IMPROVEMENTS IN THE CONSTRUCTION OF ROADWAYS, PAVEMENTS, AND IRON GIRDERS, SPECIALLY APPLICABLE FOR THE PURPOSE OF CONSTRUCTING ROADS, PAVEMENTS, BRIDGES, AND ALL DESCRIPTION OF BUILDINGS
Year: 1865

page_text: LETTERS PATENT to Constantine Henderson, of No. 43, Parliament Street,
Westminster, in the County of Middlesex, Architect, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION OF ROADWAYS, PAVEMENTS, AND
IRON GIRDERS, SPECIALLY APPLICABLE FOR THE PURPOSE OF CONSTRUCTING
ROADS, PAVEMENTS, BRIDGES, AND ALL DESCRIPTION OF BUILDINGS."
Sealed the 28th July 1865, and dated the 7th February 1865.
PROVISIONAL SPECIFICATION left by the said Constantine Henderson
at the Office of the Commissioners of Patents, with his Petition, on the
7th February 1865.
I, CONSTANTINE HENDERSON, Architect, of 43, Parliament Street, West-
minster, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE CONSTRUCTION OF ROADWAYS, PAVEMENTS, AND IRON GIRDERS, SPECIALLY
APPLICABLE FOR THE PURPOSE OF CONSTRUCTING ROADS, PAVEMENTS, BRIDGES. AND
ALL DESCRIPTION OF BUILDINGS," to be as follows, that is to say:
Hitherto the construction of the roads and pavements of the metropolis and
elsewhere has been so thoroughly misunderstood that shortly after the forma-
tion thereof the sinking and unequal settlement of the carriage and footways
renders them dangerous and almost impassable in consequence of the accumu-
lation of water and dirt in the receptacles occasioned by the sunken stones
Price 8d71

page_text: The foundations of the roadways and pavements as now prepared are
thoroughly inconsistent, and although the stones may be laid in the form of
an arch, in that capacity the arch is entirely false because it neither takes a
bearing nor is it capable of so doing, there being not the slightest pretension
of abutment, and therefore the moment any portion of the road becomes
loaded, instead of the weight being carried to the abutments, the stones thus
burdened descend into the soil, rendering our streets and pavements wholly
unfit for traffic. Again, in consequence of the moisture after rain remaining
in the sunken receptacles upon the surface, the fact also of the stones being
bedded in the soil, and through the joints of which the moisture perforates to
the assumed foundation, the surface becomes a complete mire on account of
the dirt arising upon the surface through the joints; at the same time the
stones become entirely unfit for the duty they have to perform, and it can be
easily understood the effect that traffic must necessarily produce upon the
material thus surrounded in moisture, and the impossibility for such a con-
struction to sustain the unequal weights of pressure it is subject to, and which
ultimately produces the irregularities of the surface as before mentioned.
The present means of retaining the thrust of an arch within its span and
general mode of framing girders are of a very complicated nature and most
expensive and tedious in construction. To meet this want the girder herein-
before mentioned will be applicable to all manner and kind of buildings,
bridges, and other erections, but especially to a most important project the
petitioner has in view for the purpose of relieving the enormous traffic of the
metropolis.
The Construction of Roads.-I propose in the construction of roadways to
remove the soil so far as may be necessary, and at suitable distances build
solid footings or dwarf walls in the usual way, and upon these walls or footings
I place iron girders of two thicknesses, the lesser thickness being formed to
the slope of an arch, the radius being regulated according to the width of the
road; the extra thickness I carry down to a small flange, and at the extreme
ends of each girder 1 leave a given portion of the double thickness the entire
depth of the girder. 1 cut the inner portion of this extra thickness to form a
shoulder to receive iron bars passing from girder to girder, the iron bars being
regulated in size and strength to the occasion and requirements, and are cut
on the inner side to an angle suitable to the radius of the proposed arch, and
securely fixed to the girders at each end. Where the distances of the said
girders are of any considerable extent, or where greater strength is required,
I secure one or more iron tie rods which pass through the entire thickness of
the side angle bars, and on either side secure same by nuts and screws.

page_text: to.
Having erected proper cradling to construct arch of the desired form, I throw
an arch across the width of the road in stone, brick, iron, or other suitable
material, abutting upon the bars as prepared, and as herein-before referred
When I apply iron for the arch I perforate same in various forms, and
when I use stone or other materials I provide openings or inlets for the
rain or other moisture for pass from the surface to the main drains. In
some instances I form the lesser thickness of the girder or tie rod in two equal
parts, leaving a space between each part; and in addition to the side angle
bars, I provide a cross girder or division bar similarly constructed to the
girders, and secure same between the girders in the centre thereof, and also
similar angle pieces, framing and securely combining the several parts into
one complete iron perforated framework. I then fill in the spaces with iron,
stone, brick, wood, or other suitable material cut to the form of the proposed
arch, cement, or otherwise secure the same together. On this principle of
constructing roads I can excavate the earth or soil beneath the arch to any
required extent, and thereby form subterraneous roads, footways, or tramways
of any description.
The Construction of Pavements.-In preparing the foundation for pave-
ments I remove the soil a given depth, and construct at desirable distances
sleeper walls of brick, or stones or footings to receive iron or other suitable
material, framing with intermediate divisions, the form thereof being square,
angular, or oblong, as the case may be. This framing is perforated throughout
the divisions. The spaces in the framing I fill up with stones, earthenware,
tiles, wood, or any other suitable material; the soil beneath this framing and
between the said footings 1 level and bring up to a hard surface with a
suitable fall which will admit of the water running off so soon as the rain or
moisture passes through the perforated framing into the main drain. I
construct the curbing of the pavement in iron, stone, or otherwise, leaving a
space in each length thereof between the footings, in order to allow the water
to pass into the main drain. By this mode of construction I secure the
following desirable objects:-There can never occur a sinkage of any portion
of the pavement, which now arises in consequence of the uncertain settlements
of the soil, and which frequently occasions accidents resulting from the foot
coming upon a sunken stone, and the following step bringing the other foot
into contact with the adjoining stone. The deplorable state of our London
street pavements after a few minutes' rain, in consequence of the dirt arising
through the joints and the water accumulating in pools wherever the sunken
stones occur, will by these improvements be entirely obviated. Inasmuch as
it will be impossible to alter the level surface of this new pavement and the

page_text: moisture will be immediately carried off through the perforations in the
divisions of the framing, and the stones, tiles, bricks, wood, or other suitable
material, not being laid on the soil but securely fixed in the divisions of the
framing, will prevent the dirt arising as at present, and the constructional
nature of the entire arrangements is calculated to last for many years without
any material repair.
Another System-I adopt upon the foundation as before referred to, that
is, in lieu of the perforated framing and the filling in, I lay on the said sleepers
or footings cast-iron perforated plates the whole width or space from sleeper
to sleeper, securing same to prepared rebates on sleepers and the iron or stone
curbing as aforesaid.
Another Method. In this case I prepare, after removing the soil, footings
or sleeper walls as aforesaid, and thereon place a particular formed cast or
wrought iron girder, with a single flange, and of the form and on the principle
referred to, and at the end of each and on either side 1 leave solid a portion of
this girder of an extra thickness. I then place within this extra thickness a
solid iron slab skewback, and I form the curbing, which is either in iron,
stone, or other suitable material, the inner side thereof as a skewback of a
similar rake to the opposite side. I then throw an arch across the space or
width of the proposed pavement in brick, stone, or any other suitable material
cut and formed to fit the said skewbacks, taking care to bring the entire surface
to one uniform level; and it will be clearly seen that by this means it will be
impossible for any portion of the pavement to give way; and although in this
instance perforations are not provided, the rain or moisture will speedily run
off the incline surface, and the accumulation of the soil and wet on the
pavement will be effectually prevented in consequence of the arch being
entirely clear of the soil.
Another Method.-Still adhering to the former foundations, but in lieu of
the framing as hereto-before mentioned, lay between the spaces from sleeper to
sleeper, or dwarf wall to dwarf wall, two or more layers of tiles, breaking
joint in cement, making up and bringing to a solid and complete surface the
pavement with asphalte or other suitable materials. It will be here observed
that the pavement cannot fail to retain its level condition, and all dirt will
be entirely prevented from rising to the surface.
The Improved Girder-The girder here introduced I specially claim, not
only for the objects herein contained, but also for all manner of works,
apertures of every description, and especially for enabling me the petitioner to
carry out a project for cutting subterraneous roads, footways, and tramways of
every description, and for fireproof flooring. The form thereof and the prin-

page_text: ciple of the skewbacks attached being calculated to fulfil the duties of the
present complicated constructional matters required to be done where any
thrust has to be retained within its immediate space. These girders with
intermediate iron framing, as referred to in the paving construction, I fill in
with stone, brick layers of tiles in cement, or any other fireproof material; and
by this means I form a complete level floor without thrusting pressure on the
side walls.
SPECFIICATION in pursuance of the conditions of the Letters Patent, filed
by the said Constantine Henderson in the Great Seal Patent Office on
the 7th August 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CONSTANTINE
HENDERSON, of No. 43, Parliament Street, Westminster, in the County of
Middlesex, Architect, send greeting.
WHEREAS Iler most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of February, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Constantine Henderson, Her special license that 1, the said
Constantine Henderson, my executors, administrators, and assigns, or such
others as I, the said Constantine Henderson, my executors, administrators,
or assigns, should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man; an
Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF ROADWAYS, PAVEMENTS,
ALD IRON GIRDERS, SPECIALLY APPLICABLE FOR THE FURPOSE OF CONSTRUCTING
ROADS, PAVEMENTS, BRIDGES, AND ALL DESCRIPTION OF BUILDINGS," upon the
condition (amongst others) that I, the said Constantine Henderson, my
executors or administrators, by an instrument in writing under my hand and
seal, should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Constantine Henderson, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the

page_text: following statement, reference being had to the accompanying Drawings and
to the letters and figures marked thereon, that is to say:-
My said Invention relates to certain peculiar modes or methods of con-
structing or forming roadways and pavements, and also to a peculiar construc-
tion of iron girder, specially applicable to roads, pavements, bridges, and all
descriptions of buildings.
Hitherto the construction of roads and pavements in towns has been so
misunderstood that shortly after the formation thereof the sinking and unequal
settlement of the carriage and foot ways renders them dangerous and almost
impassable, in consequence of the accumulation of water and dirt in the
receptacles occasioned by the sunken stones.
The foundations of the roadways and pavements as now prepared are
thoroughly inconsistent, and although the stones may be laid in the form of
an arch, in that capacity the arch is entirely false because it neither takes a
bearing, nor is it capable of so doing, there being no abutment, and therefore
the moment any portion of the road becomes loaded, instead of the weight
being carried to the abutments, the stones thus burthened descend into the
soil, rendering the streets and pavements wholly unfit for traffic. Again, in
consequence of the moisture after rain remaining in the sunken receptacles
upon the surface, the fact also of the stones being bedded in the soil, and
through the joints of which the moisture percolates to the assumed foundation,
the surface becomes a complete mire on account of the dirt working up to
the surface through the joints between the stones, whilst at the same time the
stones become entirely unfit for the duty they have to perform. The effect
that the traffic must necessarily produce upon the material thus surrounded
by moisture, and the impossibility of such a construction sustaining the
unequal weights or pressure to which it is subjected, and which ultimately
produces the irregularities of the surface as before mentioned, will be readily
understood.
The present means of retaining the thrust of an arch within its span, and
the general mode of framing girders, are of a very complicated nature, and
most expensive and tedious in construction. To meet this want I have devised
the peculiar girder herein-before mentioned, which is applicable to all kinds
of buildings, bridges, and other crections, but especially to a most important
project, namely, the relieving the enormous traffic of the metropolis.
I propose in the construction of roadways to remove the soil so far as may
be necessary, and at suitable distances build solid footings or dwarf walls in
the usual way, and upon these walls or footings I place iron girders of two
thicknesses, the lesser thickness being formed to the slope of an arch, the

page_text: radius being regulated according to the width of the road; the extra thick-
ness I carry down to a small flange, and at the extreme ends of each girder
I leave a given portion of the double thickness the entire depth of the girder.
I cut the inner portion of this extra thickness to form a shoulder to receive
hollow or solid iron bars or stretchers passing from girder to girder; these
stretchers being regulated in size and strength to the occasion and require-
ments, and are cut on the inner side to an angle suitable to the radius of the
proposed arch, and securely fixed by bolts, bands, or otherwise to the girders
at each end. Where the distances of the said girders are of any considerable
extent, or where greater strength is required, I secure one or more iron tie
rods which pass through the entire thickness of the side stretchers, and on
either side secure the same by nuts and screws. Having erected proper
cradling to construct an arch of the desired form, I throw an arch across the
width of the road in stone, brick, iron, or other suitable material abutting
upon the stretchers as prepared, and as herein-before referred to. When I
apply iron for the arch 1 perforate the same in various forms, and when I use
stone or other materials 1 provide openings or inlets in the bars or stretchers
for the rain or other moisture to pass from the surface to the main drains.
In some instances I form the lesser thickness. of the girder in two equal parts,
leaving a space between each part, and in addition to the side angle bars or
stretchers I provide a cross girder or division bar, similarly constructed to the
girders, and secure same between the girder in the centre thereof and also
similar angle or diagonal pieces, which serve to frame and securely combine
the several parts into one complete iron perforated framework. I then fill in
the spaces with iron, stone, brick, wood, or other suitable material, cut to the
form of the proposed arch, and cement or otherwise secure the same together.
On this principle of constructing roads I can excavate the earth or soil
beneath the arch to any required extent, and thereby form subterraneous
roads, footways, or tramways of any description.
In preparing the foundation for pavements I remove the soil a given depth,
and construct at desirable distances sleeper walls of brick or stone, or footings
to receive a framing of iron or other suitable material, having intermediate
divisions or spaces, the form thereof being square, angular, or oblong, as the
case may be, and this framing is perforated throughout the divisions. The
spaces in the framing I fill up with stones, earthenware, tiles, wood, or any
other suitable material. The soil beneath this framing, and between the said
footings, I level and bring up to a hard surface, with a suitable fall, which
will admit of the water running off so soon as the rain or moisture passes
through the perforated framing into the main drain. I construct the curbing

page_text: of the pavement in iron, stone, or otherwise, leaving a space in each length
thereof between the footing, in order to allow the water to pass into the main
drain.
By this mode of construction 1 secure the following desirable objects,
videlicet, avoidance of sinkage of any portion of the pavement, which now
arises in consequence of the uncertain settlements of the soil, and which
frequently occasions accidents.
The deplorable state of the street pavements of large towns after a few
minutes rain, in consequence of the dirt rising and working up through the
joints, and the water accumulating in pools wherever the sunken stones occur,
will by these improvements be entirely obviated, inasmuch as it will be
impossible to alter the level surface of the new pavement, and the moisture
will be immediately carried off through the perforations in the divisions of the
framing, and the stones, tiles, bricks, wood, or other suitable material not
being laid on the soil, but securely fixed in the divisions of the framing, will
prevent the dirt rising as at present, and the constructional nature of the
entire arrangements is calculated to last for many years without any material
repair.
According to another system.-In lieu of the perforated framing and the
filling in, I lay on the said sleepers or footing cast-iron perforated plates the
whole width or space from sleeper to sleeper, securing same to rebates on the
sleepers, and the iron or stone curbing as before.
According to another method.-I prepare, after removing the soil, footings
or sleeper walls as before, and place thereon a particular formed cast or
wrought iron girder with a single flange, and of the form and on the principle
before referred to, and at the end of cach, and on either side, I leave solid a
portion of this girder of an extra thickness. I then place within this extra
thickness a solid iron slab skewback, and 1 form the curbing, which is either
in iron, stone, or other suitable material, the inner side thereof as a skewback
of a similar rake to the opposite side. I then throw an arch across the space
or width of the proposed pavement in brick, stone, or any other suitable
material, cut and formed to fit the said skewbacks, taking care to bring the
entire surface to one uniform level, and it will be clearly seen that by this
means it will be impossible for any portion of the pavement to give way; and
although in this instance perforations are not provided, the rain or moisture
will speedily run off the inclined surface, and the accumulation of the soil and
wet on the pavement will be effectually prevented in consequence of the arch
being entirely clear of the soil.
According to another method, but still adhering to the former foundations,

page_text: in lieu of the framing, as herein-before mentioned, I lay between the spaces
from sleeper to sleeper, or from dwarf wall to dwarf wall, two or more layers
of tiles, breaking joint in cement, making up, and bringing the pavement to a
solid and complete surface with asphalte or other suitable materials. It will
be here observed that the pavement cannot fail to retain its level condition,
and all dirt will be entirely prevented from rising to the surface.
The peculiar girders, herein-before referred to, with intermediate iron
framing are well adapted for fire-proof buildings, in which case I fill in the
spaces with stone, brick, layers of tiles in cement, or any other fire-proof
material, and by this means 1 form a complete level floor without thrusting
pressure on the side walls.
And in order that my said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the annexed Sheet of Drawings, the same
letters of reference indicating corresponding parts in all the corresponding
Figures.
Figure 1 of my Drawings represents a complete trausverse vertical section
and perspective view of a street or roadway constructed according to my said
Invention; Figure 2 represents a detail side elevation on a larger scale of my
improved girder; Figure 3 is a corresponding plan of the same; Figure 4 is a
transverse section thereof showing the adjoining ends of the skewbacks;
Figure 5 is an enlarged plan of one end of one of the skewbacks, showing the
mode of shaping it to fit against the side of the girder; Figure 6 is an end
elevation of the same; Figure 7 is an elevation of a portion of the outer
side or face of one of the skewbacks; Figure 8 is a transverse section of the
same in its place on the end of the girder, and showing the water ducts inside
thereof; Figure 9 is a perspective transverse sectional elevation of a girder
made in two halves united together, and provided with openings for the free
escape of water therethrough; Figure 10 is a plan on a smaller scale shewing
the general combination of the girders and longitudinal skewbacks; Figure
11 is a plan showing two modes of constructing the foot pavement; and
Figure 12 is a vertical section of a portion of the same.
A, A, are two solid footings or dwart walls of brick or masonry, which are
built on opposite sides of the excavation intended to form the subway B under
the street paving C. Resting upon and bridging across the space between
these dwarf walls are a series of wrough-iron girders D, D, placed at con-
venient distances apart, and maintained at such distances by the intermediate
longitudinal skewbacks E, E, which abut at their opposite ends against the
sides of the girders, and obtain their support therefrom. The section of the

page_text: girder between its ends is an inverted T, the longitudinal vertical rib a being
curved or arched to any desirable radius, according to the width of the road.
At the two extremities the girder is thickened, as shown at b, b, to the full
width of the bottom flange c, such thickened portion extending the full depth
of girder at those parts, and being sloped on the inner side to an angle corre-
sponding to the radius of the arch. The ends of the skewbacks E obtain a
firm bearing upon the flange c of the girder, and against the sloped face of the
thickened end b of the girder, and may or may not be secured in their places
by bolts, bands, or other well-known appliances. The inner sides or faces of
the skewbacks are also sloped to the angle of the radius of the arch, as shown
clearly in Figures 1 and 8 and in the dotted lines at Figure 2, and are provided
with water ways or ducts d, d, for the free escape of the surface water to the
drains below; an arch e of stone, brick, iron, or other suitable material (shown
clearly in Figure 1), is now constructed by the aid of proper cradling across the
roadway so as to abut upon the skewbacks, which, being firmly united or tied
together by the cross girders D, D, act as the abutment piers for receiving the
whole of the thrust of the arch, the dwarf walls merely serving as vertical
supports for the load. If iron be used for the arch, it is perforated to allow
the surface water to flow off freely, but if stone paving be used the water may
flow away through the ducts d, d, in the bars or skewbacks E, and through
ducts or openings d', d', made in the girders, as shown in Figure 9, which
represents a girder composed of two halves D, D', held together by bolts or
otherwise, but having pieces of iron f, f, interposed at intervals between the
junction faces so as to leave a row of openings d' through the centre of the
girder.
Figure 1 illustrates also my method of constructing foot pavements. The soil
having been removed to a given depth, sleeper walls or footings F, F, of
brick or stone are. constructed at the proper distance asunder, according to
the width of footway, and upon these footings are laid framings G, as shown in
Figures 11 and 12, of iron or other suitable material, which is perforated
to allow the wet to escape, and has its square, oblong, or other shaped spaces
fitted in with correspondingly shaped stones, earthenware, tiles, wooden
blocks, or slabs of other suitable material, as shown at H, H; the surface of
the soil, which is some inches below this framing and blocks, is hardened and
laid with tiles I, or otherwise finished to a smooth inclined surface, as represented
in Figure 1, with a view to the easy flow of the water whieh has percolated
the pavement into the concealed gutter K, whence it passes to the main drain
through openings left at intervals in the curbing L, which may be of iron or
stone. In lieu of using a frame G, having blocks H inlaid therein, perforated

page_text: cast iron plates M (Framing 11) may be laid across from footing to footing,
as shown in Figure 1.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent is,--
First, the peculiar form of girder, and its combination with longitudinal
bars, stretchers, or skewbacks, substantially as and for the purposes herein-
before described.
Second, the peculiar construction of skewback, and the mode of applying
the same to a girder, substantially as and for the purposes herein-before
specified.
Third, the construction of roads and streets in such a manner that the thrust
of the arch of the pavement shall be retained within its immediate span as
herein-before described.
Fourth, the peculiar mode of constructing the foot pavement of roads or
streets, as herein-before described.
Fifth, the application of my peculiar girder and skewbacks or longitudinal
bars in the construction of fire-proof buildings and other erections, where it is
important that the thrust of the arch shall be retained within its immediate
span, as herein-before described.
In witness whereof, I, the said Constantine Henderson, have to this
my Specification set my hand and seal, the Thirty-first day of July,
in the year of our Lord One thousand eight hundred and sixty-five.
CONSTA AUTENG
HENDERSON