Albert Gisclard
Albert Victor Hippolyte Léon Gisclard was a French designer and patentee of a 'rigid' suspension bridge system.
Born in Nîmes, 13 July 1844. Died at Sauto, Pyrénées-Orientales, 31 October 1909).
The first bridges built to Gisclard's patent were: four bridges in the Haut Ogooué in the Congo and a footbridge over the Foa in New Caledonia (opened in June 1909). The first bridge, of 28 m span, was fully erected in Arnodin's works.
Wikipedia lists the following bridges built on Gisclard's system by Arnodin in conjunction with Gisclard:-
Passerelle Marguerite: La Foa, New Caledonia.
Pont de Bourret (Tarn-et-Garonne).
Pont de Très-Cassès, Castelsarrasin (Tarn-et-Garonne).
Pont de Cassagne, Cerdagne (Pyrénées-Orientales).
Various bridges in Morocco.
The following bridges were built after Gisclard's death:-
Rochers Noirs Viaduct (Corrèze).
15 bridges reconstructed after the First World War.
Lézardrieux bridge, on le Trieux, Britanny.
Construction of the above bridges was supervisd by Gaston Leinekugel Le Cocq.
The Pont de Deir ez-Zor (Syria), on the Euphrates.
See here and here for numerous photographs and several drawings.[1]
GISCLARD-ARNODIN SUSPENSION BRIDGE (From The Engineer, 26 January 1906)
Two rigid suspension bridges, involving a novel and important detail of construction, have been recently designed to
carry the railway from Ville£ranche to Bourg-Madame over
the river Yet at different sites. The scheme of the structures
is the conjoint production of M. Gisclard and his collaborator
M. Arnodin, the latter gentleman being an engineer well
known for his work in connection with the erection of transporter bridges. Before sanctioning the execution of the
project the authorities submitted the design to examination by
a commission of experts. In order that their report may be
properly understood, it will be necessary to describe the
general features of the proposed bridge, of which a skeleton elevation appears in the accompanying cut.
Between abutments the total length is 772ft., which is divided into three spans,
one central of 514ft., and two shore or side spans of 128ft. 8in.
each. The width between parapets is 20ft. From one slope
of the valley to the other the line is on a uniform gradient of
1 in 16, which leaves a headway at the centre of 247ft. above
the water level of the Yet. This inclination, together with
the consequent difference in the apparent height of the piers,
which is the same for both from track surface, detracts from
the general appearance of the structure. The piers are
founded upon the solid rock, are built of masonry up to the
underside of the platform, and of steel above that datum.
Although the masonry part of one of the piers is 7ft. 6in.
more in total height than that of the other, the area of both at
their junction with the steel work is 27ft. by 14ft., with a
batter of 1 in 25. Both piers carry at the apices a set of
expansion rollers.
Cross girders connect the longitudinals. They are braced
underneath by diagonal members arranged in the form of a
St. Andrew cross, and overhead by a series of metallic plates,
which serve also to support the ballast and permanent way.
The whole flooring is suspended by vertical rods to a type of
framework in which more especially consists the originality
of the design. From the summit of the piers radiate the
inclined metallic shrouds, five of them in the direction of the
shore spans, and ten towards the centre of the principal
opening, which are completely analogous to those used in the
Arnodin transporters. In those structures, the lower ends of
the inclined suspension members are directly attached to
the platform of the bridge, and act as an auxiliary to the
ordinary parabolic cable, that is to a cable passing over the
apex of the piers, and having its lowest point at the centre
of the main span. In the present instance, the inclined ties
are connected at their extremities to a cable, which has its
highest point at the middle of the central opening, at a
height of 20ft. above the flooring. The other ends of the
cable terminate near the piers, 7ft. above the platform, and
are entirely free from any attachment to them. It follows
from this degree of freedom and the absence of stresses due to
the effects of temperature, that the calculations respecting
the strength and resistance of the structure can be undertaken with facility and security. There are three articulations in the principal span, one on each of the piers, and one
at the centre of the lower cable where the maximum rise
occurs.
In addition, all the radiating suspension bars or
rods, together with the free lower cables, that is all the
structural members, are under stresses, solely of a tensile
character, whatever may be the nature, position, and amount
of the loading to which they are subjected. It is consequently
unnecessary, when employing long suspension members, to
be obliged to use a quantity of extra metal, to enable them
to resist moments of flexure. It may be here generally
remarked that long suspension rods are always liable to
bending moments, so that ordinary constructive triangulation would be altogether inadequate, except theoretically,
to ensure the requisite indeformability of the whole system
of framework.
It appears from a report drawn up by M. Maurice Levy,
Inspector-General of the Ponts et Chaussees, published in
the Annales des Travaux Publics de Belge, that the appointed
Commission has expressed opinions respecting the proposed
design, which, while tolerant, are equally guarded. It
is stated that from a purely theoretical point of view there is
nothing to object to, but from a practical, since it has not
yet received the stamp of actual experience, there may be.
The Commission observes that the design, in the light of a
material structure, has many features in common with
ordinary suspension bridges, and especially with the transporter bridges of M. Arnodln, and possesses the same facilities
for erection. Again, referring to the Ordish system of
suspension, there seems no reason why the example under
notice should not be endowed with the same degree of
rigidity as a type which has already undergone and survived
the ordeal of constant working traffic. It should be borne
also in mind that there is nothing in the principle of bridges
of the system Gisclard, forbidding its realisation, although
certain questions of detail may be reserved for future inquiry.
The Commission lays stress upon the great interest that is
connected with the practical execution of the design, which
is well adapted for spans of very large dimensions
See Also
Sources of Information
[2] Wikipedia entry