Steel truss bridges - Computational Analysis and Design of Bridge Structures - page 304

Figure 10.7 Forth Rail Bridge, Queensferry, Scotland.

Back (or anchor) span Main span Back (or anchor) span

Anchor arm Cantilever arm Suspended span Cantilever arm Anchor arm

Figure 10.8 Cantilever truss bridge and its terminology.

foundations beneath the central towers. Many truss cantilever bridges
use pinned joints and are therefore statically determinate with no mem-
bers carrying bending moment.
Although some continuous truss bridges resemble cantilever bridges
and may be constructed using cantilever techniques, there are impor-
tant differences between the two forms. Cantilever bridges need not con-
nect rigidly midspan, as the cantilever arms are self-supporting. Even
though some cantilever bridges appear continuous due to decorative
trusswork at the joints, these bridges will remain standing if the con-
nections between the cantilevers are broken or if the suspended span
(if any) is removed. Conversely, continuous truss bridges rely on rigid
truss connections throughout the structure for stability. Removal or
deterioration of any truss member in midspan of a continuous truss will