Civil Engineering Reference
In-Depth Information
FIGURE 1.6
The railway suspension bridge built in 1854 across the Niagara Gorge between
NewYork, USA, and Ontario, Canada. (Niagara Falls Public Library.)
was also replaced only four years after completion due to poor performance under
live loads.
∗
The railway suspension bridge constructed in 1860 at Vienna, Austria,
was also prematurely replaced with an iron arch bridge in 1884 after concerns over
the flexibility of the suspended span. The early demise of these and other suspension
bridges generated new concerns among some American engineers over the lack of
rigidity of cable-supported bridges under steam locomotive and moving train loads.
The first all-wrought-iron bridge in the United States, a lattice truss, was completed
in 1859 by the NewYork Central Railroad.
†
In the same year, the LehighValley Rail-
road built the first pin-connected truss. In 1861, the Pennsylvania Railroad pioneered
the use of forged eyebars in a pin-connected truss over the Schuylkill River. After
this manyAmerican railway bridges were constructed with pinned connections, while
European practice still favored the use of riveted construction. Riveted construction
was considered superior but pin-connected construction enabled the economical and
∗
The suspension bridge was replaced by a stone masonry bridge.
†
The NewYork Central Railroad also initiated the use of iron stringers (as opposed to wooden) in railway
trusses in the 1860s.
