U.S. patent number 3,736,716 [Application Number 05/132,186] was granted by the patent office on 1973-06-05 for means for reducing slippage of steel beam relative to concrete slab.
This patent grant is currently assigned to Long Span Bridge Consultants Inc.. Invention is credited to Akira Nishimura.
United States Patent |
3,736,716 |
Nishimura |
June 5, 1973 |
MEANS FOR REDUCING SLIPPAGE OF STEEL BEAM RELATIVE TO CONCRETE
SLAB
Abstract
A slip-preventive means to prevent a steel beam from slipping
relative to a concrete slab in a bridge or the like structure,
which includes one or more ribs welded to the upper flange of the
steel beam, the ribs being connected to reinforcing iron bars in
the concrete slab.
Inventors: |
Nishimura; Akira (Sakyo-ku,
Kyoto City, JA) |
Assignee: |
Long Span Bridge Consultants
Inc. (Chuo-ku, Tokyo, JA)
|
Family
ID: |
12305607 |
Appl.
No.: |
05/132,186 |
Filed: |
April 7, 1971 |
Foreign Application Priority Data
|
|
|
|
|
Apr 11, 1970 [JA] |
|
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45/30503 |
|
Current U.S.
Class: |
52/334;
52/667 |
Current CPC
Class: |
E04B
5/29 (20130101) |
Current International
Class: |
E04B
5/17 (20060101); E04B 5/29 (20060101); E04b
001/38 () |
Field of
Search: |
;52/334,667,684 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Faw, Jr.; Price C.
Claims
What is claimed is:
1. Slip preventive means for reducing undesired movement between
structure steel beams and a concrete structure which the beams
support, comprising a structural beam including a central web
portion and a perpendicular flange portion, first and second
longitudinal extending spaced parallel rib members affixed to said
flange, each rib including means defining a plurality of spaced
openings extending through each of said ribs, said openings in said
first and second ribs arranged along a mutual alignment axis, said
axis extending parallel to said flange and perpendicular to the
longitudinal axis of said beam, and metal rods constituting a
portion of the reinforcing system of the concrete structure
extending through at least one selected aligned pair of openings in
said rib members whereby to impede undesired slip between said
concrete structure and said structural beam.
2. A slip-preventive means as claimed in claim 1 in which the ribs
have open notches for receiving the reinforcing iron bars
therein.
3. A slip-preventive means as claimed in claim 1 in which there are
at least two steel beams and said iron bars extend between and are
connected to the ribs of each respective beam.
4. A slip-preventive means as claimed in claim 3 in which the ribs
have holes for passing the reinforcing iron bars therethrough, the
holes being in registry such that each registered set on two
respective beams will receive one continuous iron bar.
5. A slip-preventive means as claimed in claim 4 in which each set
of registered holes retains two reinforcing iron bars, one
positioned above the other.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a means for preventing a steel beam for
slipping relative to its coacting concrete slab.
2. Description of Prior Art
When a bridge or bridge-like structure is formed by making a steel
skeleton and forming concrete slabs on the steel skeleton, upon
loading on the bridge or the like structure, a force is produced in
the steel beams of the skeleton which tends to cause the steel
beams to slip relative to the concrete slab in the longitudinal
direction of each beam. One method of preventing the concrete slab
from being separated from the steel beams is to weld a plurality of
U-shaped or horsehoe-shaped dowels to the slab-facing side of the
steel beams. Thus, the steel beam surface is roughened to increase
the contact area between the steel beam and the concrete slab.
Such conventional practice, however, has a shortcoming in that it
is time-consuming to weld many dowels to the steel beam one by one
and that the use of extra dowels makes the structure costly.
SUMMARY OF THE INVENTION
An object of the present invention is to obviate the aforesaid
difficulties of the conventional practice, by providing an improved
slip-preventive means prevent a steel beam from slipping relative
to a concrete slab. According to the present invention, steel beams
are welded to those reinforcing iron bars in the concrete slab
which extend at right angles to the longitudinal direction of the
steel beams, so that slipping of the steel beams relative to the
concrete slab can effectively be prevented by the shearing strength
of the reinforcing iron bars thus welded to the steel beams. With
the slip-preventive means of the present invention, the need for
extra dowels and the time-consuming process of welding the dowels
to the steel beam are completely eliminated. Furthermore, with the
present invention, proper disposition of reinforcing iron bars is
ensured in the concrete slab.
BRIEF DESCRIPTION OF THE DRAWING
For a better understanding of the invention, reference is made to
the accompanying drawings, in which:
FIG. 1 is a schematic perspective view of a structure which
incorporates the slip-preventive means constructed according to the
present invention;
FIG. 2 is a vertical sectional view of an essential portion of the
structure of FIG. 1, taken at right angles to the longitudinal
direction of steel beams therein;
FIG. 3 is a vertical sectional view of the structure, taken along
the longitudinal direction of the steel beams; and
FIG. 4 is a schematic perspective view of another embodiment of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 to 3, a steel beam a for a bridge or the like
structure comprises a web 1, an upper flange 2 and a lower flange
3. One or more ribs 4 (two ribs are shown in the embodiment of FIG.
1) are welded to the upper surface of the upper flange 2 of each
beam a, so as to extend in parallel with the longitudinal direction
of the steel beam. Holes 5 are bored through the rib 4, for passing
reinforcing iron bars 6 therethrough. Additional reinforcing iron
bars 7 may be provided above the aforesaid bars 6 penetrating
through the holes 5 of the ribs 4. A concrete slab b is formed by
pouring concrete 8 in a space surrounding the reinforcing iron bars
6 and 7.
The construction of the rib 4 is not restricted to that which is
shown in FIG. 1. For instance, in another embodiment of the
invention as shown in FIG. 4, U-shaped notches 105 are formed on a
rib 104 welded to the upper flange 102 of a steel beam, and no
holes are bored therethrough.
Thus, with the aforesaid construction according to the present
invention, it is possible to provide a concrete slab b which
comprises one or more ribs 4 welded to upper flanges 2 of support
beams, reinforcing iron bras 6 disposed in the slab and passing
through the ribs 4 at either holes 5 or notches 105, optional
reinforcing steel bars 7, and concrete 8 surrounding the
reinforcing iron bars.
If the ribs of FIG. 4 are used, the reinforcing iron bars 6 can
properly be disposed simply by laying them in the slab while
fitting them in the notches 105 of the ribs 104.
With the aforesaid construction of a structure, according to the
present invention, any force caused by load on the structure in
such a direction as to force the steel beam a to slip relative to
the concrete slab b is borne by the shearing strength of the
reinforcing iron bars 6 connected to the ribs 4 welded to the steel
beam a. Thus, the slipping between the concrete slab b and the
steel beam a can be prevented more effectively by the construction
of the present invention than by conventional construction using
roughened surfaces of steel beams. More particularly, as compared
with conventional slip-preventive means using dowels disposed
between the concrete slab and the steel beam, the slip-preventive
means according to the present invention is more effective, because
the concrete slab b is directly connected to the steel beams a.
In FIG. 4, the notches 105 are shown made vertically. But the
notches 105 may be cut in inclined direction to increase the
rigidity of overall construction.
Furthermore, according to the present invention, the reinforcing
iron bars can very easily be disposed, and orderly positioning of
the reinforcing iron bars is ensured.
* * * * *