Author: Snelgrove, E Copeland
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Snelgrove, E Copeland
THE word new in the title of this article is used in a double sense; it means not, only new bridges, but new kinds of bridges. Speculation on this subject is interesting, and, I believe, useful also, since some of the developments to which it leads appear quite possible (if not inevitable) for the near future. Now the chief reason for the (erection of a new type of bridge is the creation of a new type of obstacle to traffic. To build a bridge for the purpose of crossing an obstacle is nothing new and yet this motive has for some time been quitle overshadowed by another and less elementary. Several factors (the greater speed of traffic being one) contributed towards the beginning the industrial age to make the question of a uniform level the principal one in way making. From that moment bridges were built to take a road over something that wars not in itself an obstacle at all, but merely an actual or a potential inconvenience. It is thus that we get the viaduct and aqueduct, both of which are cast across a valley merely in order to maintain a uniformity of level; whether the one carries a road or a railway, or the second a conduit or a canal, does not materially affect the question. Their purpose differs from that of the earlier bridge in that the maintaining of a fixed level is not a necessity of permanent communication; it is an aid to easy and rapid communication. Nor is the lower way to be compared with the upper, which is as straight, direct and concentrated as the lower (if this can indeed be called a way) is extended and diffused, and consequently it cannot claim the same inflexional courtesy that is always shown to a navigable river confined within definite bounds. The viaduct, and aqueduct, in other words, are typical products of the immediate past, whose chief task was the perfecting of our methods of communication to the farthest possible limit. Christian Barman
Thc first stretch of street paving in concrete was laid down in Bellefontaine, Ohio, thirtythree years ago by Mr. Snyder, a contractor, who was called in to make a crossing that would stand up to heavy loads of lumber and the hoofs of horses then used to haul the waggons and drays. This crossing constructed for the lumber company is still in use. Major R.A.B. Smith
A remarkable pronouncement in favour of concrete houses was made by Sir Charles T. Ruthen before the Institution of Structural Engineers on Thursday, January 7. The meeting was specially summoned to discuss Sir Charles Ruthen's Presidential Address on alternative methods of building.