Improvements in the Construction of Vaults, Tunnels, Reservoirs, Aqueducts, Silos, Roofs, and other Structures of Masonry.
Year: 1893

page_text: Date of Application, 25th Mar., 1893-Accepted, 2nd June, 1893
COMPLETE SPECIFICATION.
Improvements in the Construction of Vaults, Tunnels, Reservoirs,
Aqueducts, Silos, Roofs, and other Structures of Masonry.
We, MATTHIAS KOENEN, Government Architect, of 97 Alt-Moabit, Berlin
N.W., and GUSTAV ADOLF WAYSS, Engineer, of 95 and 96, Alt-Moabit, Berlin
N.W., both in the Empire of Germany, 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:-
Our invention relates to vaults, tunnels, aqueducts, reservoirs, roofs and other
structures of masonry.
According to our invention we make use of stone and mortar as hitherto and in
the joints between the stones or in corresponding hollows in the stone we insert
metal bars of any suitable cross-section which afford great internal strength to the
structure in which they are employed, and render its erection easier and cheaper.
To enable our invention to be fully understood we will describe how it can be
carried into practice by reference to the accompanying drawings, in which :-
Figures 1 to 9 illustrate portions of buildings of various kinds having metal
bars inserted in the joints between the stones; and,
Figures 10 to 13 illustrate portions of buildings having metal bars embedded in
corresponding grooves in the stones according to our invention:
Figures 1 and 4 are sections of flat roofs carried between I girders:
Figure 2 is a transverse section of Figure 1; and,
Figure 3 is a plan of the underside of the same.
The metallic insets a which may be of any suitable cross-section such as round,
quadrangular, flat, L, U, 1 or I-shaped are supported at their ends by the flanges
of the girders d. They are inserted in the joints of the stonework and are com-
pletely enclosed by it and by the mortar.
It is advisable to so lay the metal bars a that they lie in that zone of the vault
or of the roof upon which the stress is thrown since their cross-section is of great
assistance in bearing this stress. If the stones are laid so low down that their
under edges project below the level of the flanges of the girders d, as shewn in
Figures 1 to 3, it is necessary that the bars a should be curved downwards close to
the point upon which they rest, so that they lie in the zone of greatest strain.
This arrangement has also the practical advantage that the floating may be carried
right over the lower flange of the girders d.
In Figure 4 this is disregarded, and in that case the bars a are straight.
Figure 5 is a section of the roof of a vault provided with our metal bars or
insets. The arrangement is exactly the same as that hereinbefore described
with reference to Figures 1 to 4 except that the bars a are curved to correspond
to the outline of the vault.
In cases in which the strain falls upon one side of the vault, it is advisable
to make use of several insets a, a¹, as shewn in Figure 6 which is a similar view to
Figure 5, since tensile strains are thereby thrown upon the upper zone.
Figure 7 is a section of part of a reservoir shewing the method of constructing
the walls of the same upon this plan. According to the size of the reservoir one
or several insets may be inserted into the joints between the courses in the
structure. In this case it is best to employ flat bars of iron. The insets afford
firm resistance to the circular strain which occurs, so that the rupture of wall-
built reservoirs which so frequently takes place is effectually guarded against.
Reservoirs may of course be constructed either of a round, oval, or quadrangular
form.
Our invention allows of the construction of silos of any desired form and size,

page_text: g
and in order that vertical rigidity may be secured notwithstanding the height of
such silos, which is generally very considerable, the corners of the flat bar iron
insets a may, as shewn in Figures 8 and 9, (which are respectively a plan and an
elevation of part of the silo) be drilled, and vertical rods extending the whole
height of the silo be passed through the holes. The insets of the adjacent com-
partments are likewise traversed by these corner rods, so that a combined frame-
work results, which affords support to the masonry in a horizontal as well as in a
vertical direction. It is also advisable to bond the separate courses of masonry.
Other kinds of masonry may of course be constructed in the same way, that is
to say, tied together horizontally and vertically. In all the cases above alluded
to the insets may be mechanically or chemically roughened to ensure their more
perfect adhesion to the mortar. In the methods of construction hereinbefore
described, the insets have been described as being simply laid in the mortar of the
joints.
In the following modifications the insets are not laid in the joints but in grooves
of corresponding form in the stone.
Figures 10 and 11 are respectively a section and a plan of the arched roof of a
vault constructed in this way.
Figure 12 is a cross section of a similar roof with insets of different forms and
drawn to a somewhat larger scale.
Figures 13 and 14 are sections of a flat roof constructed in a similar way.
Figures 15 and 16 are sections of an arched roof with several insets of different
forms and arrangements.
C
The construction of the vaults, etc. is effected as follows:-The metal bars a of
any suitable cross section such as round, quadrangular, flat (hoop-iron) shaped, etc.
are first laid in position in sufficient numbers and at suitable distances. The masonry
is then carried out, stones provided with corresponding grooves c being used and
laid either in English or Flemish bond, the grooves being first filled with mortar,
and the stones so laid that they are made to press as regards their grooves (which
are filled with mortar) upon the metal bars in such a way that the latter are
completely enclosed in mortar. The rods may be either smooth, rough, or provided
with projections.
In the flat roof shewn in Figures 13 and 14, the bars a are bent downwards close
to their points of support, so that they are made to lie in the zoue upon which the
greatest tensile strain is exerted, in case it should be required to cover the lower
Hange of the girder d with plaster. If this is not required, the bars may remain
straight. In the vault-roof shewn in Figures 15 and 16, insets are placed in both
the corresponding grooves in the stone, above and below. This arrangement is
recommended in cases in which the vault is loaded on one side, in which case tensile
strains are exerted in the upper zone of the vault to some extent. A special
advantage of the present method of constructing vaults lies in the fact that no
templet and no scaffolding are required for the construction, so that the work is
cheaper, business under such a vault is not hindered, and the danger of inward
collapse which frequently follows a premature removal of the scaffolding is quite
averted.
The insets can, as shewn in the section at Figure 2^, be placed in lateral grooves
in the stones, both for arched and flat roofs.
Tunnels, reservoirs, silos, and aqueducts, as well as other masonry can of course
also be constructed upon the same plan as that previously described.
In erecting ordinary walls, it will be advantageous to so lay the stones that the
insets are in the joints of the layers, as shewn in section at Figure 17, and the
grooves hollowed into the surfaces which are to form the joints between the layers.
In contrast to the arrangement shewn in Figures 1 to 9 in which the insets are
simply placed in the mortar of the joints, the plan of inserting them in grooves in
the stone offers the advantage that the metal bars, without increasing the size of
the joints can be surrounded with mortar, which strengthens their adhesion, and it
also allows of the use of stouter bars of any suitable form. To this must be added

page_text: another important circumstance. By inserting the mortar in the grooves of the
stone bands or ribs are formed which enter the stone and unite the separate
components in the same way as a groove and tongue. We thus cause greater
adhesion by covering larger surfaces than hitherto with mortar, and considerably
enhance the aggregate strength of the masonry by reason of the portions which
are engaged with one another, since the bands or ribs must be disintegrated before
any shifting of the courses can occur. In fact the strength of a piece of masonry
so constructed is considerably greater than heretofore even without the metal
insets. The form of groove shewn in the section at Figure 18 will be found
especially suitable. The grooves in this case are of dovetail shape, thus ensuring
a good bond between the separate courses, vertically to the direction of their
surfaces of contact, since the stones can only be raised after the strips of mortar
have been torn away.
The form of the metal insets may in these latter methods of construction be the
same as in those previously described, that is to say, they may be of any suitable
shape. They may be of the same cross section as the previously described metal
insets shewn in Figures 1 to 16, but it is to be remarked that in the present case,
as the result of the grooves, their application is easier and more advantageous.
For instance, flat bar iron may be used placed on edge and the aggregate stability
of the masonry thus considerably increased, as shewn in Figure 19 which is a
section of part of a reservoir having flat insets so placed.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The method of constructing flat roofs, vaults, aqueducts, tunnels, reservoirs
and other masonry structures consisting essentially in the use of metallic bars as
insets in the joints of the mortar, such bars being of any suitable cross section,
substantially as herein before described.
2. The method of constructing flat roofs, vaults, aqueducts, tunnels, reservoirs
and other masonry structures consisting essentially in inserting metal bars or insets
of suitable cross section in grooves in the stones by the aid of mortar, substantially
as hereinbefore described.
3. In the construction of roofs, vaults, aqueducts, tunnels, reservoirs and other
masonry structures, the use of stones which are furnished with grooves running
across the surfaces which form the joints of the courses, which grooves serve for
the reception of metal bars or insets, and also in conjunction with the mortar to
ncrease the aggregate strength of the masonry, substantially as hereinbefore
described.
4. In the construction of masonry, especially walls, silos and reservoirs, the
employment of vertical metallic rods or insets in conjunction with horizontal bars
or insets for the purpose of ensuring a vertical bonding of the structures, substan-
ially as hereinbefore described.
Dated the 25th day of March 1009
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.