CA1124543A - Externally reinforced concrete stairs - Google Patents
Externally reinforced concrete stairsInfo
- Publication number
- CA1124543A CA1124543A CA341,081A CA341081A CA1124543A CA 1124543 A CA1124543 A CA 1124543A CA 341081 A CA341081 A CA 341081A CA 1124543 A CA1124543 A CA 1124543A
- Authority
- CA
- Canada
- Prior art keywords
- soffit
- members
- bottom wall
- stressed
- sidewalls
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04F—FINISHING WORK ON BUILDINGS, e.g. STAIRS, FLOORS
- E04F11/00—Stairways, ramps, or like structures; Balustrades; Handrails
- E04F11/02—Stairways; Layouts thereof
- E04F11/022—Stairways; Layouts thereof characterised by the supporting structure
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G13/00—Falsework, forms, or shutterings for particular parts of buildings, e.g. stairs, steps, cornices, balconies foundations, sills
- E04G13/06—Falsework, forms, or shutterings for particular parts of buildings, e.g. stairs, steps, cornices, balconies foundations, sills for stairs, steps, cornices, balconies, or other parts corbelled out of the wall
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G13/00—Falsework, forms, or shutterings for particular parts of buildings, e.g. stairs, steps, cornices, balconies foundations, sills
- E04G13/06—Falsework, forms, or shutterings for particular parts of buildings, e.g. stairs, steps, cornices, balconies foundations, sills for stairs, steps, cornices, balconies, or other parts corbelled out of the wall
- E04G13/062—Falsework, forms, or shutterings for particular parts of buildings, e.g. stairs, steps, cornices, balconies foundations, sills for stairs, steps, cornices, balconies, or other parts corbelled out of the wall for stairs or steps
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04F—FINISHING WORK ON BUILDINGS, e.g. STAIRS, FLOORS
- E04F11/00—Stairways, ramps, or like structures; Balustrades; Handrails
- E04F11/02—Stairways; Layouts thereof
- E04F2011/0203—Miscellaneous features of stairways not otherwise provided for
- E04F2011/0205—Stairways characterised by the use of specific materials for the supporting structure of the treads
- E04F2011/021—Stairways characterised by the use of specific materials for the supporting structure of the treads mainly of stone or stone like materials, e.g. concrete; mainly of glass
- E04F2011/0212—Stairways characterised by the use of specific materials for the supporting structure of the treads mainly of stone or stone like materials, e.g. concrete; mainly of glass mainly of concrete
- E04F2011/0214—Stairways characterised by the use of specific materials for the supporting structure of the treads mainly of stone or stone like materials, e.g. concrete; mainly of glass mainly of concrete cast in situ
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Mechanical Engineering (AREA)
- Forms Removed On Construction Sites Or Auxiliary Members Thereof (AREA)
- Reinforcement Elements For Buildings (AREA)
Abstract
EXTERNALLY REINFORCED CONCRETE STAIRS
ABSTRACT OF THE DISCLOSURE
An externally reinforced concrete structure including a plurality of elongated C-channels interconnected to form a unitary body. The unitary body created by the C-channels is utilized to function as formwork to aid in erection of a concrete structure and to lend structural support of the concrete upon the concrete being set by creating a stressed-skin construction.
ABSTRACT OF THE DISCLOSURE
An externally reinforced concrete structure including a plurality of elongated C-channels interconnected to form a unitary body. The unitary body created by the C-channels is utilized to function as formwork to aid in erection of a concrete structure and to lend structural support of the concrete upon the concrete being set by creating a stressed-skin construction.
Description
~r~L3 B~CKGROUND OF TE1E INVE~TION
__ This invention relates in general to concrete slab structures S and, in particular, to a stressed-skin construction.
More specifically, this invention relates to a concrete stairway having a plurality of interconnected soffits which form a stressed-skin structure when erected in a building and the like.
In prior stairway systems used in conjunction with buildings, it has been common practice to construct a form~ork comprised of various elements at a building site to receive concrete and form the stair structure in conjunction with the use of risers. The function of the prior art formworks is primarily directed to the retention and control of the concrete when the structure is being erected. With such techniques, the structural elements of the formwork such as soffits or pans do not make any significant contribution to the structural integrity of the stairway after the concrete has set both in a lateral and longi-tudinal direction.
To attain sufficient load carrying characteristics, a plurality of elongated reinforcement bars extend through the set concrete to add strength internally to the final stair structure. Thus, much of the strength of the concrete structure is significantly attributable to the reinforcing bars, whereby 25 ~c the bottom formwork which receives the concrete plays little or no structural function. The prior art formwork is either re-moved from the finished structure or is left merely as an aesthetic covering of the bottom surfaces of the concrete stair or landing.
~l ¦ he use of reinforcement bars as strengthening means in ¦ a concrete slab construction has resulted in stairs and landings ¦ of sufficient an~ safe strength, but the utilization of such bars ¦ also occasions several disadvantayes. Structural steel bars in ¦ the form of long xods unnecessarily add weight to the structuxe and oontribute significantly to the overall expense of the stair I way or landing being installed. ~uch added expense results both ¦ from the cost of materials and the added labor time required of ¦ an installer in erecting the stairway. An important factor ~10 ¦ therefore which creates the need for such reinforcing rods is ¦ that the structure of prior art formworks is not intended or capable of adding structural integrity to the set concrete slab.
~:
SVM~Y OF THE INVENTION
It is, therefore; an object of this invention to improve ~15 concrete slab structures.
Another object of this invention is to utilize a stressed-skin construction to contribute structural integrity to a slab.
A further object o~ this invention is to produce a concrete stairway and landing structure eliminating the necessity of reinforcement bars.
' Still another object of this invention is to couple a stressed-skin structure of the invention to a conventional concrete structure having reinforcement bars and the like.
These and other objects are attained in accordance with the present invention wherein there is provided an improved concrete slab structure utilizing a stressed-skin construction.
~ ~2'~L5~3 ¦ As used in connection with the invention of the applica-¦tion, stressed-5kin con~truction refers to a load carrying structure whose panel, casing or "skin" carries all or a signifi-cant part of the internal stresses resisting an applied load.
In the case of a stairway, for e~ample, the applied load would include the weight of the structure itself ancl any load applied thereto. Stifening members are ~enerally employed in stressed-skin constructions to give the skin support, shape and stability.
The improved structure of the invention utilizes a plurality of elongated troughs integrally coupled together which, upon setting of concrete poured therein, acts as a stressed-skin construction to add structural strength to the concrete slab in the form of an externally reinforced system. The use of the stressed-skin construc.tion of the invention eliminates the necessity of utilizing costly reinforcing bars in the construction of stairways and landings. The construction of a stairway or ;~ landing according -to the invention achieves such economy from reduced labor and material costs, since the interconnected soffit troughs function both as an initial formwork in which the concrete forming the structure is poured and retained unti~ s~t and further contributes to the structural strength of the installation upon setting of the concrete. The unique C-shape cross section of the integrally connected troughs achieves a stressed-skin condition in the bottom walls of the troughs while stiffening is contributed hy side walls of the troughs. The invention of the application thus provides a technique of forming a landing, stairway or other I ~ILZ~543 ¦concrete slab having considerable strength and structural ¦ integrity while~ reducing the expense of erecting these structures attributable to the prior art techniques.
DESCRIPTION OF THE DRAWINGS
. . .
Further objects of the invention, together with additional features contributing ~hereto and advantages accruing therefrom, will be apparent from the ollowing description of several embodiments of the invention when read in conjunction with the accompanying drawings, wherein:
FIG. 1 is a perspective illustration of a stair system utilizing the improved stressed-skin construction of the invention;
~:
; FIG. 2 is a partial sectional illustration of a stairway shown in FIG. l;
': . ' .
FIG. 3 is a perspective illustration of one of the soffi troughs of the invention utilized in the stairway of FIG. l;
:~ ~ ' .
FIG. 4 is a sectional view taken along line 4-4 illustrating the interconnection of the troughs of the stairway of FIG. l;
FIG. 4a is an end view of the troughs of the invention utilizing an improved damming technique of the invention;
~ 2~
¦ FIG~ 5 is a side schematic illustxation with parts in .
¦ section of the coupling of the stressed-skin constructlon of the ¦ inventiOn o a standard prior art structure; ..
I
¦ FIG. 6 is another embodiment of the stressed-skin.
: 5 ¦ construction of the invention coupled to a standard concrete l slab construction;
_ I
¦ FIG. 7 is still another embodiment of the stressed-skin ¦ construction of the invention coupled to a conventional platform . I having reinforcement bars;
, FIG. 8 is another embodiment of the s~ressed-skin : construction of the invention coupled to a landing at its top;
: , FIG. 9 is a schematic side illustration of the stressed-skin construction of the invent.ion coupled at its bottom to a landing;
.` '., : 15 FIG. 10 .is a partial side pérspective illustration of still another embodiment of the stressed-skin construction of the invention; and .. ' '.
.~ FIG. 11 is a partial end sectional illustration of the . embodiment of FIG. 10.
__ This invention relates in general to concrete slab structures S and, in particular, to a stressed-skin construction.
More specifically, this invention relates to a concrete stairway having a plurality of interconnected soffits which form a stressed-skin structure when erected in a building and the like.
In prior stairway systems used in conjunction with buildings, it has been common practice to construct a form~ork comprised of various elements at a building site to receive concrete and form the stair structure in conjunction with the use of risers. The function of the prior art formworks is primarily directed to the retention and control of the concrete when the structure is being erected. With such techniques, the structural elements of the formwork such as soffits or pans do not make any significant contribution to the structural integrity of the stairway after the concrete has set both in a lateral and longi-tudinal direction.
To attain sufficient load carrying characteristics, a plurality of elongated reinforcement bars extend through the set concrete to add strength internally to the final stair structure. Thus, much of the strength of the concrete structure is significantly attributable to the reinforcing bars, whereby 25 ~c the bottom formwork which receives the concrete plays little or no structural function. The prior art formwork is either re-moved from the finished structure or is left merely as an aesthetic covering of the bottom surfaces of the concrete stair or landing.
~l ¦ he use of reinforcement bars as strengthening means in ¦ a concrete slab construction has resulted in stairs and landings ¦ of sufficient an~ safe strength, but the utilization of such bars ¦ also occasions several disadvantayes. Structural steel bars in ¦ the form of long xods unnecessarily add weight to the structuxe and oontribute significantly to the overall expense of the stair I way or landing being installed. ~uch added expense results both ¦ from the cost of materials and the added labor time required of ¦ an installer in erecting the stairway. An important factor ~10 ¦ therefore which creates the need for such reinforcing rods is ¦ that the structure of prior art formworks is not intended or capable of adding structural integrity to the set concrete slab.
~:
SVM~Y OF THE INVENTION
It is, therefore; an object of this invention to improve ~15 concrete slab structures.
Another object of this invention is to utilize a stressed-skin construction to contribute structural integrity to a slab.
A further object o~ this invention is to produce a concrete stairway and landing structure eliminating the necessity of reinforcement bars.
' Still another object of this invention is to couple a stressed-skin structure of the invention to a conventional concrete structure having reinforcement bars and the like.
These and other objects are attained in accordance with the present invention wherein there is provided an improved concrete slab structure utilizing a stressed-skin construction.
~ ~2'~L5~3 ¦ As used in connection with the invention of the applica-¦tion, stressed-5kin con~truction refers to a load carrying structure whose panel, casing or "skin" carries all or a signifi-cant part of the internal stresses resisting an applied load.
In the case of a stairway, for e~ample, the applied load would include the weight of the structure itself ancl any load applied thereto. Stifening members are ~enerally employed in stressed-skin constructions to give the skin support, shape and stability.
The improved structure of the invention utilizes a plurality of elongated troughs integrally coupled together which, upon setting of concrete poured therein, acts as a stressed-skin construction to add structural strength to the concrete slab in the form of an externally reinforced system. The use of the stressed-skin construc.tion of the invention eliminates the necessity of utilizing costly reinforcing bars in the construction of stairways and landings. The construction of a stairway or ;~ landing according -to the invention achieves such economy from reduced labor and material costs, since the interconnected soffit troughs function both as an initial formwork in which the concrete forming the structure is poured and retained unti~ s~t and further contributes to the structural strength of the installation upon setting of the concrete. The unique C-shape cross section of the integrally connected troughs achieves a stressed-skin condition in the bottom walls of the troughs while stiffening is contributed hy side walls of the troughs. The invention of the application thus provides a technique of forming a landing, stairway or other I ~ILZ~543 ¦concrete slab having considerable strength and structural ¦ integrity while~ reducing the expense of erecting these structures attributable to the prior art techniques.
DESCRIPTION OF THE DRAWINGS
. . .
Further objects of the invention, together with additional features contributing ~hereto and advantages accruing therefrom, will be apparent from the ollowing description of several embodiments of the invention when read in conjunction with the accompanying drawings, wherein:
FIG. 1 is a perspective illustration of a stair system utilizing the improved stressed-skin construction of the invention;
~:
; FIG. 2 is a partial sectional illustration of a stairway shown in FIG. l;
': . ' .
FIG. 3 is a perspective illustration of one of the soffi troughs of the invention utilized in the stairway of FIG. l;
:~ ~ ' .
FIG. 4 is a sectional view taken along line 4-4 illustrating the interconnection of the troughs of the stairway of FIG. l;
FIG. 4a is an end view of the troughs of the invention utilizing an improved damming technique of the invention;
~ 2~
¦ FIG~ 5 is a side schematic illustxation with parts in .
¦ section of the coupling of the stressed-skin constructlon of the ¦ inventiOn o a standard prior art structure; ..
I
¦ FIG. 6 is another embodiment of the stressed-skin.
: 5 ¦ construction of the invention coupled to a standard concrete l slab construction;
_ I
¦ FIG. 7 is still another embodiment of the stressed-skin ¦ construction of the invention coupled to a conventional platform . I having reinforcement bars;
, FIG. 8 is another embodiment of the s~ressed-skin : construction of the invention coupled to a landing at its top;
: , FIG. 9 is a schematic side illustration of the stressed-skin construction of the invent.ion coupled at its bottom to a landing;
.` '., : 15 FIG. 10 .is a partial side pérspective illustration of still another embodiment of the stressed-skin construction of the invention; and .. ' '.
.~ FIG. 11 is a partial end sectional illustration of the . embodiment of FIG. 10.
2 0 D CRIPTION OF A PREFERRED EMBODIMENT
Referring now to FIG. 1, there is shown one embodiment of a concrete slab structuxe having the stressed-skin construc-tion according to the inventlon. Although the invention is shown and described with reference to use with a concrete slab structure utilized in a stairway system of a building, the technique of the invention of utilizing a stressed-skin con-struction is not intended to be limited to such an application, 5.
,, . _ , ~since it can be used in con~unction with various types of concrete slab structures for numerous applications.
The externally reinforced structure 1 of the invention shown in FIGS. 1, 2 and 4 is in the form of a stairway ha~ing a pair of stringexs 2, one of which is illustrated. Structure 1 is a uniti~ed construction having a plurality of pan-like~ soffit troughs 3 of a suitable metal affixed together as a single body.
The pluxality of trvùghs 3 have e~ongated bodies to substantially span a desired dimension such as, for example, between a floor and O a landing, floor to floor or numerous other well known situations.
Elongated troughs 3 are in contact with each other in a side by side arrangement and are welded together or otherwise secured by any suitable method of attachment to create a rigid one piece body.
Troughs 3 are ~n the form of a C~channel which includes ~;` two parallel sidewalls 3a having flanges 3b extending perpendi-cular thereto. The outer surface of the sidewalls 3b is secured in flush contact with the sidewall o~ an adjacent trough, whereby the two affixed walls 3a rigidize the unitary soffit trough structure created by the plurality of elements. Although the outer surfaces of adjacent walls 3a are in flush contact as shown in FIGS. 1 and 4, it should be recognized that the walls 3a may be angularly disposed to each other and be affixed at the point of contact, such as created by alternate cross sections of the S ~-channels.
The tops of the troughs 3b are adapted to be coupled to plurality of riser plates 4 as shown in FIG. 1 supported by means of a suitable number of brackets 5 welded respectively to soffit
Referring now to FIG. 1, there is shown one embodiment of a concrete slab structuxe having the stressed-skin construc-tion according to the inventlon. Although the invention is shown and described with reference to use with a concrete slab structure utilized in a stairway system of a building, the technique of the invention of utilizing a stressed-skin con-struction is not intended to be limited to such an application, 5.
,, . _ , ~since it can be used in con~unction with various types of concrete slab structures for numerous applications.
The externally reinforced structure 1 of the invention shown in FIGS. 1, 2 and 4 is in the form of a stairway ha~ing a pair of stringexs 2, one of which is illustrated. Structure 1 is a uniti~ed construction having a plurality of pan-like~ soffit troughs 3 of a suitable metal affixed together as a single body.
The pluxality of trvùghs 3 have e~ongated bodies to substantially span a desired dimension such as, for example, between a floor and O a landing, floor to floor or numerous other well known situations.
Elongated troughs 3 are in contact with each other in a side by side arrangement and are welded together or otherwise secured by any suitable method of attachment to create a rigid one piece body.
Troughs 3 are ~n the form of a C~channel which includes ~;` two parallel sidewalls 3a having flanges 3b extending perpendi-cular thereto. The outer surface of the sidewalls 3b is secured in flush contact with the sidewall o~ an adjacent trough, whereby the two affixed walls 3a rigidize the unitary soffit trough structure created by the plurality of elements. Although the outer surfaces of adjacent walls 3a are in flush contact as shown in FIGS. 1 and 4, it should be recognized that the walls 3a may be angularly disposed to each other and be affixed at the point of contact, such as created by alternate cross sections of the S ~-channels.
The tops of the troughs 3b are adapted to be coupled to plurality of riser plates 4 as shown in FIG. 1 supported by means of a suitable number of brackets 5 welded respectively to soffit
3 and riser 4. Soffit troughs 3 and stringer 2 create a con~inuou b~ttQm wall *(j receiv~ L~nd control ~lucnt concrL~ t}lrough the us~
of an inwardly directed flange 6 formed on ~he bottom ~f stringers 2, partially pxojecting under s~ructure 1.
From the foregoing description, it should be apparent that the pair of stringers 2, soffi$ troughs 3 being integrally interconnected, and risers 4 Eorm a structure which when erected at the job site acts as a formwork to receive A settab~e material in a fluent state such as unhardened concrete. Upon setting of the concrete as a slab structure, the bottom of sofEit 3 formed by the bottom wall 3' becomes a stressed-skin structure carrying nternal stresses of the applied load which adds significant tructural integrity and strength both laterally and longitudina~l o the concrete slab which it supports eliminating the necessity o einforcing bars required by the prior art. Thus, the integrally oupled soffits perEorm the dual function of being a formwork and tructural component to support the applied load as an external einforcing agent. If benefit of both the stressed-skin construc~
ion of the invention and reinEorcing bars is desirea, both can be ncorpoxated in the same concrete slab for extra strength ln nusually heavy load situations or extreme length.
Referring to FIG. 5, there is illustrated another embodi ent of the improve~ stressed-skin construction of the invention hich demonstrates that the novel stressed-skin stairway herein e ~ ibed is capable of being interconnected with a stanaard ;
anding having`conventional reinEorcing bars. Specifically, xternally reinforced structure 1 and stringer 2 are connectable ?
o standard slab construction such as lan~ing 20 which possesses a lurality of reinEorcing bars 21 for its strength~ Reinforcing od 21 extends at its lower end 21a into a bracket 22 having a , uitable notch to receive the reinforcing bar. Bracket 22 acts as ~C~3 ~ 4;>`~
an additional mechanical connection between the bar and the l~wer portiun of the stairway. In such situations, landing 20 may be constructed by conventional techniques using formworks and the lik~ whereby upon setting of the poured concxete a suitable tie ~ 5 between landing 20 and the system o~ the present invention is ; achieved with the extension of reinforcing bars into the structure 1 as shown. It has been found that such adequate strength without other elements is created by such~attachment of the stressed-sXin 0 system having troughs 3 to the conventional reinfoxcement bars extending from landing 21. This interco~nection allows ~he stressed-skin construction of the invention to be utilized in conjunction with conventional platforms and stairs.
Referring ~to FIG. 6, there is illus~rate~ still another ~5 embodiment o~ the invention The embodiment of FIG. 6 is similar to that described with reference to FIG. 5, except that the con-ventional landing 3~ of concrete includes a pair of reinforcing ars which extend downward into the stressed-skin stairway system of the invention. When concrete is poured into the stairway 0 system, a union of suitable strength is created.
Referring to FIG. 7, there is illustrated another technique of utili~ing the stressed-skin stairway system of the invention by which the landing i5 formed at the bottom of the stairway system, and reinforcement bars 41 extend upward into the stressed-skin s~stem of the invention for suitable coupling.
Referring to FIGS. 8 and 9, there are illustrated other uses by which the stressed-skin system of the invention may be coupled above to a landing 50 of concrete by the use of conven-¦¦ioDal stu 1 or below to a laDding 60 by stud 61.
Il 8.
,, ~ ~ ~ ( ~ 3 Referring now to FIGS. 10 and 11, there is shown another embodiment of the concrete slab structure having the stressed~skin construction according to the invention. ~he embodiment of FIGS. 10 and 11 is similar to the embodiment described with reference to FIGS. 1 to 4 with the exception that the stringers are eliminated illustrating the externally-reinforced and self-supporting properties of the stressed-skin construction of the invention.
The externally reinforced structure of the invention shown in FI~S. 10 ana 11 ;;is shown used as a stairway and is formed in a unitized construction having a plurality of pan-like, soffit troughs 3' of a suitahle metal affixed together as a single body self-supportiny unit. The plurality of troughs 3' have eIongated bodies to substantially span a desired dimension such as, for example, between a floor and a landing, 100r to floor or numerous other well known situa-tions. Elongated troughs 3' are in contact with each other in a side by side axrangement and are welded together or other-wise secured by any suitable method o~ attachment to create a rigid one piece body.
Troughs 3' are in the form of a C-channel which includes two parallel sidewalls 3a' having flanges 3h extending perpendi-cular thereto. The outer surface of the sidewalls 3b' is secured in ~lush contact with the sidewall of an adjacent trough, whereby the two affixed walls 3a' rigidize the unitary sof~it trough structure created by the plurality of ele~ents. Although the outer surfaces of adjacent walls 3aare in flush contact as shown in FIGS. 1 to 4, it should be recognized that the walls 3a' may be angularly disposed to each other and be affixed a~ the point of contact, such as created by alternate cross sections of the C-channels.
. ~
~.~ ( ( The tops of the troughs 3b' are adap~ed to be coupled to a plurality of riser plates 4' as shown in FIG. 10 supported by means of a suitable number of brackets 5' welded respectively to soffit 3' and riser 4'. Soffit troughs 3' create a continuous bottom wall to receive and control fluent concrete.
From the foregoing description, it should be apparent _ that soffit troughs 3 being integrally interconnected/ and risers 4 form a structure which when erected at the job site acts as a formwork to receive a settable material in a fluent state such as unhardened concrete. Upon setting of the concrete as a slab structure, the bottom of soffit 3 ormed by bottom wall 3' becomes a stressed-skin s~ructure carrying internal stresses of the applied load which adds significant structural integrity and strength both laterally and longitudinally to i the concrete slab which it supports eliminating the necessity of reinforcing bars, stringers and other external support members required by the prior art. Thus, the integrally coupled soffits perform the dual funtion of being a formwork and structural component to support the applied load as an external reinforcing agent~ If benefit of both the stressed-skin construction of the invention and reinforcing bars is desired, both can be inaorporated in the same concrete slab for extra strength in unusually heavy load situations or extreme length. In the embodiment o FIGS. 1 to 4, the stringers i are used for purely aesthic or conventional reasons, but are not needed to support the concrete slab construction because of the self-supporting stressed skin structure of the inven tion. As shown in FIGS. 10 and 11, the stressed-sking construc-tion of the invention does not require stxingers since the load is carried by trouyhs 3' in-tegrally coupled as a unit to support the load~
~12`~S~3 ' ~ - , .
., : ¦ While the invention has been described with reference ¦ to preferred embodiments, it will be understood by those .
. I skilled in the art that various changes may be made and `: ¦ equivalents may be substituted for elements thereof without i ¦ departing from the scope of the invent.ion. In addition, many modifications may be made to adapt a particular situation ¦ or material to the teachings of the invention without departing from the essential scope thereof. Therefore~ it is intended : that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this ,~. invention, but that the invention will include all embodiments f~ lin ithin the scope ot the appended claims.
'~
.: .
~.~ 11.
,' I
of an inwardly directed flange 6 formed on ~he bottom ~f stringers 2, partially pxojecting under s~ructure 1.
From the foregoing description, it should be apparent that the pair of stringers 2, soffi$ troughs 3 being integrally interconnected, and risers 4 Eorm a structure which when erected at the job site acts as a formwork to receive A settab~e material in a fluent state such as unhardened concrete. Upon setting of the concrete as a slab structure, the bottom of sofEit 3 formed by the bottom wall 3' becomes a stressed-skin structure carrying nternal stresses of the applied load which adds significant tructural integrity and strength both laterally and longitudina~l o the concrete slab which it supports eliminating the necessity o einforcing bars required by the prior art. Thus, the integrally oupled soffits perEorm the dual function of being a formwork and tructural component to support the applied load as an external einforcing agent. If benefit of both the stressed-skin construc~
ion of the invention and reinEorcing bars is desirea, both can be ncorpoxated in the same concrete slab for extra strength ln nusually heavy load situations or extreme length.
Referring to FIG. 5, there is illustrated another embodi ent of the improve~ stressed-skin construction of the invention hich demonstrates that the novel stressed-skin stairway herein e ~ ibed is capable of being interconnected with a stanaard ;
anding having`conventional reinEorcing bars. Specifically, xternally reinforced structure 1 and stringer 2 are connectable ?
o standard slab construction such as lan~ing 20 which possesses a lurality of reinEorcing bars 21 for its strength~ Reinforcing od 21 extends at its lower end 21a into a bracket 22 having a , uitable notch to receive the reinforcing bar. Bracket 22 acts as ~C~3 ~ 4;>`~
an additional mechanical connection between the bar and the l~wer portiun of the stairway. In such situations, landing 20 may be constructed by conventional techniques using formworks and the lik~ whereby upon setting of the poured concxete a suitable tie ~ 5 between landing 20 and the system o~ the present invention is ; achieved with the extension of reinforcing bars into the structure 1 as shown. It has been found that such adequate strength without other elements is created by such~attachment of the stressed-sXin 0 system having troughs 3 to the conventional reinfoxcement bars extending from landing 21. This interco~nection allows ~he stressed-skin construction of the invention to be utilized in conjunction with conventional platforms and stairs.
Referring ~to FIG. 6, there is illus~rate~ still another ~5 embodiment o~ the invention The embodiment of FIG. 6 is similar to that described with reference to FIG. 5, except that the con-ventional landing 3~ of concrete includes a pair of reinforcing ars which extend downward into the stressed-skin stairway system of the invention. When concrete is poured into the stairway 0 system, a union of suitable strength is created.
Referring to FIG. 7, there is illustrated another technique of utili~ing the stressed-skin stairway system of the invention by which the landing i5 formed at the bottom of the stairway system, and reinforcement bars 41 extend upward into the stressed-skin s~stem of the invention for suitable coupling.
Referring to FIGS. 8 and 9, there are illustrated other uses by which the stressed-skin system of the invention may be coupled above to a landing 50 of concrete by the use of conven-¦¦ioDal stu 1 or below to a laDding 60 by stud 61.
Il 8.
,, ~ ~ ~ ( ~ 3 Referring now to FIGS. 10 and 11, there is shown another embodiment of the concrete slab structure having the stressed~skin construction according to the invention. ~he embodiment of FIGS. 10 and 11 is similar to the embodiment described with reference to FIGS. 1 to 4 with the exception that the stringers are eliminated illustrating the externally-reinforced and self-supporting properties of the stressed-skin construction of the invention.
The externally reinforced structure of the invention shown in FI~S. 10 ana 11 ;;is shown used as a stairway and is formed in a unitized construction having a plurality of pan-like, soffit troughs 3' of a suitahle metal affixed together as a single body self-supportiny unit. The plurality of troughs 3' have eIongated bodies to substantially span a desired dimension such as, for example, between a floor and a landing, 100r to floor or numerous other well known situa-tions. Elongated troughs 3' are in contact with each other in a side by side axrangement and are welded together or other-wise secured by any suitable method o~ attachment to create a rigid one piece body.
Troughs 3' are in the form of a C-channel which includes two parallel sidewalls 3a' having flanges 3h extending perpendi-cular thereto. The outer surface of the sidewalls 3b' is secured in ~lush contact with the sidewall of an adjacent trough, whereby the two affixed walls 3a' rigidize the unitary sof~it trough structure created by the plurality of ele~ents. Although the outer surfaces of adjacent walls 3aare in flush contact as shown in FIGS. 1 to 4, it should be recognized that the walls 3a' may be angularly disposed to each other and be affixed a~ the point of contact, such as created by alternate cross sections of the C-channels.
. ~
~.~ ( ( The tops of the troughs 3b' are adap~ed to be coupled to a plurality of riser plates 4' as shown in FIG. 10 supported by means of a suitable number of brackets 5' welded respectively to soffit 3' and riser 4'. Soffit troughs 3' create a continuous bottom wall to receive and control fluent concrete.
From the foregoing description, it should be apparent _ that soffit troughs 3 being integrally interconnected/ and risers 4 form a structure which when erected at the job site acts as a formwork to receive a settable material in a fluent state such as unhardened concrete. Upon setting of the concrete as a slab structure, the bottom of soffit 3 ormed by bottom wall 3' becomes a stressed-skin s~ructure carrying internal stresses of the applied load which adds significant structural integrity and strength both laterally and longitudinally to i the concrete slab which it supports eliminating the necessity of reinforcing bars, stringers and other external support members required by the prior art. Thus, the integrally coupled soffits perform the dual funtion of being a formwork and structural component to support the applied load as an external reinforcing agent~ If benefit of both the stressed-skin construction of the invention and reinforcing bars is desired, both can be inaorporated in the same concrete slab for extra strength in unusually heavy load situations or extreme length. In the embodiment o FIGS. 1 to 4, the stringers i are used for purely aesthic or conventional reasons, but are not needed to support the concrete slab construction because of the self-supporting stressed skin structure of the inven tion. As shown in FIGS. 10 and 11, the stressed-sking construc-tion of the invention does not require stxingers since the load is carried by trouyhs 3' in-tegrally coupled as a unit to support the load~
~12`~S~3 ' ~ - , .
., : ¦ While the invention has been described with reference ¦ to preferred embodiments, it will be understood by those .
. I skilled in the art that various changes may be made and `: ¦ equivalents may be substituted for elements thereof without i ¦ departing from the scope of the invent.ion. In addition, many modifications may be made to adapt a particular situation ¦ or material to the teachings of the invention without departing from the essential scope thereof. Therefore~ it is intended : that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this ,~. invention, but that the invention will include all embodiments f~ lin ithin the scope ot the appended claims.
'~
.: .
~.~ 11.
,' I
Claims (6)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An externally reinforced stairway structure comprising a plurality of elongated soffit members arranged in a side by side relationship and adapted to be supported solely at their respective ends, means for supporting said soffit members solely at said ends, each of said soffit members having a bottom wall and a pair of spaced sidewalls integrally projecting from said bottom wall, said bottom wall and sidewalls extending longitudinally between said end of said soffit members, at least one of said spaced sidewalls of said soffit members being rigidly coupled to the sidewall of an adjacent soffit member to form a unitary support structure, said soffit member acting as a formwork created by said bottom wall and said pair of spaced sidewalls to receive settable material in a fluent state, riser means coupled to said soffit members adapted to form a plurality of steps from said settable material, a settable material arranged in a fluent state on said formwork created by said soffit members and said riser means and being supported by said soffit members and said riser means upon setting, and said soffit members further acting as a stressed skin structure to provide lateral and longitudinal strength to said material upon setting, said stressed skin structure being created by said bottom wall of each soffit member acting as a stressed skin member, said bottom wall of each soffit member carrying a significant part of the load applied to the soffit members upon setting of said fluent material.
2. The structure of Claim 1 wherein said pair of sidewalls of each of said soffit members lie in a plane disposed substantially perpendicular to said bottom wall.
3. The structure of Claim 2 wherein said contacting sidewalls are coupled together to form said unitary structure.
4. The structure of Claim 1 wherein a plurlaity of soffit members comprises three or more members.
5. The structure of Claim 1 wherein said spaced sidewalls include an edge having an angular disposed portion to support a riser coupled thereto.
6. The structure of Claim 1 wherein at least one reinforcing bar extends into a portion of said settable material in spaced relation to said plurality of soffit members, said reinforcing bar acting to couple said unitary structure to a concrete structure at least one reinforcing bar.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US96798778A | 1978-12-04 | 1978-12-04 | |
| US06/086,919 US4250672A (en) | 1979-10-22 | 1979-10-22 | Externally reinforced concrete stairs |
| US086,919 | 1979-10-22 | ||
| US967,987 | 1992-10-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1124543A true CA1124543A (en) | 1982-06-01 |
Family
ID=26775305
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA341,081A Expired CA1124543A (en) | 1978-12-11 | 1979-12-03 | Externally reinforced concrete stairs |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU5343979A (en) |
| CA (1) | CA1124543A (en) |
| GB (1) | GB2038394B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2663069A1 (en) * | 1990-06-06 | 1991-12-13 | Fournel Joel | Prefabricated module permitting the production of a stairway step without any special tooling equipment |
| WO1998057010A1 (en) * | 1997-06-11 | 1998-12-17 | Stairform Designs Pty. Ltd. | Staircase form |
| FR2935412B1 (en) * | 2008-09-04 | 2010-09-10 | Dsn Design Service Network | LOST FORMWORK FOR REALIZING A CAST CONCRETE STAIRCASE |
| GB2534033A (en) * | 2015-01-06 | 2016-07-13 | Flight Products Ltd | Casting concrete steps or stairs |
| CN107178185A (en) * | 2017-07-25 | 2017-09-19 | 佛山市正轻钢房屋有限公司 | The permanent template system and manufacture method of concrete staircase |
| CN113070624B (en) * | 2021-04-09 | 2022-07-26 | 碧源建工有限公司 | Regularization steel stair welding frock of marking time |
-
1979
- 1979-12-03 CA CA341,081A patent/CA1124543A/en not_active Expired
- 1979-12-04 GB GB7941747A patent/GB2038394B/en not_active Expired
- 1979-12-04 AU AU53439/79A patent/AU5343979A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| GB2038394A (en) | 1980-07-23 |
| AU5343979A (en) | 1980-06-12 |
| GB2038394B (en) | 1982-11-24 |
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| MKEX | Expiry |