Improvements in Fireproof Floors, Bridges, Roofs, Staircases, and similar Constructions.
Year: 1895

page_text: Date of Application, 17th Jan., 1395
Complete Specification Left, 17th Oct.. 1895-Accepted. 7th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in Fireproof Floors, Bridges, Roofs, Staircases, and
similar Constructions.
EDWARD WILLIAM BONSON of Westminster Chambers, 9 Victoria Street,
Westminster, London, S. W. Commercial Traveller and Estimator do hereby
declare the nature of this invention to be as follows:-
An improved system of fireproofing floors, roofs, bridges, soffites of staircases
and such.
Various systems are in vogue for fireproofing floors, bridges, roofs, soffit of
staircases, joists, girders and such (all of which are hereinafter included and
implied by the words or term "floors, and the like") by means of terra cotta or
earthenware lintels, tiles, blocks or bricks (all of which constructional forms are
bereinafter included and implied by the words or term "lintels, and the like") the
ends or sides of such lintels and the like resting or being supported upon the
flanges of joists or girders and carrying or superposing a layer of concrete either
direct or indirectly & in effect directly on the top of such lintels, and the like.
The object in view is to obtain air spaces, passages or chambers between the
ceiling or soffit and the concrete or other material used, by such lintels, and the
like (being hollow or by using said lintels in a flanged form in conjunction with
other means) creating such spaces and the like; to prevent bringing the concrete
into direct contact with flame, heat and water in case of fire; and to do away with
the necessity for centering as required in the case of solid concrete or other
monolithic floors, etc. It is a generally accepted fact that joists or girders whether
in iron, steel or other material when entirely enveloped or blocked in by concrete
increase their carrying capacity and strength-according to some authorities to
the extent of trebling their strength as bare joists-as with this blocking in they
are transformed into solid beams. The systems already mentioned, by taking up
a portion of the web area of the joists and practically the whole of the bottom
flange, or by breaking up the concrete between flanges into sections, prevent
the formation of a solid beam, the lintels, and the like, themselves being segmental
in relationship and non-adhesive. Consequently, comparatively large joists are
required for given work. The lintels, and the like, being of terra cotta or
earthenware are themselves crushable & in the event of great weight being placed
upon them are liable to collapse.
By my invention I almost if not entirely do away with the bearing on joists, by
attaching similar lintels, and the like, (preferably of the particular characteristics
mentioned by me hereafter) to the underside or soffit of floors, etc., by means of
dovetail grooves or mortices sunk iu, or oblique or radiating flanges on the upper
side of such lintels, and the like. Instead of forming the boarded centering as in
the case of solid concrete floors, I use only the bearers, slings or struts without
boarding, and on such bearers I lay the lintels, and the like, they, in effect, taking
the place of the boarding. The concrete or other soft material to be superposed
when placed on the lintels, and the like, runs into or is rammed into the dovetail
grooves or mortices or between such oblique or other flanges as mentioned and,
when "set," keys the lintels, and the like, solidly and homogenously to the concrete
itself. When the scaffolding & bearers are removed the result is a solid floor as
in ordinary concrete flooring filled in between joists, with a fire-resisting shell or

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sheathing on the under side, such shell or sheathing being independent of the joists
or girders but protecting them on the underside in the same measure as the
concrete. Where required the lintels, and the like, may be rounded or arched in
the upper part, thus forming the super added concrete into an arched flooring,
thereby attaining the greater strength possessed by arched floors, and the like, or
by using bearers shaped to required radius the lintels may themselves also be
shaped to required radius on top and bottom with splayed or chamfered sides
to give the floor, and the like, an arched soffit.
No particular material is essential for the manufacture of the lintels, and the
like, used under my system, but providing it is fire-resisting, any material may be
used, and for cheapness, general tacility in working and fire-resisting properties
terra-cotta or similar earthenware material is generally employed. No particular
form of lintel, and the like, is essential, but any reasonable shape or size inay be
employed providing such form affords the requisite dovetail grooving or mortices
or oblique, radiating or other shaped flanges or other means for keying or jointing
into or otherwise associating the lintels, and the like, with and to the concrete or
other super-added material used. I also use hollow lintels, and the like, instead of
tee or other flanged forms, as in the event of fracture of the bottom side there
would still be the upper side of the hollow lintel, and the like, to protect the floor,
and the like, and the webs usually formed between the upper and lower sides of
such lintels, and the like tend to greatly strengthen the whole against the force of
impingement and fracture. It is preferable to dovetail or otherwise key each
lintel, and the like, to its neighbours to form bonding between them; this may be
done by any of the usual means of male and female jointing. Where the lintels,
and the like, come under the bottom flanges of joists, girders or other constructional
ironwork or such, the portion of the lintel, and the like, so coming under such
flange should preferably be extended beyond such flange to give the necessary
keying space or surface so that the lintel, and the like, may be keyed to the
concrete or other material on both sides of such flange and by alternating the
extension of lintels, and the like, under flanges a "half-brick joint" effect may be
secured as in brickwork and thus key the lintels, and the like, int two bays of the
concrete used. This arrangement will prevent the jointing or butting of joints or
ends of lintels, and the like, under such flanges, where the greatest strain on
the lintels, and the like, fire resisting properties would probably occur in case of
fire. The soffit or underside of lintels, and the like, may have grooves or mortices
or other means for keying plastering to same, or may be finished plain or moulded
as desired.
A further novelty in my system is the principle of giving extra support to
lintels, and the like, used for the purpose described, where necessary, by means of
bar, tee, angle or other iron, steel, or other substance, or wire, run through the air
spaces, passages or chambers as described as being, or as may be specially provided
for the purpose, in such lintels, and the like, resting, supporting, fixing or tying the
ends of the bar, tee, or other iron, steel or other substance, or wire, to walls or other
means for carrying or supporting such ends. In the case of the application
of such lintels, and the like, to the underside or soffit of wood joists as in ordinary
dwelling-house floors, etc., I screw or otherwise affix a flanged, bulbed or tri-angular
rail along the joists and along such rail I run the lintels, and the like (provided with
dovetail grooves as before mentioned), into position, (as in the case of ruaning the
chair along a railway rail), the iron or other rail taking the place of the concrete
in filling groove and forming key. I protect the wood joists from any charring
action that might be caused by the heating of such rail in the case of fire, by means
of a thin strip of asbestos or other non-conducting material placed between the rail
and joist. To permit of this rail being filled up with lintels, and the like, I do not
fix the end of rail at first but allow it to hang down and then when filled with
lintels, and the like, draw it up to the joist by means of an irou band run through
a slot in the rail, the ends of such band being afterwards screwed, bolted or
otherwise fixed to the top or sides of wood joists.

page_text: The advantages I claim for my system are
(1.) The complete blocking in between joists flanges thus giving to the joists
greater carrying strength.
(2.) The employment of lighter joists and lintels, and the like, the lintels, and the
like, having to carry practically no weight.
(3.) The consequent greater lightness of the whole floor, and the like.
(t.) The attainment of all the fireproofing, ventilating, and other qualities
required in such floors, and the like.
(5.) More thorough protection to joists, girders or other constructional ironwork
used in such floors, and the like.
(6.) The applicability of my system to the underside or soffit of staircases,
landings and sloping ways.
(7.) Its applicability for enveloping main joists or girders.
(8.) Its applicability for wood-joisted floors, and the like.
(9.) The minimising or prevention of the ringing vibratory sound given off by
other systems as mentioned (where lintels, and the like, are placed or supported on
joists or girders) by walking thereon or talking in a room ceiled on such
other systems.
(10.) The doing away with the liability of such lintels, and the like, to collapse
under weight.
(11.) Great facility in applying my system to any span.
(12.) Consequent greater efficiency and cheapness of my system.
Dated this 14th dow of Louan 100%
Improvements in Fireproof Floors, Bridges, Roofs, Staircases, and
similar Constructions.
I, EDWARD WILLIAM BONSON, of 12 Kelmscott Road, Wandsworth Common,
London S.W. (late of 9 Victoria Street Westminster) Commercial Traveller, 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 improvement in the construction of floors, bridges,
roofs, staircases and the like and has for its object to encase and protect the iron,
steel, or other joists or girders, or other appliances for carrying the dead weight of
such floors and the like and also the concrete or other material used in the
formation of the body of such constructions as floors, bridges, roofs, and staircases
from the destructive action of fire; to provide air spaces for the purpose of
ventilation between the concrete and its fireproof sheathing; to do away with the
necessity for wood boarding or centering in forming concrete floors and the like,
and to permit the use of comparatively smaller joists or girders than are usually
used in other systems having the other foregoing objects in view.
My invention consists of a floor, roof, bridge or staircase constructed with joists,
girders, or other weight carrying appliances either of iron, steel, wood, or other
material and concrete or other material which may be applied to fill in the spaces
between the joists, girders and the like, but instead of laying or embedding the
concrete upon wooden or other centering to allow it to set as is usual in forming
such floors, 1 form a suitable wood or other skeleton framing or scaffolding on
which to lay my tubes or hollow tiles. As the special feature of my invention
I then provide and lay on the framing tubes or hollow tiles formed of fireclay or
other fire resisting material, and of suitable sections and shapes, with dovetail
grooves or mortices sunk in, or radiating oblique or serpentine flanges or tongueя

page_text: "
66
set
projecting from their top sides to key into or connect the tubes or hollow tiles to
the concrete. The concrete or other material being then laid upon the tubes or
tiles and packed into the grooves, or mortices, or between the flanges or tongues on
the top of the tubes or hollow tiles, when "set or hardened binds the tubes
together and keys or connects them to the underside of itself and the joists, girders,
When the concrete is
or such carrying the dead weight of the whole.
"the
skeleton framing is taken away and the underside of tubes or hollow tiles is finished
in plaster or otherwise to form a ceiling, or the tiles may be perforated on the
underside to permit air to pass up into the inside of tubes or tiles and thence to an
outlet in walls, or such for the purpose of ventilation. The object of the special
feature described is to protect the joist, girder, or other floor carrying appliance
and the concrete or other material filled in between such joists and the like from
the destructive action of fire. In the accompanying drawing showing the general
arrangement of a bay of a floor constructed on my principle as described
"a" denotes the body of the concrete forming floor, "6""" the joists or girders
carrying the floor, "c," "d," "e," the tubes or hollow tiles with flanges "f"
embedded or jutting into the concrete and bonding the tubes or hollow tiles to the
concrete. The grooves "g" are to form a key for plaster or other ceiling finish
and "" denotes au air space, or ventilating flue running longitudinally with the
length of tube or hollow tile formed by the tubes or tiles being hollow.
The tube or hollow tile "c" in the drawing I purposely make shallower or
thinner in order to allow of a larger body of concrete being formed under the
bottom flange of joist or girder the object being to effect the greater strength,
carrying power and rigidity given to any such joist or girder by being thus
embedded in a solid body of concrete and thus forming a beam for the greater
support of the floor.
The tubes or hollow tiles may be made of any suitable length, and may be laid in
relation to the cross section of the joist as shewn in the drawing, namely, at. right
angles or longitudinally, obliquely or otherwise, the tubes or hollow tiles being
entirely independent of the joists for support in contradistinction to other systems
which are supported on the bottom flange of the joists or girders.
Having thus now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
:-
1. The construction of fire-proof Hoors, bridges, roofs, staircases, and the like
formed substantially in the improved manner herein before described.
2. The improved method of securing the fire proofing qualities of fireclay, or
other fire resisting materials to the underside of floors, bridges, roofs, staircases,
and the like by means of tubes or hollow tiles of such substances or materials
keyed into the body of floors, and such in the manner as herein before described
by me.
3. The improved arrangement and construction of the tubes or hollow tiles under
the joists or girders to secure greater strength and carrying capacity to the said
joists or girders in the manner hereinbetore described by me.
4. The improved method of applying tubes or tiles of fireclay or other material in
the construction of floors, roofs, bridges, staircases and the like by causing them to
take the place of the wood boarding or other centering usually employed in the
construction of fireproof floors, as hereinbefore described instead of placing them
on the flanges of joists or girders or other weight-carrying appliances, the tubes or
hollow tiles being under my improved method entirely independent of the joists,
girders, or other such appliances, carrying the weight of the floor, roof, or such.
Dated this 17th day of October 1895.
EDWARD WILLIAM BONSON.