The Sun.
London, England, 1862-05-26 00:00:00

THA NEW WESTMINSTER BRIDGE.

Satarday morning, at a quarter past 4 o'clock
the roadways and tramways of the new Westmin-
ster-bridge were opened for traffic. This early hour
fa•_ the opening was selected, as it was the hour of
the birth of her Majesty on the 24th of May, 1819,
at Kensington, A salute of 25 guns was fired at
the nine time, corresponding with the number
of years which her Majesty has reigned. The plan
which has been adopted of building the bridge by
halves necessitated the use of the footways in the
first instance for the light traffic, and a few days
will elapse before the footways are laid. As Mr.
Cowper had promised that the bridge should be
opened in May, Mr. Page, the engineer, exerted
himself to the utmost to have everything ready for
the traffic, and it was very appropriately decided
that, as far as possible, this should be completed by
the Queen's birthday. But for the lamented death
of the Prince Consort her Majesty would have her-
self been pesent at the opening. The now bridge is
very nearly twice as wide as any of the bridges
over the Thames. Within the parapets it is 84f 2in
wide. Of this the footways occupy 2811, the road
for the light traffic 39ft, the tramways 14ft Bin, and
the space between them 2ft bin. The tramways
consist of iron plates, bolted to timbers, and laid
upon an elastic bed of cork and bitumen, The curb
of the footway is formed of Ross of Mall granite;
the footway itself is of Blashfield's terracotta. It
inclines towards the parapet with a fall of liin, and
a gutter on each side carries off the water. The
value of this material for paving purposes may be
estimated by the fact that when rubbed with sand
and water against Yorkshire stone the stone lost
twice as much as the terracotta. The pavement is
laid in diamonds, and it has a very pleasing effect.
The bridge consists of seven arches. The spans and
heights of the different arches are _ _

Nos. 1 and 7.

Ft. In.
Arch span
Height above Trinity datum
Arch span
Height above Trinity datum
Arch span
Height above Trinity datum 19 31
Centre arch span
Height above Trinity datum

Nos. 2 and 6,

Nos, 3 awl 5.

The arches are formed of seven ribs, which are of
cast iron, with the exception of the crown or centre
pieces, which are of wroaght iron, as owing to their
not being so deep at this part, greater strength of
metal is required. When the seven ribs of each
arch were fixed, the upper surfaces were covered
over with cast iron buckle plates, pieces of iron plate
about six feet square, turned up at the edges some-
thing like huge tea trays. These were belted on to
the top of the arches in what al:,-peared like the
body of some monstrous armadillo or crocodile.
Over these iron shells are laid blocks of wood, so
cut as to fit into the interstices or grooves between
each plate. These are covered with pitch and bitu-
men, and over the whole is laid a surface three or
four inches thick of cork and bitumen. The founda-
tions of the bridge were formed without the use of
the time-honoured coffer-dam, and the large expen-
diture which the construction of them would have
involved has therefore been saved. A series of piles
were driven into the bed of the river, which form
the base upon which the piers were to rest. There
are 145 piles in each pier, and they are driven to
an average depth of 29 feet, The piles were driven
so far that in each case, after 10 blows on the head
with an iron ram one ton in weight, the pile sank
only one inch. This was the test applied to ascer-
tain whether the bearing piles were driven in to a
sufficient depth. Round these timber or bearing
piles, which are placed one foot apart, and which
cover the whole area of the foundations, 44 cast-
iron piles are driven to a depth of 24 feet. These
are cast with grooves on two of their opposite sides ;
and between each pair of them iron plates, 15 feet
in length, are driven down 21 feet below low water
mark, or 14 feet below the bed of the river. the
spot upon which each pier stands is thus formed on
the outside with thick sheeting plates of iron ; and
the foundations are encased in this armour up to
within a few inches of low water mark. It appears
from experiments made by a committee of a British
Association that a plate of iron one inch in thick-
ness will take 3,362 years to corrode, with one side
exposed to the action of the air and water, and half
that time if both sides are subjected to the same
corroding agencies. There is not much fear there-
fore with respect to the durability of the piers of
the foundations of the new bridge. But, in
order to make security doubly sure, there is round
the sides of the iron casing a trench 6 feet in depth,
-which has been dredged out through the bed of the
gravel at the bottom of the river, and down to the
upper stratum of the London clay; and into this
trench there has been placed a solid bank of con-
crete, which forms an additional protection or but-
tress to the foundations. The mass of concrete rests
upon the clay, and against the sides of the iron cas-
ing nearly level up to the level of low water. The
following is a statement of the quantitiesof materials
used in the construction of the new bridge :
Timber in bearing piles cubic feet 45,700
Cast iron (in foundations)
Ditto (iii superstructure) ..... „ 2,600
Wrought iron (in foundations) .... 12 70
Ditto (ia superstructure)
Granite and other stones (in the piers
and abutments
Brickwork (in Portland cement).. cubic yards 21,000
Concrete (in Portland cement) .... „ 30,000

The pressure on the bearing piles of the bridge is
15 tons, while upon London-bridge it is as much as
80 tons; the pressure on each square foot of ground
is but two tons, as compared with five and a half
tons at London• bridge. The roadway of the new
bridge is 12 feet lower than that of the old West.
mineter-bridge, the gradient at the centre arch is
one in 362, at the two next ono in 123 and one in 75,
the two next one in 57, and on the abutments one
in 54. The following statement of the length and
brf adth and cost per square foot of the metropolitan
bridges wilt aff,id an accurate idea of the cost of the
new bridge:_.

Name.

Length. Breadth. Cost
53 6
.£ll 6 °
London.. . l9'ol' Ft. in. Per sq. foot.
Southwark BOO 42 6 11 5 10
Blackfriirs ... . 995 42 0 315 6
Waterloo ........ 1,380 41 6 10 0 0
Hunger-ford' .... 1,536 13 4 416 6
Westminster, old 1,160 43 0 716 0
Westminster, new 999 80 0 40 0
Vauxhall B4O 36 2 916 0
Chelsea .. 922 40 0 2 5 0
Proposed new
bridge at Black- 1 980 76 0 35 0
friars.

ht inter-
ruption Th.) old bridge, which has now been superseded,
has stood for 110 years, and with very
tcr-
ruption had,during the whole of that period, afforded
accommodation for the yearly increasing traffic be-
tween the two sides of the river. The bridge was
commenced in 1739, and after 12 years was com-
pleted at a cost of £389,500. It was originally in.
tendesi to have been built of wood. and some pro.
gress was male in the foundations of the piers for
a work of that dc.scription, when it was afterwards
found necessary to build it of stone. 'Westminster
was the second bridge erected in the metropolis, and
at that time there existed only the crazy old L
don-bridge, with its deep ascent and narrow road-
way of 20 feet, with a row of houses on each side
of it, a noble gatewAy, a chapel, and other buildings
of architectural merit. Old London-bridge, which
had stood for nearly six centuries, had 20 arches, the
whole waterway being but 450 feet. When Lalor-
dayo proposed, therefore, to open the river by a
stone bridge with only 13 arches, he was considered
a bold and rash man. He, however, succeeded, and
Westminster-bridge was accounted one of the won-
ders of the world. The arches were 13 in number,
with two small culvert arches. It provided a clear
waterway of 820 feet, or nearly double that of Old
London-bridge. The height of the centre arch was
26 feet, the width of carriage way 28 feet, and of
each of the two footpaths seven feet; the gradient
was as much as 1 in 15, which by subsequent altera-
tions Was, however, reduced to in 22. The headway
of the new bridge is 20 feet ; and there are seven
instead of 13 arches; it is u
hl: the width of the
old bridge, and the gradient is reduced by making
10
the new at the centre feet lower than that of
cost
the old bridge. The
of the old structure
was £389,500. The greatest span of anyarc
of the old bridge (the eli
teone) was 76 fed;
the centre arch of the
new bridge is 120
feet span.
Each of the arches of the.
e
ald strut-1
tare decreased in span four feet, and the smallest
was not more than 52 feet. The present bridge
was commenced in May, 1854, and the works con-
-1556- when they were
tinned in progress to March,