US2752868A

US2752868A - Roof construction

Info

Publication number: US2752868A
Application number: US258860A
Authority: US
Inventors: Blumfield Cyril Vernon
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-11-30
Filing date: 1951-11-29
Publication date: 1956-07-03
Anticipated expiration: 1973-07-03

Description

Y 6 Q. v. BLUMFIELD 2,752,868

OOOOOOOOOOOOOO ON y 3, 1956 c. v. BLUMFIELD 2,752,868

ROOF CONSTRUCTION Filed Nov. 29, 1951 2 Sheets-Sheet 2 //I men 72/ C/RIL VERA/DIV Bump/no A fo/weys.

R0015 CONSTRUCTION Cyril Vernon Blumfield, Woking, England Application November 29, 1951, Serial No. 258,360

Claims priority, application Great Britain November 30, 1950 7 Claims. (Cl. 108---1) This invention relates to the construction of roots for buildings and especially to barrel vault roofs. It is an object of the invention to simplify the erection of a roof of this kind by constructing it in the form of a basketlike or lattice framework which, while being of adequate strength, is of light weight, enabling it to be completed or substantially completed on the ground and then raised into position for connection to its supports.

According to one aspect of the invention a barrel vault root comprises at least two spaced transverse stiffening members each having a curved upper part, and longitudinal, transverse, and diagonal members secured together and to the said curved upper parts of the stifiening members so as to form a curved openwork beam structure.

According to a further aspect of the invention a barrel vault roof is formed of at least two spaced transverse stiffening members having their upper parts shaped to the required curvature of the roof, at pluralityof spaced longitudinal members interconnecting the stiffening members at their upper parts, at least one layer ofspaced transverse members secured to the longitudinal members, and bracing members secured diagonally to said stiffening, longitudinal and transverse members at points ofintersection therewith. The open-work or basket-like structure thus provided may be completed in any desired manner such as by means of glazing or internal and external layers of appropriate material.

The invention is illustrated by way of example in the accompanying drawings, wherein:

Figure l is a perspective view showing one form of barrel vault roof construction according to the invention;

Figure 2 is a detail sectional View, to a larger scale, on line 11-11 of Figure 1;

Figure 3 shows a form of spacing clip interconnecting a pair of upper and lower transverse members; and

Figure 4 is a fragmentary perspective view illustrating a modification.

The barrel vault root illustrated in Figure 1 comprises a plurality of spaced, parallel longitudinal members it) secured at their ends to the upper curved parts of a pair of stiffening beams 11, a plurality of spaced pairs of upper and lower transversely extending members .12, 13 secured to the longitudinal members at their points of intersection therewith, and diagonal bracing members 14. The stiiieuing beams 11 are shown as comprising braced girdersand may be fabricated from metal rod or tubing or from material of any other suitable cross-section. The stiffening beams may be secured at their ends to vertical supporting posts (not shown) forming the corners of the building to be rooted. They may alternatively be formedintegrally with or be constructed as, the end walls ofthe buillding.

The longitudinal members maybe made from any suitable material and may be of any convenient cross-sectional shape. I may use, for example, two-inch steel or aluminum tubing similar to the now universally known scat folding; or I may use bars of square, rectangular, round, H .or 2 section. Timber poles may also be used. The

"ice

ends of the members 10 are shown as secured tothe curved top edges of the curved upper parts of the stilfening beams by bolts 15, but they may equally well be secured to the curved bottom edges of said beam parts, or to the top edges near the crown and to the bottom edges near the sides. They may alternatively be secured to the beams by welding, riveting or in any othermanner affording a rigid joint. The members lit) may be arranged at any desired spacing depending on the material used, their crosssectional dimensions and shape, the size of the roof, and the load, and may be more closely spaced at the sides, or at the sides and the crown, than at the remaining parts.

The

transverse members

12, 13 may be of similar crosssectional shape to the longitudinal members but, as shown, I prefer to use in the construction of the transverse members flat metal bars of rectangular cross-section, for example, one and one quarter inches wide by three sixteenths of an inch thick. These bars are arranged in pairs one above the other and are curved to radii struck from a common centre so that they are evenly spaced throughout their length, the curvature of the lower bars conforming to that of the upper edges of the stiiiening members. The transverse bars of each pair are secured to the longitudinal members it) on opposite sides thereof by bolts 16 (see also Figure 2) which extend completely through said members and the bars and carry nuts lda at their lower ends. Where the longitudinal members are relatively widely spaced, clips are preferably fitted between the upper and lower transverse bars of each pair, as illustrated at 17 in Figure 1, to hold said bars in parallelism. If the transverse members are of other than flat bar construction, e. g., metal tubing, only the lower layer 13 need be provided.

Thebracingmembers i i, which are arranged diagonally across the corners of the roof and cover the entire roof area or at least the greater part thereof, are secured at spacedpoints in their length to the other roof members lit"), l2, l3 by the

bolts

15, 16 which connect said other members together. The diagonals may, however, be wider than shown in the drawings so as to allow for the provision of at leasttwo fixing bolts where they intersect each iongitudinal. Alternatively the diagonals may be fitted with gusset plates at their fixing positions. Those bracing members nearer the corners of the roof may extend from the sidemost longitudinal members to the stiffening beams, while the bracing members remote from the roof corners may terminate at or adjacent the longitudinal and transverse centres of the roof. Thus there are four groups of bracing diagonals which may extend over a quarter or substantially a quarter of the roof area. In the arrangement shown in Figure 1, the diagonals of each group extend from the longitudinal member nearest the longitudinalcenhe of the roof to the second nearest transverse pair of membersto the transverse centre of the roof, but this can be modified according to requirements.

The diagonals 1d are preferably made from .flat metal bar of rectangular cross-section similar to the

transverse members

12, 13. Usually only one layer of members 14 need be provided and in Figures 1 and. 2 these members are fitted between the upper transverse members 12 and the longitudinal members it). They may, however, be arranged above the transverse members 12 or below the longitudinal members or lower transverse members 13. In cases where the load and bending stresses are considerable, an additional layer of diagonal members 14 may be provided and in the arrangement illustrated, these additional diagonals are preferably located between the longitudinal members and the lower transverse members 13. The additional diagonals maybe arranged parallel to those of the corresponding upper group or inclined in a direction opposite, for example at right angles, thereto.

The diagonals may alternatively be madefrom material of the same cross-section as the .longitudinals, e. g., metal tubing, in which case they may consist of short lengths splayed at the ends and welded to the longitudinals.

The diagonal members 14-are illustrated in Figure 1 as being curved to conform to the shaft of the roof. These members, however, as well as the

transverse members

12, 13, may be angularly bent at intervals corresponding to the spacing of the longitudinal members so as to provide flat rectilinear portions between adjacent longitudinal members.

Figure 3 shows one form of spacing clip 17 for tying together each pair of upper and lower

transverse members

12, 13. The clip consists of two

identical elements

18, 19 formed from metal strip and provided at their ends with shouldered return bent or U-shaped portions 20 which engage over the edges of the transverse members. The

elements

18, 19 are centrally drilled to receive a tie-bolt 21 by which they are secured together and clamped in the required position. Similar clips may, if desired, be fitted to the diagonal members 14 where two layers of such members are provided with the upper and lower members of each group extending in the same inclined direction. Clips of the kind described have the advantage, in relation to the well known form of tie-bolt carrying a spacing sleeve that the members to which they are fitted are not weakened along those parts between their points of connection to the longitudinal members.

Instead of tying the upper and lower transverse members by means of clips, these members may be integrally connected by a vertical web which is apertured for the passage of the longitudinal members. With such an arrangement the use of diagonal compressional members 14, attached as in Figures 1 and 2, to the longitudinal and transverse members by the bolts 16, may not be practicable and it may be referred to employ short diagonal members of a length such as to fit tightly across each of the roof spaces bounded by adjacent longitudinal and transverse members. Such a construction is shown in Figure 4 where each diagonal member 22, constructed as in the case of the members 14, from metal strip, has its ends formed to a wedge shape so as to abut the web part 23 of each pair of

transverse members

12, 13 and also the longitudinal members 10. The diagonals may be welded to said members if desired.

The several longitudinal, transverse and diagonal members may be spaced at any desired intervals consistent with the required strength of the roof. In the arrangement of Figure l, which illustrates a roof covering an area of thirty feet in length and twenty-five feet in width, with a curvature radius of fifteen feet at the inner edge of the lower transverse bars 13, the two longitudinal members at each side of the roof may have their centres spaced at nine inches and the remaining longitudinals may have their centres spaced at three feet. The

transverse members

12, 13 may all be spaced with their centres three feet apart, except for the four centremost members, where the spacing may be reduced to two feet. This provides for six members 10 at each side of the longitudinal centre and six pairs of

members

12, 13 at each side of the transverse centre. As the spaces formed by the longitudinal and transverse members, except at the sides of the roof and at the transverse centre, are square, the

diagonals

14 or 22 lie at an angle of 45 to said members.

In the construction and erection of a roof according to the invention the longitudinal members, if necessary rigidly built up to the required length, may be placed on a pair of temporary rigging girders having their upper edges curved to the same shape as the upper edges of the stiffening beams. The temporary girders are so spaced that they are positioned slightly inwardly, for example, twelve inches, from the ends of the longitudinals. After being positioned at the required spacing the longitudinals are then secured to the temporary girders in any readily detachable manner, for example, by being clipped or tied thereto. The diagonals 14, if they are to be fitted above the longitudinals, and the upper transverse members 12 are then placed in position on the longitudinals and the bolts 16 then inserted in the holes previously formed in said members. The lower diagonals, if provided, and the transverse members 13 are then positioned over the bolts and the assembly as thus far prepared is then made rigid by the attachment of the nuts 16a. The transverse and diagonal members may also be built up to the required length. The assembly is then raised, for example by means of poles, and is placed on the stiffening beams, the latter having already been secured at the required positions. The end bolts 15 are then applied to secure the assembly to the stiffening beams and the temporary girders thereafter removed. The lifting operation can be effected quite easily since an assembly of the size required to cover a roof space measuring thirty feet by twenty-five feet may weigh less than thirty hundredweights, while a larger roof measuring sixty feet by thirty feet may weigh less than three tons. Where the diagonals are constructed as in Figure 4, these can be fitted at the same time as the nuts 16a.

A roof structure according to the invention is thus an open or basket-like framework in which the stiffening beams enforce the curvature of the transverse and diagonal members and ensure that the longitudinal members lie in a predetermined curved plane. By curving the transverse members of the upper and lower layers to radii struck from a common centre and securely fixing said members to the longitudinal and diagonal members, a rigid structure is obtained in which the said layers take up the bending moments without buckling. The stiffening beams also transmit the load brought to them by the other members to the supporting walls or columns. The longitudinal members are grouped so as to resist the compressive and tensile forces which result from the beam action. Where these longitudinal members are in the form of tubes, post-tensioning cables may be provided within the tubes at the sides of the roof, said cables being subsequently tensioned.

The roof curve may be cylindrical, elliptical or of any other desired form and may be tilted to one side so as to allow for the provision of a north light roof. A number of separate curves may be arranged side by side.

The basket-like roof structure described above may be completed, either before or after erection, in any desired manner. For example, glazing may be provided between the transverse members or the space between the upper and lower layers of transverse members may be filled with concrete or other material. Outer and innet skins may be fitted to said transverse members as required, said skins being of any suitable material such as flat or corrugated steel, aluminium or asbestos sheet, plywood, Wall board or expanded metal lathing. When glazing is to be used, the diagonals nearer the centre of the roof may be omitted, leaving only those near the roof sides and ends, the load on the longitudinals nearer the crown then being transmitted by the end diagonals. When concrete or other filling is to be used, a temporary shuttering may be fitted within the roof. The filling material may be arranged partially or wholly to enclose the members from which the roof framework is constructed and thus protect said members from corrosion or fire.

The expression stiffening member or stiffening beam used in the foregoing description is to be understood to mean a member of sufficiently rigid construction per so that it is able to resist all the forces imparted to it through its connection to the other roof members without becoming materially deformed.

I claim:

1. In a barrel vault roof structure, a pair of rigid end girder members adapted to be supported at least at their ends and each having an upper curved part corresponding to the required curvature of the roof and a lower straight part and bracings between the upper and lower parts, a first series of spaced parallel longitudinal members supported at their opposite ends by the curved parts of said end members, the lowermost parallel members of said series being unsupported between their ends and are in tension while the uppermost member of said series is in compression, a second series of spaced parallel members having a shape conforming to that of the curved parts of said end members, said second series of members being arranged parallel to and intermediate the said end girder members and being secured to the first series of members at points of intersection therewith, and a third series of spaced members arranged in the tranvesrsely curved plane formed by said first and second series of members and at an angle across each of the corners formed by said first and second series, each member of said third series being secured to at least two of the members of the other two series, and at least some members of said third series being also connected to the said end girder members, and means connecting the longitudinal members to the curved faces of the end girder members to provide a roof structure capable of being supported only at its ends in the manner of a substantially non-deformable beam, the members of at least one of said three series being made from tubular metal.

2. In a barrel vault roof structure, a pair of rigid end girder members adapted to be supported at least at their ends and each having an upper curved part corresponding to the required curvature of the roof and a lower straight part and bracings between the upper and lower parts, a first series of spaced parallel longitudinal members supported at their opposite ends by the curved parts of said end members, the lowermost parallel members of said series being unsupported between their ends and are in tension while the uppermost member of said series is in compression, a second series of spaced parallel members having a shape conforming to that of the curved parts of said end members, said second series of members being arranged parallel to and intermediate the said end girder members and being secured to the first series of members at points of intersection therewith, and a third series of spaced members arranged in the transversely curved plane formed by said first and second series of members and at an angle across each of the corners formed by said first and second series, each member of said third series being secured to at least two of the members of the other two series, and at least some members of said third series being also connected to the said end girder members, and means connecting the longitudinal members to the curved faces of the end girder members to provide a roof structure capable of being supported only at its ends in the manner of a substantially non-deformable beam, the members of at least one of the first and second series being made from tubular metal, the members of the third series being made from flat strip metal.

3. In a barrel vault roof structure, a pair of rigid end girder members adapted to be supported at least at their ends and each having a curved part corresponding to the required curvature of the roof, a first series of spaced parallel members supported at their opposite ends by the curved parts of said end members, a second series of spaced parallel members having a shape conforming to that of the curved parts of said end members, said second series of members being arranged parallel to and intermediate the said end members and being secured to the first series of members at points of intersection therewith, and a third series of spaced members arranged in the transversely curved plane formed by said first and second series of members and at an angle across each of the corners formed by said first and second series, each member of said third series being secured to at least two of the members of the other two series, and at least some members of said third series being also connected to the said end members, and means connecting the longitudinal members to the curved faces of the end girder members to provide a structure capable of being supported only at its ends in the manner of a substantially non-deformable beam, the members of at least one of the first and second series being made from channelled metal, the members of the third series being made from flat strip metal.

4. In a barrel vault roof structure a pair of rigid end members adapted to be supported at least at their ends and each having a curved part corresponding to the required curvature of the roof, a series of spaced parallel tubular members secured at their ends to the curved parts of said end members, a series of spaced, parallel channeled members having a shape conforming to that of the curved parts of said end members, said channelled members being arranged parallel to and between said end members and being apertured to receive said tubular members, means securing the tubular and channelled members together at points of intersection thereof, and a series of spaced members arranged at an angle to said tubular and channelled members, said angular members each engaging at least two of said tubular and channelled members.

5. A barrel vault roof structure as in claim 4, wherein the tubular and channelled members are bolted together at points of intersection thereof, the angular members being welded to the tubular members;

6. In a barrel vault roof, a pair of rigid end members each having a curved face corresponding to the required curvature of the roof, a first series of spaced longitudinal members each of unitary construction extending horizontally between said end members, a second. series of spaced parallel members each of unitary construction extending transversely of said first series, the members of said second series being curved lengthwise to correspond to the requircd curvature of the roof and being arranged in two layers one above and one below the first series of members, a series of spaced diagonal members arranged between the longitudinal members and at least one layer of said transverse members, said diagonal members being arranged in groups one extending across each corner of the roof structure, means connecting the transverse and diagonal members to the longitudinal members at points of intersection therewith, and means connecting the 1ongitudinal members to said end members.

7. A barrel vault roof as in claim 6, wherein spacing clips disposed between the points of connection of the transverse members to the longitudinal members are provided to interconnect corresponding upper and lower transverse members, said clips each comprising a pair of plates and a bolt connecting said plates together at their centres, the plates having upper and lower portions shaped to engage around the edges of said transverse members.

References Cited in the file of this patent UNITED STATES PATENTS 169,101 Gruwe Oct. 26, 1875 1,659,471 Pantke Feb. 14, 1928 1,704,275 Badel Mar. 5, 1929 1,753,862 Johnson Apr. 8, 1930 2,390,418 Brown Dec. 4, 1945 FOREIGN PATENTS 18,085 Great Britain of 1891 142,677 Switzerland Dec. 16, 1930 OTHER REFERENCES Engineering News Record for March 22, 1945, pages 106-108.