U.S. patent application number 11/545548 was filed with the patent office on 2007-05-17 for method for casting hollow core slabs.
This patent application is currently assigned to Elematic Oy Ab. Invention is credited to Aimo Seppanen.
Application Number | 20070107334 11/545548 |
Document ID | / |
Family ID | 35185177 |
Filed Date | 2007-05-17 |
United States Patent
Application |
20070107334 |
Kind Code |
A1 |
Seppanen; Aimo |
May 17, 2007 |
Method for casting hollow core slabs
Abstract
A method for producing hollow-core slabs substantially with a
horizontal slipforming process, the concrete mix to be cast being
fed in said method through a limited cross section to form a
product with a desired form, whereby the areal weight of the
hollow-core slab to be cast is changed by changing the width of the
hollow core of the hollow-core slab and/or by casting a part of the
hollow-cores to be solid.
Inventors: |
Seppanen; Aimo; (Saaksmaki,
FI) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Elematic Oy Ab
Toijala
FI
|
Family ID: |
35185177 |
Appl. No.: |
11/545548 |
Filed: |
October 11, 2006 |
Current U.S.
Class: |
52/236.8 |
Current CPC
Class: |
B28B 17/009 20130101;
B28B 1/084 20130101; B28B 7/30 20130101 |
Class at
Publication: |
052/236.8 |
International
Class: |
E04H 1/00 20060101
E04H001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 14, 2005 |
FI |
20051037 |
Claims
1. A method for producing hollow-core slabs substantially with a
horizontal slipforming process, the concrete mix to be cast being
fed in said method through a limited cross section to form a
product with a desired form, wherein the areal weight of the
hollow-core slab to be cast is changed by changing the width of the
hollow core of the hollow-core slab and/or by casting a part of the
hollow-cores to be solid.
2. A method according to claim 1, wherein the height of the hollow
core of the product to be cast is kept substantially constant.
3. A method according to claim 1, wherein the width of the hollow
core is changed by changing the hollow-core forming element of the
casting apparatus to be used.
4. A method according to claim 1, wherein the casting of a hollow
core to be solid is provided by removing the hollow-core forming
element from the casting apparatus to be used.
5. A method according to claim 1, wherein the width of at least one
of the hollow cores of a hollow-core slab to be cast differs from
the width of the rest of the hollow-cores.
6. A method according to claim 2, wherein the width of the hollow
core is changed by changing the hollow-core forming element of the
casting apparatus to be used.
7. A method according to claim 2, wherein the casting of a hollow
core to be solid is provided by removing the hollow-core forming
element from the casting apparatus to be used.
8. A method according to claim 3, wherein the casting of a hollow
core to be solid is provided by removing the hollow-core forming
element from the casting apparatus to be used.
9. A method according to claim 6, wherein the casting of a hollow
core to be solid is provided by removing the hollow-core forming
element from the casting apparatus to be used.
10. A method according to claim 2, wherein the width of at least
one of the hollow cores of a hollow-core slab to be cast differs
from the width of the rest of the hollow-cores.
11. A method according to claim 3, wherein the width of at least
one of the hollow cores of a hollow-core slab to be cast differs
from the width of the rest of the hollow-cores.
12. A method according to claim 4, wherein the width of at least
one of the hollow cores of a hollow-core slab to be cast differs
from the width of the rest of the hollow-cores.
13. A method according to claim 6, wherein the width of at least
one of the hollow cores of a hollow-core slab to be cast differs
from the width of the rest of the hollow-cores.
14. A method according to claim 7, wherein the width of at least
one of the hollow cores of a hollow-core slab to be cast differs
from the width of the rest of the hollow-cores.
15. A method according to claim 8, wherein the width of at least
one of the hollow cores of a hollow-core slab to be cast differs
from the width of the rest of the hollow-cores.
16. A method according to claim 9, wherein the width of at least
one of the hollow cores of a hollow-core slab to be cast differs
from the width of the rest of the hollow-cores.
Description
[0001] The present invention relates to a method for casting hollow
core slabs with a slipforming process. More precisely, the
invention relates to casting of hollow core slabs having a
substantially standard height with a desired areal weight by means
of the extruder slipforming technique.
[0002] In the extruder slipforming technique, the mass to be cast,
like the concrete mix in general, is extruded by means of feed
screws through a mold or nozzles, and the casting apparatus
proceeds driven by the reacting force of the feed screws. The
ready-cast product remains on the casting bed. The hollow cores of
the product to be cast are formed by means of hollow core mandrels
of desired shape following the feed screws, the concrete mix being
extruded over the mandrels.
[0003] The hollow-core slabs cast with extruder technique are
traditionally manufactured with cross-sections standardized by the
equipment suppliers. In these standard slabs the height of the slab
is increased, whereas the number of the hollow cores and the number
of the mandrels, respectively, decreases. Normally the standard
slabs have hollow cores with constant sizes, whereby also the areal
weight of the slab is constant. The building systems using
hollow-core slabs have been designed based on the height of these
standard slabs. The most essential objects of use of hollow-core
slabs in the building industry are the intermediate floors of
buildings.
[0004] Soundproofing requirements, especially related to the impact
sound, have increased the need of using more massive hollow-core
slabs in the buildings. This has led to a need of using higher
hollow core slabs in order to achieve the required massiveness of
the slab. The use of higher slabs, however, has the effect, that
higher wall elements must be used with these slabs. All such
manufacturing sizes differing from the standard building systems
considerably increase the construction costs of buildings.
[0005] In the present invention, the height of the hollow-core
slabs to be produced corresponds to the standard heights defined
for the hollow-core slabs to be produced, in other words, the slab
heights typified by the constructor. The required areal weights of
the slabs are adjusted to fulfill the requirements by changing the
width of the hollow cores of the hollow-core slab.
[0006] More precisely, the method according to the invention is
characterized by what is stated in the characterizing part of Claim
1.
[0007] The invention will be described by way of example in more
detail in the following with reference to the enclosed drawings,
wherein
[0008] FIGS. 1a-1d show cross-sectional views of four exemplifying
hollow-core slabs having different areal weights with the same slab
height, implemented with the method of the present invention,
and
[0009] FIG. 2 shows a cross-sectional view of an alternative
hollow-core slab implemented with the method of the present
invention.
[0010] FIG. 1a shows a cross-sectional view of a hollow-core slab
cast by means of the method of the present invention, said
hollow-core slab having the smallest areal weight among the
hollow-core slabs shown in FIGS. 1a-d, for example about 302
kg/m.sup.2. The exemplified hollow-core slab of FIG. 1a is cast
with wider hollow-core forming elements than the feed screw,
whereby the width of the hollow core is the biggest among the
examples of FIGS. 1a-d.
[0011] FIG. 1b shows a cross-sectional view of a hollow-core slab
having a slightly bigger areal weight than the example of FIG. 1a,
said hollow-core slab having for example an areal weight of about
350 kg/m.sup.2. The example of this Figure has been produced with
hollow-core forming elements having substantially the width of the
feed screws, whereby the width of the hollow core of the product
corresponds to the width of the feed screw.
[0012] FIG. 1c shows a cross-sectional view of a hollow-core slab
having a bigger areal weight than the example of FIG. 1b, said
hollow-core slab having for example an areal weight of about 380
kg/m.sup.2. The example of this Figure has been produced by using
hollow-core forming elements having a smaller width than the feed
screw, thus providing narrower hollow-cores than the width of the
feed screw.
[0013] FIG. 1c shows a cross-sectional view of a hollow-core slab
having the biggest areal weight among the examples of FIGS. 1a-d.
In the case of this slab, a part of the hollow cores are cast
totally solid, whereby for example an areal weight of about 476
kg/m.sup.2 can be achieved. When producing this slab, hollow-core
forming elements have been removed after desired feed screws, and
with the rest of the feed screws, narrower hollow-core forming
elements than the width of the feed screw have been used, as shown
in the example of FIG. 1c.
[0014] FIG. 2 shows a modification of the cross-sections of the
hollow-core slabs cast with the method according to the present
invention, shown in FIGS. 1a-1d. The slab having the cross-section
shown in this Figure has been produced so that connected with some
of the feed screws narrower hollow-core forming elements are used
for forming narrower hollow-cores into the hollow-core slab, and
respectively connected with the other feed screws wider hollow-core
forming elements are used for forming wider hollow cores into the
hollow-core slab.
[0015] By means of the solution according to the example of FIG. 2,
the areal width of the hollow-core slab can be adjusted between the
examples shown in FIGS. 1a-d, and thus the amount of the
hollow-core forming elements needed for adjusting the areal weight
can be decreased. The areal weight of the example of this Figure is
for example about 362 kg/m.sup.2, in other words, between the areal
weights of the hollow-core slabs shown in FIGS. 1b and 1c, whereby
as well hollow-core forming elements used for casting the
hollow-core slabs of FIG. 1b as those of FIG. 1c have been
used.
[0016] With the method according to the invention, as described
above, hollow-core slabs having with the same slab height different
areal weights can be produced by changing the width of the hollow
core of the hollow-core slab or by casting a part of the hollow
cores of the hollow-core slabs solid. In this way, the constructors
can be supplied with slabs suitable for different types of sound
isolation solutions without drawbacks characteristic of the
solutions of prior art.
[0017] In the method according to the present invention, the height
of all hollow cores of the weight series meant for one and the same
slab height is substantially constant.
[0018] Among others, the following advantages can be reached by the
method according to the invention: [0019] for changing the areal
weight of the hollow-core slabs to be cast having the same height,
only the hollow-core forming elements of the slipforming apparatus
need to be changed, [0020] the sound insulation of the hollow-core
slabs to be cast can be efficiently and profitably increased,
[0021] the fire endurance of the hollow-core slabs to be cast can
be improved, because the reinforcement strands can be positioned
higher from the bottom of the slab, when the hollow-cores are
narrower than usually, and [0022] existing building systems don't
need to be changed, because the hollow-core slabs with standard
heights can be used.
[0023] The method according to the invention is not limited to the
extruder slipforming technique only, but it can also be applied to
other slipforming techniques like for example slipformer-techique
or casting implemented with fixed casting units.
* * * * *