An Improved Construction of Flat Arches or Vaults.
Year: 1898

page_text: Date of Application, 1st Nov., 1898-Accepted, 17th Dec., 1898
COMPLETE SPECIFICATION.
An Improved Construction of Flat Arches or Vaults.
I, MATTHIAS KOENEN, of 101-102, Leipziger-strasse, Berlin, Germany,
Government Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement;-
My invention relates to an improved construction of arches or vaults for
floors, ceilings, and other arched structures in which a flat middle portion of
the arch is supported by two arched haunches in combination with longi-
tudinal iron bars imbedded in the arch and secured to the abutments thereof,
as I will describe with reference to the accompanying drawings.
My invention has for its object to enable the span and carrying power of
arches or vaults having a flat middle portion to be greatly increased, which
I effect by imbedding in the arch or vault (which may be either of masonry or
concrete) iron bars a such as are shewn in Figs. 1 to 3 and 10 to 13. such bars
being curved in a downward direction within the lower part of the flat portion
of the arch, while the portions within the upper portions of the haunches and
spandril filling are bent upward and are secured to the walls b or girders c
forming the abutments.
The haunches of the arch are supported upon the bottom flange of the girder,
or upon a special shoe or corbel fixed to the girder or other abutment, while
the connection of the iron bars a to the bearers c can be effected in various
ways. Thus for example they may be secured by rivets or screws, or the ends
may be bent so as to embrace the top flange of the bearer, as shewn at Figs. 1
and 2, which shew respectively a vertical section of an arch, and a plan of the
girders and iron bars that are imbedded in the arch; or the ends may be passed
through holes in the top flange or upper part of the web of the girder and be
bent down as at Figs. and 5; or again, they may be suitably formed to engage
with hooks or cramps fixed to the bearers."
When two arches abut against each other; the bars of the one arch may be
carried through into the brickwork or concrete of the adjoining haunch of
the contiguous arch, the strain on the bars being in that case taken by the
brickwork adhering to the iron bars, and transmitted thereby to the bearer,
as at Fig. 6; or the ends of the bars of the one arch may be connected in any
suitable manner to the ends of the bars of the other arch. According to another
modification, the mass of brickwork or concrete B Fig. 7, formed by the abut-
ments of the haunches of two arches may have supporting bars a passing
through it, and suitably secured to abutments so as to dispense with iron
girders or bearers. The connections with the walls is effected by supporting the
launches of the arches upon corbels or wall brackets, the wall being if necessary
recessed for the arch to key into it, as at Fig. 3, while the iron bars may be
secured to iron rails e Fig. 3 which are secured to the wall by suitable anchor-
ings such as fg. Or, as shewn in section and plan at Figs. 8 and 9, the ends
of the bars may be secured to a zig-zag rod imbedded in the wall.

page_text: In this way a reliable connection of the arches to the walls or abutment
supports, as also a considerably increased strength of the flat part of the arch
and consequently of its supporting power can be insured.
Also, the height of the arch can be considerably reduced relatively to the
span as compared with ordinary flat arches without imbedded tie bars.
In the arrangements shewn at Figs. 10 to 13 the curved haunches of the arch
are formed separate from the flat middle portion carried thereby, the haunches
being tied to the bearers c by the tie bars à so as to constitute brackets or canti-
levers. In Figs. 10 and 11 the flat middle part ? merely fits in between the
haunches and is supported by the iron bars, a, while in Fig. 12 the flat part
rests upon the haunch and in Fig. 13 it is fitted thereto with a keying or
wedging action.
In the arrangement at Figs. 10 and 11, the joints at a being cemented,
the flat part is also supported by the adhesion or resistance to shearing at
the joints.
The essential features common to all the above described constructions are as
follows.
A flat plate is interposed between two arched haunches q consti-
tuting cantilevers as at Fig. 10, (all parts being made either of brickwork or
concrete) and is supported by tie bars so arranged that the horizontal thrusts
exercised by the haunches are taken partly by the plate 2, and partly by the
adhesion to the tie-bars a which transmit the thrust as a tensional strain to
the bearers cor brickwork walls or abutments b (Fig. 3).
At the same time any inward turning or twisting of the bearers or walls
due to such tensional strain is resisted by the counter thrust of the flat plate
and spandi filling.
The iron bars thus fulfil simultaneously four functions:-
1. They support the bearers or walls against outward bulging.
2. They serve as catenaries imbedded in the arch and thus enable this to be
made with a considerable span.
3. They serve as anchors for the haunches of the arch, and by being inti-
mately united thereto, and to the concrete or brickwork spandrel filling, they
constitute therewith cantilevers which are secured thereby against either up-
ward or downward motion.
4. The bars serve to hang the flat plate on to the haunches or cantilevers so
as to assist the same in resisting any sheering or slipping action at the joints.
Having now particularly described and ascertained the nature of this in-
vention, and in what manner the same is to be performed, I declare that what
I claim is —
In arches or vaults, the combination of a flat plate such as p with two arched
haunches supported by bearers or walls b, and with iron bars a imbedded
in the arch and so arranged as to pass through the lower part of the flat plate
and through the upper parts of the haunches the ends thereof being secured
to the bearers, walls or abutment supports, substantially as described.
Dated this 1st day of November 1898.
ABEL & IMRAY,
Agents for the Applicant.