US20050055922A1

US20050055922A1 - Prefabricated cage system for reinforcing concrete members

Info

Publication number: US20050055922A1
Application number: US10/932,560
Authority: US
Inventors: Mohammad Shamsai; Halil Sezen
Original assignee: Individual
Current assignee: Ohio State University
Priority date: 2003-09-05
Filing date: 2004-09-02
Publication date: 2005-03-17
Also published as: WO2005026466A1

Abstract

A device for reinforcing concrete. The device includes a perforate load-bearing member with first and second surfaces around which concrete can be placed. Apertures in the perforate load-bearing member form connectivity points between concrete disposed on the first and second surfaces to promote bonding of the concrete such that a contiguous mass of concrete forms upon curing. The resulting reinforced concrete structure is of integral construction. In one embodiment, the device can be configured as cage-like structure. In addition, the device may define a unitary structure that can be prefabricated, thereby reducing the time and cost of formation of a reinforced concrete structural member.

Description

This application claims the benefit of U.S. Provisional Application Ser. No. 60/500,885, filed Sep. 5, 2003.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was supported by the government under Contract No. CMS-0355321 awarded by the National Science Foundation (NSF). The government has certain rights in the invention.

BACKGROUND OF THE INVENTION

The present invention generally relates to reinforcement for use in building structures, and more particularly to concrete reinforcement that forms a structure with concrete to perform the role of both longitudinal and lateral reinforcement.
The use of reinforced concrete members is well-known in the building art. Some of steel's outstanding properties, such as high tensile strength, high ductility and availability are combined with concrete's beneficial properties, including high compressive strength, good formability, low cost and high temperature and fire resistance. Combinations employing these two materials are a good choice for designing members used in bridges, tunnels, stadiums, multistory commercial and residential dwellings and related structures, hereinafter collectively referred to as buildings or building structures. Examples of steel/concrete combinations used in building structures include conventional reinforcing bar (rebar) reinforced concrete systems, concrete-filled tubular systems, steel-concrete composite systems, and welded wire fabric systems.
Typical rebar-based systems employ cylindrical steel rebar interlocked into a skeletal frame inside a concrete matrix. In such systems, steel rebar is used for carrying the tensile stresses and improving member ductility. The rebar is usually used as longitudinal and lateral (transverse) reinforcements in such systems for columns, beams and other related reinforced concrete structures. The process of arranging numerous longitudinal and transverse reinforcement with tie wires into a skeletal frame, then placing forms around the frame pouring concrete into the interstices is labor intensive, and hence expensive. Moreover, the complexity of such systems increases the likelihood of loose tolerances and related lowering of load-carrying capacity.
In steel-concrete composite systems, steel profiles (for example, I-beams) are placed inside the member to provide higher axial strength. This system helps provide a high strength in a relatively small cross-sectional area to avoid the limitations of traditional rebar-based systems, where the spacing of the bars in a relatively small section may be less than the allowable amount. Composite sections are usually used in high rise buildings, where a high axial strength with the minimum area provided for columns are desirable. The concrete cover protects the steel against fire, moisture and other environmental elements. The high metal reinforcement ratio, as well as its placement near the center of the reinforced concrete member, may result in a relatively inefficient system with limited ductility, flexural and torsional resistance.
In the concrete-filled tubular system, a hollow steel section like a pipe or a rectangular box is filled with concrete. This system is useful especially when very high axial strength and concrete confinement with the least cross-sectional area is desirable. One of the chief attributes of the tubular system is its efficiency of structure, where the tensile strength is mainly provided by the steel, which is at the outer most level from the center. Nevertheless, because the steel is situated at the outermost portion of the system, it is exposed and therefore subject to fire and corrosion damage.
In the welded wire fabric system, a prefabricated wire steel system is used for carrying the tensile stresses. In the welded wire system, steel wires/bars are laid in two perpendicular directions and are welded at intersections using rollers and roll welding process. This system is usually used for providing reinforcements in planar sections such as tunnels and shear walls. The steel wires are usually the same in diameter and spacing in both directions, but they can be produced to be different in the two directions.
What is needed is reinforcement for concrete structures that can satisfy the stringent load-carrying and environmental requirements of building components. What is additionally needed is such reinforcement that is easy and inexpensive to fabricate and allows for fast construction.

SUMMARY OF THE INVENTION

These needs are met by the present invention, where a reinforcement for reinforced concrete members is disclosed. While it is understood that the present invention reinforcement is applicable to various concrete structural members (as will be discussed in more detail below), much of the following discussion takes place in the context of a reinforced concrete column. Deviations from column-particular features will be apparent from the context.
In a first aspect of the invention, a concrete reinforcing device made up of a perforate load-bearing member having first and second surfaces is disclosed. The device is configured to accept concrete such that upon pouring concrete around the surfaces, apertures that give the load-bearing member its perforate nature allow concrete from the first and second surfaces to contact and bond, thereby forming a contiguous mass of the concrete. This creates an interlocked relationship between the device and the concrete such that an integral structure is formed.
Optionally, the material making up the device is a metal or metal alloy. In a preferred embodiment, the device is made from steel. In another option, the device is of unitary (i.e., one-piece) construction such that longitudinal and lateral reinforcements (also referred to as longitudinal and lateral reinforcement stripes) are defined by the apertures formed in the device. These reinforcements, by defining the portion of the device that remains upon formation of the apertures, are substantially coplanar with the portions of the first and second surfaces that define the reinforcement. The unitary construction of the present invention can be used to perform the role of both longitudinal and transverse reinforcement in rectangular and circular reinforced concrete columns without the need for supplemental, assembled components, such as rebar, tie wires, welded wire fabric or disparate composite members. Inherent in the unitary construction of the device is that the intersections of longitudinal and lateral reinforcement stripes define a continuous and uninterrupted structure.
The device may be formed in either a substantially two-dimensional (i.e., planar) or three-dimensional shape. In one particular three-dimensional embodiment, the device is configured as a cage such that the first surface is substantially inward facing and the second surface is substantially outward facing. Regardless of whether the device is configured to be planar, cage-shaped or some shape in-between, the apertures can be arranged in a substantially repeating pattern (such as along rows and columns), and may be formed in numerous preferred shapes, such as rectangles (with or without rounded corners), circles or the like. It will be appreciated by those skilled in the art that apertures formed from rectangular or related sharp-cornered shapes can be rounded to reduce stress concentration in corners. In one embodiment, all of the apertures are substantially similar in size, while in another, they can be of various sizes. In this latter configuration, larger apertures can be used near the middle portion of the reinforcing device used as column reinforcement, where less transverse reinforcement is required, while the dimensions of the apertures can be reduced with less spacing near the top and bottom of the device to promote enhanced shear strength under high lateral load conditions. As the amount of transverse reinforcement is increased by using smaller spacing, the shear resistance of that part of the column also increases.
According to another aspect of the invention, a reinforced concrete structure is disclosed, including a concrete reinforcing device comprising a perforate load-bearing member having a first surface and a second surface, and a mass of concrete coupled with the perforate load-bearing member such that apertures defining the perforate load-bearing member facilitate bonding between a portion of the mass of concrete disposed on the first surface and a portion of the mass of concrete disposed on the second surface. As with the first aspect discussed above, this cooperation made possible by the perforate load-bearing member results in an integral structure between the mass of concrete and the device.
Optionally, the perforate load-bearing member comprises a cage into which the portion of the mass of concrete disposed on the first surface is placed, and outside of which the portion of the mass of concrete disposed on the second surface is formed. Where a large and heavily reinforced concrete structural member cross-section is required, two or more cages of differing size can be placed concentrically to provide the required reinforcement. The structural member may be (among other things) a column, beam, pile, shear wall, retaining wall, foundation, slab or joint between a column and beam. In addition, the device can be used as the whole or as part of the necessary reinforcement for the reinforced concrete structure. It will be appreciated by those skilled in the art that other applications involving the use of reinforced concrete members are possible. For example, any beam or column-like member such as a tapered bridge pier, pier with interlocked reinforcement, and coupling beams can be reinforced with the system of the present invention. Furthermore, the system of the present invention can also be used in uncommon structural components, such as precast folded plates and reinforced concrete shell structures.
According to another aspect of the invention, a reinforced concrete column is disclosed. The column includes a perforate load-bearing metal cage and a concrete mass cooperative with the cage. The cage is of unitary construction, and is configured such that it has at least an inward-facing first surface and an outward-facing second surface. The apertures defined in the cage (i.e., that give the cage its perforate attributes) form a channel through which concrete can flow and ultimately cure such that upon such curing facilitates bonding between a portion of the mass disposed on the first surface and a portion of the mass disposed on the second surface to effect an integral structure between the mass and the cage. Optionally, the apertures are substantially circumscribed by transverse and longitudinal reinforcements that are formed into and make up the lattice-like structure of the cage. The apertures and one side (for example, the inward-facing side) of the reinforcements define the first cage surface, while the apertures and an opposing side (for example, the outward-facing side) of the reinforcements define the cage second surface.
According to another aspect of the invention, a method of reinforcing a building is disclosed. The method includes configuring at least one load-bearing structure and placing it in a position in the building such that it carries at least a portion of a structural load in the building. The load-bearing structure includes a concrete reinforcing device comprising a perforate member having a first surface and a second surface, and a mass of concrete cooperative with the perforate member such that apertures defining the perforate load-bearing member facilitate bonding between a portion of the mass of concrete disposed on the first surface and a portion of the mass of concrete disposed on the second surface to form an integral structure between the mass of concrete and the device. Optionally, the perforate member is generally cage-shaped, and can be of unitary construction.
According to yet another aspect of the invention, a method of making a concrete column is disclosed. The method includes configuring a load-bearing metal cage to have at least an inward-facing first surface and an outward-facing second surface such that a plurality of apertures defined between the first and second surfaces define numerous channels, flowing a concrete mass onto the cage, and curing the concrete mass. During placement of the concrete, a portion of the mass forms substantially against the first surface, a portion of the mass forms substantially against the second surface and a portion of the mass forms in the channels defined by the apertures. The presence of a concrete portion in the channels promotes connectivity between the concrete portions placed against the first and second cage surfaces, and results in a substantially contiguous concrete structure that is formed around the cage. Once the concrete cures, it forms a rigid concrete mass around the cage. Optionally, forms can be placed around the cage prior to the flowing the concrete mass in order to give the column a predetermined shape. After the concrete has cured, the forms can be removed. In another option, the columns can be either formed in a substantially horizontal position such that upon concrete curing can then be lifted into place, or formed in situ.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The following detailed description of the preferred embodiments of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
FIG. 1A illustrates a welded wire fabric system of a reinforced concrete column according to the prior art;
FIG. 1B illustrates a rebar reinforced concrete column according to the prior art;
FIG. 1C illustrates a steel-concrete composite reinforced concrete column according to the prior art;
FIG. 1D illustrates a concrete-filled tubular column according to the prior art;
FIG. 2 illustrates a prefabricated load-bearing member configured as a cage according to an embodiment of the present invention being used to reinforce a concrete column;
FIG. 3 illustrates a plan view of the reinforced concrete column of FIG. 2;
FIG. 4A illustrates three bonding mechanisms for the prefabricated load-bearing member of FIG. 2;
FIG. 4B illustrates the resisting mechanism between adjacent concrete surfaces at apertures formed in the cage of FIG. 2;
FIG. 4C illustrates the resisting mechanism due to concrete bearing on the lateral reinforcing strip of the prefabricated cage of the system of FIG. 2;
FIG. 5 illustrates an alternate embodiment of a reinforced concrete column; and
FIG. 6 illustrates an alternate embodiment of a reinforced concrete column with concentrically-placed cages.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIGS. 1A through 1D, various forms of concrete reinforcement by the prior art are shown, where the load-bearing abilities of a concrete mass 10 are augmented by various longitudinal and lateral reinforcements. Referring with particularity to FIG. 1A, a welded wire fabric system is shown. In the system, rebar 20 is laterally spaced and connected by wire or other rebar 30 with welds 40 at contact points. Although reasonably capable of carrying large shear forces, the welded wire fabric system is not well-suited to supporting axial loads, including having a rather high susceptibility to buckling. While able to carry some flexural loads, its torsion resistance is limited when used as a planar member such as a shear wall. Referring next to FIG. 1B, a conventional rebar system to form a column is shown. In it, rebar 20 is given supplemental hoopwise assistance by column ties 50 (which could in the alternate be transverse rebar) looped around the periphery of and secured to the rebar 20 with ties and end-hooks 60. Together, rebar 20, column ties 50, and hooks 60 define a skeletal frame that is impregnated with concrete to form the reinforced concrete column. This system is extremely sensitive to how well the hooks 60 are detailed, such that torsional resistance can be easily compromised. In addition, the longitudinal rebar 20 can buckle under high axial loads. Furthermore, fabrication efforts are difficult, as detailing (the process of securing column ties 50 and end-hooks 60 to longitudinal rebar 20, and the calculation of rebar spacing) takes a significant investment in time. This detailing can cause reinforcement congestion and can especially be hard to construct in heavily reinforced columns and joints in structures with special or intermediate moment-resisting frames. This fabrication process, by virtue of being individually performed on the job site for a particular structural member, is not considered to qualify as “prefabricated”. Referring next to FIG. 1C, the composite system, while capable of carrying high shear and axial forces, and less prone to fabrication mistakes than rebar system of FIG. 1B, doesn't provide good bonding unless some shear studs (or related protrusion) are attached to the steel profiles located near the column center. The shear studs increase the bonding through concrete bearing on them and through the friction between steel and concrete. The stronger the bonding between concrete and steel, the stronger the member as the tensile or compressive stresses in the member can be resisted by both materials without separation or splitting failure. The flexural capacity and efficiency of the composite system is reduced if the standard steel profile 70 (shown as an I-beam in FIG. 1C) is placed close to the center relative to the rebar 20, which is typically the case. Referring with particularity to FIG. 1D, the presence of the encapsulating tubular wall 80 in the system gives it high axial, torsional and shear strength. Because the steel of tubular wall 80 is disposed on the outer portion of the system, it is susceptible to fire and corrosion.
Referring next to FIGS. 2 and 3, a reinforced concrete structure, in the form of a column 100, is shown. Column 100 includes concrete mass 10 and a reinforcing device, presently shown in the form of a cage 110. In applications such as column 100, which requires three-dimensional attributes, the reinforcing device, which is generally fabricated from a plate, can be rolled or bent to a desired cylindrical or box shape to produce cage 110. In this latter form, opposing edges of the plate are brought together and welded or otherwise joined. In an alternative form, the cage 110 can be made from a tube-shaped member; this form eliminates the need to bend and join the plate. Another alternative may be to manufacture the whole system as a cage by known casting methods. The cage 110 can be prefabricated and brought to the construction site before casting concrete. In the present context, components such as the cage that make up a concrete reinforcing system are considered “prefabricated” when they are put together, typically (although not necessarily) in a factory or related off-site facility, prior to their use within a particular concrete member, thereby removing the need for individually manufacturing the components at the job site. Cage 110 includes numerous longitudinal reinforcements 120 and transverse reinforcements 130 that together make up a lattice-like structure that defines apertures 140 between the reinforcements 120 and 130. Each aperture 140 defines a channel that extends from one (inward-facing) surface 110 a of the cage 110 to the opposing (outward-facing) surface 110 b. Concrete 10 can flow into the channels defined by the apertures 140, and once cured, forms a bond between concrete formed against inner and outer surfaces 110 a, 110 b of cage 110. The longitudinal reinforcements 120 function similar to the longitudinal rebar 20 of the rebar system of FIG. 1B, while the lateral reinforcements 130 provide enhanced load-carrying capacity relative to the transverse reinforcement 50 of FIG. 1B or the wires 30 of the welded wire fabric system of FIG. 1A. Concrete mass 10 includes well-confined (i.e., core) concrete 10 a disposed inside cage 110 such that it cooperates with inward-facing surface 110 a, unconfined (i.e., external) concrete 10 c formed outside cage 110 such that it cooperates with outward-facing surface 110 b, and partially-confined (i.e., transitional) concrete 10 b that forms in apertures 140 and is used to bond or link well-confined concrete 1 a to unconfined concrete 10 c so that the entire concrete mass 10 is contiguous, thereby forming an integral column 100 reinforced with cage 110 to give the column 100 a composite-like structure. The unconfined concrete 10 c protects the cage 110 from environmental and thermal effects. Moreover, the presence of apertures 140 in cage 110 is beneficial for other reasons as well; when used in locations where seismic activity is of particular concern, where after significant seismic events (such as a big earthquake), even if the unconfined concrete 10 c spalls off, the well-confined concrete 10 a performs better as it is confined by the cage 110. Also, the confined concrete can be observed through the apertures 140, thereby facilitating post-event inspection.
Referring with particularity to FIG. 3, the nature of the interconnection of concrete 10 throughout the column 100 is exemplified by the well-confined concrete 10 a, partially-confined concrete 10 b and unconfined concrete 10 c forming a single, contiguous structure. As in the rebar system of FIG. 1B, the concrete mass 10 can envelop the reinforcement, providing a solid combination of concrete and steel. This promotes a stronger bond with an additional resisting force due to the partially-confined concrete 10 b passing through the apertures 140. In contrast to the rebar system of FIG. 1B and the composite system of FIG. 1C, the closed nature of the reinforcement provides a considerable amount of confinement for the concrete mass 10 inside the cage 110. In fact, it provides levels of confinement approaching that of the tubular system of FIG. 1D, while possessive of higher structural efficiency, metal protection and ductility. In addition, the bonding and the interaction forces acting between cage 110 and concrete mass 10 will be much higher (for reasons mentioned above) compared to the composite system.
Referring next to FIGS. 4A through 4C, there are three bond resisting mechanisms acting on the cage 110 and concrete 10, including the friction bonding forces F_facting at the surface of the lateral and transverse reinforcements 120, 130, the shear resistance F_sof the transverse reinforcement 130, and the compressive concrete reaction forces F_cbearing on the transverse reinforcement 130 at the bottom of the apertures 140. The shear forces v depicted in FIG. 4B are those that exist between adjacent layers of concrete 10, for example, between partially-confined concrete 10 b passing through the apertures 140 and unconfined concrete 10 c that forms a protective cover over cage 110. In operation, the adjacent concrete surfaces produce some friction and resistance between them before the unconfined concrete 10 c spalls off. The total bonding will be the summation of these three forces. F_b=F_f+F_c+F_s. These mechanisms are either nonexistent or work differently in the structural members illustrated in FIG. 1A through 1D. For example, the bonding mechanism in the reinforced concrete column shown in FIG. 1B is basically through the friction resistance F_falone.
There are at least three possible methods for fabricating the apertures 140 into cage 110. In one method, a punching system can be used to punch the apertures 140 into the plate. The thickness of the plate, size of the apertures 140, and the distance between adjacent horizontal and vertical apertures 140 can be made to vary depending on the longitudinal and transverse strength needs. In a second method, the apertures 140 can be cast directly into the plate, where melted steel is cast through a framework in the shape of the cage 110. This approach has the advantage of allowing the cage 110, including the apertures 140 to be cast in multiple shapes, including cylinder or box shapes, avoiding the necessity of performing additional steps such as shaping, forming, cutting or welding. In yet another method, various cutting approaches, such as laser, flame, plasma, abrasive jet, electrochemical machining, electrical discharge machining, milling or related automated or semi-automated schemes, can be used to form apertures 140. The choice of which of the different methods to use is driven by various factors, including cost, quantity, need for precision, finished product or the like. Producing various cages 110 with different thicknesses and different aperture 140 sizes is possible and easy with these methods.
Column 100 has additional advantages over the traditional rebar system of FIG. 1B. For example, the cage 110 can be built ahead of time (i.e., prefabricated) and be transferred to the construction site, reducing the construction time considerably. If the transverse reinforcement 50 of the rebar system is not precisely placed relative to the longitudinal rebar 20, the system won't work properly. In addition, if transverse rebar 50 fractures, or if end-hook 60 is opened, the whole connection between them may become compromised. In contrast, the integral formation between the lateral reinforcements 130 and longitudinal reinforcements 120 of the present system 100 ensures structural integrity even if the lateral reinforcement 130 is damaged locally. As previously mentioned, a cage 110 of the prefabricated cage system 100 can be formed in numerous geometric shapes, where circular and rectangular cross-sections are the most common. The reinforcement system of the present invention is expected to perform well in torsion due to its inherent rigidity and structural continuity.
The inherent rigidity and structural continuity enabled by the unitary construction of cage 110 results in very efficient transfer of loads between the longitudinal and transverse reinforcements 120, 130. This helps provide a higher load-carrying capacity with the same amount of steel, resulting in a more efficient use of the longitudinal reinforcement 120. As previously mentioned, such a configuration also eliminates weak points in the cage 110 due to the mistakes in construction as well as decreasing the time spent assembling it. In addition, tailored structural properties are easily integrated into the device (whether in plate or cage form), as the dimensions and spacing of the apertures 140 need not be the same over the height of the column 100.
The confinement provided by the cage 110 of FIGS. 2 and 3 is higher than the confinement provided by rebar system of FIG. 1B, yet less than the confinement provided by tubular system. Therefore, it is expected that the proposed reinforcement will perform something between the traditional rebar reinforced system and the equivalent tubular system.
Referring next to FIGS. 5 and 6, reinforced columns according to alternate embodiments of the present invention are shown. In FIG. 5, the column 200 formed by cage 210 and concrete 10 is cylindrical along its longitudinal axis. As before, apertures 240 form channels that allow partially-confined concrete 10 b (not presently shown) to form a contiguous concrete structure with well-confined concrete 10 a and unconfined concrete 10 c. Inward-facing surface 210 a and outward-facing surface 210 b are oriented similar to those of the previous embodiment. In FIG. 6, two cages (shown as inner cage 310 and outer cage 311) are placed in concentric arrangement relative to each other, while both are embedded within concrete 10. While the cages 310, 311 are presently shown with substantially overlapping arrangement such that apertures 340, 341 do not align, it will be appreciated that they can be arranged such that the apertures 340, 341 do substantially align.
Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. More specifically, although some aspects of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the present invention is not necessarily limited to these preferred aspects of the invention.

Claims

1. A concrete reinforcing device comprising a perforate load-bearing member having a first surface and a second surface, said device configured such that upon placement of concrete in cooperative arrangement with said surfaces, apertures defining said perforate load-bearing member facilitate bonding between concrete disposed on said first and second surfaces to effect contiguous mass of said concrete that forms upon curing an integral structure with said device.

2. The device of claim 1, wherein material making up said device comprises a metal.

3. The device of claim 1, wherein said device is of unitary construction.

4. The device of claim 1, wherein said device is configured as a cage such that said first surface is substantially inward facing and said second surface is substantially outward facing.

5. The device of claim 1, wherein said apertures defined in said device are arranged in a substantially repeating pattern.

6. The device of claim 5, wherein said apertures are substantially rectangular in shape.

7. The device of claim 5, wherein all said apertures are substantially similar in size.

8. The device of claim 5, wherein said apertures comprise a plurality of sizes.

9. The device of claim 1, wherein said apertures are substantially circumscribed by a plurality of transverse reinforcements and a plurality of longitudinal reinforcements such that said apertures and one side of said reinforcements define said first surface of said load-bearing member while said apertures and an opposing side of said reinforcements define said second surface of said load-bearing member.

10. The device of claim 9, wherein said lateral and longitudinal reinforcements are substantially coplanar with one another within each of said surfaces of said load-bearing member.

11. A reinforced concrete structure comprising:

a concrete reinforcing device comprising a perforate load-bearing member having a first surface and a second surface; and

a concrete mass cooperative with said perforate load-bearing member such that apertures defining said perforate load-bearing member facilitate bonding between a portion of said mass disposed on said first surface and a portion of said mass disposed on said second surface to effect an integral structure between said mass and said device.

12. The structure of claim 11, wherein said load-bearing member comprises at least one perforate cage into which said portion of said mass disposed on said first surface is placed.

13. The structure of claim 12, wherein said structure is a column.

14. The structure of claim 13, wherein said column comprises a substantially cylindrical shape along its longitudinal axis.

15. The structure of claim 13, wherein said column comprises a substantially rectangular shape along its longitudinal axis.

16. The structure of claim 12, wherein said structure is a pile.

17. The structure of claim 14, wherein said pile comprises a substantially cylindrical shape along its longitudinal axis.

18. The structure of claim 12, wherein said perforate load-bearing member comprises a plurality of cages each of which sized to facilitate concentric placement of said plurality of cages into said mass of concrete.

19. A reinforced concrete column comprising:

a perforate load-bearing metal cage having at least an inward-facing first surface and an outward-facing second surface, said cage comprising a unitary construction; and

a concrete mass cooperative with said cage such that apertures defined in said cage facilitate bonding between a portion of said mass disposed on said first surface and a portion of said mass disposed on said second surface to effect an integral structure between said mass and said cage.

20. The column of claim 19, wherein said apertures are substantially circumscribed by a plurality of transverse reinforcements and a plurality of longitudinal reinforcements such that said apertures and one side of said reinforcements define said first surface of said load-bearing member while said apertures and an opposing side of said reinforcements define said second surface of said cage.

21. A method of reinforcing a building, said method comprising:

configuring at least one load-bearing structure to comprise:

a concrete reinforcing device comprising a perforate member having a first surface and a second surface; and

a mass of concrete cooperative with said perforate member such that apertures defining said perforate member facilitate bonding between a portion of said mass of concrete disposed on said first surface and a portion of said mass of concrete disposed on said second surface to effect an integral structure between said mass of concrete and said perforate member; and

placing said load-bearing structure in a position in said building such that it carries at least a portion of a structural load of said building.

22. The method of claim 21, wherein said perforate member is configured as a cage.

23. The method of claim 22, wherein said cage is of unitary construction.

24. A method of making a concrete column, said method comprising:

configuring a load-bearing metal cage to have at least an inward-facing first surface and an outward-facing second surface such that each of a plurality of apertures defined between said first and second surfaces defines a channel therebetween; and

flowing a concrete mass onto said cage such that a portion of said mass forms substantially against said first surface, a portion of said mass forms substantially against said second surface and a portion of said mass forms in said apertures such that a substantially contiguous concrete structure is formed by said mass around said cage; and

curing said concrete mass.

25. The method of claim 24, further comprising placing forms around said cage prior to said flowing said concrete mass such that upon said flowing said concrete mass, a layer corresponding to said mass forming substantially against said second surface becomes substantially bounded by said outward-facing second surface and said form.

26. The method of claim 25, further comprising removing said forms from said column once said concrete has cured.