Trilithic and/or twin shell dome type structures and method of making same

Abstract

Trilithic Shell, Twin Shell, Multiple Shell, Curvilinear Shell as well as Free-formed Structures described herein each employ an inflatable membrane having a peripheral edge secured to an outer foundation base. An ultra-light membrane (air-form) having a network of internal cross connecting restraints is additionally secured to the inner foundation base to permit a novel and unique curvilinear surface. Pressurization then creates the backdrop upon which various urethane layers are applied which when laced with rigidifying tubes become the defining backdrop beneath which numerous cross connecting braces which when snapped into position effectively lock an inner framework to an outer framework thereby producing a self supporting truss like structure both compatible with either current dome construction and / or conventional construction practices. Shotcrete being then sprayed from the interior over said urethane coated backdrop forms highs at framework intersections and natural lows in between followed by the insertion of inflated cell tubes which span the created network of horizontal and vertical cavities are next over sprayed with urethane foam necessary to form the next natural backdrop over which two or more shotcrete / steel reinforced separate yet cross connected planes may be achieved. Such multiple yet independent rigid layers now having thousands of inner-connecting cross braces through which interior voids become natural chase-ways effectively displace 50% or more of what might otherwise be solid concrete as would be the case with all prior art thin shell structures and / or conventional stem wall construction practices. Such Free Formed curve-linear structures effectively reduce material and labor costs by as much as 50%, eliminate snap-through or oil-can buckling tendencies, enhance overall structural capacity, eliminate all height to diameter restraints, permit larger structures, facilitate floor suspension and attachment, and allow mechanical, electrical and HVAC distribution through interior chase-ways which cannot be achieved with prior art concrete thin shell single thickness structures and / or conventional stem wall, construction practices to date.

Description

BACKGROUND OF THE INVENTION [0001] Present invention relates to conventional stem wall construction practices, roof shell construction practices, tunnel construction, and more specifically to concrete dome shell structures which are most commonly referred to as Thin Shell structures within in the industry. [0002] Such structures to date typically have been constructed utilizing numerous and / or various construction methods whereby a single shell thickness of concrete is achieved. Essentially, varying methods of layering dissimilar materials necessary to define the outer dimension of such structures and in particular dome structures have been used for decades by spraying concrete for example to either the inside and / or outside of a form. [0003] Structures for example being typically constructed by inflating an air-form, followed by applying an insulating urethane foam material to the interior of said air-form, followed by securing a reinforcing mesh and / or rebar to said urethane foam ...

AI Technical Summary

Benefits of technology

[0015] b. A novel concept of interconnected cross bracing herein defined as Universal Snap In Standards (USIS Braces) that results in either a free standing “twin shell” dome like 'structure, “multiple shell” or “Trilithic shell” shell like structure, thereby providing far superior load bearing strengths then heretofore obtainable.

[0016] c. The novel insertion of inflated cell tubes thereby creating voids for the exact purpose of eliminating concrete volume whereby significant weight displacement is achieved, thereby causing structural strengths to escalate dramatically, also proves to be a substantial advancement over previous art then heretofore obtainable.

[0019] b. A novel method of levitating floors constructed at ground level up and into position and thereafter quickly connecting said floors to the multiple shell structure in an efficient manner due to the improved structural capacities and weight transference abilities associated using multiple shell assemblies as disclosed herein, then heretofore obtainable.

[0022] Briefly: In constructing such a superior strength multiple shell structure the peripheral edge of a new lightweight air-form typically weighing several times less then conventional air-forms is secured to the base or foundation over which the multiple shells is to be constructed. The lightweight air-form while incorporating slightly oversized stitched tubes or sleeves at designated seams produces an equal distant pattern of support. Once the lightweight air-form is inflated, rigid thin wall urethane or type similar tubes are inserted into said stitched sleeves thereby producing a cross pattern of support after which the insertion of vertical tension lines being first secured to the base foundation while secondly horizontal tension lines are circumferentially strung whereby the combined effect is to both limit and restrain movement of the air-form during the construction process. Thereafter, and upon slightly increasing the air-form interior pressure whereby creating a slight but noticeable exterior cross pattern to emerge on the outer shell, a urethane elastomeric penetrating resin is applied from the inside to both adhere and bind sleeves, seams and inserted urethane tubing together. Once fully cured the lightweight air-form becomes even more stabilized and strengthened after which the first of three additional urethane foam applications in color coded layers are applied successively which insures a more uniform thickness application while permitting one to more easily distinguish between one application and the next.

[0024] Once the outer horizontal and vertical rebar framework has been attached by way of such lengthened hanger brackets the strategic application of Universal Snap In Standards (USIS Braces) serve to create the unique cavity or separation between the outer rebar reinforcement framework and an inner reinforcement framework. Once the inner-most horizontal rebar is snapped into the USIS brace receiver, the inner vertical rebar can be quickly attached thereby causing a multiple shell framework that is virtually self supporting. Shotcrete being then sprayed through the inner framework builds surface thickness over the outer framework and against the light weight and strengthened air-form which has become essentially a backdrop upon which shotcrete is applied, while specific attention is given to applying more shotcrete thickness at intersecting points where the USIS Braces connect to both vertical and horizontal rebar thus reinforcing all such attachment points to the outer shell framework. The resulting appearance will be that of highs and lows in vertical rows around the perimeter of the multiple shell structure. Thereafter flat (un-inflated) cell tube (ribbons of polyethylene film) will be next drawn from the floor upward and between the created rectangular cavities on toward the apex of the structure. After inflation of said cell tubes the voids separating each inflated cylinder will be sprayed with either lightweight 1.5 lb density urethane foam and / or lightweight shotcrete consisting of cement and Styrofoam and less aggregate depending on intended use of said cell tube void. The inner resulting surface once leveled over with urethane foam will appear just as the outer application of urethane foam appeared before the first coating of shotcrete was applied. This new second surface will then receive a second inner thickness of 6,000 PSI shotcrete thereby creating the inner wall of the inner shell portion of a Multiple Shell Type structure.

Problems solved by technology

South then discloses further in his second sentence of page 1 paragraph 3, that: “One drawback to these known dome structures is that they are restrictive in size.

As the inflatable air-form is made larger to produce a larger diameter dome, such as a diameter exceeding 300-400 feet, the higher air pressure required to inflate and raise the heavier form may cause the form to tear.

Such domes South states “have the further disadvantage that they are relatively complex and expensive to make, as compared to a dome structure as disclosed in U.S. Pat. No. 4,155,967 which cannot be constructed in excess of 300′ in diameter”.

South, however, does not emphasize that his U.S. Pat. No. 5,918,438 having both an exterior cables system as well as its massive interior caged ribs system must be first free hand assembled externally, then free hand assembled internally before carefully and artistically spraying literally dozens of successive layers of shotcrete to achieve a dimensionally consistent beam width, one rib at a time—layer upon layer, which is logically more complicated, more time consuming and certainly much more demanding labor wise then any prior art he references to therein, be it U.S. Pat. Nos. 4,442,059, 5,408,793, and / or 4,155, 967.

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