IMPROVEMENTS IN GIRDERS
Year: 1885

page_text: I, THOMAS DYKES of 65 West Regent Street Glasgow in the County of Lanark,
Architect, do hereby declare the nature of the said invention for "IMPROVEMENTS
IN GIRDERS" and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
This invention, which relates to improvements in girders made of iron, steel, or
other metal, has for its object to combine in such structures the maximum, or a
large degree of strength and lightness with (where the girders are used as supports
for, or in conjunction with wooden flooring or for like purposes) a minimum of
necessity to cut or check out depthwise, the scantling of the timber joists in fitting
same to the girder.
"T
1
The girder constituting the invention' consists of upper and lower flanges,
composed each of one or more thicknesses and lengths of plate; both flanges being
flat, or the lower one flat and the upper one of channel or other desired transverse
section. These flanges are retained at the required distances apart by vertical
plates or pieces to which they are each secured; the said pieces extending either
across the entire' width of the girder or partly across that width; and being
composed of plates of channel, double angle or other transverse section. Any
desired number of such pieces may be employed in the length of the girder, and
from or about the points where they are bolted or connected to the upper and lower
flanges; bracing rods or bars extend in an oblique transverse direction from one
vertical strap or distance piece to another, that is to say, each bar lies diagonally
and crosswise from the point of its connection near the outer edge of the upper
part of one cross distance piece, to a corresponding point near the opposite edge of
the lower part of the next cross distance piece; what may be termed a quadruple
cross-diagonal bracing being thereby constituted.
.
When timber or metallic joists or bars are used with the girders so constructed;
the vertical straps or distance pieces are, or may be, so arranged as to leave at the
required distances, apart, spaces through which the joists or bars may be passed
transversely, and where required fitted so as to rest on a series of the girders, and
this without the necessity of undoing more than each alternate set of vertical
straps or distance pieces, with their relative braces, thus obviating the taking apart
of the main portions of the girders. By another method the upper flange of the
girder may be removed and the timber joists' fitted into the spaces at intervals left
for them through the body of the girder; the upper flange being thereafter refitted

page_text: and secured in position as before. In some cases the vertical cross plates may be
dispensed with long bolts in such instance, serving the double purpose of keeping
the girder flanges in position at the required distance apart and securing the
diagonal bracing.
And in order that my said Invention may be properly understood I have here-
unto appended an explanatory sheet of drawings illustrative of several systems or
modes in or under which it may be used or carried out in practice.
Figure 1, of the drawings is a longitudinal elevation representing several
moditications of detail in the construction of the improved girder; a, being the top
and b, the bottom flange, each composed of a plate, flat in transverse section, as
seen at figures 2, 3, 4, 5, 6 and 7; or as seen at figure 8, the lower flange b, only,
may be flat; the top flange a, being of channel or other desired section.
The top and bottom flanges a, b, are maintained at the proper distances apart
and connected together by vertical plates or straps of channel section bolted in
position as seen at c; or of box section, constituted by two reversed channel plates
as at c¹.
The vertical straps have either a space between their backs as at d, or they are
placed together as at e; or under a modification of the latter arrangement, the
plates may be made of H section as at f, figure 1, To the wings or bearing flanges
of the plates c, braces g, of round or other suitable section are attached either
directly or through separate connecting pieces x, by means of long bolts as at h,
passing right through the girder or by short bolts as at i.
In the former case besides the tightening nuts j, jamb nuts k, are employed to
hold the parts firmly together and when desired the nuts j, at one end of the
bolts h, may be dispensed with; a head being in that case formed on the bolt and
countersunk into one or other of the flanges a, b. Heads may also be formed on
the short bolts, and countersunk into one or other of the flanges so as to obviate
any projections beyond the outer surface of such flange.
The braces g, as seen in transverse section at figures 2, 3, 7, and 8, and in plan
at figures 9, 10, and 11, cross each other, that is to say (looking at the girder
endwise) the two braces connected at the top of one vertical plate or strap c, are by
their other ends connected at the bottom of the next vertical plate or strap thus
forming quadruple cross diagonal bracing.
As seen at figs., 3, and 5, each vertical plate c, may extend right across the top
and bottom flanges, in which case it may be lightened by cutting or punching out
part of the metal, or as seen at figs., 2, 4, 7, and 8, two such plates may be used in
the width of the girder; these being preferably placed in line, near the outer edges
of the top and bottom plates a, b, and with a space left between them. Under
a modification in the bracing, shown in cross section at fig. 12, two braces g,
instead of four may be used between each pair of vertical plates c; the brace in
that case (looking at the girder endwise) extending from the top right or left hand
of one plate c, to the bottom left or right hand of the next and vice versa.
When wooden joists are to be inserted in, and supported by, the girders, the
construction illustrated at A, fig. 1, is adopted, the joists 1, being passed into the
spaces left between each pair of coupled or braced vertical distance and supporting
plates c; the joists passing in the same manner transversely through any desired
number of girders. In so inserting the joists the two vertical plates or two sets of
plates braced together, that is to say, referring to A, fig. 1, the plates marked c*,
are unbolted and removed, and after the insertion of the joists again replaced and
bolted as shown.
The timber joists l, rest on the lower plate b, direct, or when greater strength is
required in the bottom flange, a plate m, may be inserted between the plate b, and
the lower flanges of the vertical plates c, as shown at B, fig. 1; in which case the
joist rests on the said plate m, At its top side the joist is cut or checked out
transversely to receive the plate a, and in such manner that the upper surface of
the timber and the upper surface of the plate are flush with each other; or as seen
at figs., 7, and 8, the upper surface of the joist may project sufficiently above the

page_text: plate or flange a, to admit of the insertion into the checked out portion of the joist
of timber "bridle" pieces o, which permit of the upper surfaces of the joists being
maintained at the level of the flooring boards p, thereby admitting of the flooring
boards being laid parallel with the girders and nailed in position in the ordinary
manner.
C, fig. 1, shows the adaptation of the improved girder to the carriage of metal
The said
joists r, in the space between each coupled pair of vertical straps c.
joists, may, in this case, rest directly on the bottom flange b, as shown; or on a
plate, placed upon the said flange as at m, or on a stool or seat 8, of channel, or
other desired transverse section.
The construction shown at D, fig. 1, is more particularly adapted for the carriage
of loads generally other than joisting, though it, as well as the construction
illustrated at A, B, C, may also have metallic joists, bars, or angle irons, passed
through it transversely where the braces cross as shown at t, and be adapted for
the support of concrete or other floors, or structures.
In some cases where such great stiffness is not required the vertical cross
plates c may be dispensed with and only the bolts and bracing used to connect the
upper and lower flanges of the girder as illustrated at figs., 13, 14, 15, and 16, of
the drawings annexed.
Having 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
First. The improved girder consisting of top and bottom flanges, connected
together by vertical distance and supporting pieces of channel, I, or analogous
section, these being tied together in pairs or continuously by two or four braces
extending diagonally from top to bottom, and transversely, from side to side, with
or without a space between the pairs so tied as and for the purposes set forth with
reference to the drawings appended.
Second-The improved girder consisting of top and bottom flanges tied together
and kept by bracings at desired distances apart, each such bracing consisting of
two or four bars extending diagonally from top to bottom and transversely from
side to side of the girder substantially as described.
Tintinth 1st 100×