CANADA AND THE GREAT TUBULAR BRIDGES

摘要

The mid 1800's saw major changes in bridge design. The introduction of "new" bridgebuilding materials, cast iron and wrought iron resulted in both success and failure. Attempts to achieve along span rigid deck bridge to carry rail traffic resulted in one of the major innovations in design, the"tubular" bridge. Only five of these "Train Size" Tubular bridges were ever built. Of these, the two bestknown are the Britannia and Conwy Bridges in Wales, built to serve the Chester and Holyhead Railway.However, the last and longest of these historic structures was built in Canada.The Victoria Bridge across the St. Lawrence River at Montréal is one of the great engineeringachievements of the nineteenth century. At the time of its construction it was the largest bridge project inthe world. It was also the last major project of the last of the "legendary" engineering figures of the"Victorian" era of engineering, Robert Stephenson. There were many doubters as to the ability of theengineers of the day to construct a project of this size given the physical conditions of the site. The story ofthe construction of the Victoria Bridge is one that combines business imperatives, engineering designskills and construction ingenuity with the enormous challenges presented by one of the world's great, fastflowing rivers and the with the severity of Canadian winters and the massive "ice shoves" that occur as aresult.Following its completion, controversy raged as to who deserved most credit for the conception and designof the bridge. Constructed between 1854 and 1860, the bridge was formally opened by the Prince ofWales in the summer of 1860. As originally conceived, the bridge had a relatively short life. The singletracklayout, together with other weaknesses in design meant that reconstruction or replacement becameinevitable within a few decades. Starting in 1897, the original Tubular Superstructure was replaced by pinconnectedthrough trusses designed to carry two rail tracks with a roadway and sidewalk cantilevered outon each side. The reconstructed bridge was formally reopened on October 16, 1901 and was renamed asthe "Victoria Jubilee Bridge". It continues to serve rail and road traffic to the present day.