several factors may come into play when determining which of these
type of anchorage to install, the primary considerations are the current velocity and
river conditions. Table 2 provides guidelines for the selection of an upstream
anchorage system.
DOWNSTREAM ANCHORAGE SYSTEM
The downstream anchorage system protects the floating bridge against reverse
currents, tidal conditions, eddies, and high winds or storms which might
temporarily alter or reverse the natural flow of the river. Shore guys and overhead
cable systems can be used as methods of anchoring the bridge downstream. Once
again, the design of downstream anchorage systems can be based upon several
factors. River bottom conditions and the velocity of the expected reverse current will
be of primary importance. Table 3 provides guidelines for the design of downstream
anchorage systems.
TM 5-5420-278-10
0035 00
0035 00-6
BRIDGE ANCHORAGE (Contd)
APPROACH GUYS (Contd)
CURRENT
UPSTREAM ANCHORAGE HOLDING THE BRIDGE
AGAINST THE RIVER’S CURRENT
DOWNSTREAM ANCHORAGE PROTECTING
AGAINST TIDES AND WINDS
APPROACH
GUYS
APPROACH
GUYS
Figure 6. Three Components of a Long-Term Anchorage System.
