DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.1311#0171
OF THE WORLD'S INDUSTRY 141
two girders were supported at two points, 100 feet apart from each, end, from a wrought-
iron tube above, which stretched across the whole span, and this tube resisted the com-
pression. This tube also was raised at a considerable elevation above the bottom
girders, so that the weight, such as trains, &c, passing along the line, might be
properly resolved or distributed over the tube by means of the tye-rods and stays; the
100 feet spans being crossed simply by wrought-iron beams.
Stephenson's High-level Bridge, at Newcastle-upon-Tyne, was also exhibited in model,
by Hawks and Co., who were contractors for the iron-work. The banks of the Tyne,
both at Newcastle and Gateshead, are exceedingly steep, and are connected by a viaduct,
1,375 feet in length, running at a height of 112 feet above high-water mark. There are
six principal openings, each of 126 feet span. The principle of construction is the bow and
string; the arches, which form the bow, are of cast-iron, and the rods, which form the
strings, are of wrought-iron, to resist tension; there are four arches to each span, two on
each side; which bear properly on the piers, through the medium of bed-plates, on which
the arches rest; and the strings of each arch consist of two wrought-iron rods, keyed to
the arches of the abutments. Cast-iron columns, connected to the arches, support a
platform above, on which three sets of rails are laid, and they also support another platform
below for a carriage-road, the footpaths running between the two arches on each side;
this road, in fact, runs along the strings, but has no connexion with them; the arches
take the whole weight of both platforms, above and below, leaving the strings independent,
to resist only the tension. The iron-work required the adjustment of an immense
number of parts; yet no joints, and hardly any fastenings are to be seen; in fact, it
is difficult to make out how it has been put together.
Ouse-burn Viaduct.—Amongst other objects of interest exhibited by B. Green, of
Newcastle-on-Tyne, was a model of the central arch of the Ouse-burn viaduct, on the
Newcastle and North Shields Railway; the arches were of timber, built up of layers or
planks sufficiently thin to allow being bent to the required sweep. The arch having thus
been built up to the required size, was bound together by iron straps, bolts, &c. It was
then scientifically strutted, to resist and distribute the thrust properly.
Shields' Models of Bridges, &c, from New South Wales, were exhibited in the
colonial department. These engineering contrivances are especially suitable for New
South Wales, where, the cost of iron-work being very considerable, the engineer has to
economise to the utmost extent the use of this valuable material, and in cases, where
practicable, to dispense with it altogether. Mr. Shields' model of a "lattice bridge,"
and also that of a "railway trestle frame," were of the latter character; and were,
therefore, suitable for many other parts of the world—New Zealand, for instance, which
abounds with valuable timber, suitable for bridges and similar works. The American
engineers have long paid considerable attention to the best disposition of timbers in the
construction of their bridges and extensive railway viaducts; and these have been
followed, to some extent, both in the railways of England and Ireland. Mr. Shields'
lattice bridge is of round timber, thus getting rid of much expense in the shape of
labour, and also in the entire absence of iron fastenings. The model consisted of three
lines of vertical round timbers, properly notched, and having two perforations to receive
the horizontal timbers. Between each pair of vertical timbers were two diagonal pieces,
resting at the bottom on cross-timbers, and framed into the vertical timbers at the top.
There were three double sets of horizontal timbers, the upper ones supporting the joists
placed transversely, and to which the floor-boards were secured. These joists projected
on either side of the bridge, in order to gain additional width of roadway; a wooden
railing, properly strutted, completing the whole. The "railway trestle frame" was
intended specially as a substitute for embankments in countries where labour is dear
vol. u. 2 o
two girders were supported at two points, 100 feet apart from each, end, from a wrought-
iron tube above, which stretched across the whole span, and this tube resisted the com-
pression. This tube also was raised at a considerable elevation above the bottom
girders, so that the weight, such as trains, &c, passing along the line, might be
properly resolved or distributed over the tube by means of the tye-rods and stays; the
100 feet spans being crossed simply by wrought-iron beams.
Stephenson's High-level Bridge, at Newcastle-upon-Tyne, was also exhibited in model,
by Hawks and Co., who were contractors for the iron-work. The banks of the Tyne,
both at Newcastle and Gateshead, are exceedingly steep, and are connected by a viaduct,
1,375 feet in length, running at a height of 112 feet above high-water mark. There are
six principal openings, each of 126 feet span. The principle of construction is the bow and
string; the arches, which form the bow, are of cast-iron, and the rods, which form the
strings, are of wrought-iron, to resist tension; there are four arches to each span, two on
each side; which bear properly on the piers, through the medium of bed-plates, on which
the arches rest; and the strings of each arch consist of two wrought-iron rods, keyed to
the arches of the abutments. Cast-iron columns, connected to the arches, support a
platform above, on which three sets of rails are laid, and they also support another platform
below for a carriage-road, the footpaths running between the two arches on each side;
this road, in fact, runs along the strings, but has no connexion with them; the arches
take the whole weight of both platforms, above and below, leaving the strings independent,
to resist only the tension. The iron-work required the adjustment of an immense
number of parts; yet no joints, and hardly any fastenings are to be seen; in fact, it
is difficult to make out how it has been put together.
Ouse-burn Viaduct.—Amongst other objects of interest exhibited by B. Green, of
Newcastle-on-Tyne, was a model of the central arch of the Ouse-burn viaduct, on the
Newcastle and North Shields Railway; the arches were of timber, built up of layers or
planks sufficiently thin to allow being bent to the required sweep. The arch having thus
been built up to the required size, was bound together by iron straps, bolts, &c. It was
then scientifically strutted, to resist and distribute the thrust properly.
Shields' Models of Bridges, &c, from New South Wales, were exhibited in the
colonial department. These engineering contrivances are especially suitable for New
South Wales, where, the cost of iron-work being very considerable, the engineer has to
economise to the utmost extent the use of this valuable material, and in cases, where
practicable, to dispense with it altogether. Mr. Shields' model of a "lattice bridge,"
and also that of a "railway trestle frame," were of the latter character; and were,
therefore, suitable for many other parts of the world—New Zealand, for instance, which
abounds with valuable timber, suitable for bridges and similar works. The American
engineers have long paid considerable attention to the best disposition of timbers in the
construction of their bridges and extensive railway viaducts; and these have been
followed, to some extent, both in the railways of England and Ireland. Mr. Shields'
lattice bridge is of round timber, thus getting rid of much expense in the shape of
labour, and also in the entire absence of iron fastenings. The model consisted of three
lines of vertical round timbers, properly notched, and having two perforations to receive
the horizontal timbers. Between each pair of vertical timbers were two diagonal pieces,
resting at the bottom on cross-timbers, and framed into the vertical timbers at the top.
There were three double sets of horizontal timbers, the upper ones supporting the joists
placed transversely, and to which the floor-boards were secured. These joists projected
on either side of the bridge, in order to gain additional width of roadway; a wooden
railing, properly strutted, completing the whole. The "railway trestle frame" was
intended specially as a substitute for embankments in countries where labour is dear
vol. u. 2 o