cast iron component connecting the tops of the vertical timber and diagonal metal members to the timber top chord in a de Burgh Truss
Bailey bridge
portable, prefabricated metal bridge system developed in the 1940s for military use
chord
the horizontal member of a truss, either the lower, the bottom chord, or the upper, the top chord
compression
pushing force, opposite to tension – see forces
corbel
timber member to increase the load bearing length of a timber girder over a pier, after decay has begun (as it generally does) at the ends of the girder
cross girder
transverse bending member spanning the upstream and downstream trusses to support the deck; primary cross girders are located at panel points and of larger dimensions, with secondary cross girders located between panel points
deck
the component directly supporting vehicles
diagonal
member of a truss placed at an angle, other than a principal
fishplate
the metal plate covering joints in a laminated timber bottom chord
flitch
one of two elements bolted together with spacers to form a single member
forces
girder
a longitudinal member spanning piers and supporting the deck
headstock
horizontal member at top of pier or abutment to support corbels
laminated
three or more rows of parallel components joined together (by glue, bolts or stressed strand) to form a single member longer than each component
members
the elements, or parts, of a bridge
panel
the area between the main joints of a truss
panel points
the main joints of a truss
pier
support for the adjacent ends of two spans, often comprising piles beneath a headstock and various horizontal and diagonal bracings
pile
vertical or inclined member driven deep into the ground
potted pile
vertical or inclined member placed in a hole dug out of rock where the soil is too shallow to drive a pile to sufficient depth
principal
the primary end (diagonal) timber member in a truss
shear
sideways force – see forces
shoe
metal component in a truss connecting the ends of the principals or diagonals to top and bottom chords
SLT
stress laminated timber
splice
a connection consisting of two pieces of timber joined together at the ends, generally with metal splice plates
stress
the force per unit area of a member to which the force is being applied
stringer
longitudinal member spaning cross girders supporting a deck
sway brace
a member located outside the truss between the top chord and a cross girder, to resist sway of the truss and sometimes to provide lateral support to the top chord
tension
pulling force, opposite to compression – see forces
tension rod
metal bar connecting the top and bottom chords of a truss
truss
structure with members connected at joints to permit rotation, so each member carries either tension or compression only
wale
horizontal timber members in piers designed to provide lateral stiffness
wind bracing
system of metal rods under the deck connecting the upstream and downstream bottom chords to provide lateral resistance to wind loads
