Lacon Bridge is an iron bridge of
old that has done more than its
function as a creek crossing in
Marshall County. The 75-year-old
trusswork is an example of a
continuous truss bridge. It is a
type of bridge that extends to both
ends without any hinges or joints
across three or more support beams
running the length of its body.
A continuous truss bridge uses
less material. A series of simple
trusses distributes the bridges’
load across all the spans. This
simple type of design enables the
bridge to support the entire load of
traffic travelling its length. Some
types of continuous truss bridges
are similar to cantilever bridges.
They may be constructed using
cantilever techniques; which have
two forms with each varying greatly
from the other.
Cantilever bridges do not need to
attach firmly mid-span, as the
cantilever arms systems support
itself. Some cantilever bridges
appear continuous, as if one single
ironwork. This is due mainly to the
decorative trusswork at the joints.
These decorative trusswork serve as
camouflage to the gaps. Yet even
with such gaps and non-rigid
trusswork, these bridges will remain
standing even if the connections
between the cantilevers are broken.
They can even remain aloft and
sustain the weight they bear if the
suspended span is detached.