Abstract: A frame for a projection screen or the like may be fabricated of elongated round tubular members running one direction and polygonal (preferably rectangular) cross section members running in the other direction connected together into a grid by clamps at their intersections. The clamps are parallel plates affixed to the parallel surfaces of the polygonal support members and have a rounded groove in an edge generally conforming to the rounded cross section. Clamp means to hold the round members in the grooves are conveniently formed of U-bolts which are secured to flanges generally normal to the planar surfaces of the bracket. The frame is particularly useful for compound curved surfaces including generally spherical domes. In such configurations the rectangular elongated support members are arranged as latitudes and the round section members as longitudes outside of the rectangular members.

Abstract: A dome shaped structure, and the method of constructing it, are described using curved gore-shaped construction panels which have grooves in their side edges. Rectangular tubular joining members are placed in the grooves, secured therein, and serve to join adjacent panels together. This provides a level surface where the panels are joined so that such adjacent edges of joined panels are even making the interior surface suitable for use as a projection surface.

Abstract: This invention is a beam clamp assembly (100) for use in conservatories where the roof beams (108) radiate from a central part. The beam clamp assembly (100) of the present invention allows use of beams (108) with end surfaces cut at right angles to the longitudinal length of the beam (108).A beam clamp assembly (100) has a base piece (100), a cap piece (12), abutments for beam ends, and means for clamping the base and cap pieces together with the ends of beams (108) held between them. Beams (108) generally slope downwardly away from the assembly. To allow beam ends cut square to lie flush with the abutments, these are correspondingly angled. They may be provided by facets of a polygonal wall (22) or L-shaped abutment pieces (14) than can be exchanged to allow for different slopes.

Abstract: A frame for a projection screen or the like may be fabricated of elongated round tubular members running one direction and polygonal (preferably rectangular) cross section members running in the other direction connected together into a grid by clamps at their intersections. The clamps are parallel plates affixed to the parallel surfaces of the polygonal support members and have a rounded groove in an edge generally conforming to the rounded cross section. Clamp means to hold the round members in the grooves are conveniently formed of U-bolts which are secured to flanges generally normal to the planar surfaces of the bracket. The frame is particularly useful for compound curved surfaces including generally spherical domes. In such configurations the rectangular elongated support members are arranged as latitudes and the round section members as longitudes outside of the rectangular members.

Abstract: An arrangement for interconnecting and supporting a pair of hexagonal building structures includes a pair of common support columns each having a hexagonal shaped connector tube mounted to an upper end thereof. Each connector tube includes apertures in each of the six lateral walls thereof which are adapted for receiving a nut and bolt combination for coupling the tube to the eave beams and roof trusses of two hexagonal building structures. The nut and bolt combinations are hidden from view within the connector tube and adjacent beams to provide a clean, attractive appearance and are not exposed to the elements. The use of common support columns and a common eave beam for adjacent hexagonal building structures simplifies assembly, reduces the number of structural components and building cost, and integrates two or more of such building structure for increased structural strength.

Abstract: A super high-rise tower is disclosed which is formed from a central rigid core supported by a pretensioned cable network.

Abstract: A shell structure comprises a single body of reinforced plastic defining a hollow, open bottom housing member which includes an elongate portion having a substantially parabolic cross-sectional shape and two gables closing the elongate portion at the opposite ends thereof. The gables are inclined towards the central plane of the housing member, and a flange-shaped reinforcement portion extends along the edge of the open bottom of the housing member. The elongate member and the two gables are corrugated such that their corrugations extend substantially perpendicularly to the edge of the open bottom and wherein the corrugations of the elongate portion and the inclined gable extend in the same phase at junctures between the elongate portion and the gables.

Abstract: In an openable roof capable of opening and closing a central space having a certain point, a stationary roof section is arranged in spaced relation to the certain point of the central space. The stationary roof section has an inner periphery which defines the central space. A movable roof section is arranged on the stationary roof section and is radially movable relatively thereto toward and away from the certain point of the central space. The movable roof section is divided into a plurality of movable roof units having their respective apexes which are substantially identical in central angle with each other. In a closed position where the central space is closed by the movable roof section, the apexes of the respective movable roof units are abutted against each other and the movable roof units cooperate with each other to close the central space.

Abstract: A portable shelter especially for leafcutter bee nest, consists of six identical molded plastic panels and a molded roof cap. The panels are fastened together using molded in place tabs and pins to form a circular wall that is domed at the top and capped at the center with the roof cap, also fastened in place with integral pins and holes in a peripheral flange.

Abstract: A polygon-shaped house is composed of a foundation frame having a symmetrical polygonal shape; columns the lower ends of which are connected to the polygon-shaped foundation frame at vertices of the foundation frame; a beam frame disposed over and in parallel with the foundation frame having a polygonal shape similar to that of the foundation frame, said beam frame being connected at its vertices to the upper ends of the corresponding columns; angle rafters whose lower end portions are connected to the beam frame respectively at the vertices of the beam frame and whose upper ends extend obliquely and upwardly toward a position over the center of the beam frame; and a weighty post member supported by the upper ends of the angle rafters, said upper ends being connected to the post member, and exerting downward force on the angle rafters by its own weight. The polygon-shaped house is simple in framework, permits its easy construction, has sufficiently high strength, and provides a wide free space.

Abstract: The vaulted building structure comprises a shell (1) made of a composite construction material and formed of arcuate elements (4) of a uniform width having their ends (5) mounted on a base (3). The shell (1) is shaped as a cylindrical vault of which the vertical axis of symmetry includes a vault ridge (2). The ends (5) of the arcuate elements (4) are hingedly braced to the base (3) for rotation about a horizontal axis parallel with the vertical plane of symmetry. The convex outer surface of each arcuate element (4) has its curvature gradually diminishing lengthwise of the arcuate element (4) towards its ends (5) and ridge (2) for levelling out strains generated in the shell (1) upon rotation of the ends (5) of the arcuate elements (4).

Abstract: A suspended membrane structure, comprising:a plurality of suspending members arranged substantially parallel or substantially radial fashion;a membrane downward hung by a plurality of wire members (or hanging members) from a plurality of points on each suspending member; anda plurality of bracing cables each provided on the membrane in the same direction with that of said suspending member at each middle position between said suspending members, and capable of imparting a tensile force to said membrane.

Abstract: A prefabricated building structure having a dome-shaped configuration and which is made from a plurality of insulating panels is described. Adjacent panels are connected together by means of a locking device and supporting gasket located at the edges of adjacent panels.

Abstract: A set of hexagonal playing pieces, of a shape which when played side to side in beehive pattern create a base, for successive interlocking levels of play. Each player attempts to place his tiles in the most strategically advantageous position.

Abstract: A prefabricated building is provided. The prefabricated building consisting of wall panels having two resilient plates joined by honeycomb core and secured together by an upper frame which secures the top edges of the wall panels, a lower frame which secures the bottom edges of the wall panels and a plurality of connecting members with each connecting member securing two side edges of two corresponding wall panels. A roof is also provided to shelter the joined wall panels.

Abstract: The residential building is composed of an indeformable triangulated framework provided with a covering defining a volume having a triangular, square or hexagonal base and three or four faces whose pitch is greater than 45 degrees and facades or connecting planes between modules, resulting from the division of a pyramid by vertical planes. The apex is provided with a hook intended for the transport of the modules by helicopter.

Abstract: A framework module for a modular building structure has a plurality of elongate frame members (10, 11, 12, 13) assembled to form two inverted V-frames oppositely inclined to the vertical, the two frames defining respective faces of first and second imaginary pyramids (19, 20). When two such modules are assembled together, one of the inverted V-frames of the second module defines an adjoining face of either the first or second pyramid defined by the first module.

Abstract: A plurality of panels of strawboard are erected in a closed figure, preferably a square, on a foundation and their base edges mechanically secured to the foundation. The side edges of the panels are butted together and joined, for instance using tape and adhesive on both faces. A wall cap of novel construction is mounted to the upper edges, and a hip roof, preferably of pyramidal figure and made of corresponding cut panels of like strawboard are fitted in place. The foot of each roof panel fits in the wall cap, and its upper edge typically forms a definition line of the roof hip. The roof panels are similarly united using a tape and adhesive joint. Other types of roofs may be provided but are not presently preferred. In instances where strawboard is available in lesser thicknesses, multiple thicknesses of such thinner material, may be laminated to provide panels which are 4, 6 or more inches in thickness.

Abstract: Ventalation structure for farm storage bins and the like comprising a series of bracing members to hold a bin roof structure above a bin wall structure thereby opening the structure to uniform air circulation. Screening material is provided to prevent bugs and other objects carried by the air from entering the bin and a baffle member protect the ventalation structure from windblown rain and snow. The ventilation structure enables stored commodities to dry faster and minimizes the risk of dust explosions.

Abstract: Integral, elongated panels have sets of converging corrugations arranged on lines defined by folded, transversely triangular elements. These elements extend laterally across the panel, and are dimensioned such that a pair of adjacent parallel side edges of two corresponding panels can mate. Preferably, each corrugation has a planar element arranged on lines generally perpendicular to the side edges defining congruent elements with triangular faces meeting at the apex.By such arrangement, a panel is obtained which in conjunction with other such panels, can produce a curved surface, which curvature may be reversed in direction in any point along a structure surface, by inverting the next adjacent series of panels.

Abstract: Disclosed herein is a dry boat storage building comprising a floor surface having a center, a plurality of substantially vertical outer support columns disposed circumferentially around the center in spaced parallel relationship to one another and having upper and lower ends, a substantially annular boat storage rack disposed circumferentially around the center between the center and the vertical outer support columns, a plurality of elongate rafters respectively extending from a point spaced substantially vertically above the center to the upper ends of the vertical support columns and connected to the boat storage rack between the point and the upper end, a plurality of roof panels disposed over the rafters to form a continuous roof over the floor surface, and a plurality of wall panels disposed around the vertial support columns to form a substantially continuous wall around the boat storage rack.

Abstract: A building for use in harsh environments where drift materials, such as snow, tend to collect against exterior walls. One or more exterior walls formed of wall panels extend upwardly from a base perimeter of the building, and provide a building exterior surface. The surface curves outwardly and upwardly adjacent the base perimeter so that the exterior walls have an undercut region adjacent that base perimeter. The building is portable, and can be dismantled when not being used.

Abstract: A teepee structure having a plurality of circumferentially spaced poles of different lengths forming a conical frame covered by an insulated cover member or skin and mounted upon a cylindrical foundation wall submerged in the ground. The upper end portions of the longest poles are fastened to a top ring member which is covered by a cap member covering the ring member, upper end portions of the poles and the upper end portions of the cover member.

Abstract: A multi-conic shell and a process of creating multi-conic shells from flat materials which are bent and thereby forced into the configuration of continuous regions from oppositely oriented, tangential cones to create variably configured building structures and variably configured lightweight structural panels. The process of creating multi-conic shells from connecting cone segments corresponding to a theoretical array of regular (opening downward) and inverted (opening upward) cones provides an unlimited number of variations for the design of building structures and the design of structural panels. Such multi-conic structures achieve excellent strength to weight ratios by distributing loads into tension and corresponding tetrahedron structures which propogate throughout the shell.

Abstract: A building structure includes an upstanding substantially vertical wall portion constructed from a plurality of interlocking wall sections and forming a closed shape. The wall sections are formed from a thermally insulating material. A retainer band is provided for placement about the periphery of the wall portion, and is adapted to be tensioned to maintain the wall portion in its closed shape. The exterior surface of the wall portion is coated with a concrete-like material, or any other satisfactory weather resistant coating material, to protect the insulating material of the wall sections from weather. A roof structure is adapted to be placed atop the wall portion. In one embodiment, the wall portion is circular in plan, and the roof structure comprises a plurality of wedge-shaped sections, with the base portion of the wedge sections adapted for placement atop the wall portion. The retainer band overlaps the base portion of the wedge sections and interlocks the roof and the wall portion.

Abstract: A central hub carries a main pivotal shaft, on respective sides of which extend pivotal links, to each of which is fixed an end of a truss which trusses can be moved together and parallel when the links are in a straight line for displacement of the structure, and can be spaced and radiating when the links are disposed along a closed contour, for use of the structure.

Abstract: A dome-shaped shelter of a plurality of water-proof foldable light-weight panels. Each panel is of three sections, trapezoidal base and middle sections and a truncated triangular top section with a transverse seam joining the sections. Each foldable panel has lateral flanges on each side. The flange along one side is flat and vertical while the flange on the other side is of an inverted U-shape, so that it can loop over the flat vertical flange on the adjacent panel and a sping clip holding the flanges together. Apertures in the panels form doors or windows therein.

Abstract: A portable swing assembly having a pair of vertically disposed rectangular supports 13, 14 supporting a cross-bar 92 that suspends a porch-type swing 11 therefrom. A horizontal deck 15 is releasably suspended between rectangular supports 13, 14 via screw hooks 31, 31a (FIGS. 4 and 5). A pair of roof panels 16, 17 are supported on vertical roof support(s) 20 with adjustment bars 81, 82 and adjustment screw(s) 87 serving to retain and slidably adjust the relative positions of roof panels 16, 17. Metal corner braces 61 provide positive bracing on the rectangular supports 13, 14 with arch supports 18. The entire swing assembly may be provided in kit form and readily assembled or dismantled by unskilled labor, such as the ordinary homeowner.

Abstract: Integral, elongated panels have sets of converging corrugations arranged on lines defined by folded, transversely triangular elements. These elements extend laterally across the panel, and are dimensioned such that a pair of adjacent parallel side edges of two corresponding panels can mate. Preferably, each corrugation has a planar element arranged on lines generally perpendicular to the side edge defining congruent elements with triangular faces meeting at the apex.By such arrangement, a panel is obtained which in conjunction with other such panels, can produce a curved surface, which curvature may be reversed in direction in any point along a structure surface, by inverting the next adjacent series of panels.

Abstract: A dome-shaped roof structure for a large construction such as an athletic stadium is capable of partly opening according to the environmental conditions such as weather conditions. The dome-shaped roof structure includes a stationary roof section having a central opening and fixedly secured along an outer periphery thereof to the side wall of the large construction, and a movable roof section including a plurality of roof units corresponding to a plurality of divisions of the central opening and each capable of being radially moved between an open position where the roof unit is supported on the stationary roof section and a closed position where the roof unit is supported on a beam in the central opening.

Abstract: A plurality of panels of strawboard are erected in a closed figure, preferably a square, on a foundation and their base edges mechanically secured to the foundation. The side edges of the panels are butted together and joined, for instance using tape and adhesive on both faces. A wall cap of novel construction is mounted to the upper edges, and a hip roof, preferably of pyramidal figure and made of corresponding cut panels of like strawboard are fitted in place. The foot of each roof panel fits in the wall cap, and its upper edge typically forms a definition line of the roof hip. The roof panels are similarly united using a tape and adhesive joint. Other types of roofs may be provided but are not presently preferred. In instances where strawboard is available in lesser thicknesses, multiple thicknesses of such thinner material, may be laminated to provide panels which are 4, 6 or more inches in thickness.

Abstract: A gazebo structure having an octagonal configuration with a base structure comprising corner posts and side panels. The roof comprises a plurality of triangularly shaped roof sections having radially extending beams at edge portions thereof. There is an apex center piece having a plurality of U-shaped mounting brackets, with each bracket receiving therein the apex ends of two adjacent side beams from two adjacent roof sections. The roof sections are prefabricated and can be erected into the completed roof quickly and conveniently.

Abstract: A gazebo and a lean-to shelter have rigid panels with a soft material canopy spread over an arrangement of spokes or ribs. The gazebo has a compression spoke arrangement for holding the canopy in a dome configuration. The spokes of the gazebo include a flat hook underneath each spoke adapted to engage a draw cable at the top periphery of the rigid panels, and a sleeve fits over the end of the spoke and the end of the flat hook to lock the draw cable within the hook. A tip engages the end of the tube and the sleeve to lock it in position on the flat hook. The ribs of the lean-to have a toggle arrangement for extending the ribs when the lean-to shelter has been assembled and to apply tension on the canopy. The end of the toggle is adapted to fit in a rail which in turn also receives the edge of the canopy, and the rail is mounted in a track.

Abstract: An improved dome-type structure having a plurality of load bearing rib elements extending upwards from a base and meeting at a common vertex, a roof deck extending over and supported by these rib elements and vertical side panels are all disposed so as to form an enclosure. The improvement comprises using components for forming the roof deck which are generally trapezoidal and rectangular in shape. The structure is assembled with the interconnection of the trapezoidal and rectangular-shaped components with and without structural ribs which are of inverted T-shape in cross-section. A water trap is provided at one or more places around the base of the structure, and, in locations where there is a scarcity of water, an underground reservoir is provided beneath the structure. The arrangement provides protection against earthquakes and earth tremors.The invention also contemplates the transportation of a complete shell unit under its own power by air lift.

Abstract: A self supporting roof structure comprises a plurality of vertically adjacent circular upwardly inwardly inclining at least partial rings stacked one on another. Each ring comprises a plurality of like horizontally adjacent panels each of which is an aliquot of the ring. Each panel comprises an outer surface which is convex from side to side, upwardly converging rectilinear sides, a concave top plate member, and a convex bottom plate member. The top and bottom plate members in each ring conform to respective upper and lower inwardly downwardly sloping conical surfaces of which the apex coincides with the axis of the roof structure. Preferably, at least one ring has a number of panels which is an integral number greater than one times the number of panels of the ring above.

Abstract: A support structure for forming eave corners on a hipped roof of a steel framed structure comprises a rectangular frame having two triangular sub frames tiltable along their adjacent diagonal sides. The inner corner of the rectangular sub frame is supported above the outer diagonal corner to form triangular planes coplanar with adjacent roof planes on each side of a hip line, the rectangular frame being cantilevered over the corner walls of the building to form an eave corner. The support structure may also be used to form internal or external corners on a verandah roof. A method for constructing hipped roofs on steel frame buildings is also provided.

Abstract: An inexpensive, expandable and easily erected shelter structure. The structure comprises a multi-sided roof supported by a single center upright, the roof being assembled using metal tubes and fittings. A center member is attached to the top end of the upright, the center member supporting a plurality of short tubes for receiving the corresponding ends of a plurality of elongated tube members. The other end of the elongated tube members are each connected to a fitting, each fitting also receiving the ends of two peripheral tubes. The other end of the upright is placed in a pipe sleeve anchored in the ground. A mechanism is provided to secure the roof to the center member. Two or more shelters can be easily interconnected to form larger structures with a minimum of ground support required.

Abstract: Integral, elongated panels have sets of flanges arranged on lines which define folded, transversely triangular elements. These elements extend laterally across the panel, and are dimensioned such that a pair of adjacent parallel side edges of two corresponding panels can mate. The flanges preferably extend along the entire length of the lines defining the folded transversely triangular elements, and may usefully be linear and arranged on lines defining congruent elements with triangular faces, and sloping side edge portions of the panel. By such arrangement, a panel is obtained which in conjunction with other such panels, can produce a curved surface, which curvature may be reversed in direction in any point along a structure surface, by inverting the next adjacent series of panels.

Abstract: A portable shelter for hunting, fishing, storage, and the like, comprises a collapsible base having a regular, polygonal configuration, and a collapsible side wall having a plurality of dihedrally shaped panels mounted on the base. A collapsible roof is supported on the side wall, and comprises a plurality of dihedrally shaped panels which are detachably interconnected to form a pitched roof over the assembled side wall. A door is mounted in one of the side wall panels to permit ingress and egress from the shelter.

Abstract: A domed building structure comprised of panels, convex from side to side, each panel including converging planar side members with straight outer edges, top and bottom planar plate members having curved outer edges, and a convex structural sheet attached to and conforming to the outer edges of the framework of side and plate members, the panels being arranged to form substantially conical frustums stacked one upon another with successively lower angles of inclination, the plate members bisecting the angles between the frustums.

Abstract: A building structure is formed using four by eight foot plywood panels as raw material because of their ready availability. Hexagonal pyramids are formed by first cutting a panel diagonally to form two right triangles. These two right triangles are joined to form a triangular section having a height equal to its base. Six such sections are joined to form the hexagonal pyramids. Pentagonal pyramids are formed by cutting the panels using the eight foot lengths as the dimension of the hypotenuse. Each panel can produce two triangles and they are combined to form an equilateral triangular section. Five of these sections are combined to form each pentagonal pyramid. Reinforcement pyramids are joined in the interior of each pyramid. These are similar to the pyramids they reinforce, but of one half the size. The pyramids are combined using them as substitutes for the plane hexagonal and pentagonal surfaces of regular and semi-regular polyhedrons.

Abstract: An improved dome-type structure having a plurality of load bearing rib elements extending upwards from a base and meeting at a common vertex, a roof deck extending over and supported by these rib elements and vertical side panels are all disposed so as to form an enclosure. The improvement comprises using components for forming the roof deck which are generally trapezoidal and rectangular in shape. The structure is assembled with the interconnection of the trapezoidal and rectangular-shaped components with and without structural ribs which are of inverted T-shape in cross-section. A water trap is provided at one or more places around the base of the structure, and in locations where there is a scarcity of water, an underground reservoir is provided beneath the structure. The arrangement provides protection against earthquakes and earth tremors.The invention also contemplates the transportation of a complete shell unit under its own power by air lift.

Abstract: A prefabricated modular building includes a plurality of lightweight contoured panels which are interconnected. Each of the panels has arcuate top, bottom and side edges so that the panels provide identically sized and contoured segments of an oblate spheroid. A securement mechanism is associated with each of the side edges of the panels and the securement mechanism of adjacent panels are interengaged for securing the panels together. The top edges cooperate and define a circular opening of substantial diameter. A fastening mechanism is associated with the top edge of each of the panels and a compression ring is cooperatively engaged with the fastening system of each of the panels for positively accurately positioning and aligning the panels and for thereby providing a rigid structure.

Abstract: The specification discloses a structural module for forming and protecting an enclosed space over a floor and a method for constructing a structural module. The structural module includes at least three apex hypars joined together at an apex to form the enclosed space with at least three triangular openings formed between the apex hypars and the floor. At least one base hypar is formed between one of the triangular openings in the floor. The apex hypers include a pair of linear wall edges extending upwardly and outwardly from a support point on the floor and a pair of linear roof edges attached at the upper edges of the linear wall edges and being joined at the apex. The base hypar includes a pair of base edges extending along the floor from two of the adjacent support points for the wall edges of the apex hypar to a base point. Two upright edges extend upwardly from the support points and each is coextensive with the linear wall edge of an adjacent apex hypar.

Abstract: A device for sealed attachment of substantially flat-surfaced cover strips, especially of sheet metal, for single- or double-curve roof surfaces of buildings, with top and bottom clamping members, which can be braced for the side attachment of adjacent cover strips by opposing bolts and which can be attached to a supporting frame. The clamping members have flat clamping surfaces to contact the substantially flat-surfaced cover strips and have clamping bolts that extend through openings on the lengthwise edge of at least one of any two adjacent cover strips. Cover rails are attached to the top clamping members and pass therethrough and are clamped by means of crosspieces which feather out to the side, which on their lengthwise edge carry sealing strips pressed against the outsides of adjacent cover strips.

Abstract: A roll-formed frame is provided for portable enclosures of the type comprising a series of screened wall panels with flexible hinges interconnecting the upright edges of the same. The wall panels are arranged into a closed polygon configuration, and support a domed, fabric roof. A pair of flexible cables extend around the top and bottom of the wall panels with retainers interconnecting the same, and retain the wall panels and roof in position. Roll-formed frame segments are interconnected to form the rectangular margin of the wall panels, and include a roll-formed channel in the outer peripheral edge. The channel has a dovetailed shape to interchangeably receive and retain therein a bead portion of the hinge, the fastener cables, and a body portion of the retainers. Preferably, the beads on the flexible hinge have a wedge shape which fits loosely into the side channels, and the cable retainers are symmetrical, so that they can be used on either end of the wall panels.

Abstract: This invention relates to an improved self-adjusting hub and strut-endcap assembly for tent frame roof and wall struts characterized by a two-part hub section sandwiched together in stacked relation to define a set of four sockets, each of which has a channel-shaped entryway which is adapted to receive the socket-forming neck projecting from the ball on the inner end of one of the strut endcaps for limited side-to-side movement therein when in extended position as well as movement between its extended position and a folded position wherein the strut connected thereto lies in nested essentially parallel relation to the other struts of the frame.

Abstract: A solar generator support structure mounting standard photovoltaic panels thereon is disclosed. The solar panels are housed in flat planes (bays and courses) which include a plurality of parallel, symmetrically faceted and stepped areas that are a maximum at the base and over the center of the support structure and which planes define a dome-shaped segment called a hemidome. The planes face upwardly and are stepped, ramped (or a combination thereof) with respect to each other. Single or double axis tracking is provided so that the sun's movement is followed.

Abstract: A solar energy concentrator and collector having a concentrator made up of one or more anticlastic panels that feature a non-developable doubly curved surface. The panels are concave in the north-south direction and convex in the east-west direction. In one embodiment, the panels are formed to have parallel circular arcs in the north-south direction of increasing radius from the center of the panel to its edges and having a curved cross-section in the east-west direction. The concentrator reflects light to a narrow zone of concentration which moves within a plane in response to changes in the angle of incidence of sunlight thereon. A method for forming the specially shaped reflective fiber reinforced plastic panel is also disclosed.

Abstract: A cover and erection method for a tank, sedimentation device or building cover constructed over or within a generally continuous upstanding circular side wall (30), made up of a series of concentric spaced thrust rings (11, 12, 21) having multiple short curved radial beams (14, 19) bridging the annuli between the rings and cover plates (17, 21) extending across the spaces between adjacent ones of the beams between each of the spaced rings. Erection may be from the wall inwardly or from the center to the wall. In either event an intermediate thrust ring is temporarily supported at an elevation above and within the side wall and the beams set across the rings in relatively short radial spans prior to welding of beams and plates to the respective rings. By this technique, small lightweight beams can be utilized for building large-diameter covers or domes with each rise span being of relatively small length.