The
Canadian Forces are replacing many of their tracked vehicles with wheeled
vehicles in a move towards a “primarily
wheeled Army”. However, there is a loss
of cross-country mobility associated with this change, which creates a need for
lightweight, inexpensive, short span bridges. Owing to its favourable
properties, FRP was the target material for the construction of these bridges.
A structural concept, adapted to the material properties of commercially
available glass FRP (GFRP) pultruded products, is presented. A 10 m span
full-scale box-beam was built from commercially available GFRP pultruded
sections that were bonded throughout to form a tapered boxbeam, with a width of
1.22 m and a height at mid-span of 0.9 m, plus 0.04 m (1.575 in.) for a ribbed
GFRP panel for the wearing surface. The box-beam represents a single
track of a
double-track bridge, whose tracks are to be lightly laced together. The design
considered the concepts for modular assembly, methods of transporting,
launching and recovering of the structure. The design of a hinge at mid-span to
accommodate these features was a major focus. Finite element
analysis of the
design was used to predict deflection behaviour.