The Longest Bridge Span in the World.

Oamaru Mail, Volume XXXI, Issue 8959, 7 December 1905, Page 4

The Longest Bridge Span in the World.

The honor of having the longest span, which was wrested, from the Brooklyn' bridge by the Forth bridge on its comp'etion'in 1890. is shortly to return to this continent, as work is now in progress on the great cantilever bridge across the St.. Lawrence, near Quebec, the main span fit which "'ill exceed that or the Fordi b'. i;illv 90 feet. Americans are said ~o admire "bigness" above all other qualities, and our chagrin that our Canadian consiiv are to tarry off the prize rather than our-, solves li'.av be tempered by the thought ("hat we are Imildincc the bridge for them, all the great girders and otlier steel-work bring f u by the I'iifunix Bridge Compnnv, of Phcemxville, Pa. Ihe stru-.*-ture. too. is of characteristic American pa'.T«rn! being pin-connected throughout. 'Hie central span, of ISCO feet, extends almost from bank to bank of the_ river, with a central suspended girder 6/5 feet long and 150 feet deep at' the centre, while t!v anchor snnns are eacli 500 teet wide and the approach spins 210 feet wide. The followingdata are from an article in En-1

gineenng: — -The site selected is some sis miles above. Quebec, at a point where the river narrows to less than 2000 feet at low water. From this point up-stream to Montreal, a distance of 165 miles, there is no bridg-.-now existing., while below Quebec the river widens out so much as to make the bridging of the river below the city very improbable: so that this bridge will, when finished, be the only one between Montreal I and the sea, a distance of very nearly j 10C0 miles. It will afford direct council : tion between the Great Northern Railway of Canada, the Quebec and St. .Tolm Rail way. and the Canadian Pacific Railway on the one side, and the fSrand Trunk Railroad, the Intercolonial line, and the Qu°beo Central Railway on the south side of the river. The bridge will also form a link in the projected (irand Trunk Pacific Transcontinental line. In addition lo thus facilitating the exchange of railway traffic the new bridge is also intended to aei <l'or.d a*~d tramway tr*ifi:' !,(> ! for on roadways earned outside the main trusses by cami-k-vcr extensions of the cross-girders. Two tracks for railway traffic will be provkWl between the trusses, which are 65 feet 1 apart. . . . The. clear headway pro-, vided is 150 feet, which, owing to the; height of the river-banks, is attained with-, out an excessive length of approach via-' duct, and with a gradient not- exceeding 1 per cent. "The height of the nost over each riverpier is 315 feet, corresponding to about 350 feet above the level of ordinary high water. This post is 10 feet wide by 4 feet in depth, ard rests at its lower end on a pin 24 inches in diameter. Pin connections have Iwon us.h! throughout, the usual size of the pins on the main and anchor spans being 12 inches, though, as stated, the main pins over the river-piers are double this."

No castings, we are told, are used for any portion of the bridge, even the main shoes and pedestals being built up of rolled ]i!atc-.s and angels. To quote further "The railway approach to the bridge site was completed last July, and the traveller erected immediately afterward, the first portion, the permanent metal, being put in place on July 22. On September 1 the main anchorage bent on the south side of the bridge, and all the lower chords and bracing of the south anchor arm, the main pedestal shoes over the main pier were in position, and the erection of the web members of the main truss was started early in the. present month. Work will, however. have shortly to be suspended for the. winter, as it is generally impossible at Quebec to carry on operations of this character between November 15 and April 15."