Blasting and Burning away a great Wreck.

Progress, Volume VI, Issue 4, 1 February 1911, Page 547

Blasting and Burning away a great Wreck.

Last of the Quebec Bridge. A wreck that has been only half cleared away after ten months of unremitting toil must be confessed to he something of a wreck. Ever since New Year’s Day of last year a large force of men have been working on the ruins of the great Quebec steel cantilever bridge, which went down in a tangled mass of bent and twisted steel on August 29, 1907. The 10,000 tons of steel were buried in deep and wild confusion, yet it is a remarkable fact that there were no loose ends. Like devoted members of a loving family in disaster, every piece of steel clung to its neighbour with a firm grip when the crash came, and it now takes a blast of dynamite or the oxy-acetylene flame to sunder them. Says Mr, H. P. Borden, a Canadian engineer, in describing this work in Engineering News (New York, November 10) : “The magnitude and difficulties of the job cannot be appreciated unless one has personally visited the wreck and seen this enormous tangle of huge steel members piled high and in utter confusion, yet with no loose ends. Every ton of metal moved, whether eyebar, chord, or post, must first be cut loose from its neighbour or subdivided into many pieces before it can be handled. The various members are twisted and bent almost beyond recognition, yet they are still firmly bound one to

the other. Only one broken eyebar has been found in the whole wreck. Before these eyebars can be removed they must be broken or cut in two or three pieces. All the members radiating from a panel-point still have their connections intact at that point. A chord ... weighing 50 or 75 tons must be broken or cut at either side of this panel-point and then cut into six or eight similar sections, to bring it within the capacity of the derricks. Most of the pieces removed in this way will still have to be broken up into even smaller sections before they have a marketable size as scrap. “When tenders were called for the removal of this wreck, contractors, as a rule, were entirety at sea as regards the best way of cutting the material or as to the probable cost of such an operation. Both dynamite and the oxy-acetylene flame had been used on work of a similar nature, but for work of such enormous proportions there was absolutely no precedent. The work for the first month or two was, therefor, almost entirety experimental. Various grades and strengths of dynamite were tried, as well as gelignite, but it has been found that a 60-per cent, dynamite gave the most satisfactory results, everything considered. The oxy-acetylene flame has also been extensively used, and has shown some remarkable results.... The oxy-acetylene torch cuts the steel very rapidly, and leaves a thin, sharply defined slot,, not wider , than that made by a saw. The torch itself weighs only a few pounds, and, as a consequence, can be used in any point, no matter how. inaccessible, so long as it can be reached by the operator.

This torch and method has been fully described in Progress, and is now in the Dominion.