US2427021A

US2427021A - Prestressed all-metal roof structure

Info

Publication number: US2427021A
Application number: US655625A
Authority: US
Inventors: George M Rapp
Original assignee: John B Pierce Foundation
Current assignee: John B Pierce Foundation
Priority date: 1946-03-19
Filing date: 1946-03-19
Publication date: 1947-09-09
Anticipated expiration: 1964-09-09

Description

Sept. 9, 1947.. G. M. RAPP PRESTRESSED ALL-METAL ROOF STRUCTURE Filed March 19, 1946 4 Sheets-Sheet l INVENTOR O Sept. 9, 1947. RAPP 2,427,021

PRESTRESSED ALL-METAL ROOF STRUCTURE INVENTOR GEORGE M. RAPP fi?i bus/ TORNY'EY Sept. 9, 1947. RAPP PRESTRESSED ALL-METAL ROOF STRUCTURE Fi led March 19, 1946 4 Sheets-Sheet :s

INVENTOR 4Q GEORGE M RAPP I gm Sept. 9, 1947.

G. M. RAPP 2,427,021

YRESTRESSED ALL-METAL ROOF STRUCTURE Filed March 19,- 1946 4 Sheet-Sheet 4 INVENTOIL GEORGE M. RAPP ATTORNEY Patented Sept. 9, 1947 PRESTRESSED ALL-METAL ROOF STRUCTURE George M. Rapp, New Haven, Conn., assignor to John B. Pierce Foundatian, New York, N. Y..

a corporation of New Yo Application March 19, 1946, Serial No. 655,625

20 Claims. (01. 1081) The invention relates to pre-stressed arched roof structures.

An object of the invention is to provide a. roof structure embodying the assembly of mutually correlated component sub-structures individually comprising a resilient slender member which is pre-stressed to bowed or arched configuration, the resulting roof structure being particularly adapted for building construction wherein low costs of material and of labor, lightness of weight and durability of assembly are paramount. Preferably, such pre-stressed resilient slender member is of metal, notably-steel, thereby attaining enhanced structural strengths, and co-ordinating remaining elements of the roof structure also of metal, whereby resistance against fire is also attained.

In general, embodiments of the invention comprise a plurality of sets of individual substructures, each set of sub-structures spanning the opening tobe covered by the roof structure, each such sub-structure comprising a slender member of resilient material, preferably of metal, pre-stressed to bowed formation, combined with co-ordinating parts for supporting such prestressed bowed member and maintaining the same in its said pre-stressed bowed status, the plurality of sets of such sub-structures respectively interconnected in seriatim overlapping relation with respect to one another completing the'expanse of the roof. Usually each such set comprises two such sub-structures which when installed are conjoined, the pre-stressed members comprising component parts of a stable and load supporting structure, which may have general truss or triangular or general curvilinear or arch-like configuration, the abutting juxtaposed face portions of the conjoined pair of substructures at or adjacent the ridge line of the roof being secured to one another.

More specifically, pursuant to the most.preferred forms of the invention, the roof comprises a plurality of pairs of such sub-structures of sulmtantlally duplicate construction, the pre stressed member of each sub-structure being in the form of a corrugated sheet member of metal, serving as the primary roof member, the corrugations of such corrugated member extending from the cave line to the ridge line of the roof, and one or more pairs of tension elements such as lengths of pipe, rods or wires, respectively, pivotally connected to the inner face of each such corrugated member. Each of these tension elements is provided with a tum-buckle,

sleeve nut or the like for adjusting and prethe central ridge member.

stressing the corrugated member to its desired bowed configuration. Suitable ridge members are provided for spanning the joints at the abutting juxtaposed face portions of such pairs of such sub-structures at the ridge of the roof. The thrusts or outward forces caused by the truss or arch-like shape are carried by tension ties secured at their opposite ends at or adjacent to the eave lines. Suitable vertical strut members support these tension ties at their mid-span points, which they connect to the ridge line of the roof; The roof thus is completed by duplicates of such pairs of sub-structures disposed in mutually seriatim overlapping relationship with one another.

The invention afiords low cost of material in that ample factor of safety is attained by enhanced mechanical strengths imparted by the pre-stressed member, enabling relatively light materials to be utilized. Savings in labor costs are attained in that each such sub-structure may be assembled at a central location and shipped to the site of erection. Desirably, each such sub-structure is shipped "fiat, that is to say, the corrugated or like member being in flat status, the operation of pre-stressing such member being carried out at the site of erection by turning the turn-buckles or sleeve nuts to prestress the respective members to the desired uniform arch configuration.

Further features and objects of the invention will be more fully understood from the following detailed description and the accompanying drawings, in which:

Fig. 1 is a perspective of a preferred form of roof construction embodying the invention, a

pair of sub-structures being shown in substantial entirety, and indicated portions of adjacent seriatim overlapping sets of duplicate pairs of sub-structures.

Fig- 2 is a detail sectional view on line 2-2 of Fi 1.

Fig. 3 is a detail section Fig. 1.

Fig. 4 is a detail view of the parts shown in Fig. 3, as appears from line 4-4 of Fig. 3.

1 view on line 3-3 of Fig. 5 is a perspective view of the left hand sub-structure of the roof shown in Fig. 1, and its triangular support.

Fig. 6 is a top plan view of the sub-structure shown in Fig. 5, with the addition of a portion of Fig. 7 is. a bottom plan view of Fig. 6.- Fig. 8 is a detail sectional view on line 8-8 of Fig. 5, however, showing the sub-section in flat,

1. e. non-stressed status.

Fig. 9 is a sectional view of Fig. 1, taken transversely of a pair of correlated sub-structures. supported in triangular relation with respect to the eave lines of opposite walls of the building.

Fig. 10 is a detail sectional view of a central portion of Fig. 9, on an enlarged scale.

Fig. 11 is a detail sectional view on line il-H of Fig. 9, on an enlarged scale.

Fig. 12 is a detail sectional view through the non-stressed roof element, showing a variant form or corrugation.

Fig. 13 is a detail section through the nonstressed roof element, showing another variant form of corrugation.

Referring to the preferred embodiment of the invention illustrated in Figs. 1, and 9 of the drawings, the roof structure comprises a pinrality of pairs of duplicate, conjoined sub-structures, the roof being completed by duplication of such pairs of conjoined sub-structures in seriatim overlapping relation, as is indicated in Figs. 1 and 7. 20 designates generally the pair of conjoined roof sub-structures shown in entirety in Fig. 1. 2!, 2|, indicates fragmentarily a pair of such duplicate conjoined sub-structures extending to the right of the

pair

20, 29; 22, 22. similarly indicates fragmentarily a pair of such duplicate conjoined sub-structures extending to the left of the

set

29, 20. Each pair of roof substructures abut one another at their juxtaposed faces, i, e., centrally of the roof, a ridge member serving to close the line of jointing thereat, such ridge members being arranged in seriatim overlapping relation, as appears more fully hereinafter,

Each roof sub-structure comprises primarily a slender resilient member 23, preferably of sheet formation and of steel or the like, which is subjected to pre-stressing; preferably, also, such member 23 is corrugated, the apices of the corrugations extending from the cave line to the central ridge line. Desirably, such pre-stressing is eifected, as shown, by means of a pair of

stress rods

24, 24, one end of each rod being pivotaily fulcrumed with respect to the inner face of the member 22, respectively adjacent the cave and ridge end portions of the member, tension being applied to such pair of

rods

24, 24, as by a turn-buckle or sleeve nut 25, to thus pre-stress the corrugated member 22 under tension to its desired bowed configuration.

Specifically, the pivoted end of each of the pair of stress rods for each member 22 is pivotally fulcrumed in a clevis-like element. The clevis-like element at the cave: line of each member 22 is designated 22; it is shown welded to a face 21a of one leg of the L-shaped plate 21, the face 21b of the other leg of the L-shaped plate being spot welded to the inner apices of the corrugations of the member 22, as shown in Figs. 1, 2, 5, 9, and 11. The pivoted ends of the cooperating stress rods 24 adjacent the ridge line of each member 22, are fulcrumed in the clevislike elements designated 22, a face of each of which, see Figs. 1, 5, 9 and 10, is welded to the inner face of the member 22 adjacent its ridge line. The two clevis-

like elements

28, 22 of each member 22. are welded, as appears in Figs. 5 and 8, to a face 22a of one leg of the L-shaped plate 23, and the face 23b of such L-shaped plate is welded to the inner apices of the member 22. I

Intermediate the cave line and the ridge line of each member 22, and on the inner face there- 4 of are

plates

20, 30, shown of flattened U-shape, which are spot welded to the inward apices .of the corrugations of each member. Each plate 20 is provided with transverse closed-ended slots 30a, 20a, through which pass the

respective stress rods

24, 24, 24, 24.

Upon joining the pair of correlated sub-structures spanning a given portion or the roof, the abutting juxtaposed faces of the L-

shaped plates

29, 29, are rigidly connected to one another, as by bolting, which may be performed on location.

Desirably, the joint at the ridge line of the roof and the adjacent ridge portions of each pair of conjoined sub-structures are sheathed by a ridge member, preferably an arcuated ridge member 2|, as shown in Figs. 1, 5, 9 and 10, such ridge member being rigidly secured to the underlying ridge portions of such pair of substructures, preferably by self-tapping screws, indicated at 32, 32, in Fig. 10.

Each pair of sub-structures, as shown in the illustrated preferred embodiment, is supported in triangular spanned relation relative to the walls of the building or other construction, as by the assembly of horizontal beams in turn carrying at their centers vertically extending plates in turn supporting the ridge portions of the sub-structures. As illustrated in Figs. 1, 5 and 9, and fragmentarily in Fig. 10, such triangularly confilgurated assembly includes the horizontal extending beams 33, shown of U- shape. The opposite eave ends 33a of each of such beams are shown secured to

plates

34, 34, as by means of bolts or equivalent indicated at 35,

such plates

34, 34, being secured to the upper faces of the building walls indicated at 35, 35. As shown,

such plates

34, 34, are each secured to the underfaces of the respective

clevislike elements

26, 26, as by welding, and in turn secured by

bolts

36, 36, to the

respective walls

37, 31, of the building. Desirably. as shown in Fig. 2, a buttress of wood or steel indicated at 38 secured to the top of each wall 35, is interposed, with which buttress the associated clevisiike element 28 is secured, as by the bolts 28. Such buttress 23 serves as a cushion of limited yield, advantageous in the circumstance when the roof structure is subjected to substantial stresses, as under :high wind conditions.

It will be observed from Figs. 1, 2 and 9, that the free ends of the eave disposed L-shaped plates 21 of the seriatim pairs of conjoined substructures butt one another. The joints thus formed may be protected so as to accomplish a weather-seal by bolted or screw-attached splice plates.

Associated with such horizontal extending beam 22 are the vertically extending supporting plates 33, see Figs. 1, 5, 9 and 10, shown carried at their lower ends by the beams 22. Such plates 28, as indicated, may be of U-shape, and secured at the lower ends of the respective beams 22 by bolts. as indicated at 40 in Fig. 9. To the upper end of each supporting plate 23, as shown in Figs. 9 and 10, is secured a bracket 4|.

As indicated in Figs. 1, 5 and 9, the extent of pre-stressing of each roof member ,22 is determined by the total span of the roof, the individual roof members 22 being bowed to substantially uniform arch configuration. In general, such arch is of low arcuate configuration, the plurality of sets of conjoined sub-structures forming a resulting roof of low pitch.

When shipped from the factory. or other location of pre-assemoly, and/or when placed in relation with the storage, each sub-structure is desirably in flat status, as is illustrated in Fig. 8, that is to say, the turn-buckle 25, or equivalent being in

slack stress rods

24, 24, the root element 23 being thus in flat status.

Upon bowing the respective roof members 23 to the desired pre-stressed status, as indicated in Figs. 3 and 4, a yoke bolt 42 may be employed to interconnect each rod length 24 with the lower flange of the U-shaped plate 30, and tightened by nuts 43. Desirahly, shims, indicated at 44 in Fig.3, are interposed between the flange of the plate 38 and the free ends of the yoke bolt, and tightened by nuts 44.

From the above'it is apparent that the resulting roof structure may be constituted of relatively light weight reason of the high mechanical strength imparted by the pre-stressed roof members 24 and their

respective pairs

24, 24, 01 stress rods in tension, the roof structure possesses a. high factor of safety.

The roof structure attained by the embodiment illustrated in Figs. 1- through 11 is of particular application for farm service structures, suchas barns. sheds, poultry and hog houses, com cribs, etc., for which purpose the pre: stressed corrugated sheet members 23 the primary roof elements.

In Figs. 1 throughll the members 23 are indicated of uniform arcuate corrugations; however, other forms of,.,corrugation for the members 23 may be employed. Figs. 12 and 13 illustrate variant types of corrugation applicable to the invention. In Fig. 12 theresilient sheet member has rectangular trough-like corrugations,

parts, and nevertheless byserve as whereas theresilient sheet member, shown in Fig. 13 the corrugations are of frusto-tapering formation.

Non-corrugated sheets ofresilient metal such as steel or of other suitable material may also be.

employed for the members 23, as will; be apparent. In such application of the invention the outer surfaces of the non-corrugated members may be covered by conventional sheet roofing,

material, secured by asphaltic or like waterrepelling and weather-resisting cement.

I claim:

1. A roof sub-structure comprising in combination a member of resilient sheet material; correlated slender elements fulcrumed at their respective one ends to an inner faceof said sheet memher; and means respectively connected to the respective opposite ends of said-slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration.

2. A roof sub-structure comprising in combination a member of resilient corrugated sheet material; correlated slender elements fulcrumed at their respective one ends to an inner face "of said sheet me her; and means respectively connected to th respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration.

bination a member of resilient sheet material,

said sheet member being corrugated and having its peaks of corrugations extending from the cave line upwardly of the roof; correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; and means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration.

' 4. A roof sub-structure comprising in com bination a member of resilient corrugated metallic sheet material; fulcrumed at their respective one ends to an inner face of said sheet member; and means respectively connected to the respective oppositeends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration.

5. A roof ub-structure comprising in combination a member of resilient metallic sheet material, saidsheet member being corrugated and having its peaks of corrugations extending from the eave line upwardly of the roof; correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; and means respectively connected to the respec tive opposite ends 'of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration.

6. A roof sub-structure comprising in combination a member of resilient sheet material; correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheetmember to assume a bowed configuration; and means of general triangular configuration for supporting said roof substructure.

7. A roof sub-structure comprising in combination a member of resilient corrugated sheet material; correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected .to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration; and means of general triangular configuration for supporting said roof sub-structure.

8. A roof sub-structure comprising in combination a member of resilient sheet material, said sheet member being corrugated and having its peak of corrugations extending from the cave line upwardly of the roof correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points-of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed'conflguration; and means of general triangular conflguratlon for supporting said roof sub-structure.

9. A roof sub-structure comprising in combination amemberof resilient corrugated metallic sheet material; correlated slender elements fulcrumed at their respective one ends to an inner 'face .of said sheet-member; means respectively correlated slender elements 7 connected to the slender elements for drawing the stated points or fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration; and means of general triangular configuration for supporting said root substructure.

10. A roof sub-structure comprising in combination a member of resilient metallic sheet material, said sheet member being corrugated and having its peaks of corrugations'extending from the eave line upwardly oi the roof; correlated slender elements iulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration; and means of general triangular configuration for supporting said roof substructure.

11. A roof structure formed of a plurality of sets of conjoined roof sub-structures, each roof sub-structure comprising in combination a member of resilient sheet material; correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration; means of general triangular configuration for supporting said roof substructures; and ridge enclosing means secured to the resulting roof structure adjacent and extending over the juxtaposed portions of the respective sets of conjoined roof sub-structures.

12. A roof structure formed of a plurality of sets of conjoined roof sub-structures, each roof sub-structure comprising in combination a member of resilient corrugated sheet material; correlated slender elements iulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration; means of general triangular configuration for supporting said roof sub-structures; and ridge enclosing means secured to the resulting roof structure adjacent and extending over the juxtaposed portions of the respective sets of conjoined roof substructures.

13. A roof structure formed of a plurality of 'sets of conjoined rooi sub-structures, each roof sub-structure comprising in combination a member of resilient sheet material, said sheet member being corrugated and having its peaks of corrugations extending from the eave line upwardly of the roof; correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration; means of general triangular configuration for supporting said rooi sub-structures; and ridge enclosing means serespective opposite ends oi said cured to the resulting roof structure adjacent and extending over the juxtaposed portions of the respective sets of conjoined roof sub-strucures.

14. A roof structure formed of a plurality of sets of conjoined roof sub-structures, each rooi sub-structure comprising in combination a member of resilient corrugated metallic sheet material; correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said elongated elements to thereby subject said sheet member to tension and thereby causing said sheet member to assume a bowed configuration; means of general triangular configuration for supporting said roof sub-structures; and ridge enclosing means secured to the resulting roof structure adjacent and extending over the juxtaposed portions of'the respective sets of conjoined roof sub-structures.

15. A root structure formed of a plurality of sets of conjoined roof sub-structures, each roof sub-structure comprising in combination a member of resilient metallic sheet material, said sheet member being corrugated and having its peaks of corrugations extending from the eave line upwardly of the roof; correlated slender elements fulcrumed at their respective one ends to an inner face of said sheet member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated point of fulcrum of said slender elements to thereby subject said sheet memberto tension and thereby causing said sheet member to assume a bowed configuration; means of general triangu; lar confiiguration for supporting said roof substructures; and ridge enclosing means secured to the resulting roof structure adjacent and extending over the juxtaposed portions of the respective sets of conjoined roof sub-structures.

16. A roof structure formed of a plurality 0! sets of conjoined roof sub-structures, each roof sub-structure comprising in combination a member of resilient slender material; correlated slender elements fulcrumed at their respective one ends to an inner face of said slender member;

means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said slender member to tension and thereby causing said slender member to assume a bowed configuration; and means of general triangular configuration for supporting said roof sub-structures.

17. A roof structure formed of a plurality of sets of conjoined roof sub-structures, each roof sub-structure comprising in combination a member of resilient corrugated slender material; correlated slender elements fulcrumed at their respective one ends to an iner face of said slender membenmeans respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said slender member to tension and thereby causing said slender member to assume a bowed configuration; and means of general triangular configuration ior supporting said roof sub-structures.

18. A roof structure formed of a plurality of sets of conjoined root sub-structures, each roof sub-structure comprising in combination a member of resilient slender material, said slender member being corrugated and having its peaks of corrugations extending from the cave line upwardly of the roof; correlated slender elements fulcrumed at their respective one ends to an inner face of said slender member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said slender member to tension and thereby causing said slender member to assume a bowed configuration; and means of general triangular configuration for supporting said roof sub-structures.

19. A roof structure formed of a plurality of sets of conjoined roof sub-structures, each roof sub-structure comprising in combination a member of resilient corrugated metallic slender material; correlated slender elements fulcrumed at their respective one ends to an inner face of said slender member; means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said slender member to tension and thereby causing said slender member to assume a bowed configuration; and means of general triangular configuration for supporting said roof sub-structures.

20. A roof structure formed of a plurality of sets of conjoined roof sub-structures, each roof sub-structure comprising in combination a member of resilient metallic slender material, said slender member being corrugated and having its peaks of corrugations extending from the eave line upwardly of the roof; correlated slender elements fulcrumed at their respective one ends to an inner face of said slender member means respectively connected to the respective opposite ends of said slender elements for drawing the stated points of fulcrum of said slender elements to thereby subject said slender member to tension and thereby causing said slender member to assume a bowed configuration; and means of general triangular configuration for supporting said roof sub-structures.

GEORGE M. RAPP.