The Ketchum keystone. [volume] (Ketchum, Idaho) 1885-1899, 1890-02-08
srupeNpovs PROJECT,
A Steel Bridge Across the Channel ffoD
EnglAnd to France,

England to France.
A great steel bridge across the En-
Rlish channel is projected. The bridge
will stretch over the shallowest and
narrowest part of the channel between
Cape Girls Nez and Folkstone and will
be supported by columns resting on
the bottom of the sea. The amount OF
metal and machinery to be provided
would represent an aggregate weight
of about 1000, 600 tons, the assumption
being that each country will have to
supply one-half of this amount Re
garding the cost of the work a rough
calculation gives, with reasonable cer*
taintv. $50. 0OO, 900 francs for masonry
supports and 48O. 900, 600 francs for the
metallic superstructure-in all b6O,-
OOO. 600 francs, or 834, 400. 600, The
time required for the undertaking may
be fixed at about ten years.
The whole of the pillars will occupy
q little over one-twelfth of the section
of the channel. The distance between
the piers, fixed at 500 and 800 meters
for the large spans, will not be less
than 200 and 100 meters respectively
for the small ones, and will be sum
Gent to prevent their proving an OBJ
stacle to the free navigation OF sailing
vessels. As for the metallic super
structure, the metal columns firmly set
upon the platforms of the supporting
piers of masonry are of a distinctly
cylindrical shape, and vary in height
between 40 and 42.78 meters, and on
them will be placed the main girders
of the bridge. There will thus be be-
tween the lower part of the beams and
the level of the sea at low water free
space varying in height between 81 and
63.78 meters, which height at high wat
er will be reduced to 81 and 56.78 me-
tiers, respectively. This height is am
ply ficient for the passage OF vessels
Of whatsoever description or tonnage.
BY placing the flooring upon vertical
cylindrical columns the minimum
height of 81 meters is kept throughout
the whole width of the span, q result
not achieved in the bridge over the
Forth. The girders are to be simple.
unlatticed, and trussed, so as to insure
the proper distribution of all stresses.
The level of the permanent way is ~
meters above the low-water level.
There will be double set OF rails, and
the width of the flooring proper will be
8 meters.
The width of the bridge is variable.
the greatest distance being between
the axes of the main girders, % meters
"a space necessary to insure the sta
bility of the structure under the action
of violent gusts Of wind. The road
ways are Of the ordinary width OF 10
meters between the axes and the rails.
the latter set in grooves to obviate &C.
cident. The floor, made of ribbed
sheet-iron, is to cover the bridge
throughout its length, so as to make
every part accessible to the men APP
pointed for its supervision. Between
and outside the roadways pavements
are provided for the men to stand on,
and thus keep out of the way Of pass
ing trains. On the flooring may be set
up refugees. stations for the guards.
signal-boxes, switches, etc. All these
arrangements can be multiplied accord
ing to the requirements of the traffic,
and scattered over convenient points
and spans on the piers. Lighthouses
may be erected to indicate obstacles to
be avoided. The various kinds of
lights used in lighthouses may also
serve to indicate to shippers the dis
lance from the Colbart and Varne
banks TO meet military objections
arrangements could be made for max
ing the span at either end of the bridge
unfit for use; the two end spans. pota-
bly,, which are in contact with the
abutments, might be removable or re-
vOlve.