US3812632A

US3812632A - Dome structure

Info

Publication number: US3812632A
Application number: US00284142A
Authority: US
Inventors: R Robertson; G Francis
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-08-28
Filing date: 1972-08-28
Publication date: 1974-05-28
Anticipated expiration: 1991-05-28
Also published as: GB1395977A

Abstract

A dome shaped building structure comprising at least three structural arch members which are small circles of a sphere and each extending in a respective vertical plane from two ground anchorage points. The apex of each of the adjacent arch members are interconnected by a horizontal arc shaped member itself a portion of a small circle whereby a continuous ring is formed by the arc shaped members connected to at least three structural arch members. A spherical triangular shaped frame is formed between adjacent apexes and two adjacent structural arch members and extend from one of the anchorage points. At least one of the reinforcing members is a segment of a great circle extending from the arc shaped member radially outward and downward to connect with the anchorage point or the arch shaped member. These reinforcing members provide support for the vertical load on the arc member between the apex connections.

Description

United States Patent [191 Robertson et al.

[ 51 May 28, 1974 DOME STRUCTURE [76] Inventors: Robert C. Robertson, 1629 Selkirk Ave., Montreal, Quebec, Canada; G. V. Francis, 60 Hill Top Ave., Cheadle Hulme, England [22] Filed: Aug. 28, 1972 21 Appl. No.: 284,142

i Q I Primary Examiner-John E. Murtagh [5 7 ABSTRACT A dome shaped building structure comprising at least three structural arch members which are small circles of a sphere and each extending in a respective vertical plane from two ground anchorage points. The apex of each of the adjacent arch members are interconnected by a horizontal are shaped member itself a portion of a small circle whereby a continuous ring is formed by the are shaped members connected to at least three structural arch members. A spherical triangular shaped frame is formed between adjacent apexes and two adjacent structural arch members and extend from one of the anchorage points. At least one of the reinforcing members is a segment of a great circle extending from the are shaped member radially outward and downward to connect with the anchorage point or the arch shaped member. These reinforcing members provide support for the vertical load on the arc member between the apex connections.

10 Claims, 6 Drawing Figures PATENTEDIIAY 28 1914 SHEU 1 Bf 3 FIG 2 FATENTEDIAYZB i914 3.812.632

SHEEI 2 [IF 3 BACKGROUND OF INVENTION a. Field of the Invention The present invention relates to building structures and more particularly to a dome shaped structure.

b. Description of Prior Art The structural design of dome structures is based on the assumption of providing a continuous membrane over the dome surface, usually approximated by a regularly reticulated framing geometry. Any breaks or holes in this membrane, other than the spaces which result as a natural consequence of the framing geometry, must be reinforced with beams capable of assuming the forces that were carried by the removed members. When holes are provided in the surface such as doorways or any other access opening which because of size and location will result in the disruption of the natural framing geometry, a reinforcing beam costing more than that of the removed members must be provided around these openings.

SUMMARY OF INVENTION A feature of the present invention is to provide a primary framing system having large arch shaped openings in the surface of a dome and incorporating a tension ring which connects to the apexes of the arches. The tension ring is supported vertically along its length between the apex connections by radial members occurring between two adjacent arches. Any secondary dome framing system superimposed on the primary system will then complete the structural framing.

An advantage of this primary framing is that additional expense for framing such openings in a dome building will not be incurred since the primary framing system is a basic and integral part of the complete framing system.

Further, on a hemispherical dome building where normally the dome clear span is the base diameter, in the case of a four arched structure, the clear span diameter of the conventionally framed dome cap portion (upper dome) is reduced to 0.707 times the base diameter of the building and the tension ring for this dome is already built in as part of the primary framing system. Also, if a continuous curved ribbed dome geometry is used as the secondary framing system, the effective length of radial ribs in the example above is cut in half compared to a curved rib dome without the primary framing structure with a resulting economy in size of the member section. Although the primary framing geometry of the present invention can be used for any dome, it is especially advantageous economically when connecting domes in a modular fashion to each other, or another structure, or for canopies to cover pools, foyers, malls and balconies where large openings are essential either to allow movement of people or vehicles, or passage of sun or air.

According to the above-mentioned advantages of the present invention, from a broad aspect, the invention provides a building structure comprising at least three structural arch members which are small circles of a sphere and each extending in a respective vertical plane from two ground anchorage points. The apex of each of the adjacent arch members are interconnected by a horizontal are shaped member itself a portion of a small circle whereby a continuous ring is formed by the are shaped members connected to at least three structural arch members. A spherical triangular shaped frame is formed between adjacent apexes and two adjacent structural arch members and extend from one of the anchorage points. A dome shaped building structure comprising at least three structural arch members which are small circles of a sphere and each extending in a respective vertical plane from two ground anchorage points. The apex of each of the adjacent arch members are interconnected by a horizontal arc shaped member itself a portion of a small circle whereby a continuous ring is formed by the are shaped members connected to at least three structural arch members. A spherical triangular shaped frame is formed between adjacent apexes and two adjacent structural arch members and extend from one of the anchorage points. At least one of the reinforcing members is a segment of a great circle extending from the arc shaped member radially outward and downward to connect with the anchorage point or the arch shaped member. These reinforcing members provide support for the vertical load on the arc member between the apex connections.

BRIEF DESCRIPTION OF DRAWINGS A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: I

FIG. 1 is a side view of the primary framing and a curved ribbed secondary framing, with a section thereof in phantom lines;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a top view illustrating the primary system of four domes connected together;

FIG. 4 is a side view illustrating the primary system of a further dome configuration of the present invention;

FIG. 5 is a fragmented top view of the glazing framework illustrating an intersection; and

FIG. 6 is a view along cross-section lines Vl-Vl in FIG. 5. I

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2, there is shown, the structural framing of a sphere segment dome structure 10 of the present invention. The structure 10 is formed basically of a lower zone of a sphere section B and an upper spherical cap dome section A with the transition line at the horizontal tension ring 11. As hereinshown, there are four structural arch members 12 which are small circles of the sphere each extending in a vertical plane from two ground anchorage points 13. The apex 14 of each of the arch members 12 is connected to two adjacent horizontal are shaped members 15 also portions of a small circle of the sphere whereby the interconnection of all the members 15 in the structure constitutes the tension ring 11 for the upper spherical cap dome.

A spherical triangular shaped frame 16 or pendentive frame, is formed by the framing between adjacent apexes l4 and two adjacent structural arch side members 17 extending from a common anchorage point 13. Thus, as shown in FIG. 2, there are four such spherical triangular shaped frames 16 interconnected to each other at the ends of their top member 15 to form four arch members 12 and a tension ring 11.

A plurality of reinforcing members 18 are secured within each pendentive l6 and lie preferably in the same spherical surface or alternatively extends in a straight line from their ends. Members 18 are provided to add stability to the pendentive frame 16; Members 24 which are preferably a segment of a great circle extending from are 15 radially outward and downward to connect with the anchorage point 13 or the arch shaped members 17, transfer the vertical load component on are '15 shown by arrows C. Therefore, the total vertical load of the upper dome section A will bear on the tension ring 11 and be transferred to'the four anchorage points 13 via the pendentive frames 16. The complex of arch l7, tension ring segment 15 and spherical triangular frame 16, can be designed to act as a single unit in its most efficient form, under any given load, by the relative sizes of each. The framing l6 restrains the majority of bending loads imposed in 17 and 15 caused by the areas removed, 30, and any assymetric imposed loads. This is done with a minimum of bending being imposed to the frame 16. In turn the edge members l7 reduce the overall buckling problems of the frame 16 because of load distribution and edge stiffness and also avoids any effects of these loads on the upper dome or door areas. Thus, all bending moments in all members are kept to a minimum.

A plurality of primary great circle arcuate ribs 19 are secured in spaced apart relationship around the peripheral base ring 23 of the dome l and converge upwardly to secure about a top ring 20 which will accommodate a suitable ventilator (not shown). As shown, the ribs 19 may lie in the same spherical surface as the triangular frames 16 and extend therethrough. A plurality of secondary arcuate ribs 21 and a secondary ring 22 may be provided to complete the structural framing. The secondary ring 22 will lie above and concentric to the tension ring 11. If required, one or more of the arches 12 may be provided with an arch shaped door unit 30. Each door unit 30 is formed by removing portions of a segment of a hemisphere by cuts upon three or more vertical planes. Thus, this shape is defined by a vertical and a horizontal arc and the doubly curved surface of the segment of the hemisphere.

Each door unit 30 has a base perimeter are shaped member 31 which is slideably supported by bearing means such as two or more wheels or rollers (not shown) which are guided by a track beneath (not shown). The other side of this shape is an arch shaped member which is supported at its apex 32 by bearing means, such as wheels or rollers (not shown), which are guided by a track (not shown) connected to the top member ofthe pendentive frame 16 (or a portion of the tension ring 11). The interiorsurface of this doubly curved shape contains a series of members 33 which support the sheeting and stabilize the shape. Either the center lines of these members or just the connection nodes lie on the surface of this doubly curved shape. This door unit 30 may be divided on the vertical center line 34 to form two door sections 30' and 30".

One ormore door units 30 may be used on each dome structure 10 and can be moved to another location around the periphery of the structure. These doors units 30 can be hung on the inner or outer surface of the structure. They may be power driven or moved by hand. Depending on the design some portions of the door shape can be fixed in place while the remainder is theonly moveable part, however, in any case the top perimeter is a segment of the arch member 12 and the base perimeter is a section of the base ring 23.

Since the shape of the door unit 30 is supported and restrained in both radialand vertical directions along the base ring 23 and supported atthe apex 32 of the arch in radial and vertical directions. the shape will be restrained from deflecting from the spherical surface. Thus, the door unit 30 behaves structurally as a curtain wall and may be composed of substantially lighter sections than the rest of the dome structure. The resulting lightness is an advantage in a moveable door. Whether this unit is moveable or not, these shapes may make up to approximately percent of the surface area of the total dome structure, (four arch hemispherical dome) and thus a great portion of the dome surface is of relatively light construction.

As shown in FIG. 3, two or more hemispherical or segments of hemispherestructures 10 may be interconnected together. As'shown, the interconnection is effected at the arches l2 and may further be secured to a wall 35 from which the structures 10 extend. Various other configurations of composite hemispherical dome structures are also possible with the structural framing of the present invention. For example, referring to FIG. 4, two arch members 12 are provided on opposite sides of a base ring 23 whereby one tension ring 11 is secured to a ground anchorage ring 36 and the spherical triangular frames 16 are secured end to end whereby the vertical load will be distributed along the ground anchorage ring 36.

Referring now to FIGS. 5 and 6, there is shown the glazing structure for sheeting the dome l0. Numeral 40 denotes a structural member such as arcuate ribs 19 (see FIG. 1). A plexiglass glazing panel 41 is positioned with its edge extending over the edge of the outer surface of themember 40 and is retained thereon by a cover bar 42 and splice bar 39 both of which may also be formed of plexiglass. The

bars

39 and 42 are secured over the entire outer surface of member 40 by means of hold down screws 43. The respective lengths of these two layers are such that whenever a butt splice is required in one layer the other layer will be continuous. The outer surface of splice bar 39 is in contact with the inner surface of cover bar 42. A neoprene rubber washer 45 provides a water seal for the screw 43 and acts as a spacer between 39 and 40 to control'the relative positions of 39 and 40. A glazing tape 44 is positioned along the joints between the cover bar 42 and the glazing panel 41 to thereby provide a waterproof seal. The tape 44 herein provided is made of cured butyl material and undergoesapproximately 50 percent compression.

At the intersection of the structural members 40 there may be provided an intersection splice plate 46 which overlaps the cross-connection of intersecting member 40 and takes the place of the splice bar 39 at these locations while the inner layer of 42 rests on the outer surface of 46. The splice plate 46 is substantially cross shaped having two pairs of opposed projecting ends 47 and 48 and an interconnecting portion 49 each having an arcuate edge 50 extending between adjacent ends 47 and 48. The purpose of the edge 50 is to divert water away from the interconnection to further discourage leakage in this area. Also, theglazing tape 44 will extend A condensation control gutter 51 is secured to the inner face 52 of the structural member 40 by suitable under the arcuate edge 50 as shown in FIG.

securing means such as lock rivet 53. At the intersection of the gutters 51 there is provided a gutter intersection splice plate 55 which is basically the same shape as the splice plate 46. Any condensation taking place on the panels 41 and running off to the sidewalls of the member 40 will collect in the channel area 54 formed on each side of the member 40 and be diverged to the base ring of the structure where a main gutter (not shown) will dispense the collected water.

With this glazing framework, it can be seen that substantially all of the center surface area of the hemispherical dome is covered with a plexiglass, or other suitable material membrane.

It is within the ambit of the present invention to provide dome structures with at least three structural arch members. Further, the structural members can be of various cross sectional configuration and any suitable material including reinforced concrete may be substituted for the framework and glazing panels depending on the loads to be supported by the structure. Still further, many other dome interconnections are possible other than that described herein, all of said modifications being restricted by the scope of the present invention as defined in the appended claims.

We claim:

1. A building structure comprising at least three structural arch members which are small circles of a sphere and each extending in a respective vertical plane from two ground anchorage points; the apex of adjacent ones of said structural arch members are interconnected by a horizontal are shaped member itself being a portion of a small circle whereby a continuous ring is formed by the arc shaped members connected to said at least three structural arch members, a spherical triangular shaped frame formed between adjacent apexes and two adjacent structural arch members and extending from one of said anchorage points, a plurality of reinforcing members disposed within said triangular frame, at least one of said reinforcing members being a segment of a great circle extending from said horizontal are shaped member radially outward and downward through said triangular frame to connect with said anchorage point or a structural arch member; said reinforcing members providing support for the vertical load on said horizontal arc shaped member be- 1 tween said arch apex connections.

2. A building structure as claimed in claim 1, wherein a base ring member extends through said anchorage points and a plurality of arcuate ribs extend from said base ring to the apex of a spherical cap section defined above said continuous ring.

3. A building structure as claimed in claim 1, wherein said structural arch members, arc shaped members and reinforcing members lie in the same spherical surface.

4. A building structure as claimed in claim 3, wherein said arcuate ribs are disposed in the same spherical surface as said structural arch members, are shaped members and reinforcing members.

5. A building structure as claimed in claim 2, wherein said continuous ring is a tension ring, a secondary continuous ring connected between said arcuate ribs and concentric to said tension ring.

6. A building structure as claimed in claim 2, wherein a door unit is formed in the spherical surface of one or more of said at least three structural arch members, said door unit having an are shaped base perimeter slideably supported on bearing means slideable within a track secured to said base ring member.

7. A building structure as claimed in claim 6, wherein said door unit is arch shaped with the apex of said arch shaped door having a bearing means secured thereto and guided within a track secured to a portion of said continuous ring.

8. A building structure as claimed in claim 2, wherein a panel is provided over the area between adjacent arcuate ribs, are shaped members and structural arch members, each said panels having the edges thereof extending over a portion of the outer surface of said ribs and members, a rubber glazing tape disposed on the outer surface of each said panels adjacent the edges thereof a glazing intersection splice bar and splice plate, a cover bar extending over said splice bar and plate and extending over said tape and secured whereby said edges of said panels are sealingly engaged over said ribs and members.

9. A building structure as claimed in claim 8, wherein a condensation gutter system is secured to the inner surface of said ribs and members and extending across said ribs and members whereby to form channels to collect water condensate and diverge it to said base ring where the water is collected and dispensed.

10. A building structure as claimed in claim 9 wherein said gutter system comprises gutter channel sections, a gutter intersection splice plate secured at the intersection of said channel sections.

Claims

1. A building structure comprising at least three structural arch members which are small circles of a sphere and each extending in a respective vertical plane from two ground anchorage points; the apex of adjacent ones of said structural arch members are interconnected by a horizontal arc shaped member itself being a portion of a small circle whereby a continuous ring is formed by the arc shaped members connected to said at least three structural arch members, a spherical triangular shaped frame formed between adjacent apexes and two adjacent structural arch members and extending from one of said anchorage points, a plurality of reinforcing members disposed within said triangular frame, at least one of said reinforcing members being a segment of a great circle extending from said horizontal arc shaped member radially outward and downward through said triangular frame to connect with said anchorage point or a structural arch member; said reinforcing members providing support for the vertical load on said horizontal arc shaped member between said arch apex connections.

4. A building structure as claimed in claim 3, wherein said arcuate ribs are disposed in the same spherical surface as said structural arch members, arc shaped members and reinforcing members.

6. A building structure as claimed in claim 2, wherein a door unit is formed in the spherical surface of one or more of said at least three structural arch members, said door unit having an arc shaped base perimeter slideably supported on bearing means slideable within a track secured to said base ring member.

8. A building structure as claimed in claim 2, wherein a panel is provided over the area between adjacent arcuate ribs, arc shaped members and structural arch members, each said panels having the edges thereof extending over a portion of the outer surface of said ribs and members, a rubber glazing tape disposed on the outer surface of each said panels adjacent the edges thereof a glazing intersection splice bar and splice plate, a cover bar extending over said splice bar and plate and extending over said tape and secured whereby said edges of said panels are sealingly engaged over said ribs and members.