The Sun.
London, England, 1868-07-31 00:00:00

NEW BLACKPIII.4I?S-BRIDGE;

It is some months since the progress of these
great works was noticed, and t•ince then their ad-
vance has been So rapid as to leave no doubt that
by about the end of the year the new bridge will
be fit to be used as a thoroughfare, and before next
M ty it can be finished to the utmost coruplaion of
its inciA ornamental details. The long continuance
of fine weather and the unusually light and easy
tides have enabled all the labour of pier building
and turning the arches to be pushed forward with
unusual success. To summarize what has been
done, it may be stated that, beginning from the
Surrey shore, all the granite work of the abutments
is complete from foundation almost to summit.
When we say " almost to summit" it simply means
that the character of the ornamental details which
are to crown them has not been finally decided on.
Experiments are being made with light lath and
plaster balustrades, to judge of their effect ; and
the one which has apparently been chosen is singu-
larly striking in its effect. More magnificent look-
ing buttresses of granite have never been erected
for any bridge in England. Viewed from any point
their colossal proportions are in perfect harmony
with their bulk and huge solidity, and it is not over-
praising them t) say that, of their kind and for their
purpose, it would have been difficult to have de-
signed anything more suitable. In their vastness
and strength they more resemble the great Egyp-
tian works in stone than anything else we have yet
seen in London. The blocks which compose these
massive towers are all of dressed granite, and
though weighing from 12 to 15 tons each, they are
fitted together with the accuracy of cabinet-
work, and, in fact, are able to bear com-
parison with the granite work of the Thames
embankment itself, and more than this it would be
impossible to say in praise. The plan of the cornice
which is to surmount these abutments, though, as
we have said, not yet finally decided upcn, is likely
to be adopted, and is quite in keeping with the
great structure it surmounts, being very bold, and,
without being heavy, looking very monumental and
massive. It is hoped that eventually these fine ter-
minals of a fine bridge may be crowned with groups
of statuary in bronze, and in the interest of public
art it is much to be hoped that the Corporation of
London will not grudge the small sum which may
be necessary to give this complete effect to the
finest work they have lately undertaken. From the
south abutment the ironwork of No. 1 and 2
arches is completely fixed. The centreing or sup-
ports used in making these arches is peculiar, for
it was necessary not to stop the water-way, and
yet give perfect support to the mass of iron which
rested on it. To meet these difficult conditions it
has had to be devisedin a most ingenious manner,
and thus the arches, though almost perfectly com-
pleted, do not rest upon the stonework, but are kept
up by the scaffolding and timber wedges at a little
more than half an inch apart from it. These wedges
will not be removed till the centre arch, which
is the keystone, so to speak, of the whole five, is
built and resting on the stonework of its piers.
Then the wedges will be knocked from beneath the
other two arches on either side, and they will be
allowed to settle gradually down into their per-
manent beds on the stone piers. Where the iron
work is to come near the stone it will touch a layer
of lead, so that the slightest possible inequality in
the work will be able to accommodate itself to its
pressure, and the girders all bear their share in the
work of maintenance alike. In this instance, how-
ever, it is almost a needless precaution, for the
arches were built together before they were sent
down the river, and with a little tooling here and
there were made to fit with almost mathematical pre-
cision. Of course as two arches have been finished the
No. 2 pier from the south side has been completed
also. For the centre arch the scaffold is being
prepared to bear the ironwork. At No. 3 pier the
stonework is getting above the water line, at No. 4
arch the centre scaffolding is in progress. The long
difficulties at No. 4 pier have at last been overcome,
and it is above low- water mark ; and at No. 5 arch
the ironwork is partly laid. These steps in the pro-
gress towards completion are easily told, but they
mean, in effA a vast aliaou* of Tali) wlucli hai

PRICE.. •
STAMPED 51

I been got through well and quickly. It must be re -
! menibered that not only had a new bridge to be
built, but an old one to be taken away, and the last
of its old stumps of piers dragged out from the bed
of the river, before a stone of the new structure
could be laid. The first preliminary work of clear-
ing the ground and the water was one of unusual
difficulty, for the arches were so ready to fall that-it
re:,uieed no ordinary skill on the part of Messrs.
Ca.litt and, Case, the engineers, to keep them from
tumbling into the river. On the other hand, the piers
which were so dangerous became when it was wanted
to remove them possessed of a strength and tenacity
which had they shown before they would never have
been meddled with at all. It was most difficult to
remove them, and then all the new piers had to be
laid in the broken ground. The abutments, as we
have said, were easily built, and are as s ilia and as
little likely to move as the counties of Surrey and.
Middlesex on which they rest. With the piers,
however, it was a much more difficult matter.
There are only four of them, but each of tlise four
goes to an average depth of more than 3Uft. below
the bed of the river. In no case were the foun-
dations of any of these piers commenced till the
blue Loudon clay had been reached and till every
atom of moisture had been excluded from the base-
ment. They were built in caissons—that is to
say, in wrought- iron tubeS *U. at: both ends,
which were lowered over the precise slots on
which the piers were to rise. They were pumped
out, then forced down by masiive weights deep
into the soil, then dredged out insid then
weighted again till they sank. deeper and deeper,
and so ou till the clay was penetrated and they
would go no further, and were as dry inside as
so many gasometers, which, on a small scale,
indeed, they much resembled. Then only when all
was complete was the concrete laid, and on the con-
crete.the hardest bricks were set in cement to a
thickness of about 10ft. deep, and over this again
up to above high-water mark comes the granite
deposited in immense bli;tcks, weighing from 5 tons
to 15 tons each, and all firmly keyed together. In
some cases the work of sinking these piers was very
simple and mere matter of engineering routine and
care ; in others, especially the No. 4 pier, the diffi-
culties seemed for a time almost insurmountable.
This N0..4-pier is-that which is first on the Middle-
sex side, The caissons were sunk to a depth of
52ft., yet still no good foundations could be found,
nor could the water be kept from percolating up
through the soil ; and it .was not till after a great
delay and 'an immense expenditure of money that
the clay was reached and the pier begun and
completed. The cause of this extraordinary
looseness of the soil was afterwards found to
have been an old channel Which once formed an en-
trance to one of the chief tributaries of th 3 Thames
—the old River Fleete ; or, as it was afterwards
called from its use, or abuse, Fleet ditch.

Each arch of new Blackfriars is built of nine mas-
sive wrought-iron ribs set at a distance of 9f t. 6in.
asunder. This is a very much greater distance
apart than that at which those of Westminster are
set, but, on the other hatid, those at Blackfriars
are very much more thari twice as strong, being
3ft. 10in. deep at the crow* of the arch and 4ft. /in.
at the splinging, or, to speak more plainly, at the
point where they rise from Pie masonry of the piers.
The cross_ braces between These ribs are -of propor-
tionate strength and depth,: and are placed at
vals of lift. apart. Aboie these, again, come. what
are termed bearers, and bolted over these again
will be powerful buckle - plates for the road=
way. These buckle plates will be thickly -Boated
with asphalte, then a layer of hard stone
rabble, 'and ove.E. all the usual granite paving,
sack ca thatani.,l4ndon-bridg-C. There 110
test used to prove the wreagtli of the bridge before
it is openetl, simply because the sectional area of the
wrought iron under each part is ten times in excess
of the strain it would have-to bear under the most
trying exigencies of metropoli an traffic. The
gradient of the whole bridge will be only 1 in 40,
a gr(a' relief to traffic, when it is remembered that

the rise in the 011 bridge was one in 22. Tile centre
arch will have a span of no less than 185 ft., the two
immediately a ljoining this on either side a span of
173 ft, each, while the two smaller arches at the
shore ends joining the abutments will have a span
each of 155 ft. The height of the centre arch from
the water is to be 25ft. ; of the two next side
arches 21ft. Gin., and of the two shore arches
13ft. Sin. All the arches will be of a fiat elliptical
shape, and will give together a waterway more than
one-third greater than that of the ruinous obstacle
which was for so long an impediment to the navi-
gation of the Thames. The total length of the new
bridge will be from end to end 960 ft., or about GOft.
longer than Westminster. Its breadth will be 80ft.,
or almost exactly double that of the old bridge.
The roadway alone is to be 45ft. wide, or about 2ft.
wider than the whole of the old bridge from outside
to outside, and there are besides these to be two
fo)tways of 17ft. width each. These dimensions
would almost sufficiently show of themselves what
a spacious and noble structure the new bridge is to
be ; but the best idea of the real magnificence of
its proportions is to be got on its west side, where
the two Surrey arches are completed. The grace of
its lines and the whole style of its design can hardly
be overpraised. The spandrils of the arches have
been filled in with their ornamental bosses, and part
of the balustrade has been mounted. This latter is
in the Venetian Gothic style, and though in actual
fact it is very massive . and heavy, in appearance
it is very light. It is a perforated balustrade,
arranged in panels of plain and twisted columns,
which are to be gilt with the twisted cable border
which surmounts it. Some small part of the orna-
mental cornice has also been fixed, with two of the
great red granite columns, and the effect of them
all as seen from a little beneath the arches is some-
thing wonderfully fine in bridge architecture.--
Times.