US3564799A

US3564799A - Shear connector for deep corrugated steel formed composite structure

Info

Publication number: US3564799A
Application number: US788179A
Authority: US
Inventors: Richard E Hanson
Original assignee: Granite City Steel Co
Current assignee: Granite City Steel Co; Citicorp North America Inc
Priority date: 1968-12-31
Filing date: 1968-12-31
Publication date: 1971-02-23
Anticipated expiration: 1988-02-23

Abstract

A SHEAR CONNECTOR FOR COMPOSITE STRUCTURES IN WHICH CONTINUOUS DEEP CORRUGATION FORM SHEETS WITH CONCRETE ARE UNITED TO THE SUPPORTING BEAMS BY THE SHEAR CONNECTOR SHAPED TO RESIST THE LOADS IN TENSION AND TO BRIDGE CORRUGATIONS SO THAT THE CONCRETE IN THE SLAB AND THE FORM SHEETS ACT TOGETHER WITH THE SUPPORTING BEAMS.

Description

Feb. 23, 1971 R E, HANSQN 3,564,799 SHEAR CONNECTOR FOR DEEP CORRUGATED STEEL FORMED COMPOSITE STRUCTURE Filed Dec. 31, 1968 v 2 Sheets-Sheet 1 R. E. HANsoN 3,564,799 OR DEEP CCLRRUGATED STEEL FORMED Feb. 23, 1971 SHEAR CONNECTOR F COMPOSITE STRUCTURE 2 sheets-sheet z Filed Dec. 31, 1968 C /ffr U.S. Cl. 52-334 7 Claims ABSTRACT OF THE DISCLOSURE A shear connector for composite structures in which continuous deep corrugation form sheets with concrete are united to the supporting beams by the shear connector shaped to resist the loads in tension and to bridge corrugations so that the concrete in the slab and the form sheets act together with the supporting beams.

This invention relates to shear connector means for composite building structures and is particularly concerned with a shear connector having spaced legs and a bridge which transfer loads in tension over continuous deep corrugation metallic form sheets.

In a composite building structure the problem is to accomplish a tie between the concrete slab, the continuous metallic form, and the supporting beam such that when the load is applied the concrete and beam act together. When the concrete slab slips at the junction of the steel beam, the composite action is lost because the slab and beam act independently.

The use of continuous sheets in structures is the most economical method. However, the use of continuous sheets has presented the problem of developing shear connection as voids in the slab caused by the corrugations reduce the effectiveness of present connectors. Shear connectors are used to tie the concrete slab and its form to the beam. There are generally two classes of shear connectors. There is a rigid connector which stays in one position and the strength of the concrete controls the failure point. On the other hand, there is a flexible shear connector which moves or allows some slippage between the slab and beam before effective tensile stresses occur in the shear connector. However, the slippage which occurs is very damaging to the concrete around the connector and the form sheet.

An important object of this invention is to provide a shear connector wit-h bridged connector legs that are in a tension position when concrete is placed so that no slippage is required for the connector to act in tension.

It is also an o'bject of this invention to provide a bridge shear connector so that the concrete is reinforced between the legs of the connector and forces are transferred directly from one tension leg to the other.

A further object of this invention is to provide a shear connector with a pair of legs in tension positions and connected by a horizontal bridge to reinforce the concrete over the corrugations of the form sheets.

Certain preferred shear connectors are disclosed in greater detail in the following specification and the accompanying drawings, wherein:

FIG. 1 is a fragmentary view in sectional elevation of a typical building in which the form sheets for the concrete are tied to the supporting beams by the shear connectors of this invention which straddle the corrugations;

FIG. 2 is a fragmentary View in sectional elevation of a typical building, the view being taken at right angles to the view of FIG. 1 showing the shear connectors positioned with a valley between adjacent corrugation crests;

United States Patent O "ice FIG. 3 is a greatly enlarged fragmentary elevational lview of a -`shear connector positioned in bridging relation to a corrugation of a form sheet;

FIG. 3A is a top plan View of a shear connector with portions broken away to show the weldment for the legs;

FIG. 4 is a View similar to FIG. 3 but showing a modified shear connector;

FIG. 5 is a fragmentary perspective view of an assembly of form sheets supported across a load carrying member and provided with shear connectors for bridging an underiloor service conduit; and

FIG. 6 is a fragmentary view of an assembly of corrugated form sheets extending across a load bearing member and provided with shear connectors having both legs secured in the same valley of the corrugated sheets.

Referring now to the drawings, FIGS. 1 and 2 illustrate a building structure which includes a steel frame assembly of spaced vertical columns 10 supporting load bearing members such as beams 11 connected by suitable angle plates 12. and other load bearing members such as girders 13 arranged at right angles to the beams 11. The manner of effecting the connections of girders 13 follows the usual specifications employed at the present time. The open bays between girders 13 are closed by a plurality of corrugated form sheets 14 which are laid in positions in which the corrugations run perpendicular to the beams. Concrete (see FIG. 1) is poured upon the form sheets to a desired thickness such that the sheets and rods 15 are embedded and react together. Forms that use other methods for tying the sheet to the concrete and forms that do not provide any means except bond of concrete to the form may also be used. Before the concrete slab is poured in place, a plurality of the improved shear connector devices 16 are placed over the flanges of the beams 11 and oriented from the mid-span of each ybeam so that the angle of lean is away from the mid-span of the beam. The legs of each connector (FIG. l) are welded through the form sheets 14 to the beam flanges to tie the connectors and sheets to the flanges. The same orientation of shear connectors 16 is followed for the girders, as is shown in FIG. 2 and Welding is performed to tie the legs thereof through the form sheets to the girder flanges.

The foregoing assembly of shear connectors has been shown in enlarged detail in FIG. 3 which will now be described. The form sheet 14 is placed on the `flange of beam 11 such that the corrugation is perpendicular to the beam span. One corrugation crest 17 and the adjacent valley 18 is illustrated. Shear connector 16 is placed over the crest 17 such that the

legs

19 and 20 rest end-on in the valleys 18 and the connecting bridge portion spans the crest 17. The

legs

19 and 20 are substantially parallel and arerelated to the bridge 21 such that leg 19 forms an obtuse angle and leg 20 forms an acute angle, taking into account the radius R between the bridge 21 and the leg 20. A deposit W of welding material is made through the sheet 14 onto the beam flange 11A so that a secure connection is formed between the flange, the sheet and each leg. The concrete slab S is poured over the connector upon the sheet 14.

In view of FIG. 3, leg 19 forms the angle A with the plane of the valley 18, and the angle A of leg 20 is substantially the same. The

legs

19 and 20 are sufficiently long to position the connecting bridge portion 214 at the distance D above the crest 17 so that concrete may be easily worked under the bridge 21. The top plan view of the connector (FIG. 3A) shows the provisions of openings 22 for increasing the bond of the bridge to the concrete. Each connector 16 is formed of llat steel having a width of from 1 inch to 3 inches, and may be 12 gauge steel sheet to one-fourth inch steel plate. The openin-gs 22 may not be required when the clearance dimension D is large.

The angles A and A of the

respective legs

19 and 20 may vary from 45 to as much as 75. This will limit the obtuse angle between leg 19 and the bridge 21 to at least 105, while the acute angle betwen leg 20 and the bridge 21 will be of the order of 75, when the bridge 21 is substantially parallel to the beam ange 11A. The clearance dimension D may vary from not less than Isubstantially three-fourths of an inch. The distance between the bottom ends of the

legs

19 and 20 will be determined I by the pitch dimension of the corrugated sheets 14, and

may be of the order of from 21/2 inches to as much as 15 inches. The foregoing physical characteristics of the shear connector are stated by way of example and no limitation is intended to be presumed from this.

FIG. 3A illustrates a top plan view of the shear connector 16 of FIG. 3. It is there shown that indicia in the form of an arrow 23 and the legend POINT ARROW TO MID-SPAN OF BEAM is scribed on the top surface of the bridge portion 21 in order to indicate the proper orientation of the shear connector 16 upon abeam or a girder. This is important to have the slant'or lean of the

respective legs

19 and 20 properly oriented to place the same in position to be stressed in tension and to cause the bridge 21 to act to transmit the stress between the legs to assure the tension reaction. v

In FIG. 4 a modified shear connector 16A is shown. The foregoing description will apply insofar as the characteristics are the same. In the modified connector 16A the openings are eliminated, but the leg 19 is now provided with stilener means 24 which may be integral therewith. The means 24 includes a first portion 25 bent under the leg 19 to rest atwise in the valley 18, and a rebent portion 26 formed to have its end 27 abut with leg 19 to provide support therefor above the weldment W. The rebent portion 26 may be variably positioned from substantially parallel to portion 25 to an angular position of about 60 above the horizontal. The stiffener means 24 will stiffen the critical leg 19 to prevent bending at high loads. The horizontal portion 25 also provides means for positioning the connector in the valleys 18 of the corrugation to obtain maximum concrete between the adjacent corrugation and the connector leg 19. The stiffener means 24 will also provide a degree of stability to the shear connector during assembly so that Workers will be prevented from bending the connector before the concrete is poured.

The fragmentary assembly of FIG. illustrates the installation of a double row of shear connectors 16 over the beam 11. In this view, the assembly includes an underoor service conduit 28 between adjacent corrugated sheets 14, and elongated shear connectors 29 spanning the conduit 28. The form of connectors 29 correspond to connectors 16 except that the bridge portion is made longer to span the conduit 28. V

The assembly shown in FIG. 6 illustrates the corrugated form sheets 14 mounted on the girder 13 with the shear connectors mounted in a valley of the sheet over the girder flange.

In welding the shear connectors in place the weldments W are placed at the obtuse angle side of each leg so as to be stressed in tension at all times and to take advantage of the available space in which to work at leg 20. Each weldment extends the full width of the connector and penetrates the sheets so as to make a connection with the ange or surface of the load |bearing member.

The foregoing specification and'accompanying drawings will serve to illustrate certain variations by which the presently improved shear connector means may be employed to carry out the purposes of the invention. These and other possible variations are intended to be included within the scope of the appended claims.

What is claimed is:

1. -In a composite building assembly comprising:

(A) a horizontal beam having upper and lower anges spaced apart by a vertical web;

(B) a corrugated form sheet located on said upper ange of said beam;

(C) a reinforced concrete fill disposed on said corrugated form sheet;

(D) a plurality of individual shear connectors disposed on said form sheet in spaced relation to each other, and imbedded in the concrete ll, each said shear connector having;

(1) a pair of substantially parallel legs,

(2) a bridge interconnecting said legs, and held thereby above said form sheet corrugation,

(3) said legs being inclined to the horizontal upper flange of said beam and being substantially the same effective length to position said bridge in substantial parallelism with said upper ange; and

(E) welds securing said legs to said upper flange of said beam through the form sheet, with said leg inclination directed to lean away from the mid-span of said beam,

(l) said welds restricting slip of said shear connectors relative to said beam flange under horizontal shearing stress induced by vertical loading on said beam, and

(2) said shear connector legs each reacting in tension and retaining said interconnecting bridge in position to securely mate said reinforced concrete fill and corrugated form sheet to said beam under said vertical loading.

2. The composite building assembly as set forth in claim 1 wherein said form sheet has its corrugations oriented to be parallel to the upper flange of the beam and the shear connectors have the legs in the corrugations with the bridge parallel to the upper flange.

3. The composite :building assembly as set forth in claim 1 wherein the legs are inclined relative to the upper ange through an angle from substantially 45 to 75.

4. The composite building assembly as set forth in claim 1 wherein one of the legs forms an obtuse angle and the other leg forms an acute angle with respect to the bridge.

5. The composite building assembly as set forth in claim 1 wherein said form sheet has its corrugations oriented to be perpendicular to the lengthwise axis of said beam, said shear connectors have said legs in corrugations and said bridge spanning the corrugations, and said welds secure said legs through said form sheet to said upper ange, whereby said shear connectors are oriented-to relieve said form sheet corrugations of horizontal shear stress.

`6. The composite building assembly as set forth in claim 5 wherein the legs are inclined relative to the upper flange through an angle from substantially 45 to 75.

7. The composite building assembly as set forth in claim 5 wherein one of the legs forms an obtuse angle and the other leg forms an acute angle with respect to the bridge.

References Cited UNITED STATES PATENTS 775,927 11/1904 Kahn 52--336 1,014,157 1/1912 Lewen 52-336 2,340,176 1/1944 Oueni et al 52-334 FOREIGN PATENTS 467,231 8/ 1950 Canada 52-334 462,876 4/1951 Italy 52-334 FRANK L. ABBOTT, Primary Examiner J. L. RIDGILL, JR., Assistant Examiner U.S. Cl. X.R. 52-336, 454

PO-I D50 Patent No. 3.564 79g Inventor(s) Richard E. Hanson Dated UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

r Column 4 under Refere art cited in the Paten December 30, 1969 was omitted:

U.` S. Patents 1,073,542 Stewart 9-1913 1,194,003 Ford 8-1916 1,986,999 Burgess l-1935 3,177 ,619 Benjamin 4-1965 3,251,167 Curran 5-1966 Signed and sealed this 25th day of January 1972.

SEAL) Attest:

Attesting Officer* Class ROBERT GOTTSCHALK Commissioner of Patents nces Cited, the following t Office Action Sub 452 452 336 452 334