US3606418A - Structural member - Google Patents

Abstract

A SINGLE UNIFORM STRUCTURAL MEMBER THAT MAY BE LAPPED ON A LIKE MEMBER TO FORM A STRUCTURALLY CONTINUOUS MEMBER CAPABLE OF CARRYING AXIAL AND FLEXURAL STRESSES.

Description

P. s. BUKER ETAL STRUCTURAL MEMBER Sept. 20, 1971 Filed March 19, 1969 PRIORART 2 Sheets-Sheet 1 PRIOR ART PRIOR ART FIGS 1 w miM W OR A wk w n as ww S m Lm m n U V A A/A 20 BY y 4,

Sept" '1 s. BUKER 'ETAL j v 3,606,418

Q STRUCTURAL MEMBER ZShets-Sheet 3 Filed March 10, 1969 369 INVENTOR/S M PAUL S. BUKER 5 RICHARD DSHEPAIZD DAV/D PWWENAAS ATTORNEYS United States Patent Oihce 3,606,418 Patented Sept. 20, 1971 3,606,418 STRUCTURAL MEMBER Paul S. Buker, Richard D. Shepard, and David P. Wenaas,

Middletown, Ohio, assignors to Armco Steel Corporation, Middletown, Ohio Filed Mar. 10, 1969, Ser. No. 805,666 Int. Cl. F16]: 7/00 US. Cl. 287189.36R 1 Claim ABSTRACT OF THE DISCLOSURE A single uniform structural member that may be lapped on a like member to form a structurally continuous member capable of carrying axial and flexural stresses.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to structural members and more particularly to purlins and columns for metal buildings.

(2) Description of the prior art Prior art purlins have had certain shortcomings for a number of reasons. FIGS. 1 through 4 are exemplary of such prior art purlins which have generally proved to be less than satisfactory in practice.

FIG. 1 shows two C-channel shaped purlins which are bolted web to web over a rafter location. Therafters 12 are rather substantial structural members, such as the disclosed I beams, which support thepurlins 10. The purlins in turn support the roofing panels (not shown). The main shortcoming of this development is that thetop flanges 10a of the C-channel shaped purlins are not aligned down the length of the roof, making it diflicult to drill holes in the roof panels for fastening. Accordingly, the fasteners cannot be positioned in a straight line down the roof, but must be offset at the end of eachpurlin 10.

FIG. 2 discloses an overlapped prior art Z-shaped purlin 14 which overcomes some of the objections to the design of FIG. 1. Thelip stifleners 14a are positioned at an obtuse angle with theflanges 14b so that the section will nest. In practice, however, this is not the case, because, as can be seen from FIG. 3, it is impossible to nest or lap thesections 14 and have theflanges 14b completely contiguous without a gap being present. This imperfect fit causes a serious problem if the roof panels are attached with self drilling or tapping screws because theflanges 14a cannot be drawn tightly together as the fastener is driven FIG. 4 illustrates still another type of prior art Z-shaped purlin 16 wherein the flanges 16a thereof are of equal width. Accordingly, the section will not nest, and the separate splice plate 18 is used to joinadjacent purlins 16 over therafter 20. It should be apparent that this con-.

struction does not provide as much strength at arafter location 20 as is provided by a lap joint. Thepurlins 16 must therefore be larger or spaced more closely to provide additional strength.

SUMMARY OF THE INVENTION The present invention provides a single uniform structural member which comprises a web having parallel flanges at the edges thereof. The flanges may be substantially perpendicular to the web although this is not necessary. The flange edges remote from the web are folded inwardly and arranged substantially parallel to the web to form lip stiffeners. One of the flanges has a width greater than the width of the other flange by at least twice the thickness of the material stock of the member such that the overall dimension of the narrow flange is at most equal to the inside dimension of the wide flange. Accordingly, when one structural member is inverted or rotated about its longitudinal axis, it will lap in another one of the members, the narrow flanges of the members nesting or fitting inside the mating wide flanges of the members so as to provide a splice which maintains intimate contact of substantially the entire flange widths at least, and in some cases the webs and lip stiifeners as well. The lapped joint has a minimum oflset and produces a structurally continuous member capable of carrying axial and/or flexural stresses.

It will, of course, be apparent that when two uniform structural members of the present invention are joined to form a structurally continuous member, the lapped portion provides a double strength, reinforced area where required for the maximum bending moment.

According to the embodiment of the present invention, the uniform structural member may be Z-shaped in cross section. If desired, two Z-shaped structural sections may be nested in a hat spaced section and may be used as a load bearing column, the narrow flange of one section locking inside the mating wide flange of the other section and the webs being spaced apart.

According to further embodiment of the present invention, the uniform structural section may comprise a C- channel section.

Finally, the properties of the uniform structural section of this invention may be balanced by extending the lip stiffener of the narrow flange so that the properties of the flanges are equaled.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of two prior art C-channel shaped purlins which are bolted web to web over a rafter location.

FIG. 2 is a perspective view of overlapped prior art Z- shaped purlins.

FIG. 3 is a cross sectional view taken on the line 33 of FIG. 2.

FIG. 4 is a perspective piew of still another type of prior art Z-shaped purlins having flanges of equal Width.

FIG. 5 is a perspective view of two lapped or nested Z-shaped purlins according to the present invention.

FIG. 6 is a cross sectional view taken along the line 6-6 of FIG. 5.

FIG. 7 is a perspective view of two lapped or nested C- channel shaped purlins according to the present invention.

FIG. 8 is a cross sectional view taken on the line 8-8 of FIG. 7.

FIG. 9 is a perspective view of two Z-shaped purlins which are nested in a hat shaped section that may be used as a load bearing column.

DESCRIPTION OF THE PREFERRED EMBODIMENTS While the present invention will be explained in terms of a single uniform structural Z-member and a single uniform structural C-channel, it will be understood that, broadly speaking, the present invention provides a single uniform structural member which comprises a web having parallel flanges at the edges thereof. The flanges may be substantially perpendicular to the web, although this is not necessary, and the edges thereof remote from the web are folded inwardly and arranged substantially parallel to the web to form lip stitfeners. One of the flanges has a width greater than the width of the other flange by an amount equal to at least twice the thickness of the material stock of the member such that the overall dimension of the narrow flange is at most equal to the inside dimension of the wide flange. Thus, when one member is inverted about its longitudinal axis, it will lap in another one of the members, the narrow flanges of the members nesting or fitting inside the mating wide flanges of the members to provide a splice which maintains intimate contact of substantially the entire flange widths at least, and in some cases the webs and lip stifleners as well, and results in a minimum surface offset condition so as to produce a structurally continuous member capable of carrying axial and flexural stresses.

FIGS. and 6 show one preferred embodiment of the uniform structural member of this invention. As can be seen, three Z-shaped purlin members 20, 22 and 24 have been lapped or nested together and joined to tworafter locations 26 and 28. It will be obvious that in practice a plurality of Z-shaped purlins will be located at various rafter locations and that roofing panels (not shown) will be attached to the purlins.

Turning to FIG. 6-, it may be seen that each Z-shaped purlin member comprises a web a having parallel flanges b and c at the edges thereof. The flanges may be substantially perpendicular to the web and the edges thereof d remote from the web are folded inwardly and arranged substantially parallel to the web a to form lip stiffeners. As can be seen, one of the flanges c is provided with a width greater than the width of the other flange b by an amount equal to at least twice the thickness of the material stock of the member. Accordingly, the overall dimension of the narrow flange b is at most equal to the inside dimension of the wide flange 0. Thus, when one of the members is inverted about its longitudinal axis, it will lap in another one of the members, the narrow flanges b of the members nesting or fitting inside the mating wide flanges c of the members to provide a splice which maintains intimate contact of substantially the entire flange widths b and c at least, and in a preferred embodiment, of the webs a and/ or lip stiffeners d, such as when the overall dimension of the narrow flange b is substantially equal to the inside dimension of the wide flange c. This results in a minimum surface offset condition so as to produce a structurally continuous member capable of carrying axial and flexural stresses.

As can be seen from FIG. 5, the structurally continuous member is made up of the individual Z-shaped purlin members 20, 22 and 24. The individual Z-shaped purlin members 20, 22 and 24 are lapped or nested together with the narrow flanges b, 22b and 24b fitting inside the matingwide flanges 20c, 22c, and 24c of the sections. After thepurlins 20, 22 and 24 have been lapped or nested, suitable fastening means are used to join thecontiguous webs 20a-22a and 22a-24a. The fastening means 30 is also used to join the flanges 20c and 22b as well as 24c and 22b to the rafters 2-6 and 28, respectively. The purlins may also be attached to the rafters in an alternate manner, as is shown over therafter 28 where the bolts are mounted on the web and passed through atab 28a attached to the rafter.

After a plurality of purlins have been located at rafter locations, purlin ties or spacers (not shown) may be utilized as is conventional. However, if the rafters are close enough, or if the purlins are strong enough, the purlin ties or spacers will not be required.

It will be obvious that when two- Z-shaped members are joined to form a structurally continuous member, the lapped or nested portion provides a double strength, reinforced area where required for the maximum bending moment. Additionally, it is also important to note that when the lip stiffeners d are folded inwardly and arranged parallel to the Web a, thepurlin sections 20, 22 and 24 resist disengagement after they have been lapped or nested.

It should also be noted that when it becomes necessary for the properties of the uniform structural section to be balanced, the lip stiffener d of the narrow flange b may be extended so that the properties of the two flanges are equaled.

FIGS. 7 and 8 disclose a further embodiment of the present invention wherein C-channel members 32, 34 and 36 are lapped or nested overrafter locations 38 and 40. As can be seen, each C-channel member 32, 34 and 36 is provided with aweb 2 having parallel flanges and g at the edges thereof. The flanges f and g are preferably perpendicular to the web e and the edges h thereof are folded inwardly and arranged substantially parallel to the web to form lip stiffeners. One of the flanges g of the C-channel members 32, 34 and 36 is provided with a width greater than the width of the other flange by an amount equal to at least twice the thickness of the material stock of the C-channel member. Accordingly, the overall dimension of the narrow flange f is at most equal to the inside dimension of the wide flange g. Thus, when one of the C-channel members is inverted about its longitudinal axis, it will lap in another one of the C-channel members, the narrow flanges f of the C-channel members nesting or fitting inside the mating wide flanges g of the C-channel members to provide a splice which maintains intimate contact of substantially the entire flange widths f and g at least, and in a preferred embodiment, such as when the overall dimension of the narrow flange f is substantially equal to the inside dimension of the wide flange g, of the lip stitfeners h. This produces a structurally continuous C-channel member capable of carrying axial and flexural stresses.

After the C-channel members 32, 34 and 36- have been lapped or nested, they will be permanently joined by fastener means 30 and attached to therafter locations 38 and '40 in a similar manner. Additionally, purlin ties or spacers (not shown) may be utilized in the conventional manner where necessary. It should also be noted that the continuous C-channel member may be used either as a column or a beam, as desired.

It will also be obvious that balanced C-channel members 32, 34 and 36 may be produced by extending the lip stiffener h of the narrow flange 1 so that the properties of the two flanges are equalled.

It will be obvious that the present invention provides a single uniform structural member which may be lapped to form a length greater than can practically be fabricated, shipped, handled or erected. Additionally, so long as the overall dimension of the narrow flange and the inside dimension of the wide flange are maintained as provided herein, members of different thicknesses of material may be lapped. The uniform structural member of the present invention also avoids distortion of the member elements, resulting in a smoother surface condition for attaching the roof panels than is possible under present practices.

The present invention also provides a definite safety factor. This is so because the flanges are nested or fitted together when erecting the members on the roof. It is then impossible for one flange to disengage from its mating flange on the second member.

FIG. 9 of the present invention indicates a still further embodiment wherein two Z-shapedstructural members 42 and 44 are nested in a hat shaped section that may be used, for example, as a load bearing column or beam, thenarrow flange 42b of one member nesting inside the matingwide flange 44c of the other member and thewebs 42a and 44a beingspaced apart.

If desired, asuitable cover plate 46 may be positioned so as to cover the space between thenon-joining flanges 42c and 44b of the Z-shapedmembers 42 and 44. Structural integrity is enhanced by positively spacing the flanges. The continuous panel comprising theflanges 42c and 44b in thecover plate 46 will also render more decorative the inside or outside wall of an enclosure or the like.

It should also be noted that this invention provides a system for reinforcing a member by the addition of an additional segment of the same member. Furthermore, by use of a suitable fastener and hole arrangement, this invention provides a means of making a telescoping section which is adjustable in length.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination, two lapped, uniform, Z-shaped, structural members, an underlying supporting structural member, such as a rafter or the like, and self drilling screws joining said lapped Z-shaped members, each of said Z-shaped members being capable of being lapped with another one of said Z-shaped members when inverted about its longitudinal axis to form a continuous structural member capable of carrying axial and flexural stresses and comprising a web having parallel flanges at the edges thereof, said flanges being substantially perpendicular to said web, the edges of said flanges remote from said web being folded inwardly andarranged substantially parallel to said web to form lip stiffeners, one of said flanges having a width greater than the width of said other flange by an amount equal to substantially twice the thickness of the material stock of said member and such that the overall dimension of said narrow flange is at most equal to the inside dimension of said wide flange, said narrow flanges of said lapped Z-shaped members nesting inside said mating wide flanges of said lapped Z-shaped members and said self drilling screws joining the flanges of said lapped Z-shaped members, the mating flanges of said lapped Z-shaped members being drawn tightly together, to provide a splice which maintains intimate contact of substantially the entire adjacent surfaces of the 2 lapped, contiguous, Z-shaped members and results in a minimum surface offset condition, whereby Z-shaped 6 members of different thicknesses or gauges may be lapped with one another and distortion of the lapped sections may be avoided, resulting in a substantially distortion free surface condition for attaching roof panels, siding and the like.

References Cited UNITED STATES PATENTS 1,743,327 1/1930 Dornier 52-731X 1,963,416 6/1934 Minshall 5273 1X 1,970,422 8/1934 Foster 52-726 2,583,439 1/1952 Oswald et a1 52732X 2,893,073 7/1959 Humphrey 52--588X 2,950,789 8/1960 Davis et a1 52--731X 3,332,197 7/1967 Hinkle 52--732X FOREIGN PATENTS 939,599 4/1948 France 52731 629,980 12/1961 Italy 52731 694,036 9/1964 Canada 52732' REINALDO P. MACHADO, Primary Examiner W. L. SHEDD, Assistant Examiner US. Cl. X. R.

Disclaimer 3,606,418.Paul 1S. Bukeq", Richard D. Shepard and David P. Wenaas, Middletown, Ohio. STRUCTURAL MEMBER. Patent dated Sept. 20, 1971. Disclaimer filed Nov. 4, 1971, by the assignee, Armco Steel Gorpomtio'n. Hereby enters this disclaimer to claim 1 of said patent.

[Ofiicial Gazette March 7, 197%.]

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