FIELD
The present disclosure is in the technical field of general building constructions. More particularly, the present disclosure is in the technical field of three dimensional framework structures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is an isometric view of a tensional space frame structure with a triangular pattern of vertical compression members having an overall hexagonal shape with five vertical compression members aligned across the long dimension of the hexagonal shape, exemplary of one embodiment; and
FIG. 1b is a top view of the tensional space frame structure of FIG. 1a; and
FIG. 1c is an isometric view along one path of vertical compression members through the diagonal of the tensional space frame structure of FIG. 1a; and
FIG. 1d is an isometric view along one path of vertical compression members along an outside edge of the tensional space frame structure of FIG. 1a; and
FIG. 1e is a force transfer diagram along the path of vertical compression members through the diagonal of the tensional space frame structure of FIG. 1a, as shown in FIG. 1c; and
FIG. 2a is an isometric view of a tensional space frame structure of another example embodiment with a triangular pattern of vertical compression members having an overall hexagonal shape with five vertical compression members aligned across the long dimension of the overall hexagonal shape, similar to the example tensional space frame structure of FIG. 1a, except a pathway of tension members traverses four vertical compression members once removed from the diagonal path; and
FIG. 2b is a top view of the tensional space frame structure of FIG. 2a; and
FIG. 2c is an isometric view of one line of vertical compression members once removed from the diagonal path of the tensional space frame structure of FIG. 2a; and
FIG. 3a is an isometric view of a tensional space frame structure of a further example embodiment with a triangular pattern of vertical compression members having an overall hexagonal shape with seven vertical compression members aligned across the diagonal of the overall hexagonal shape, similar to the example tensional space frame structure of FIG. 1a, except the number of vertical compression members is larger; and
FIG. 3b is a top view of the tensional space frame structure of FIG. 3a; and
FIG. 3c is a front view of the tensional space frame structure of FIG. 3a; and
FIG. 4 is an isometric view of a tensional space frame structure of yet another example embodiment with a rectangular pattern of vertical compression members having an overall rectangular shape and five vertical compression members aligned across the long edge of the overall rectangular shape; and
FIG. 5 is a is an isometric view of a tensional space frame structure of one embodiment with a triangular pattern of vertical compression members having an overall triangular shape with five vertical compression members aligned across each edge of the overall triangular shape; and
FIG. 6 is an isometric view of a tensional space frame structure of another embodiment with a combination of triangular patterns and hexagonal patterns formed by vertical compression members having an overall hexagonal shape with six vertical compression members aligned once removed from the diagonal of the overall hexagonal shape, similar to the example tensional space frame structure of FIG. 3a, except with fewer vertical compression members.
FIG. 7a is an isometric view of a structure showing the path of tension members along the end points of vertical compression members; and
FIG. 7b is a front view of the structure of FIG. 7a.
DETAILED DESCRIPTION
The present disclosure describes a tensional space frame structure that includes a plurality of top chord tension members, two or more vertical compression members, a plurality of bottom chord tension members, plus a plurality of tension members sloping from the top chord to the bottom chord that determine the overall shape and transfer vertical loads from vertical compression members to the perimeter of the tensional space frame structure.
The tensional space frame structure comprises a perimeter structure for maintaining tension in the tension members. This structure for maintaining tension in the tension members can define a perimeter ring, hexagon, truncated hexagon, square, truncated square, ellipse, or various other geometries of structural members in compression. Alternatively, this structure for maintaining tension in the tension members can comprise a collection of individual structural anchors for groups of one or more tension members.
Additional complexity and advantage can occur in some embodiments when there is a larger quantity of vertical compression members. For example, a triangular pattern of compression members can include one central compression member, six secondary compression members, and a third cohort of twelve compression members. This pattern of vertical compression members can have three vertical compression members at the edge of the overall hexagonal shape and five vertical compression members across the long dimension of an overall hexagonal shape. It is possible in some embodiments to arrange tension members within this triangular pattern in such a way that the support structure depends on the three chords passing under the center compression member for the primary structural lift. In this example the use of primary tension members across the central compression member can provide sufficient structural lift that six intermediate compression members in the third cohort can be supported from the six compression members in the third cohort that are aligned with the primary chord members along the diagonal path. It is also possible in further embodiments to arrange tension members within this this triangular pattern in such a way that the support structure depends on the second cohort of six compression members for the primary structural lifting force. In this example the use of larger tension members across the second cohort can provide sufficient structural lift that the center compression member can be supported from the six secondary compression members.
Tensional space frame structures may exhibit pattern shapes other than triangles, including squares, rectangles, diamonds, and highly variable patterns of multiple geometric shapes within the same structure, similar to the variety of shapes available for arranging solid-member space frame structures. Triangular patterns and patterns of other shapes utilizing larger quantities of vertical compression members can be of value for defining and designing tensional space frame structures with controlled lower chord shapes, for example, in some embodiments it is possible to define very light-weight, long, open span structures with a nearly flat bottom chord.
Further complexity and advantage can occur in some embodiments when there are more vertical compression members in the pattern, that is, where a top chord and bottom chord tension members may span between a greater quantity of vertical compression members. Such more complex patterns can allow for variations in pathways for primary tension members such that vertical support is arranged to optimize the capability to shape the resulting tensional space frame structure.
An alternative embodiment includes a structure for dynamically adjusting the tension on specific tension members or the position of specific tension members relative to specific compression members in order to dynamically modify the shape of the tensional space frame structure.
An alternative embodiment allows that the tensional space frame structure is positioned at an arbitrary angle relative to earth's horizon, thereby allowing that the structure serve as a sloped roof, a wall, or any other built element.
An alternative embodiment allows that an additional vertical structural member is introduced within the field of vertical compression members to provide dramatic shapes within a field of vertical compression members. The additional vertical structural member may be significantly taller that other compression members and may be further supported by other structural components or foundations.
In the drawings, like numerals indicate similar elements throughout. Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. The following describes preferred embodiments of the present invention; however, it should be understood based on this disclosure that the invention is not limited by the preferred embodiments herein.
Referring to the one example embodiment in more detail, in FIG. 1a there is shown a tensional space frame structure where the top chord, bottom chord, and sloped segments of each structurally connected member is held in tension and vertical compression members separate the top and bottom chords. These tension members can carry forces of various types, including horizontal lower level forces required to stabilize vertical compression members in a vertical position, sloped lower level forces required to stabilize vertical compression members in a vertical position, horizontal higher level forces required to transfer tension loads from interior elements to the perimeter of the structure, and sloped higher level forces required to offset vertical loads imposed on vertical compression members by various sources including loads from above the structure, for example roof loads, vertical compression member weights, tension member weights, wind and pressure loads, and the weight of items suspended below the structure. In some preferred embodiments, these loads are carried by smaller horizontal bottom tension members 102, smaller horizontal top tension members 104, smaller sloped tension members 106, larger horizontal bottom tension members 112, larger horizontal top tension members 114, and larger sloped tension members 116. Vertical forces are exerted on vertical compression members 122. Tension forces can be carried by tension members that extend to the perimeter and these forces result in compressive forces acting on the hexagonally shaped compressive ring formed by perimeter compression members 134 of the tensional space frame structure.
Referring to FIG. 1b there is shown a tensional space frame structure where interior horizontal members are tension members and the outside hexagon is comprised of compression members 134 to maintain the tension members in tension. For example, the smaller horizontal top tension member 104 located along the diagonal path can remain in tension rather than being in compression as in some example rigid space frame structures. The tension member pathways are shown as comprising multiple tension members run in parallel 112 and 114 and run as sloped tension members 116 between selected compression members to resist downward vertical loads. In this example, of the 19 vertical compression members in the inside of the structure is associated with at least one sloped tension member to transfer vertical loads to the perimeter. Additionally, smaller tension members 102 and 104 traverse horizontally between compression members that otherwise are not connected by larger tension members to provide stability for the vertical compression members within the tensional space frame structure.
Referring to FIG. 1c there is shown the allocation of tension members and vertical compression members along the diagonal of the tensional space frame structure of FIG. 1a, excluding the view of the exterior ring and members not passing through the plane of the diagonal. The members shown include a larger tension member passing from the perimeter sloping to below the adjacent compression member 116a, then horizontally along the bottom of each compression member 112a, then sloping to the perimeter 116a. The members shown include a larger tension member passing from the perimeter across the top of the first compression member 114b, then sloping to the bottom of the second compression member 116b, then horizontally past the third and fourth compression member 112b, then sloping to the top of the fifth compression member 116b, then horizontally to the opposite side of the perimeter 114b. The members shown include a larger tension member passing from the perimeter across the top of the first and second compression members 114c, then sloping to the bottom of the third compression member 116c, then sloping to the top of the fourth compression member, then across the top of the fifth compression member and to the opposite side of the perimeter 114c.
Referring to FIG. 1d there is shown a portion of the tensional space frame structure shown in FIG. 1a, comprising three vertical compression members 122, top and bottom tension members 102 and 104, and sloped tension members 116, representing the edge of the overall hexagonal shape. This configuration can allow the vertical load on the center vertical compression member to be transferred to the vertical compression members on the ends of the edge.
Referring to FIG. 1e there is shown a diagram of the set of tension and vertical compression members along one diagonal path of the tensional space frame structure of FIG. 1a. The figure includes external notes indicating point loads to serve as an example for analysis of forces in each member. Notes 3 through 7 indicate vertical point loads 933, 934, 935, 936, and 937, shown above vertical compression members 901, 902, 903, 904, and 905, to indicate one possible model for roof loads resulting from a roof structure positioned over the tensional space frame structure. The assumed loads represent an evenly loaded tensional space frame structure, where loads are assigned evenly and symmetrically. For purposes of this example calculation, the vertical loads along one diagonal path are assigned values of 9000 pounds at 901 and 905, of 4500 pounds at 902 and 904, and of 1500 pounds at 903, representing the loads accumulated from the evenly loaded roof membrane and applied at each sloped tension member connected to the related vertical compression member. For purposes of this sample calculation, the dimensions of the tensional space frame structure include a right triangle with a ratio of sides of 5, 12, and 13, and this ratio determines the transfer of component forces, that is vertical and horizontal forces, along the sloped tension members 906, 907, 908, 909, 911, and 916. Any other ratio of member lengths, and many other configurations, including configurations where right triangles are not utilized, can be useful in applying various embodiments and the use of this example set of ratios with right triangles is not a limitation. Each tension member in this example is restrained at the vertical compression member connection and the sum of forces must be zero in this example in order to maintain a static structure. Taking only the tension members along one diagonal path of the overall hexagonal shape into account, the external load on vertical compression member 903 results in a balanced vertical load of 750 pounds force on tension members 907 and 908 resulting in 1950 pounds force along the tension members, the external load on vertical compression members 902 and 904 plus the vertical load transferred from tension members 907 an 908 results in vertical loads of 5250 pounds force on vertical compression members 902 and 904 resulting in 13650 pounds force along tension members 906 and 909, and the external load on vertical compression member 901 and 905 plus the vertical component load transferred from tension members 906 and 909 result in a vertical load of 14250 pounds force on tension members 911 and 916 resulting in 37050 pounds force along the tension members. In this example a tension force is required in tension members 923 and 924 to provide stability for vertical compression member 903 and, for purposes of this example, 1400 pounds force is assigned along tension members 923 and 924. The tension force in tension members 922 and 925 balances other loads at the top of vertical compression members 902 and 904, and require 3200 pounds force in this example. The tension force in tension members 921 and 926 balances other loads at the top of vertical compression members 901 and 905, and require 15800 pounds force, excluding loads from other tension members outside the one diagonal path in this example. The tension force in tension members 912 and 915 balances other loads at the bottom of vertical compression members 901 and 905, and require 34200 pounds force, excluding loads from other tension members outside the one diagonal path in this example. The tension force in tension members 913 and 914 balances other loads at the bottom of vertical compression members 902 and 904, and require 46800 pounds force, excluding loads from other tension members outside the one diagonal path in this example.
Continuing to reference FIG. 1e and expanding the analysis of forces to include forces from other tension members outside the one diagonal path, unbalanced forces existing in the edge of the hexagonal tensional space frame structure act at the top and bottom of vertical compression members 901 and 905. Vertical loads transferred through vertical compression members 901 and 905 were included in the example partial analysis above. Assuming nominal tension forces to provide stability for the center vertical compression member along each edge of the hexagon, the horizontal forces result in net forces of 6800 pounds force pulling the top of vertical compression members 901 and 905 toward the center post 903 and net forces of 1400 pounds force pulling the bottom of vertical compression members 901 and 905 toward the center post 903. Using the forces resulting from the example expanded analysis, the force in tension members 921 and 926 increases from 15800 to 22600 pounds force, the force in tension members 912 and 915 decreases from 34200 to 32800 pounds force, and the force in tension members 913 and 914 decreases from 46800 to 45400 pounds force. The external forces at the edge structure counteract the forces in the tension members along the diagonal path with an upward vertical component at notes 2 and 8, 932 and 938, of 14250 pounds force and an outward horizontal component of 56800 pounds force, assigned a negative value with respect to the direction indicated by notes 1 and 9, 931 and 939.
The example tensional space frame structure shown in FIGS. 1a, 1b, 1c, 1d, & 1e, and analyzed above is shown as having tension members distributed as continuous objects, potentially including continuous wires or cables, resulting in the circumstance of having multiple tension members traveling a parallel pathway between compression members; also the analysis above assumes that tension members are securely attached at each compression member connection so that a pathway between compression members may be established by one or more tension members, arrayed in parallel when two or more tension members are present. For example, in FIG. 1c, the diagonal path is represented as including two larger 114b and 114c and one smaller 104 tension members traversing from the perimeter connection to the top of the first compression member, this segment is similar to the tension member 921 analyzed in FIG. 1e, and this segment may be established by two large and one small tension member, or may be established by one tension member, or may be established by two or more tension members set in a parallel, cabled, or bundled configuration as suitable to the project and scale of the tensional space frame structure.
The example tensional space frame structure shown in FIGS. 1a, 1b, 1c, 1d, & 1e, and analyzed above is shown as having an overall level perimeter but it can be equally useful to define a tensional space frame structure tilted from the horizontal, with vertical compression members tilted to match, or to define tensional space frame structure tilted from the horizontal, with vertical compression members vertically arranged or arranged at an intermediate angle, so the orientation of tensional space frame structures used as examples herein is not a limitation.
The examples of tensional space frame structures herein demonstrate overall flat structural shapes inasmuch as the vertical compression members are aligned with respect to elevation. The overall shape of the tensional space frame structures can be variable across a significant range, including shapes that require slightly concave upward lower cords. For example, the sloped tension members can be defined to lift the center post, or to lift the center seven posts with respect to the perimeter post elevation. Alternately, the entire structure can have a convex bottom, with or without a concave top, and exhibit the appearance of a hanging structure. The advantages of various embodiments of a tensional space frame structure will be apparent to an engineer with regular skill in the art regarding other features of the structure, including light weight, rigid behavior, high load capacity, wind stability, etc.
Referring to FIG. 2a there is shown an isometric view of an alternative tensional space frame structure, including an arrangement of vertical compression members similar to the arrangement shown in FIG. 1a and a different distribution of tension members, using three sets of three paths, including one center 244 and two adjacent 242 paths. The three sets of three paths can provide for at least one sloped tension member connecting to every one of nineteen vertical compression members so that each one is able to transfer vertical loads to the perimeter comprised of horizontal compression members 234.
Referring to FIG. 2b there is shown a top view of the tensional space frame structure of FIG. 2a, including three sets of three paths, one center 244 and two adjacent 242 paths with each set of paths rotated 60 degrees. The perimeter, comprised of compression members 234 in this example, provides a compression ring and is defined to demonstrate that the compression ring can be assembled of many shorter members than the tensional space frame structure of FIG. 1a, eighteen members in this configuration, so as to permit perimeter compression members to have a thinner cross section than the perimeter compression members of FIG. 1b.
Referring to FIG. 2c there is shown the members of the tensional space frame structure found along one path 242 in FIG. 2a spanning four vertical compression members 122, each able to transfer vertical loads to the perimeter via sloped tension members 116 and via bottom tension members 112 and top tension members 114. Two distinct cable paths 246 and 248 are shown to demonstrate the pathway of primary tension loads in this example. An additional top tension member 104 can be utilized in some embodiments where no other tension member occurs to stabilize vertical compression members.
Referring to FIG. 3a there is shown an isometric view of a tensional space frame structure utilizing vertical compression members arranged with triangular spacing in an overall hexagonal shape, each diagonal comprising seven vertical compression members and each edge comprising four vertical compression members. As compared to the tensional space frame structure shown in FIG. 1a, FIG. 3a shows a more complex space frame utilizing 37 in lieu of 19 vertical compression members; and shows a perimeter anchor comprising a support post 336 and an anchor point 338 where a tension member can be anchored to resist a tension force.
Referring to FIG. 3b there is shown a top view of the tensional space frame structure of FIG. 3a where each vertical compression member occurring along a diagonal path is supported by a sloped tension member, each of six vertical compression members located one space from an edge is supported by a sloped tension member 116 that transfers vertical load to two adjacent diagonal paths, and each of twelve vertical compression members located at an edge is supported by a sloped tension member 116 and bottom tension member 112 that transfers vertical load to two adjacent diagonal paths. Smaller tension members including a top cord 102 and a sloped tension member 106, found in twelve locations each, stabilize the edge path of the overall hexagonal shape.
Referring to FIG. 3c there is shown a side view of the tensional space frame structure of FIG. 3a where perimeter anchors each comprising a support post 336 and an anchor point 338 where a tension member can be anchored to resist a tension force are provided to both capture horizontal tension forces and to transfer vertical loads to the ground or base location of the tensional space frame structure.
Referring to FIG. 4 there is shown an isometric view of a tensional space frame structure utilizing vertical compression members arranged with rectangular spacing in an overall rectangular shape, each long-edge path comprising five vertical compression member and each short-edge path comprising four vertical compression members. The transfer of vertical loads can occur along the edges of aligned rectangles with tension loads traversing across the rectangle, for example along the line from vertical compression member 412 to vertical compression member 414, and these loads can be carried to a perpendicular end system, or to a perimeter anchor point, as shown in this example where a perimeter anchor comprising a support post 422 and an anchor point 426 where a tension member can be anchored to resist a tension force. FIG. 4 shows sloped tension members supporting the end system vertical compression members, for example supporting the vertical compression member 412 along the path toward compression member 402. Alternatively, in some embodiment, sloped tension members may not be required for tensional space frame structures with spans of two or more vertical compression members, instead, perpendicular tension members can be used to stabilize vertical compression members as shown between vertical compression members 408 and 410. FIG. 4 shows an anchor system comprising a support post 402 and an anchor point 406 where a heavier tension member can be anchored to resist a tension force that supports vertical loads and an anchor point 404 where a lighter tension member can be anchored to resist a tension force that supports horizontal loads to stabilize vertical compression members and to maintain the overall shape of the tensional space frame structure.
Referring to FIG. 5 there is shown an isometric view of a tensional space frame structure utilizing vertical compression members arranged using an approximate triangular pattern in an overall approximate triangular shape, with five vertical compression members along each edge, for example between vertical compression members 512 and 514. FIG. 5 shows an anchor system comprising a support post 502 and an anchor point 506 where a tension member can be anchored to resist a horizontal tension force that supports vertical loads and a vertical force that supports the vertical component of sloped tension members. FIG. 5 further demonstrates an alternative example where no stabilizing or shaping tension members are added at the edge of the overall triangle shape, instead the edge is concave and the concave shape can result in forces that stabilize the edge vertical compression members. This concave shape can be utilized in embodiments of the tensional space frame structures that are configured to support vertical loads without supporting each vertical compression member at the edge of the overall pattern of vertical compression members with a sloped tension member connected to a perimeter ring or support.
Referring to FIG. 6 there is shown an isometric view of a tensional space frame structure utilizing vertical compression members arranged in a combination of hexagonal and triangular patterns in an overall hexagonal shape, with four vertical compression members along each edge, for example along path 656 to 658 and six vertical compression members along each interior path 652 to 654, connected to a compression ring comprising compression members 634.
Referring to FIG. 7a there is shown an isometric view of a structure arranged similar to the tensional space frame structure of FIG. 2a, including three collections of three tension pathways across a tension ring. The vertical loads of the structure are transferred to the compression ring via the shape of the tension member pathway, specifically the tension members follow a lens shaped pattern that causes a changing horizontal slope at the connection to each vertical compression member 722. FIG. 7a indicates a hexagonal shaped set of lighter tension members 102 and 104 connecting to the ends of edge vertical compression members to stabilize at least six vertical compression members at the edge of the overall hexagonal shape.
Referring to FIG. 7b there is shown a front view of the structure, as shown in FIG. 7a, which shows a distinct and rigidly formal lens shape stemming from the proposed structural requirements, enabled by variation in the length of vertical compression members and captured between lower cord 712 and upper cord 714 tension members which are held in tension by a compression ring comprising compression members 734.
An engineer normally skilled in the art will notice that vertical loads distributed to vertical compression members in the proposed structure of FIG. 7a would result in significant tension in the tension members and could cause significant displacement at the interior of the structure, also that a vertical load applied to one vertical compression member could cause significant displacement near and at that one vertical compression member.
The diagrams and descriptions herein generally provide for one or more sloped tension members connected to each vertical compression member, but it is possible to combine aspects of a tensional space frame structure and the structure of FIG. 7a to provide additional rigidness to a structure otherwise more like the proposed structure of FIG. 7a. Thus, the lack of a sloped tension member at each of the vertical compression members in a tensional space frame structure of the present disclosure is not a limitation.
The inclusion of fragments of rigid space frames, that is including compressive members to define one or more triangles, one or more rectangles, or one or more volumetric shapes while using sloped tension members to generally support the overall structure is not a limitation of the present disclosure.
Patent Application
20190234060
