Civil Engineering Reference
In-Depth Information
FIGURE 1.1
Gaunless River Bridge of the Stockton and Darlington Railway built in 1823 at
West Auckland, England. (Chris Lloyd,
The Northern Echo
, Darlington.)
The bridge consisted of 12.5 ft long lenticular spans
∗
in a trestle arrangement. This
earlytrestlewasaprecursortothemanytrestlesthatwouldbeconstructedbyrailroads
to enable almost level crossings of wide and/or deep valleys.
Table 1.2
summarizes
some notable cast iron railway trestles constructed between 1823 and 1860.
George Stephenson's son, Robert, and Isambard Kingdom Brunel were British
railway engineers who understood cast iron material behavior and the detrimental
effects on arches created by moving railroad loads. They successfully built cast iron
arch bridges that were designed to act in compression. However, the relatively level
grades required for train operations (due to the limited tractive effort available to
early locomotives) and use of heavier locomotives also provided motivation for the
extensive use of cast iron girder and truss spans for railway bridges.
Commencing about 1830, Robert Stephenson built both cast iron arch and girder
railway bridges in England. Cast iron plate girders were also built in the United
States by the B&O Railroad in 1846, the Pennsylvania Railroad in 1853, and the
Boston and Albany Railroad in 1860. The B&O Railroad constructed the first cast
iron girder trestles in the United States in 1853. One of the first cast iron railway
viaducts in Europe was constructed in 1857 for the Newport to Hereford Railway line
at Crumlin, England. Nevertheless, while many cast iron arches and girders were built
in England and the United States, American railroads favored the use of composite
trusses of wood and iron.
American railroad trusses constructed after 1840 often had cast iron, wrought iron,
and timber members. In particular, Howe trusses with wood or cast iron compression
members and wrought iron tension members were used widely in early American
railroad bridge construction.
∗
Also referred to as Pauli spans.
