Plate girder bridge

From Wikipedia, the free encyclopedia

Plate Girder Bridge
Below roadbed type
Ancestor	Beam bridge
Related	Trestle, truss bridge, moon bridge
Descendant	Tubular bridge
Carries	Pedestrians, automobiles, trucks, light rail, heavy rail
Span range	Short
Material	Iron, steel
Movable	No
Design effort	low
Falsework required	No

A plate girder bridge is a bridge often supporting railroad roadbeds over short spans. This bridge may be a shallow U-shape in cross section with the roadbed at the bottom of the U or the bridge may be entirely under the roadbed. Each side consists of deep steel plate shear members with a strong top and bottom chord, forming what is called an I beam. The top chord is stressed under compression, the bottom under tension. Additional light members are attached to the shear members between the top and bottom chord to add stiffness to the plate to prevent buckling.

Plate girder bridge: above roadbed type. This roadbed type cannot be completely boxed, so additional stiffeners may be provided.

For the under roadbed type the two members of the bridge will be connected at the bottom with additional light truss elements and at the top with decking to form a box structure.

[edit] See also

• Beam bridge - the ancestor of the plate girder bridge
• Box girder bridge - an evolution of the plate girder bridge
• Trestle, some modern steel trestles are composed of a number of girder bridge segments.