During recent years an interesting change has been gradually brought
about in the various methods of building construction employed in
France, and more especially at Paris, where the size and importance of
public buildings and the many-storied houses divided up into flats
necessitate special systems of construction, which possess the
advantages of combining economy in cost with strength and durability.
Parisian architects and builders, although far from approving the
extremes to which their American confrères go in the employment of
iron for the construction of their somewhat exaggerated sky-scraping
buildings, in which the style of architecture employed is often
scarcely logical or consistent with the modern methods of
construction, are nevertheless obliged to own to the necessity and the
utility of employing iron in moderation for the framework of their
buildings. Up to the present the use of iron in its ordinary form has
chiefly been confined to floors, partitions, and roofs, where, as a
rule, its presence is masked by coverings of cement, wood, or stone,
except in recent examples of the new style of buildings destined for
brasseries or drinking halls, where the iron construction is left
visible, and emphasized by means of bronze or color painting and
mosaic work, or, again, in the few examples of well known work where
the architect has endeavored to obtain a decorative effect by means of
iron lintels and columns. But where the use of iron is fast finding
favor at Paris is in its employment in combination with other
materials such as cement or concrete, and in a special form known as
the cement armé systems, in which iron or steel is employed in the
form of thick wire, trellis, or light bars embedded in cement or
concrete. This method of construction, of which there are three
different systems, has for some time been employed in the construction
of various buildings of more or less importance, and has given proof
of its strength and practical use as well as its advantages when
employed for floors, partitions, walls and roof, both as regards its
conveniences for internal arrangements, its economy, and as regards
the manner in which it lends itself to modern schemes of polychrome
decoration.
Two of these systems have been employed by the architect of the new
building now being constructed in the Rue Blanche for the Society of
Civil Engineers of France. The third system is much employed by M. De
Baudot in various buildings designed by this architect, an advocate of
rational construction and design and the logical employment of modern
building materials. It will be interesting to examine the merits of
each system as employed in these buildings, together with any other
points of construction worthy of remark.
The building for the Society of Civil Engineers is remarkable from
several points of view as regards construction and the arrangement of
plan. The façade and plans will appear in the Building News as soon as
the work is completed, and will form an interesting subject for
comparison with the building recently completed for the English
Society of Engineers, and with that about to be commenced at New York
for the American Society.
Before entering into a detailed description of the system employed, a
summary idea of the plan and general scheme of construction will not
be uninteresting. The architect, M. Fernand Delmas, has endeavored to
construct the building on economical lines, employing to a large
extent iron and those modern materials which have been tried and found
fitting as regards suitability and economy; the building will cost
£22,000, and it has been made a sine qua non that all the contractors
shall be members of the Society of Engineers.
The length of the façade is 100 ft.; the total depth of the building
is nearly equal to the frontage; the height from pavement to cornice
is 60 ft. The façade is built of solid stonework throughout its length
and height. The thickness of the masonry is 24 in. at the lower
stories and 18 in. at the upper portion. The façade wall is really the
only portion of solid masonry work in the whole building, and forms a
decorative mask to the body of the building, which is constructed of a
framework of iron. The chief supports of the building proper consist
of four framed iron uprights, 16 in. by 16 in. rising from the
basement to the roof. These uprights are solidly trussed and held
together at the floor levels by strong iron girders supporting the
iron joists of the upper floors and the light partitions which divide
up each story. This system is at once economical and practical. The
whole building is thus self-supporting, and the thick walls which
would otherwise be necessary for carrying the upper floors are thus
avoided.
[Illustration: CEMENT ARMÉ CONSTRUCTION OF FLOORS, PILLARS AND
ARCHES.]
The façade wall is built according to the system always employed at
Paris, and is formed of blocks of stone roughly cut at the quarries to
the outside dimensions of the proposed moulding and decorative work.
As soon as the whole front is erected the work of cutting it into
shape will commence, the mouldings, pilasters, and all carving work
being done while the interior is being prepared. The buildings at
Paris are by this means erected much more rapidly than when the stone
is dressed or moulded before being put into place. Greater facilities
are thus given for studying the general ensemble of the façade and the
proper scale to be given to the mouldings and decoration. The stone is
as a rule soft when first from the quarries, but becomes hard and
durable after dressing and exposure to the air. The courtyard wall of
the building is formed of light brick or metallic fillings between the
iron uprights and the party walls.
The ground floor comprises a large entrance hall or vestibule, 40 ft.
by 44 ft., forming, with the cloakroom, the principal staircase, the
rooms for the concierge, and the area, the whole front of the
building. This large vestibule is vaulted over by means of one of the
systems of cement armé to be described. The floor is constructed on
another similar system, and will be paved with mosaic work. The ground
floor of the courtyard will be occupied by the conference hall, 50 ft.
by 50 ft., to hold 300 seats. An annex, 50 ft. by 20 ft., adjoining
this hall, will open on the same by a large arched bay, and may be
separated from the larger hall by means of a special system of wooden
soundproof roller shutters. The floor of the large hall will be a
movable one, to be raised or lowered by an ingenious system of
hydraulics, and capable of being placed in an inclined position for
conference meetings, or raised to a horizontal position for ball room
purposes.
The entresol floor will comprise a large room for meeting, smoking and
conversation rooms, and a reading room, to be used as a club for the
members of the society. The first floor will contain the offices of
the society, a large committee room, and all conveniences. The second
floor will be devoted entirely to the purposes of the important
library, comprising the library proper, a room 45 ft. by 25 ft. by 17
ft. high, rising to the ceiling of the low story above, and lighted by
a large semicircular bay at either end: the surrounding rooms of the
height of the second floor will be destined for the librarian,
catalogues, drawing office, and library offices. The third floor will
be devoted entirely to the purpose of storing the books of the
library, in low rooms communicating by means of the gallery
overlooking the library below, which will be crossed by means of a
light, iron bridge. The bookcases will be suspended from the upper
floor, and will be arranged in vertical tiers hung on rollers, after
the system employed at the British Museum. The roof story will be
divided up into an apartment for the chief secretary, and reached by a
private staircase from the ground floor. The large basement, occupying
the whole of the ground surface of the building, will be used for
storing the records of the society, and will contain the heating
apparatus, stores, etc. A hydraulic lift will afford access to the
landings of each floor. The chief feature of the façade, which is
simple in style, is the wide arched bay, 24 ft. across, rising from
the pavement to above the cornice; this bay will be filled in with an
open decorative framework of wrought and cast iron.
Some of the most interesting points of the construction, besides the
large use of iron, are the systems employed in the construction of the
floor. The ground floor is built after the Coignet system, composed of
light iron bars and cement; the first floor and its supporting pillars
and arches is constructed after the Hennebique system of cement armé;
the upper floors are formed of iron joists, filled in either with the
system of light supports and plaster, much employed at Paris, or with
terracotta fillings between joints. The roof is lined internally with
agglomerated cork bricks, affording protection from excessive heat or
cold, and the walls of the area will be lined with opaline, a vitreous
material of a bluish white color, which in this case will insure
cleanliness, and afford additional light; the lavatories and water
closets will also be lined with the same material.
Speaking of the Hennebique system of cement armé, employed for the
arches and floor of the first story, it will be interesting to
illustrate the method by a few sketches, explaining the theory of this
system, which has been put to practical proofs in a large number of
buildings, chiefly for industrial purposes, in the north of France.
The perspective section will give an idea of the construction as
employed in the building for the civil engineers, a system which holds
its ground well against its rivals of other methods of cement
armé.--The Building News.
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