US742943A - Fireproof girder or beam. - Google Patents

Description

' PATENTED NOV. 3, 1903.

W. N. WIGHT. FIRBPROOF GIRDER 0R BEAM.

APPLICATION FILED JAN. 30, 1903.

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WITNESSES:

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llatented November 3, 1908.

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VILLIAM N. WIGHT, OF NEW YORK, N. Y.

FIREPROOF GIRDER OR BEAM.

SPECIFICATION 'forming part of Letters Patent No. 742,943, dated November 3, 1903.

Application filed January 30,1903. Serial No. 141,098. (No model.)

T0 @ZZ whom it may concern.-

Be it known that I, WILLIAM N. WIGHT, a citizen of vthe United States, residing in the borough of Manhattan,city, county,and State of New York, have invented certain new and useful Improvements in Fireproof Girders or Beams, of which the following is a specification.

' My invention aims to provide certain improvements in beams or girders for use in fireproof buildings which shall be very strong in proportion to their weight, shall be easily constructed, and shall be much better adapted to resist fire than the steel beams now commonly employed.

My invention provides also improvements in the process of building such a beam or girder.

My improved-beam may be constructed of concrete and reinforcing metal, such as wirenetting, although certain features of the invention are independent of the metallic reinforce.

The features of the invention which are separately new are defined in the claims hereinafter.

Referring to the drawings forming part of this specification and illustrating certain structures in which the invention is embodied, Figure l is a longitudinal section of a beam, taken on the line l 1 of Fig. 2. Fig.

A2 is a central transverse section of the beam shown in Fig. l. Fig. 3 is a section similar to Fig. 2, showing the beam in course of construction. Fig.,4 isa longitudinal section of another beam embodying the invention, the section being taken on the line 4 ltof Fig. 5. Fig. 5 is a central transverse section of the beam shown in Fig. 4. Fig. 6 is a section similar to Fig. 5, showing the beamI in course of construction. Fig. 7 is a section similar to Fig. 5,showing certain additional features applied thereto. Figs. 8 and 9 are respectively a plan and a section vsimilar to Fig. l of another beam embodying the invention. Fig. 10 is a longitudinal section near one of the side edges of another' beam embodying the invention, the plane of section being indicated at lO lO, Fig. 5. Fig.- ll is a side elevation of the beam shown in Fig. 10.

My improved beam as illustrated in its most com plete form includes upper and lower plates or chords of concrete, which are preferably substantially horizontal. The upper and lower chords are separated from each other a sufficient distance to give the desired depth to the beam, and between them is an arch for transmitting pressures on the upper chord to the lower chord, and preferably end posts for asimilar purpose. Where the arch is made of considerable length-say the entire length of the beam-I may provide addi'- tional vertical members'between' the ends of the arch for transmitting downward strains from the upper chord to the lower. Preferably the concrete is reinforced by a suitable reticulated metal reinforce. Preferably for this purpose I employ a wire netting or fabric of the generic type of which an example is illustrated in my application for patent, Serial No. 114,868, tiled July 9, 1902, and which may be briefly described as composed of straight wires in one direction and cross-wires spacing said straight wires and bound thereto at their crossing-points. The metal reinforce should be embedded in the upper and also in the lower chord, and the reinforce in the lower chord should preferably be embedded, at least in part, in the arch between the two chords. Preferably, also, the intermediate port-ions of the reinforces in the up' per and lower chords are tied to each other by suitable metal ties. force in the lower chord may be provided with vertical side portions, stiening the beam and preferably connecting the edges of the upper and lower reinforces.

Referring to the drawings, the beam shown in Figs. l, 2, and 3 comprises a lower chord A, au upper chord B, and an arch O, the ends of the latter supported on and, in fact, formed in one with the ends of the lower chord A and the central portion of the arch being, in fact, inV one with the central portion of the upper chord B. The ends of the upper chord B are supported upon the ends of the lower chord A 'by means of substantially vertical end members D. The whole structure therefore forms, in effect, a sort of trussed girder,

upon the upper portion of which the loads are received directly and the lower chord of which isstrained .in tension. The lower chord A being in tension, as stated, is provided with an embedded metal reinforce,

Also the metal reinf preferably, as shown, in the form of a steeldiameter of the wire the latter will break before it can be pulled out of the concrete, so great is the adhesion. The downward and y endwise strains which are transmitted from the upper chord through the arch C are best transmitted to the lower chord by turning up the ends of the fabric E of the lower chord, as indicated at H, into the ends of the arch. They may extend throughout the length of the arch and should be, at least in part, in the arch, as shown. By this construction the beam takes up within itself all endwise thrust,`so that the stress on the supports K is directly vertical. Preferably, also, the u pper chord B is provided with an embedded reinforce, such as the wire fabric L, the cenface of the concrete to take the tensile strains coming therein. This reinforce greatly relieves the haunches of the arch C, which accordingto known laws would have a tendency to rise under eccentric or very heavy concentrated loads. The fabric of interlaced and bound wires distributes a great part of such strains throughout the upper chord, so as to lessen the effect of the eccentricity or concentration of the load. In order that the lower chord A may be made very light, I preferably employ also 'one or more ties M, attached to the upper and lower reinforces L and E at intermediate points of the beam, so as to sustain and relieve the intermedi-ate portion of the lower chord A of its own weight and utiln ize it purely for resisting the tensile strains y' exerted at its opposite ends. The ties M are f preferably strips of heavy wire, as shown,

5o bent at their ends over the fabrics L and E.

The relative proportions of the several parts ofthe beam may be considerably varied from Athose shown, depending upon the permissible depth of the beam and the magnitude and manner of distribution of the loads to be carried. The triangular panel between the end posts D, the upper chord B, and the haunches of the arch C may be filled in with concrete without sacrificing any of the advantages of the invention except that of lightness, or this panel and the panel between the arch and the lower chord may contain a longitudinal web, such as is indicated in dotted lines at N, Fig. 2, leaving a transverse opening at each side of the beam, but not extending entirely therethrough. Instead of a single arch C extending between two end posts tral portion of which extends near the lower D a number of such arches may be used, constituting the structure, in eect, a latticed girder, and, as will be obvious to those skilled in the art, the same arch eect will be obtained whether its contour consists of curves or straight lines. The beam may be made of such length asv to extend only between two adjacent supports K, as indicated in Fig. 9, or it may be a continuous beam-that is, extending without break over more than two supports, as indicated in Fig. l-in which case each span contains the several elements referred to, and the end posts D, and preferably the upper reinforce L of adjacent spans, are integral with each other. In such a continuous beam the upper chord is strained in tension at points above the supports, and therefore a reinforce L' should extend continuously over the end post, which reinforce may be part of the fabric L and which is preferably in the upper part of the concrete where the tensile strain is greatest.

The process of building the beam described will be understood from Fig. 3. A suitable base or center O is provided, and upon this is molded the lower portion of the beam, (in the structure illustrated the lower chord A.) Upon this lower portion is then constructed a center P of any suitable material, preferably of loose granular material, which can be readily molded to the desired shape and readily Withdrawn, temporary sides Q being provided to determine the lateral edges of the beam and the center P being built substantially out to these temporary sides. On the center P the upper portion of the beam is then molded, such upper portion at itsends extending down to the lower portion of the bealn,sothatwhen the concret'ehassufciently set it is supported upon the lower portion of the beam. After the concrete has set, the sides Q of the mold are'withdrawn, and the center .P is withdrawn laterally, so as to leave a transverseopening between the upper and lower portion, which transverse opening may extend entirely through, as indicated in Fig. 3, or may extend from each edge toward the center, as indicated in dotted linesin Fig. 2. For building a beam constructed exactly as shown in the several longitudinalv sections illustrated the center P is made in suitable formto support an arch C, and after this arch is built-say in the form shown in Fig. l-the process isextended by the building of a similar center on the haunches of the arch to form the triangular panels shown, and about this center are built the upper chord B and the end posts D. The metal reinforces described may be embedded in the concrete during the laying of the same in the manner well known to those skilledinthe art. The packing and shaping of the centers of loose material may be very quickly accomplished, so that the arch ends mayjoin the ends of the lower chord and the arch center may join the center of the upper chord and the end posts be connected to the adjacentvmembers before ICC there has been any substantial setting of the concrete, so as to form a substantially integral structure. Where a number of spans are to be constructed in one, so as to form a continuous beam, the'same process may be obviously applied with facility, requiring only a multiplication of the number of centers to be constructed without any increase in the time necessary to construct them or for the laying or setting of the concrete. Since the centers are withdrawn through openings of their own full size, it is obvious that any style of centering may be employed, though for the reasons stated I prefer the loose granular material shown.

My invention provides also for stilfening concrete beams having separated upper and lower portions by means of a metallic stiifening-reinforce lying in a vertical plane and extending longitudinally of the beam and embedded at its upper and lower edges in said upper and lower portions. This improvement is applicable with advantage to any such beam regardless of the particular shape of the upper and lower portions. For example, they may be the horizontal chords above described or they may be one such chord and an arch, or the beam may comprise the several elements in the specic structure illustrated. Such a metallic stieniug-reinforce serves substantially the same purpose as the concrete web N, Fig. 2, and may be used with or without this web-as, for example, by being embedded therein-or it may extend across a transverse opening extending into or through the beam. A structure embodying this feature is shown in Figs. 4 to 7. The concrete in this case is substantially identical with that shown in Fig. 1, comprising a lower plate A, ari-upper plate B, an arch C, and end posts D, arranged above any suitable supports K. In the lower and upper chords A and B are embedded fabrics E and L, similar to those in Fig. 1 and similarly arranged. In order to provide the metallic stiiening described, the fabric E may be bent up to form vertical side portions R, preferably bound at their upper edges to the fabric L of the upper chord. The ends of the fabric E may be bent up into the end posts D, as indicated at S, and connected to the upper fabric, or they may be bent up into the lower ends of the arch, as indicated at H, Fig. 1. The ties M may be omitted where the vertical fabric is used, leaving the fabric to support the lower chord throughout its length; but I prefer to assist it with the ties. The modifications in form and proportions referred to in connection with the structure shown in Fig. 1 are also obviously applicable to the structure with metallic stienin greinforce, and, in fact,

to all the several structures shown. In buildthe opening a variation of the process illustrated iu Fig. 3 maybe utilized. Referringto Fig. 6, the center or mold-base O. and mold sides Q are identical with those shown in Fig. 3. As in the process described in connection with Fig. 3 the lower portion of the beam is molded, the vertical reinforce R being held in position, the center of loose granular material P is constructed of the desired contour, and the upper portion of the beam is then molded on this center. After giving the concrete suflicient time to set, the loose material P of the Y center may be withdrawn through the interstices of they reinforce R. As in the former case the lower portion ofthe beam may be the lower chord A and theupper portion may be an arched or a dat portion extending at its ends down to the lower chord, preferably both the arched portion C and the horizontal upper chord B being formed one after the other, as described.

Where my improved beam is to be used in exposed situations,the transverse openings at the sides may be closed-as, for example, by plastering-to give a better finish to the structure. With the vertical stiffening fabric described the mouth of the transverse opening at the side of the beam may be very conveniently covered in the manner illustrated in Fig. 7. In this construction lathing, such as the tine-mesh Wire fabric T, may be attached to the stiffening fabric R and a suitable layer of plaster or cement U applied thereto and also to the edges of the solid portions of the beam, as shown, in order to finish it nicely. This layer of plaster or cement may be made such as to reinforce the metallic stiening, and thus add to the strength of the beam.

Figs. 8 and 9 illustrate an embodiment of the invention very similar to that shown in Fig. 1. These and the following figures illustrate a simple beamthat is to say, a beam long enough to extend over only a single span between two supports K-as distinguished from the continuous beam of Fig. 1 I of more than one span in length; In such asimple beam it is preferable that the end posts D should converge upwardly, as indicated.

The lower chord A, upper chord B, and archv C are substantially identicalwith thec same parts shown in Fig. 1, as are also the reinforcing fabrics E and L. In addition to the ties M, which take the tensile strains due to the weight of the lower chord, I propose to employ intermediate vertical members or posts V, preferably of concrete and surrounding the ties M. These posts are adapted to resist compressive strains and serve, therefore, for transmitting the downward strains which come on the upper part of the beam to the lower chord,where they are converted into tensile strains.

An embodiment of the invention including the features of Figs. 8 and 9, in connection with the vertical metallic reinforce of Fig. 4, is illustrated in Figs. 10 and 11. The concrete structure in these figures is identical with that shown in Figs. 8 and 9. The embedded metallic fabric, however, is bent up IIO along each side, as indicated at R, to increase the stiness of the structure, Fig. 10 being a section along the line 10 10 of Fig. 5. The panels or transverse openings in these cases may be obtained by the processes indicated in Figs. 3 and 6, the only modification being in the number and shape of the centers of granular material to be employed.

' The closing of the mouths of the transvers openings at the side edges of the beams and the modifications in the relative arrangement and proportion of the elements of the beam referred to in connection with Fig. 1 are obviously equally applicable to the beams shown in Figs. 8 to 11.

The various types described are well adapted for use Without the lower chord, especially in situations in which other means areprovided for taking up the side thrust at the ends of the spans. The continuous beam illustrated in Fig. 1 is a good example of such a situation. The spans at the opposite ends of the complete span shown would take up the end thrust of the central span if the lower chord A were omitted.

Though I have described with great particularity of detail certain embodiments of my invention, yet it is to be understood that the invention is not limited to the specific embodiments disclosed. Various modifications of the same in detail and in the arrangement and combination of the parts may be made by those skilled in the art without departu re from the invention.

What I claim isl. In a beam, in combination, a lower chord, an upper chord, and an arch between said chords, each of said parts being of concrete.

2. In a beam, in combination alower chord, an arch supported at its ends on said lower chord, and vertical members intermediate the ends of said arch for transmitting downward strains thereon to the lower chord, each of said parts being of concrete.

3. In a beam, in combination, an arch, a horizontal upper chord above vthe arch, and vertical members joining the ends of said arch and chord, each of said parts being of concrete.

4. In a beam, in combination, alower chord, an upper chord, an arch between said chords, and vertical members joining the ends of said chords, each'of said parts being. of concrete.

5. In a beam, in combination, alower chord,

an upper chord, an arch between said chords, each of said parts being of concrete, and a metal reinforce embedded in said lower chord.

6. In abeam, in combination, a lower chord,

an upper chord, an arch between said chords,

each of said parts being of concrete, and a metal reinforce embedded in said lower chord and at least in part in saidv arch.

7. In a beam, in combination, an upper chord, an arch below said upper chord and adapted to transmit strains from the intermediate portion of said-upper chord toward the ends of the beam, each of said parts being of concrete, and a metal reinforce embedded in said upper chord to distribute the eccentric or concentrated loads. thereon and, thus relieve the haunches. of the arch.

8. In a beam, in combination, a lower chord, an upper chord, an arch between said chords, each of said parts being of concrete, and metal reinforces embedded in said upper and lower chords.

9. In abeam, in combination, a lower chord, an upper chord, an arch between said chords, each of said parts being of concrete, a metal reinforce embedded in said upper chord, and a metal reinforce embedded in said lower chord and at least in part in said arch.

10. In v-a beam, in combination, a lower chord, an upper chord, an arch between them,

each of said parts being of concrete, metal reinforces embedded in said upper and lower chords, and a tie attached to said metal rein forces to connect them to each other..

l1. In a beam, in combination, a lower chord, an upper chord, an arch between said chords, each of said parts being of concrete, a metal reinforce embedded in said upper chord, a metal reinforce embedded in said lower chord and at least in part in said arch, and a tie attached to intermediate portions of said met-al reinforces to connect them to each other.

12. A concrete beam having a transverse opening therein and a stiffening metallic reinforce in a vertical plane extending across said opening and embedded at its edges in the concrete.

13. In a beam, in combination, upper and lower portions of concrete separated from each other, and a metallic stiffening-reinforce in a vertical plane extending longitudinally of said beam and embedded at its upper and lower edges in said upper and lower portions respectively.

14. In a beam, in combination, a horizon- IOO IIO

tal chord and an arch separated from each other at portions of their length, each of said parts being of concrete, and a metallic stiffening-reinforce in a vertical plane extending longitudinally in said beam and embedded at its opposite edges in said chord and arch re-` ing horizontal portions embedded in saidA beam above and below said opening, and vertical side portions joining the edges of said horizontal portions.

17.` A concrete beam having a transverse opening therein, and a layer of plastic material extending over the mouth of said opening. 18. A lcontinuous beam comprising in combination a plurality of spans each of which is limited by end posts of concrete and cornprises an upper' and a lower portion of concrete having a transverse opening between them.

19. A continuous beam comprising a plurality of spans limited by end posts of concrete and having upper and lower portions of concrete having a transverse opening between them, and a metallic reinforce extending over the end post of two adjoining spans.

20. The process of building a concrete beam with a transverse opening therein, which consists in molding a lower portion of the beam, constructing on said lower portion a suitable center extending to the lateral edges of the beam, molding on said center an upper portion of the beam supported at its ends on the lower portion, and, after the concrete has set suciently, withdrawing the center laterally so as to leave a transverse opening in the beam.

2l. The process of building a concrete beam having a transverse opening therein and an apertured vertical metallic reinforce extending across said opening, which consists in moldinga lower portion of the beam, arranging the reinforce in position, constructing on said lower portion a center of loose granular material, molding on said center an upper portion of the beam supported at its ends on the lower portion, and, after the concrete has set sufficiently, vwithdrawing said loose material through the vinterstices of said reinforce.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

WILLIAM N. WIGHT.

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