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

Trusses with Inclined Verticals
The “Post” truss was an oft-used configuration for long-span railroad bridges from the 1860s to 1870s.
It was named after engineer Simeon Post, who popularized the form with inclined verticals, but did not
patent it.
PATENT CHRONOLOGY
Long, S. H. 1847: True verticals with additional tilted verticals in end thirds of span.
Long, S. H. 1858: Same as 1847 configuration with addition of a reversed arch.
Post, S. ca.1863: A double-intersecting Pratt configuration with verticals that are inclined a half-panel
length. Although popular for a period of about 35 years, this configuration was not patented.
Foreman 1868: Timber chords and inclined verticals. Double-intersecting diagonal rods.
Smith, F. 1869: Drawing shows a “Post truss” configuration, however the patent's focus is the connections
not the configuration.
Smith, F. 1872: Double-intersecting Pratt configuration. The centerlines of the verticals converge to a point
considerably above the center of the truss.
Jones, J. H. 1885: Timber. Multi-layered web of inclined verticals, cross-braced panels, and multi-panel
struts. Top and bottom chord panel points are offset by a half panel.
Pegram 1885: Polygonal top-chord Pratt variation. All segments of the top chord are of the same length,
resulting in a progressive tilting of the verticals.
Stephen H. Long, Patent No. 5,366 (1847)
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