US1597278A - Composite beam construction - Google Patents

Description

Aug. 24

J. KAHN COMPOSITE BEAM rCONSTRUCTION Filed April 29. 1921 3 Sheets-Sheet 1 ---uJN-M Julius Kak,

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' Aug. 24 1926.

J. KAHN GOMPOSITEBEAM CONSTRUCTION Filed April 29, 1921 3 Sheets-Sheet 2 n-fucfnoz Mins Kahn,

- Aug. y24 1926. 1,597,278

J. KAHN COMPOS ITE BEAM CONSTRUCTION @www m mld l Patented Aug. 24, 1926.

UNITED STATES PATENT OFFICE.

JULIUS KAHN, OF YOUNGSTOWN, OHIO, ASSIGNOR TO THE-TRUSCON STEEL COMPANY, 0F YOUNGSTOWN, OHIO, A CORPORATION OF MICHIGAN.'

COMPOSITE BEAM CONSTRUCTION. i

Application led April 29, 1921.

This invention relates to a novel beam construction for structural work, and particularly to a beam of the composite type wherein steel and concrete are consolidated in an advantageous manner to more effectively assimilate compression and tension strains, while at the same time eil'ecting economies in construction.

To that end, the invention contemplates utilizing structural steel as the tension member of a beam or girder in combination with concrete as the compression member, and arranging said members in such coacting relation as to best distribute and sust-ain the load stresses. More especially it is proposed so to arrange the structural steel tension member with reference to the concrete that the said tension and compression members are not enclosed one within the other, and also in that way combining structural steel and reinforcement to su port the building structure both during an after construction.

Hereto'fore, in the construction of concrete buildings it has/been customary to employ combined steel and concrete beams wherein the tension member has been embedded in and enveloped by the concrete and it has, therefore, been necessary to use temporary supports to sustain the building until the concrete sets. It is, therefore, the purpose of the present invention to so arrange thesteel and concrete that the two are securely anchored together, but the steel tension member is wholly withontconcrete and is utilized as a support for the building both during and after construrtion, thereby obviatiner the objections to the former method and also facilitating construction.

Accordingly, it will be apparent that a primary object of the invention is to provide a composite, beam wherein the tension and compression members are separate, though securely anchored together to pro- .vide in eHect a unitary beam or girder struc ture.

' Vith the above and other objects in View which will more readily appear as the nature of the invention is'belter understood, the same consists in the novel construction, combination and arrangement of parts hereinafter more fully described, illustrated and claimed.

A preferred and practical embodiment of Serial No. 465,352.

the invention is shown in the accompanying drawings in which Figure l is a vertical sectionalview of a composite beam constructed in accordance with the present invention.

Figure 2 is a vertical sectional view taken on the line 2-2 of Figure 1.

Figure 3 is a detail elevation of a simple embodiment of the invention showing a concrete slab superimposedupon an I-beam and inter-locked therewith.

Figure l .is a detail sectional view taken on the line 4-4 of Figure 3.

Figures 5 and 6 are detail sectional and elevational views illustrating another modiic'ation that may be resorted to in carrying out the invention.

Similar reference characters designate corresponding parts throughout the several figures of the drawings.

As indicated, a distinctive feature of the present invention resides in having the structural steel tension member of the beam wholly without the concrete compression member, while at the same time securely anchored thereto so as to be an intimate unit of the beam construction. The anchoring projections or tongues of the tension member are intended to serve not only to positively anchor the tension and compression members of the beam together, but may be so located as to resist the internal shearing stresses in the concrete or compression member of the beam.

To illustrate the improved features of construction reference may be had to the accompanying drawings in which the numeral l designates the structural steel element, preferably an I-beam having its top flanges sheared at intervals as at 2, permitting anchoring tongues 3 to be struck up from said iianges for cmbedment` in the superimposed concrete body C which constitutes the compression member of the beam. These anchoring tongues 3 are preferably arranged obliquely,.and, at the locations of the shear 2, the tongues which are struck up from the opposite flanges of the beam are preferably reversely related, therefore being disposed in crossing relation to more effectively op` crate as anchoring elements and as the shear members of the construction. The upper endsV of the said tongues 3 are preferably 'apparent that the concrete body U of the i compression member is formed directy over and upon the structural steel tension memi ber l upon the top flange of thelatter,

thereby providing an arrangement in which the tension member is located wholly 'without the' concrete body of the compression member, and the beam construction can, therefore, be utilized to support the buildo ing bothduring and after construction without the aid of temporary supports which are necessary where the steel tension member is enveloped by the concrete body of the compression member. 'llhe feature of the concrete body of the compression member being formed directly over and: upon the structural steel tension member l is exemplified in the simple embodiment of the invention shown in Figures 3 and 4, in which the struc# tural steel tension member l, preferably of ll-beam formation has its upwardly projecting tongues 3 embedded and anchored in a superimposed concrete slab C, thereby 'pro viding a construction wherein the two members of the composite beam construction are securelyfastenedj together in such a manner as to provide against relative slippage between the two members where they join. As'

shown in Figures eand 6, this construction also admits of the use of steel sections with .a large lower flange having the. effect of composite lowering the neutral aXis of the beam) as beam (as well as lthat of the ysteel shown at X-X Fig. 5; rlhe advantage' of this lconsgtructionis the increasirigof the ef-V fective' depth of the beam so that a relasuiiice. a

At the locations in the span of the beam where thegirders are required, the concrete body of the compression member is'de'epened as atc 6 to combine with thegirde`r tension member 7- hoaving its toplanges sheared' and struck lip-to provide the anchoring tongues 8l which `are enveloped by the concrete bod)7 .of the compression'member, as-and for the purpose already described. Figure l of the drawings shows a portion of. a beam `span madev up of the composite beam construction described and also-includes an illustration of agirder formed withthe beam, as a part of the same construction.V

tively small sectional area -of concrete willl integere As shown in Figure 1 of the drawings, the" exposed tension structural member may be covered by `a. covering 9 of lath andplasterv for fireprooiing purposes should that be desired or required.

From the foregoing, it is thought that the essential features of telle improved beam construction will now be understood, and it will also -be apparentn that minor changes in the form, proportion and details of construction may be resorted to without departing from ^thespirit or sacrificing any of the features of the invention,

l claim:

l. A composite beam comprising an llbeam tension member having its body portion in vertical position and one of its flanged portions uppermost and forming an upperbearing surface, a concrete compres-A sion member having a lbottom surface with a bearing portion substantially coeXtensive with the top'bearing surface of the tension member and resting thereon, said tension member being Wholly outside the compression member, and anchoring connections eX-` tending vfrom the l-beam and embedded in the overlying lconcrete compression member.

2. Acomposite beam comprising an beam tensionmember having itsbody portion in verticaly position with one of its angeportions uppermost and constituting an upper bearing Surface, a compression` member of concrete overlying the tension member and comprising va body having a depending portion that rests Aupon the said bearing surface, said tension member being wholly outside the compression member, and

anchoringconnections extending from the I tension member Aand embedded in the depending portion of the compression member. 3. A composite beam comprising l-beam tension membersin crossed relation with one on the other and having their bodies `in verf tical position and. their upperl fianges constituting bearing surfaces, a concrete compression member common 'to' the. tensionmembers' and having dependingV portions of different depths that respectively rest upon the bearing surfaces formed. by the uppermost flanges of the crossed l-beam tension f V members, said tension members being lofno cated outs'ide'the 'compression member, and y anchoring connections between the tensionI members and the depending portions of the 'compression member. v t

In testimony whereof hereunto am my v signature.

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