PROFILED STEEL DECKING

DISPOSITIF D'ENTREE POUVANT ETRE DEFORME MANUELLEMENT

English Abstract

Profiled steel decking comprises a steel sheet roll formed to define at least
two crests and a trough separated by inclined webs. The boundaries between the
webs and the crests are radiussed to define corners each having a smooth
curvilinear profile.

French Abstract

L'invention concerne un dispositif d'entrée pouvant être déformé manuellement, sensible à une pression exercée manuellement. Ce dispositif d'entrée comprend un matériau électroconducteur (602) pouvant être déformé, conçu pour présenter des variations de conductance (résistance) en réponse à un étirement ou à une compression permettant de quantifier la pression exercée manuellement pour déformer le matériau. Le dispositif d'entrée comprend une interface électrique (604) conçue pour fournir un courant électrique à travers le matériau électroconducteur (602) par l'intermédiaire d'une première borne (605) et d'une deuxième borne (606), le dispositif d'entrée comprenant également une troisième borne (607) connectée à une position intermédiaire par rapport à la première et à la deuxième borne. L'interface électrique (604) est conçue pour recevoir une tension provenant de la troisième borne (607), indiquant l'amplitude de la chute de tension à travers le matériau électroconducteur (602). Le dispositif d'entrée fonctionne comme un diviseur de potentiel sensible à une opération manuelle, quelle que soit la conductance absolue (résistance) du matériau électroconducteur (602).

Claims

7
WHAT IS CLAIMED IS:
1. Composite structure for a floor or ceiling comprising a profiled steel
decking
bonded to a layer of concrete poured on said steel decking which comprises a
steel
sheet roll formed to define at least two crests (1) and a trough (2) separated
by
inclined webs (3), the decking being characterised in that boundaries between
the
webs (3) and the crests (1) are radiussed to define corners each having a
smooth
curvilinear profile (8), the radius of each such corner being between 15 and
30mm.
2. A composite structure as claimed in claim 1, wherein the curvilinear
corners
have a radius of between 20 and 25mm.
3. A composite structure as claimed in claim 1 or 2, wherein each inclined web
of
the steel decking includes two or more vertically spaced linear rows of
embossments
which extend outwardly from the outer surface of each inclined web.
4. A composite structure as claimed in claim 3, wherein each embossment is
generally circular in section and is produced by roll forming.
5. A composite structure as claimed in claim 3 or 4, wherein each embossment
of an uppermost row is positioned above a land portion separating neighbouring
embossments of a lowermost row.
6. A composite structure as claimed in any one of claims 3 to 5, wherein the
diameter of each embossment lies within the range 9.0 to 15.0mm.
7. A composite structure as claimed in any one of claims 3 to 6 wherein the
spacing between the centres of neighbouring embossments lies within the range
30
to 40mm.

8
8. A composite structure as claimed in any one of claims 3 to 7, wherein the
vertical distance between the upper and lower rows of embossments is between
27
and 37mm.
9. A composite structure as claimed in any one of claims 1 to 8, wherein the
trough between the two crests of the decking is formed with two stiffening
ribs each
of which is spaced generally equidistant from a lowermost end of the
respective
inclined web.
10. A composite structure as claimed in claim 9, wherein a flange portion,
defined
between the stiffening ribs provides a site for shear stud connectors.
11. A composite structure as claimed in claim 9 or claim 10 wherein the width
of
each stiffening rib of the trough is between 15 and 25mm.
12. A composite structure as claimed in any one of claims 1 to 11, wherein
each
crest is formed with a generally 'V' shaped projection which, in use, defines
a shear
connector between the decking and a concrete layer cast over the upper surface
of
the decking.
13. A composite structure as claimed in any one of claims 1 to 12, wherein the
angle subtended by each inclined web to the horizontal lies within the range
of 75 to
85°.
14. A composite structure as claimed in any one of claims 1 to 13 roll formed
from
galvanised steel sheet whose gauge is between 0.8 and 1.3mm.

Description

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1
PROFILED STEEL DECKING
This invention relates to profiled steel decking. More especially, the
invention concerns profiled steel decking for use inter alia as a component
of a composite slab comprising steel decking bonded to a layer of concrete
cast in situ over the upper surface of the decking.
Composite structures produced by pouring light or normal weight
concrete onto steel decking are used widely in the building industry for
flooring and/or ceiling units. Conventionally, steel decking comprises one
or more sheets of steel roll formed to create one or more crests and
troughs separated by inclined webs. Shear stud connectors are
traditionally used to provide enhanced bonding between the steel decking
and the concrete layer. These shear stud connectors are placed in the
trough positions of the decking and are enveloped by the concrete layer
when it is cast.
Traditionally, the crests and troughs of profiled steel decking are
generally flat with the corners between the crests and the uppermost ends
of the inclined webs defined by acute angles. Also, the surfaces of the
inclined webs of traditional steel decking are generally planar. The
bending capacity of such profiles is limited.
Examples of traditional steel decking are to be found in US Patents
4144369, 4453364, 4593506, 4675238, 4726159, 4962622 and 3812636.
In each of these documents, the corners between the crests of the
decking and the uppermost ends of the webs are defined by acute angles.
The present invention sets out to provide improved profiled steel
decking which exhibits clear advantages over traditional steel decking.
CONFIRMATION COPY

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2
According to the present invention in one aspect, there is provided
a composite structure for a floor or ceiling comprising a profiled steel
decking bonded to a layer of concrete poured on said steel decking which
comprises a steel sheet roll formed to define at least two crests and a
trough separated by inclined webs, the decking being characterised in that
boundaries between the webs and the crests are radiussed to define
corners each having a smooth curvilinear profile, the radius of each such
corner being between 15 and 30mm.
Typically, the curvilinear corners have a radius of between 20 and
25mm.
Each inclined web of the steel decking may include two or more
vertically spaced linear rows of embossments which extend outwardly
from the outer surface of each inclined web. Each embossment may be
generally circular in section and may be produced by roll forming. Each
embossment of the uppermost row may be positioned above a land
portion separating neighbouring embossments of the lowermost row. The
diameter of each embossment preferably lies within the range 9.0 to
15.0mm. A typical diameter is 12.0mm. The spacing between the
centres of neighbouring embossments preferably lies within the range 30
to 40mm. A typical spacing is 35mm. The vertical distance between the
upper and lower rows may be between 27 and 37mm. A typical distance
being 32mm.
The trough between the two crests of the decking may be formed
with two stiffening ribs each of which is spaced generally equidistant from
the lowermost end of the respective inclined web. The flange portion
defined between the stiffening ribs may provide a site for shear stud
connectors.
The width of each stiffening rib of the trough may be between 15
and 25mm. Typically, the width of one rib is 21mm and that of the other
rib 20mm.

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Each crest may be formed with a generally `V' shaped projection
which, in use, defines a shear connector between the decking and a
concrete layer cast over the upper surface of the decking.
The angle subtended by each inclined web to the horizontal
preferably lies within the range of 75 to 850. A typical angle is 78.5 .
The decking is preferably roll formed from galvanised steel sheet
whose gauge is between 0.8 and 1.3mm. Typically gauges are 0.9 to
1.2mm. The decking is preferably manufactured using a high grade steel
having, typically, a yield value of 500 N/mm2.
The invention will now be described by way of example only, with
reference to the accompanying diagrammatic drawings, in which:-
Figure 1 is an end view of profiled steel decking in accordance with
the invention;
Figure 2 is a scrap side view to an enlarged of a section of the
decking illustrated in Figure 1;
Figure 3 is a scrap plan view from above of a section of the steel
decking shown in Figure 1; and
Figure 4 is a side view of a connection between neighbouring steel
deckings in accordance with the invention.
The steel decking illustrated in the drawings is roll formed from a
single sheet of galvanised steel and comprises two crests 1 separated by a
trough 2. Each crest is bordered with two outwardly inclined webs 3. The
lower ends of the webs are bordered by outwardly extending end laps 4,
5. Each of these end laps 4, 5 is formed with interlocks 6, 7 respectively

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which cooperate with complementary interlocks of neighbouring steel
decks to increase the effective span of the overall steel decking.
The gauge of the steel sheet from which the decking is roll formed
is typically between 0.9 and 1.5mm. A preferred gauge is 1.2mm. The
steel sheet may be coated with a bonded plastics film for protective and
aesthetic purposes. Alternatively, the sheet may be formed with a
polyester coating.
As will be seen from the drawings, the corners between the crests
1 and the adjoining webs 3 are radiussed to produce a curvilinear profile
8. These curvilineal profiles increase the bending capacity of the decking
and add strength particularly in the corner regions to inhibit failures which
occur with traditional decking. The added strength enables the span
lengths of the decking to be increased.
The actual radius of any given profiled corner 8 will depend inter
a/ia on the required dimensions of the decking. Typically, the selected
radius will be between 20 and 30mm. Preferred radii are 23.8 and 25mm.
The span of each radiussed corner is typically between 30 and 35mm. A
preferred span is 32.3mm.
As will be seen from Figures 1 and 2, each web 3 is formed with
two vertically spaced linear rows of embossments 6 which project
outwardly from the web surfaces. These embossments are produced
during the roll forming process and the boundary between each
embossment and the adjoining web surface is circular. Typically, the
diameter of each embossment is in the range 9.0 to 15.00mm. A
preferred diameter is around 12.0mm.
As will be seen from Figure 2, the embossments of the upper row
are displaced linearly with respect to those of the lower row such that
each upper embossment is positioned above a land portion of the web

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sited approximately midway between neighbouring embossments of the
lower linear row.
The rows of embossments extend along the entire length of each
web and their presence enhances the bond between the decking and the
concrete layer which, in use, is poured over the upper surface of the
decking. Typically, the vertical spacing between the rows is in the range
30 to 35mm (measured between embossment centres); a preferred
distance is 32mm. Typically, the centres of the embossments of the lower
row are positioned between 13 and 18mm from the respective side laps 4,
5, a preferred distance being 15.9mm. The centres of the embossments
of the upper row are typically positioned between 10 and 15mm below the
lowermost point of the respective radiussed corner, a preferred distance
being 12.2mm.
The spacings between the centres of neighbouring embossments of
both the upper and lower rows is typically between 32 and 37mm, a
preferred spacing being 35mm.
The shape and dimensions of the embossments may vary from
those illustrated and discussed. Thus, the embossments could be ovoid or
generally rectangular.
Each crest 1 includes a linear row of hollow projections 9 each of
whose interior is generally dovetailed in section. These projections are
produced during the roll forming process and define shear connectors
between the steel decking and the concrete layer which is poured over the
upper surface of the decking in use. The dovetail shaping of each
projection allows hangers to be supported therein. The diameter of the
lower neck of each projection is typically 12mm and the overall height of
each projection is typically 15mm. As will be seen from the drawings, the
joins between the crest and the projection are curvilinear. The crests are
also formed with two inwardly projecting longitudinal ribs 11 for stiffening

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purposes. The width of these ribs are typically between 9 and 10mm. A
preferred width is 9.5mm.
The trough 2 is formed with two longitudinal upwardly projecting
ribs 14, 15 separated by a solid land section through which shear stud
connectors can be positioned. The presence of the ribs assists accurate
location of shear stud connectors in use of the decking. The width of each
rib 14, 15 is typically 21mm and the spacing between the ribs is typically
50mm.
Each end lap 4, 5 carries an interlock. These extend along the
entire length of each end lap and are shaped in a complementary fashion
to enable two or more steel decks to be joined together to produce a
decking of any required width.
It will be appreciated that the foregoing is merely exemplary of
steel decking in accordance with the invention and that various
modifications can readily be made thereto without departing from the true
scope of the invention as set out in the appended claims.

Representative Drawing