US1708277A - Device for positioning the reenforcement of concrete structures - Google Patents

Description

April 9, 1929.

J. B. MARTIN Filed Jafi. 14, 1927 Patented Apr. 9, 1929.

UNITED STATES JOHN B. MARTIN, OF CHICAGO, ILLINOIS.

DEVICE FOR POSITIONING THE REENFORCEMENT OF CONCRETE STRUCTURES.

Application filed January 14, 1927. Serial No. 161,051.

This invention relates to a device for positioning the reenforcement of concrete structures, and is particularly adaptable for use in positioning or plumbing the reenforcement of concrete columns, and will be described with reference to its use in that connection. I

One embodiment of my invention is shown for illustrative purposes in the accompanying drawing, in which 7 Fig. 1 is a plan view of my novel positioning device shown applied to a. well-known form of column reenforcing unit positioned within the concrete retaining forms of a column, the whole being viewed substantially as indicated by the line 11 of Fig. 2.

Fig. 2 is a side elevation of the parts illus trated in Fig. 1, showing the concrete retaining forms in section, the view being taken substantially as indicated by the line 22 of Fig. 1.

The reenforcement shown in the drawings is of a well-known type comprising a spirally formed metallic element surrounding and having secured thereto, by wires or other suit-- able means, a plurality of vertically disposed uniformly spaced metal dowel bars, the unit thus formed being adapted to be positioned within the concrete retaining form of a column in a manner to be imbedded in the concrete when the latter is poured, thereby lending strengthto the column when the concrete hasbeen permitted to set.

Reenforced concrete columns are designed for specific predetermined purposes and it is intended thatthe reenforcement shall be so positioned within the column that the strains and stresses to which the column may be subjected will be uniformly distributed throughoutthe column structure. It. will be readily understood that if the reenforcing unit be comes displaced in the form and so imbeddec in the concrete that its center of gravity does not coincide substantially with the center of gravity of the concrete, the column may be materially weakened and unable to bear the strains and stresses for which it was designed. It is therefore desirable that the reenforce{ ment be situated and retained as nearly as possible in a position substantially centrally of the concrete retaining forms while the concrete is being poured and spaded, and while it is becoming set, so that the reenforcement in the finished column will contribute uniformly to the strength of the column.

Furthermore, as the building ordinances of many municipalities provide that the reen forcing units of columns be covered with a minimum thickness of concrete for protection against fire, it is desirable that an insulation of concrete of the required thickness surround the reenforcement in a manner to comply with these ordinances and protect the reenforcing element from intense heat that might occur adjacent the column due to fires or the like, it eing obvious that if the reinforcing unit is permitted to lean or incline materially from a substantially central position with respect to the column, the above mentioned ordinances may be violated, and no proper fire proofing of the reenforcement obtained.

Hcretofore, it has been the practice in positioning reenforcing units, for example, within the concrete retaining forms of columns, to attach guy wires to the unit in the number of approximately six of such wires and to carry them radially from the reenforcing unit a distance of approximately three feet and there fasten them to projections of the building structure or to nails driven in other wooden forms. This method of positioning the reinforcing units has been found to be objectionable for numerous reasons, namely, the necessity of measuring to properly position the unit and the excessive time cons'umedin adjusting, fastening and sometimes readjusting the individual guy wires to obtain the proper positioning of the unit withintheconcrete-retainingform. Furthermore, it is not unusual that the guy wires, after being so fastened, become loosened or broken before theconcrete is poured, thereby necessitating the repairing and readjusting of such wires. Also, it frequently happens that the wires become stretched or broken while the concrete is being poured and spaded, thus permitting the reenforcin g unit to sag or otherwise assume a position out of vertical alignn'ient with, and eccentrically of the column, in which case the strength and efficiency of the column is impaired, as heretofore described, and its ability to withstand strains and stresses for which it was designed is materially reduced.

One of the principal objects of the present invention is to facilitate the positioning of the reenforcing unit within the concrete retaining forms in an expeditious and economic manner, and to provide adevice whereby the reenforcing units may be held in deing wood form 7 into which a concrete mix sired position Within the form while the concrete is being poured and spaded, and while it is undergoing the process of setting.

Another object of the invention is to provide a device which may be readily and quickly attached to a standard or well-known type of reenforcing unit.

A further object of the invention is to provide'a device of simple, practical and efficient construction, which may be cheaply is intended to be poured in a-manner to surround and imbed the reenforcing unit within the concrete of the column when set, thereby contributing materially to the strength 7 of the column.

The illustrative embodiment of the inven tion comprises preferably, as shown in the present instance, a plurality of semi-circular,

or U-shaped co-operating segmental members 8 provided at their end portions with laterally or radially disposed co-operating ear or flange portions 9 having apertures formed therein adapted to receive the bolts 10 for securing the members 8 together in a manner to securely clamp the devlce around the reenforcmg unit. If deslred, the portions 9 of the members 8 may be provided with aligned grooves or notches 11 on one or both of their edges in which wires or the like may be wound for securing the co-operating members 8 together, the grooves or notches 11, in the portions 9 of one of the members being in substantial alignment with the grooves or notches in the portions 9 of the other of said members.

In the construction shown, the members 8 are provided with radially extending uniformly spaced contact arms 12 of, substantially V-shape'd form and having the'diverging ends of their leg portions secured to the members 8 by means of rivets 13 or the like. It will be understood, however, that the contact members or arms 12 may be of any suitable form and connected to the members 8 by any other suitable means as by welding or the like, or, if desired, may be formed integrally with or of the material from which themembers 8 are formed.

The form and dimensions of the members 8 are such as to surround and snugly engage the reenforcing unit when the ends of the members are'fast'ened together, and the dimensions and position of the contact arms 12 are such as to provide for a slight clearance, preferably about one-eighth of an inch, between the ends of the arms and the concrete-retaining form 7 thus permitting the insertion of the device and the positioning of the reenforcing unit within the form.

In the use of my improved positioning device, the method of positioning the reenforcing unit within the form maybe described as follows:

The unit would be lowered into the wood form 7 by means of a small derrick and suspended with its lower end portion a slight distance, approximately five or six inches from the bottom of the form, while the cooperating members 8 are positioned around and secured to the unit adjacent the upper end of the form by means of bolts 10, or by wire wound around the portions 9, after which the unit and, improved positioning device is lowered into the form with the contact members 12 adj acent, the corners thereof and the horizontal planeof the'positioning device approximately three or four inches below the upper end of the form, the arms serving in conjunction with the form to retain the upper end of the unit substantially centrally of and in uniform spaced relation with respect to the form, it being understood that thebase of the column has been prepared to suitably position the lower end of the unit. In reenforced concrete building construction, it is the practice, after a unit has been imbedded within the column, to draw and bind the upper ends of the dowel bars, which normally extend a short distance above the form, closely together and secure them in close proximity to each other by wire or other suitable means, thereby forming, in effect, a pointed upper end portion over which the lower end of a superposed reenforcin g unit of a subsequently constructed column may be placed for the purpose of positioning the lower end of such superposed unit centrally of "the subsequently formed column, leaving the upper portion of the said unit to be positioned within its form by the use of my improved positioning device after the manner above described.

It will be observed from the foregoing description that when the reenforcing unit and the device embodying my invention are positioned within the form, all guy wires are dispensed with, all interference of such wires with the placing of adjacent reenforcing units, pouring and. spa-cling of the concrete. and other objectionable features attendant upon the use of such wires or similar tieswill be eliminated, and there will be a possibility of but slight movement of the unit with re spect to the form, the unit being held in substantially a central position Within the form and approximately in alignment therewith, thereby providing a substantially uniform resistance throughout the column to receive the strains and stresses for which the column was designed, and insuring the necessary thickness of concrete around the unit to comply with the requirements contained in fire ordinances of numerous municipalities, as heretofore mentioned.

What I claim as my invention and desire to secure by Letters Patent is:

1. A device of the character described comprising a plurality of segmental members adapted to co-operate to form a ring, means for drawing said members toward each other, and radially extending spacing means carried by said members and positioned substantially uniformly around said ring.

2. A device of the character described, com prising a plurality of U-shaped co-operating members having laterally disposed flange port-ions, means cooperable with said portions for drawing said members toward each other, and radially disposed arms carried by said members.

3. A device of the character described, comprising a plurality of co-operating U-shaped members having laterally disposed co-operating flange portions, means co-operable with the flange portions of the respective members for drawing said members toward each other, and a plurality of radially disposed arms carried by the respective members.

4:. A device of the character described, comprising a plurality of co-operating U-shaped members having laterally disposed flange portions, said portions of the respective members having substantially aligned grooves formed in their opposite edges, means for securing said members together, and a plurality of spacing arms positioned on the outer faces of said members.

5. A device of the character described comprising a plurality of relatively broad members adapted to co-operate in a manner to form a band of substantial width, means for drawing said members toward each other, and radially extending spacing means carried b said members and positioned substantially uniformly around said band.

In testimony whereof I have signed m name to this specification, on this 11th day of January A. D. 1927.

JOHN B. MARTIN.

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