SYSTEM COMPRISING A COMPOSITE BEAM AND A COMPOSITE PLATE

SYSTEME COMPRENANT UNE POUTRE ET UNE PLAQUE COMPOSITES

English Abstract

(57) Abstract
The object of the invention is a system to be used in the roofs,
ceilings and floors of buildings, formed by a composite beam (2,
12) and composite plate (1), which system consists of a
composite beam (2), composite plates (1) carried by this, and a
cast component (9), and in which the composite beam (2, 12) is
formed of one or more profile plates. The intention of the
invention is to simplify the reinforcement of the system.
According to the invention the composite beam (2, 12) extends
close to the upper surface of the cast component (9) and the
upper section (4) of the composite beam (2, 12) are penetrated
by several transverse long rods (8) and/or bolts, which extend
for a considerable distance outwards from the upper edge of the
composite beam (2, 12) in such a way that they act as upper
surface reinforcement of the continuous slab or as a part of it
at the point of support.
Figure 1

Claims

Patent Claims
1. A system formed by a composite beam (2, 12) and
composite plates (1), for use in the roofs, ceilings, or floors
of buildings, which consists of a composite beam (2) and
composite plates (1) and a cast component (9) carried by this,
and in which the composite beam (2, 12) is formed by one or more
profile plates, characterized in that the composite beam (2, 12)
and its internal cast mass extends close to the upper surface of
the cast component (9) and that the upper section (4) of the
composite beam (2, 1) and its internal cast mass is penetrated
by several transverse long rods (8) and/or bolts, which extend
from the upper edge of the composite beam (2, 12) sideways to
such an extent that they create a perfect or nearly perfect
adhesion between the composite plate and the composite beam.
2. A system in accordance with Patent Claim 1,
characterized in that the transverse rods (8) extend for 20-
100 cm outwards on both sides of the composite beam (2, 12).
3. A system in accordance with Patent Claims 1 or 2,
characterized in that the transverse rods (8) extend for 10- 20
cm outwards on both sides of the composite beam, and that on top
of the composite beam there is separate surface reinforcement
(15), which acts as upper surface reinforcement of the con-
tinuous beam at the point of support.
4. A system in accordance with Patent Claims 1, 2, or 3,
characterized in that the transverse rods (8) are entirely or
partly threaded rods, by means of which the profile section
plates and/or other structures of the system are simultaneously
joined to one another.
5. A system in accordance with one of the above Patent
Claims 1 - 4, characterized in that hollow slabs (17) are used
as part of the composite plates, their end being opened at the
cavities, from which the transverse rods are bent inside and
the ends of the cavities are then cast shut.

Description

1 7 ~
A System comprising a Composite Beam and a Composite Plate
The object of the invention is a system comprising a composite
beam and composite plate for use in the roofs ceilings, or
5 floors of buildings, which consists of a composite beam, the
composite plates and cast components carried by it, and in which
the composite beam is formed of one or more profile plates. In
this the term composite plate also includes a concrete slab cast
on prestressed hollow slabs.
Composite plates and beams and their systems are known from
Finnish Patent Applications 862035, 863396, and from United
States Patent 2,064,910. In addition the profile form systems
known from EP Application Publication 240857 and from Finnish
15 Patent 63465 are broadly concerned with the field of the
invention. In FI Application 86035 a system is proposed, in
which the form for the composite beam is composed of two thin
galvanized steel sheets joined together underneath. Casting
takes place on top of the totality formed by the composite plate
20 and composite beam and thus creates a monolithic structure. In
this the composite beam must be reinforced separately, despite
the fact that the jolnt points beneath the composite beam form
an adhesive edge. Reinforcement is required in the beam itself,
in its attachment to the composite plate and at the beam as
25 upper surface reinforcement.
Finnish Patent Application 875327 shows a concrete frame system,
in which the beam component that is open underneath is cast
beforehand and composite plates are supported on flange members
30 formed in its lower section, and in which the totality formed by
the composite plates and frame beam is cast as one, so that the
construction has excellent fire protection. In the structures
according to Figures 8, 9, and 10 both the adhesion of the
interior of the beam and that between the composite beam and
35 composite plates is not complete.
The intention of the invention is to achieve a more effective
totality formed by a composite beam and composite plates, in
which the structural height in particular could be smaller than
40 previously. The principal characteristics of the invention
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appear in the accompanying Patent Claims. In the system in
accordance with the invention the bars or bolts penetrating the
beam ~ind the bean structure and the slabs so well that th~ slab
components carry the compressive force in the direction sf the
5 beam over a great breadth. In this case the neutral axis rises
considerably, when the height of the tension side increases
proportionately. The invention can also be applied when a bolt
structure is used in the system to hold the various components
together. If the transverse reinforcement is made sufficiently
10 long it can also act as upper surface reinforcement. It is,
however, most advantageously made separately.
In what follows the invention is illustrated with the aid of
the accompanying illustrations, which show various forms of
15 application of the invention.
Figure 1 shows the system in connection with a composite
beam that is open on the underside
Figure 2 shows the form of application that is regarded
as being best
Figure 3 shows a cross-section of Figure 2
Figure 4 shows the system in connection with hollow slabs
The system consists of composite beam profile 2 and composite
25 plates 1, which are carried on the flange 3 of the beam profile.
Composite beam profile 2 is precast and includes cast component
11. At this stage the transverse steel rods 8 are also placed in
the composite beam profile 2. These remain inside cast component
9 and act as upper surface reinforcement of the continuous slam
30 at the; support point. The transverse steel rods 8 are placed
through the holes 5 made close to the upper surface 4 of the
composite beam 2. Here the composite beam includes pre-stressing
elements 6, 7, and 10.
35 In this the transverse steel rods 8 have operational functions.
In addition to their acting as upper surface reinforcement for
the continuous slab at the point of support they connect the
slab to the composite beam, and thirdly they act as adhesion for
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the internal cast mass 11 of the composite beam to the composite
beam profile 2.
On the basis of practical experiments the invention is best
applied in accordance with Figure 2. Here the composite beam is
profiles as a right-angled hat profile, the lower section of
which includes flange components on top of which it is possible
to place the composite plate profiles. A beam with an overall
height of 280 mm is penetrated by steel rods 420 mm long and of
10 16 mm diameter. The beam profile 12 is precast and the trans-
verse steel rods bind the concrete firmly to the profile. The
ready composite beam is set in place and the composite plates 1
are placed on top of the flanges 15. After this casting takes
place as a result of which cast component 9 forms a unified
15 structure on top of the composite plates 1 and the composite
beam. It is most advantageous to use steel net as the surface
reinforcement 13. This extends to each side of the beam by about
a quarter of the span about 0,3 times the breadth of the span of
the compression surface can be transferred from the slam to the
20 beam, when the adhesion between the beam and the slab is
perfect. Figure 3 shows the distribution in principle between
compression and tension in a frame structure in accordance with
the invention. The compression surface area extends strongly to
the slam sections, in which case ths composite beam itself on
25 the tension side acts more effectively.
In one case the composite plate profiles can be also replaced
with hollow slams 17, Figure 4. These are placed in a corres-
ponding manner on top of the flange 15 of the composite beam,
30 but the cavities at their ends are opened for a distance of 50-
100 cm. Longitudinal rods 18 are pushed in from this opening.
These must then be bent downwards, which is not an optimal
solution from the point of view of adhesion, but is a compromi-
se demanded by this construction. During casting the ends of the
35 cavities of the hollow slams are filled with concrete, after
which they will withstand longitudinal compression.
Special note should be made of the fact that the composite beam
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profiles can also be assembled from two or more parts, in which
case the bolts used to assemble them can act as the previously
mentioned transverse steel rods, by which means one or more of
the aforementioned tasks can be carried out. On the other hand,
5 each transverse rod or bolt can only extend to one side of the
beam, but when sequential rods extend to each side in turn
reinforcement on both sides is achieved in thie respect.
. . . . .
. . .

Representative Drawing