History and Development of Steel Railway Bridges - Design of Modern Steel Railway Bridges - page 14

FIGURE 1.4 The Britannia Bridge built in 1849 across the Menai Straits, Wales. (Postcard
from the private collection of Jochem Hollestelle.)
pressure, and thermal effects. Fairbairn's empirical work on fatigue strength and
plate stability during the design of the Conway and Britannia bridges is particularly
significant. ∗
A small 55 ft long simple span tubular wrought iron plate girder bridge was built
in the United States by the B&O Railroad in 1847. However, the only large tubular
railway bridge constructed in North America was the Victoria Bridge built in 1859
for the Grand Trunk Railway over the St. Lawrence River at Montreal † ( Figure 1.5) .
The Victoria Bridge was the longest bridge in the world upon its completion. ‡ The
bridge was replaced with steel trusses in 1898 due to rivet failures associated with
increasing locomotive weights and ventilation problems detrimental to passengers
traveling across the 9144 ft river crossing with almost 6600 ft of tubular girders.
Table 1.4 indicates some notable continuous span railway bridges constructed after
1850.
These tubular bridges provided the stiffness desired by their designers but proved
to be costly. Suspension bridges were more economical but many British engineers
were hesitant to use flexible suspension bridges for long-span railroad crossings. §
Sir Benjamin Baker's 1867 articles on long-span bridges also promoted the use of
∗ Also, later in 1864, Fairbairn studied iron plate and box girder bridge models under a cyclical loading
representative of railway traffic. These investigations assisted in the widespread adoption of wrought
iron, in lieu of cast iron, for railway bridge construction in the latter quarter of the nineteenth century.
† The Victoria Bridge over the St. Lawrence at Montreal was also designed by Stephenson.
‡ The longest span in the Victoria Bridge was 330 ft.
§ The first railway suspension bridge built over the Tees River in England in 1830 (with a 300 ft span) had
performed poorly by deflecting in a very flexible manner that even hindered the operation of trains. It
was replaced by cast iron and steel girders, respectively, in 1842 and 1906.The Basse-Chaine suspension
bridge in France collapsed in 1850, as did the suspension bridge at Wheeling, West Virginia, in 1854,
illustrating the susceptibility of flexible suspension bridges to failure under wind load conditions.