A fine railway bridge (1888) spans the Ohio.
The North Bridge, a fine iron structure, spans the valley, giving connexion between the opposite higher parts of the town.
It had spans of 172 and 1 93 ft., and may be taken as a representative FIG.
An hour is likely to reach 40 to 50% for girder spans of less than 50 ft.
The advantage claimed for roofs formed with one or two large spans is that they permit the platforms and tracks to be readily rearranged at any time as required, whereas this is difficult with the other type, especially since the British Board of Trade requires the pillars to be not less than 6 ft.
Away from the edges of the platforms. On the other hand, wide spans are more expensive both in first cost and in maintenance, and there is the possibility of a failure such as caused the collapse in December 1905 of the roof of Charing Cross (S.E.R.) station, London, which then consisted of a single span.
It is the junction between the Oudh & Rohilkhand and East Indian railways, the Ganges being crossed by a steel girder bridge of seven spans, each 350 ft.
A steel bridge spans the river.
The intervening ground upon which the railway lines and buildings stood was sold for building sites, the sum obtained being more than sufficient to cover the cost of the majestic central terminus (the third largest in the world), which, in addition to spacious and handsome halls for passenger accommodation, has three glass-covered spans of 180 ft.
"the bridge") owes its name to the magnificent Roman bridge which spans the Tagus on the north-west.
Long bridges of several spans are often termed " viaducts," and bridges carrying canals are termed " aqueducts," though this term is sometimes used for waterways which have no bridge structure.
It is only since metal has been used that the great spans of Soo to 1800 ft.
For moderate spans brick, masonry or concrete can be used without excessive cost, but for longer spans steel is more economical, and for very long spans its use is imperative.
In some recent masonry arched bridges of spans up to ' so f t.
In suspension bridges the principal members are in tension, and the introduction of iron link chains about the end of the 18th century, and later of wire ropes of still greater tenacity, permitted the construction of road bridges of this type with spans at that time impossible with any other system of construction.
In the simplest case the main girders are supported at the ends only, and if there are several spans they are discontinuous or independent.
5) which now spans roadways, the streams which formerly flowed under it having been diverted, is one of the earliest known stone bridges in England.
The Amoskeag bridge over the Merrimac at Manchester, N.H., U.S.A., built in 1792, had 6 spans of 92 ft.
The Bellows Falls bridge over the Connecticut (built 1785-1792) had 2 spans of 184 ft.
As railway loads increased and greater spans were demanded, the Howe truss was stiffened by timber arches on each side of each girder.
In length, built in 1851-1852 in Io spans, lead timber trestle piers 190 ft.
Iron suspension bridges began to be used at the end of the 18th century for road bridges with spans unattainable at that time in any other system.
The Brooklyn bridge, begun in 1872, has a centre span of 15952 and side spans of 930 ft.
The clear width of the two shore spans is 270 ft.
For spans over 75 ft., expansion due to change of temperature is provided for by carrying one end of each chain girder on rollers placed between the bearing-plate on the girder and the bed-plate on the pier or abutment.
Itl ' At first girders had soli or plate webs, but for spans o 9 over ioo ft.
On the first English railways cast iron girder bridges for spans of to 66 ft.
16) has two spans of 460 and two of 230 ft.
Though each girder has been made continuous over the four spans it has not quite the proportions over the piers which a continuous girder should have, FIG.
The spans were in fact designed as independent girders, the advantage of continuity being at that time imperfectly known.
As no scaffolding could be used for the centre spans, the girders were built on shore, floated out and raised by hydraulic presses.
Now plate web girders are only used for spans of less than ioo ft.
The centre span was 264 ft., and the side spans 138 ft.
It has two spans of 455 ft.
And seventeen smaller spans, the roadway being ioo ft.
The side spans are erected first on staging and anchored to the piers.
And the side spans 490 ft.
The total weight of iron and steel in three spans was about 5000 tons.
- It has been stated that if in a girder bridge of three or more spans, the girders were made continuous there would be an important economy of material, but that the danger of settlement of the supports, which would seriously alter the points of contrary flexure or points where FIG.
It is available for spans greater than those practicable with independent girders; in fact, on this system the spans are virtually reduced to smaller spans so far as the stresses are concerned.
The two main spans are each 1710 ft.
Waddell has shown that, in some cases, it is convenient to erect simple independent spans, by building them out as cantilevers and converting them into independent - (5) The Poughkeepsie bridge over the Hudson, built 1886-1887.
The girders over the second and fourth spans are extended as cantilevers over the adjoining spans.
The girder spans are 525 ft., the cantilever spans 547 ft., and the shore spans 201 ft.
The bridge consists of three spans of about 315 ft.
The bridge has three spans, each formed of arches of cast steel.
And the side spans 502 ft.
'The centre span is a two-hinged parabolic braced rib arch, and there are side spans of 190 and 210 ft.
The main span weighed 1629 tons, the side spans 154 and 166 tons (Buck, Proc. Inst.
It is formed by a crescent-shaped arch, continued on one side by four, on the other side by two lattice girder spans, on iron piers.
The lattice girders of the side spans were first rolled into place, so as to project some distance beyond the piers, and then the arch ribs were built out, being partly supported by wire-rope cables from (3) Draw or Bascule Bridges.
At Konigsberg there is a road bridge of two fixed spans of 39 ft., and a central span of 60 ft.
Two spans are arranged for opening easily.
The Runcorn bridge crosses the Manchester Ship Canal and the Mersey in one span of woo ft., and four approach spans of 552 ft.
Span, riveted braced girders for spans of 50 ft.
The Moerdyk bridge in Holland, with 14 spans of 328 ft., was erected in a similar way.
(3) If a bridge consists of girders continuous over two or more spans, it may be put together on the embankment at one end and rolled over the piers.
The following are some of the results Large as these loads are on short spans, they are not more than must often be provided for.
(3) This percentage decreases rapidly for longer spans, becoming about 25% for 75-ft.
Spans, and 5% for loo-ft.
It is generally reckoned to be uniformly distributed, but in large spans the distribution of weight in the main girders should be calculated and taken into account.
There is a mound; and a few inscriptions are built into a bridge, which here spans the river, carrying the road from Niksar to Tokat.
A railway bridge also spans the Main at this point.
The girders of the side spans were rolled out so as to overhang the great span by 105 ft., and formed a platform from which parts of the arch could be suspended.