US2480180A - Method of applying steel reinforcement to existing columns - Google Patents

Description

Hg. 30, 1949. J. D. BOLTON 2,480,180

METHOD OF APPLYING STEEL REINFORCEMENT TO EXISTING COLUMNS Filed June 5, 1948 2 Sheets-Sheet l INVENTOR.

J. D. BOLTON METHOD OF APPLYING STEEL REINFORCEMENT TO EXISTING COLUMNS 2 Sheets-Sheet 2 Aug. 30, I949.

Flled June 5 1948 Fatented Aug. 30,1949

METHOD OF APPLYING STEEL REINFORCE- MENT TO EXISTING COLUMNS John D. Bolton, Evanston, Ill., assignor to John D. Bolton & 00., Inc., Evanston, 111., a corporation of Illinois Application June 5, 1948, Serial No. 31,373

This invention has to do with the strengthening of structural columns in existing buildings, as distinguished from new building construction, and it deals specifically with the problem of applying helical steel-rod reinforcement to existing columns, in situ, as a step preliminary to the application of added external thicknesses of concrete.

A highly favored form of concrete column reinforcement consists of a continuous steel rod helix expanded lengthwise of the column, together with a group of vertical reinforcing rods tied to the helix and equally spaced circumferentially of the column; and on new building construction the helices can be coiled in advance to the desired radius of curvature and put in place in the forms without any particular difficulty. But sometimes it is necessary to reinforce existing columns by adding thereto further thicknesses of concrete; and Where, in such cases, the architect or engineer specifies helical reinforcement, the problem of applying the reinforcement to the existing columns has proved to be a formidable one, because it is not practicable to coil the steel rod before setting it in place, as is done on new work.

As an example, take a job involving a large factory building wherein the floor space is occupied by machinery and other fixed equipment, and where it is necessary to proceed without removing any of the machines or equipment or interfering materially with normal factory operation-it would not be possible to apply the helical reinforcement to the existing columns by any of the methods or procedures heretofore known. To meet such a situation, according to the present invention a portable rod bending machine is provided to be moved from column to column and set in place immediately adjacent each successive column, and then, with the machine so positioned, the rod is run through the machine and the resultantly curved rod is led around the column as it emerges from the machine. By so doing it is possible to bend and apply to each column a specified length of perhaps six hundred lineal feet of round steel rod at the rate of about five minutes per column-a most satisfactory solution of the problem above stated, and one which may be achieved without significant interference with normal factory operations.

Portable rod-bending machines have previously been known, and no claim herein is made to any novelty of major importance in the disclosed bending machine per se. But the method herein 4 Claims. (01. 29-155) to be described, which comprises bending a long rod into a helix of many turns and simultaneously wrapping the same around an existing column, as it emerges from the bending machine, is a feature of primary importance which, in short, is the substance and purport of the instant invention.

Referring now to the accompanying drawings,

Figure l is a small scale elevational view of an existing building column, together with upper and lower floor sections, showing a steel-rod helix which has been Wrapped around the column and expanded axially, the vertical reinforcing rods and new concrete having been omitted from this view in order to simplify the showing;

Fig. 2 is a perspective view showing the lower end portion of an existing building column, together with a portable bending machine resting on the floor adjacent the column, and illustrating how the reinforcing rod is bent and passed around the column as it emerges from the machine;

Fig. 3 is a horizontal View in section, taken on line 3--3 of Fig. 2;

Fig. 4 is a vertical sectional view, taken on line 44 of Fig. 3;

Fig. 5 is a sectional view, taken on line 5-5 of Fig. 3; and

Fig. 6 is a fragmentary section, taken on line 6--6 of Fig. 3.

In Fig. 1 there are shown two successive floor sections to and I2, and an intervening column M, which is to be reinforced, and around which there is shown wrapped a helix 15 consisting of a considerable number of turns of steel rod. And in addition to the helix I5 the reinforcement ordinarily would include a number of vertical steel rods equally spaced around the column and secured to the helix by means of wire ties. The vertical rods have not been shown because they would tend to obscure the showing of the helix, and the invention is concerned only with the helix and its application to the column;' and for a like reason the subsequently applied added shell of concrete has been omitted from the view.

It will, of course, be understood that after the reinforcing steel has been put in place, a form is built around the column, enclosing the added reinfor-cement, and the concrete then poured'in or perhaps applied by the gunite process. So far as the present invention is concerned it is of no consequence whether the column to be reinforced is made of concrete or of wood, steel, brick or any other material; and the cross-section of the existing column, whether round or rectangular, is a matter of indifference.

Unless the helix i5 is of very much larger di- 3 ameter than the column to be reinforced, it would be impracticable, if not utterly impossible, to apply a previously formed helix to the column, assuming the helix to be made of stiff steel rod, as distinguished from relatively flexible wire; but the method of procedure according to the present invention completely and successfully circumvents that difficulty.

For the purpose of carrying out my invention, I employ a portable bending machine, such as is shown in Figs. 2-6, inclusive, and identified as a whole by the reference numeral 20: Thisimachine is well adapted to the job for'"which*'lt"is= intended because the bending-rollscanabe.placed conveniently close to the column. Thesteeltrodt' is bent by such a machine and simultaneously the bent portion of the rod is passed around the.

existing column, as it emerges from the bending rolls as illustrated in Figs. 2 and 3 wherein sforl" the sake of conformity with Fig. 1, I have identified the. steel rodby the. reference numeral Hi, this being the same numeral usedforeidentifying the helix in Fig. 11

EromFig. 3' it willnbetseen that therodllfi; is being passed through the bending machine, wherein it is first straightened. andthenmbent. to themequired radius of. curvature;. and thatlthe curved rod emerging iromthemachine is directed around the column, thus forming amultiple .turn coil l encircling the-column. As the coil builds up, its weight increases so that it may be necessary for the workmenin attendance. to .lift and pull it arou-ndwith suitable tackle; .and'it may be helpful to place some heavy blocks ,on thefloor and against the columnv toaprovide supports for thecoil .so that itcan be manipulated around :the column more easily. In'Fig.v 21 thev coil I5 is shown asif floating in space, but it will be understood that this has-been done to. clarify the drawing, and that in actuality the coil will .rest.

partlyon the floor and partly on the bending machine unless some other coil-supporting means isprovided; such as the above-suggested blocks.

The bending machine includesa truck con:- sistlng; of a steel platform 2| --equippedrwlth-i-our roller casters 22. Extending horizontally from the platform 21 and'spaced-a-part, -(see Fig, 3) are two arms 24, 24 which bear against the column and serve to position the machine: relatively to the :column; The machine may beanchored to the column by means of a steel-band -2'5,.bhe- -encls of which are detachably connected-to the arms2 3 While the band 25-serves-toanchorthe :bendi-ng machine with certainty, andmay in some-cases be important operationally, itschief value is that ofaa'safetyprovision. If used in :a factory; where there are employees present and movingi about, a fixed anchorage of the machine may become important to prevent injury resulting fromiinadvertent displacement and rollingsof the machine acrossthe .floorr;

Welded to" the platform'21 and rising vertically therefrom are atpairof spacedtchannel irons; 25;; 265011 which is pivotally-mounted :a base :plate: 21 forming a support for an electric ;motor-2E8,- -havingFa pulley 29, which is connected through a v-beltz3fl to the pulleyfizl of a right-angledspeed reducing "transmission 32. A-coil spring 33-iis attached ?at its upper end to? the 'basewplate 25F and at its'flower. end to the-platform 2 I, and serves :to keepthe be1t30 under suitabletension.

The transmission 32*ismounted on a bracket 34' which, in turn, is welded-to theplatform .24.; and it includes a vertical shaft which ex-tends downwardly through the-platform 2i and carries 4 a pinion 36 (see Fig. 6) the function of which will presently be explained. Rotatably mounted on vertical studs 38 which are secured to the platform 2| are six straightening rolls 39, ar-

ranged in pairs, the members of each pair being spaced apart just sufliciently to receive the rod l5; and positioned at the receiving endof the straightening rolls is a guide plate 40, welded to the platform 2| and having a horizontally elongated opening of a width, vertically, sufficient to clear the rod. The rod is regularly shipped to the sites-of I'zoperation' in the form of coils, since it is too Icngto' be handled otherwise, and it must besstraightenedabefore being bent to the desired curvature. That isithe function of the straightening rolls 39':

Immediately adjacent the output end of the group of straightening rolls 39, there is mounted on'the' platform 2| a pair of grooved driving or feed rolls 42, 42, each off'which is keyed to a verii-631 5113111143; .43 journaled in' suitable bearings andeachmarryinga gear 44,- 24 at its lower end see-Fig. 6). The two latter gears are inter.- meshediand -of the same pitch diameter, ,so that theztwo ieedrollsAZ, 42. are .driven at the same speed,- andone of :said gears is also meshed wit thespinionQBG throughwhich the feed rollsare driven.

Ite'will be. apparent that the. feed rolls. 42, 42 grip thelrod. l5 :andserve toforce the same lengthwise-throughthestraightening rolls; As the rod emergeswfrom the ieed rollsiitlpasses between-a pairofguidarollslfi, which, like the straightening,rolls;.are-mounted-on vertical studs 63,41; and-ilfzisithereupon 'eng-aged'by a bendiugroll 55 which cooperates; with the guide rolls 46, 8 to applybending' pressure-to the rod. The hen-sling roll z5llds-rotatablymountedon astud .5! the lower endloiwhich :isssecured'to a carriage 52 whichiis slidably -mounted in a guide member tie and provided with an upstanding lug 54 to which is pivotally connected by'means of a pin 55; av twopieceelinkififorming an armxof a toggle 5'"! whose other'a'rm comprises: a link 58'; The latter is pivotallyconnectedxatnone endito the adjoining 'endof thelink l'ss bymeansof a pin seam: at'its otherend 'iti-is" pivotally' connected by a pin: 68 to'-'a-'-clevis B l-which, in turn, is fixedly secured toone'endof anadjusting screw '62, which passes through-an" aperture-in a lug 63 welded to the platform Hi the adjusting screw being secured by a'paii' of lock nuts 64', 64; An upstanding arm 65 is"rigidly"secured to the link 58 and serves as a means'whereby a' workman can manipulate the toggle" 51: to" effect forward and backward movement offthe bending roll 50 and its carriage 52;

Thcoperative position of the bending roll 50 is determined by the adjustment of the screw 62 whoseupositionis. then fixed by adjustment of the lock. nuts 64.. T'he v curvature imparted to the rodis, .oicourse, a iunction of the operative position ofsthenbending roll, relative to the guide rolled-BI l'nworder to ,startthe bending opera tion whenia freshrod'is inserted, it is necessary tometract the bending roll 50 and then force it forwardly against the. rod, andthis is accomplished by meansof. the toggle arm 65 in the manner already, explained; It is desirable to ad'- justi-the bendingmachine o thatithe curvature impartedto therodwill resultin a helix ofthe prescribed-diameter.. Thiscan readily be..done Joy-runningi throughltheimachine a length of..;rod and-measuring itscurvaturewitha templet, as

adjustments proceed, until exactly the right curvature is obtained.

I claim:

1. The method of applying an encircling steelrod coil to an existing building column, which comprises progressively bending the steel rod at a fixed point adjacent the column to the desired curvature and passing the curved rod lengthwise around the column as the bending operation proceeds forming a multiple turn coil around the column in situ.

2. The method of applying an encircling steelrod coil to an existing building column, which comprises placing a bending machine in a fixed position adjacent the column and passing the steel rod therethrough to bend the same to the desired curvature, and leading the curved steel rod lengthwise around the column as it emerges from the bending machine forming a multiple turn coil around the column in situ.

3. The method of reinforcing an existing structural column which comprises progressively bending a steel rod in a fixed position adjacent the column to form a multiple turn coil thereof, and continuously leading the bent rod around the column, lengthwise of the rod, as the bending operation proceeds, so that the coil, upon completion, encircles the column, then axially expanding the coil longitudinally of the vertical dimension of the column to form a helix extending lengthwise of the column, disposing a plurality of vertical reinforcing rods in spaced relation around the column and securing the same to the helix to provide support for the helix, and then applying to the exterior of the column a shell of plastic concrete mixture of a sufiicient thickness to embed the rod reinforcement.

4. The method of applying an encircling steelrod coil to an existing building column, which comprises progressively bending the steel rod at a fixed point adjacent the column to the desired curvature and passing the curved rod lengthwise around the column as the bending operation proceeds forming a multiple turn coil around the column in situ and then expanding the multiple turn coil axially longitudinally of the vertical dimension of the column.

JOHN D. BOLTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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