Occasional Electronic Publication No. 1 - Society for Industrial ...

Pratt Configurations
Vertical web members are in compression and diagonals in tension. The basic difference between these
Pratt configurations is the cross-sectional shape of the various members of the truss and/or the way
they are joined together.
Wernwag 1829: Timber arched-truss configuration with single, iron diagonals in the panels in addition to
cross-bracing timber diagonals.
Pratt & Pratt 1844: Timber chords and verticals with crossed iron diagonals. Four-panel-long strut at ends.
A second configuration with a curved top chord and without the multi-panel strut is also shown.
Rider 1845: Cast-iron compression and wrought-iron tension members. Diagonals are bars not rods.
Sprague, J. 1859: Iron pipe used for compression members, rods for tension members.
Jacobs 1860: Timber except for crossed diagonals of continuous strapping.
Canda 1869: Verticals and top-chord segments are tapered.
Adams 1870: Swivel stirrups under posts. Lower chord is spliced with clevis and pin.
Brundage 1870: Crossed diagonals in all panels. Tapered verticals. Convoluted joints.
Truesdell 1870: Counter diagonal in end panel is anchored directly into masonry abutment.
Canda 1871: Crossed diagonals. Tapered verticals.
Morgan 1871: Wire rope used for bottom chord and cross-bracing in panels.
Adler 1872: Hollow compression top chord.
Bonnell 1872: Sloped end post. Joint variation.
Bogardus 1874: Pratt-like capacity, but also functions as Howe and as a double-intersection Warren.
Hammond & Abbott 1874 (Patent No. 150,151): Top chord composed of channels. Star iron verticals.
Hammond & Abbott 1874 (Patent No. 150,152): Top chord composed of channels and tees. I-beam
verticals.
Hammond & Abbott 1874 (Patent No. 150,153): Top chord composed of plate and channels. I-beam
verticals.
Truesdell 1879: Iron. Crimped connections.
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