US3885360A

US3885360A - Reinforces inflatable

Info

Publication number: US3885360A
Application number: US511281A
Authority: US
Inventors: Donato M Fraioli
Original assignee: AIR Tech IND Inc
Current assignee: ASATI INTERNATIONAL Inc A DE CORP
Priority date: 1973-07-03
Filing date: 1974-10-02
Publication date: 1975-05-27
Anticipated expiration: 1992-05-27

Abstract

A reinforced inflatable building in which an elongated fabric shell, anchored and sealed to the ground around its periphery, is supported by filling the enclosed volume with air at above atmospheric pressure. The entire outer surface of the building is overlayed with a cable network wherein the individual cables are arranged to form two intersecting sets of parallel cable lines. Each set of cable lines is oriented at an acute angle to the longitudinal axis of the building.

Description

[111 3,885,360 1451 Mayr/,197s

United States Patent [191 Fralol 3,059,655 10/1962 '3.744.191 '7/1973 Bird [5,41 RElNroRcEs INFLA'TABLE [75] lvntor: DhtoMLlf'rloll, Marlnaroneck, I 3 765 134 wlw Gilc-n v NY.

` i I. v i l n. FOREIGN PATENTS'OR APPLICATIONS [73] Assignee:

[22] Filed:

Primary Examiner- John E. 'Murtagh Attorney, Age'nh'or Firm-Gerald Durstewitz Oct. 2,1974

] Appl. No.: 511,281

UNITED STATES PATENTS 3,024,196 3/1962 Bamm... .loclaimfbrawing Figures PATH-NEUW 27 |975 SHEET (210?.4

v 1-loads.

' Anotherobjecty is to'provide such a building includ This invention. relates to inflatable buildings yof' the' type wherein afabric shell is f azrchoredand sealed-to the ground around 'its periphery and the enclosed volurne is filled withair having apressure greater than`at-" mosphericA pressure. The 'shell is lifted bythe internal pressure and takes on a dome like configuration above the ground which forms the lloor of the building.

One conventional form of inflated structure has a central section whichis semi-'cylindrical and has two j SUMMARY oF Trie INVENTION Accordingly, it is an object of the present invention to'provide an improvedreinforced inflatable building capable of withstandinggreater static'and dynamic y, ing'a'cable system which uniformly releaves fabric tension in'alldirections under all conditions.

Another object isl to provide such a building wherein the tension generated inthe fabric skin in all directions by static pressure is greatly reduced.

end sections whichar'e quarter isphjes or truncated segments of duarter'spheres. Theaction ofth'e air pressure on the fabric skinproduces a tensile stress in the fabric skin. Where'theskin takesonacurvedfcongu-` duced by the internalair pressure is directlypropordg. tional to the radius of the c urve.,l`he tensile'stress -in the fabric is also effectedby the4 action of wind againstthe building. Wind loading adds tothe'overall stress of the fabric and also deformsthe lbuildinga'nd'rthereby redistributes the forces within various portions ofl skin.

Another object is to provide such a building highly resistant to deformation and twisting under wind loading v The foregoing objects are accomplished-by providing a reinforced inflatable"buildingcompressing an inflatable fabric skin adapted to be supportedby air pressure within the enclosedvolume'and a plurality of cables arration, as for example,betweenthejtwo edges of .the

semi-cylindrical center section, the. tensile`force`proranged to form first` and second intersecting sets of pargallel'equally spacedl cablelines overlying the entire outer surface of the'skin',`each of the cable lines extending alongthe surface of the skin between peripheral ground`anchors, each cable line extending from its ground anchors at j-'an acute angle to a vertical "plane taken throughthebuilding perpendicular to the surface sonable weight is ca'pable'of'withstanding the pressures v generated by the staticinternal pressure andbywind loading. However,v whenthe 4size lof thesbuilding'is' in-j creased, the radii of the arched portionsinciease and 1 a fabric of reasonable weightwili no -longer'beable to ff carry the forces generated,particularly; under.heavywind conditions. x

lt `has been common practice in fthepast-to -releave the tension in the fabric by ext endi ng' parallel.cables over the outer surface of the skinand ,anchoringthe' ends of the cables to'the ground at the edges of-the building. One type ofcable system previously used consists of a series of parallel cables extending perpendicu lar to the longitudinalaxisof the structure such as shown in U.S. Pat'. No. 3,651,609. Thesecablesreleave DErAILED vDESCRIPTINv 0F THE DRAWINGS I is shown inthefaccompanying drawings, forminga part vof the specification, whereinz' l '.FlG. llis'a side elevational view of areinforced inflat- .able-"building'according .tofthe present 'invent ion`.'f=

' FlG.` 2 is a'elevationalf ,1-Yie`woftheleft end of the I building shown' In` FIG.- 1j. v

FIGjz's Isra top;vewor'thebuilding,shown in FIG. I. FlG.'4 showsa'fcable connector used in the cable netwrkofthe banding shawn In FIGS. 1 3.

the hoop tension generatedinfabricskin andenable the building to withstandza greater degeeofwind loading, however,under.high windloads,thefabric will fail between the cables. lWhen-suelta failuresocc :urs the fabric will rip along a line'paralleltothe cables and the' structure will collapse.

ln other cable systems,l theseitransverse or hoop ca 5 bles have been augmentedbya'series 'of'parallel cables 5 igro und yanchor-bolts.. running longitudinally.- of the structure fromend toend.

Systems of this general'type'are shown in U'.S. ivat'. Nos. l

1,302,182 and l,402,077.

Such two directional cable systems' give added strength to the buildings and under static conditions would help to prevent rips or cuts from propagating cause high stresses in the fabric andfedistributethe` FIG. 5 isa view/ taken along line 5 1- 5 on FlGL4.

FIG. 7g-is anelevationalviewof door installation in a building. according tothe present invention.

DESGRIPTIONGFTHEPREFERRED v 'I MIsoDIIt/IENT.-

` v vR je ferring t o thev drawings in detail, there is shown a reinforced inflatablebuilding according .to the-present invention' which includes, a .fabric skinflanchored .around its peripheryjtofground;anchor bolts and a systern of, interse,ct ing plasticcoated'steelcables overlying .theouter surface ofthe, skinland also anchored to the two end'sectionsifland13which-are in the form of loads on the cables so that ripscan propogate .past the a longitudinal cables causing collapse of the building.

ltruncatedquarterfspheres `and are sewn to the-'section l1,alo' ng lines i4 and-l5 respectively. The section ll is fabricatedfrom a number of fabricfstrips 16 which are sewn togetherf'at their edges and extend transversely or hoop wise'to-the longitudinal axis of the building. The

end sections

12 and 13 each comprise z pair of generally triangularside panels 17 and a gener all'y 1t`riangular end panel 18 which are sewn togethei along lines 1 9 and 2 0. Eachof i these panels are fabri cated froma number of vertically oriented fabric strips 3 t A catenary cable 2l is sewn to fabric pockets in the ground engaging edge of the skin, in accordance with standard practice, and is connected to ground anchor bolts 22 at regularintervals base of the building.

The building is .inflated.byan airblower'unit 2 3@l around'y theperiphery ofthe 4 ln cable section D.c ables 30D to 34D are arranged in a similarmanner to that employed in section C, while in cable sections E and F. the cables are arranged in a mannersimilar to that employed in sections A and B.

through a fabric conduit 24 inaccordancewith stanl dard practice. The cable system is divided into `six`inter 'Aswill be seen mostlearlyin FIG. 3, the cables in leach cable section are aligned rwith cable-portions of like numberlinthe other sections lto form continuous Kcablelines'extending at'equalacute angles to the longiconnected sectionsA, B, C` D, Eand F toI facilitate the clamped rigidly together bycableclamps 25 of conveno tional design and-.the cablesjin` adjoining. sections are interconnected byconnectors26." Cable sections A and B each-cover one half of .theend section12`,".cable sec@ tions C and D` each cover one half "of the center section ll, and the 'cable sections E and F each cover onehalf of the end section 13.

.tudinalaxis of lthe building between ground anchor bolts.f'.1 4 o l As shownin FIGS. 4-6, the connectors 26 include a metal bar 40 provided with a hook 4l ateach end and a piece of fabric tape 42 for attaching the bar 40 to the skin ofthe building. A spring metal strip 44 is attached .to the bar 40 and extends overthe openings ln the -v hooks. The cable is insertedinto the hook by bending the end ofthe spring s'tripf4fl1which then snaps back to .prevent accidental vd' engagement during erection of the' building;t s j The tape 42 is wrapped loosely around the bar 40 and stitched.` along lines 45 and the ends of the tape are As shown in F1os. 1eme cblefseiion Ajneiudes 'f from ground anchor bolts at the end ofthe building up-y wardly and toward the center line ofthe building at an acute angle. At the center of the building,v these cable pass through connectors 26 andmake a right angle turn and extend to the .junction line' 14 between the end building section l2 and the center building section'll. These cables pass through connectors 26at the line 14 and make another rightangle turn and rextend down-v wardly toward the end ofthe building lto ground anchor bolts. Cables 34A.to'37A.'extendfrorn ground anchor bolts upwardly at an acute 'angle towardthe side ofthe building and over the corner ofthe building to anchor' bolts at the side ofthe skin endfsec'tio'n l2. 4

ln cable section' B, the cables 30B to 33B extend up,

wardly from anchorbolts toward the center-of v he stitched to a fabricskin of the'building.

. As shown in'FlG. 7,'one ormore doors can be positioned on the side or end walls ofthe building without weakeningithe cablesystern.`

. By means of a slight'local'modification of the cable system, as shown in FlG. v"l, one or more doorways can be positioned at any convenient positionin the side or fend walls of the building.l .The doorstructure, which may be of any design conventionally used in such buildings, includes a door mounted within a door frame 5l. The cable systemislaltered by removing the portions of the vcables which wouldpass through the door location.l These shortenedgcables are attached. to a header-cableISZ at the pointswhere they are clamped to thecables which intersect with them just above the doorway.- ln' FIG. 7, the cables `which are shortened to accomodate the door-are indicated by the reference building and pass through the sameconnectorswhich 30B to 33B make right angle turns and extend u'pwardly to connectors 26 on the junction line 14 and then downwardly to anchor bolts. Cables 34B to 37B numerals 54 and ',55.' The cables'intersecting `the shortened `cable.'. above'the doorwayare indicated by the reference numerals 5 6'and 57.

The h'eader cablei52ex'tends.upwardly from aground anchorbolt to the junction of

Acables

54 and 56, then extend upwardly and away from the longitudinal center line ofthe building in the same-manner as cables 34A to 37A.

ln cable section C, cables 30C "to33 C extend upwardly to the junction line 14 and' f .pas s.through thehorizontally to the junction of cables 55 and 57, and then downwardly to a ground anchor bolt.

The cables parallel Ito and below the shortened

cables

54 and 5 S1are indicated by reference numerals59 and same connectors 26 which-respectively`hold cables 30A to 33A. From the connectors, thefcables `extend upwardly at an .angle-tothe top of .therbuildin'g where they pass through yconnectors 26 joining the sections C and D and thence downwardly towardthe end-.13ct' the building. The cables 30 C to 32C extend to the junction line l5 where they lpass.through'another set of 'connec tors spaced along the junction-line and areV redirected downwardly towardl the end l2v of the building to ground anchor bolts.Th e cable 33C extends vdirectly from the top of the building toa ground anchor bolt. The cable 34C extends upwardly from "an anchor bolt toward the end 13 of the building and passes through a connector at the top of the building. lt then extends downwardly to a connectoronthe junction line 17 and extends downwardly toward the building end l2 to an anchor bolt.

respectively.'-The endsof lthe cables 59'and 60 are attached to the Vanchorboltsto -which the ends of the header jcable 52 are attached;`

lnzconstruct'ing'th'e, building,.the section ll and the panels l7' and 1 84 ofthe fabric' skin are fabricated from strips of fabric-and `the s ectionsand panels are sewn togetherialon'g `the'line`s. 14,1$, 1 9'and v20. The catenary cable is .sewn into'pocket's'a'roundthe base ofthe building and tliejcon'nectors26.'aresewn tothe fabric skin at 4the-appropriate locations.y Each of the cable sections A-F are laid outon a flat surface and the intersecting cables arelocked together at right angles by the cable clamps 25. p

' The elements of `the building can then be moved to the erection site. In erecting the building, the doorway is anchored in place, the skin is spread .over the ground arid the catenary cable is secured to ground anchor bolts at regular. intervals. The edge of the skin is sealed tothe ground by conventionalmethods and the skin is secured to the door frame.zThe cable sections are then laid over the fabricefskinon the ground andy thefree` ends of the cables are secured to anchor bolts. The cables at the edges of each lsection are then placed inthe hooks of the appropriate-.connectors 26. The blower During fthe finflation'fsoftheskini' the-conne'ctors 26 maintain. the cable" system in properf'orientation with respectto the sk i 1 f The forces generatedv e ly the pressuref within the-in'-I flated', building 'aref largely carried by thecable system." The'fabric skinspanningeach diamond-'shaped aren` bef- Y the surface of the buildingfaf-dimpled effect. Each of thesebalooned sections of fabricassumesa -curvature having a veryv short radiusin all directions. Therefore,4 the stress in the-(fabric. isfsever'ely reduced in all 'clir'ec-y tions. 5 Y .g i...

Each of the cables in the cable systern'is."equallymtensioned by the internal pressure becauseof theirorientav tio'n with rcspect'tofthe longitudinal-axis of Vthebuild- '20 ing. The tension in the'cables-in eachlsectionis transmitted to the cables intheadjoiningsections throughv the connectors 26, whichfare partof the sarne cable lines. s

ln buildings employing cable'systems using cables extending longitudinally yand'tran'sverselythoop wise) with respect tothe longitudinal axis ofthe buildin`g,v"th`c transverse or hoopv cables*are'subjeetedpto' about'twice l the tensionI as are .the longitudinalfcables.The lfabric' was therefore insufficientlyreinforeed one direction 30 and the entiretruct'ure'would-collapse'if the-'stress on 1 the fabric nthat directionexc'eeded thatwhich thefabric couldv withstand. Also, becaus'eo'f this uneven'static loading, such a prior art building is highly subject'to twisting under wind loading -which could transferthey entire tension in one direction from thecables-tfthe fabric. 1

lt has been foundthat a building constructed according to the present inventionis extremely-,stable under wind loading. It is believed thatthis' extreme stability under wind loadingis theresult of aenumber of factors.

Sincethe cablesare equallyfvtensioned:under.static loadingconditions there' are"no inequalities to be'rnagnified by windloading. Wind loads perpendicular tothe side-or the endof the buildingja'reequallyabsorbedlby the intersecting cable line's'be'causethe Cable lines'yare ,L

at equal angles tothe wind.-Wind loads at an'angletog.

the building have components perpendicular to the,side. 'y of the building-andthefehd ofnthebuilding. The "cablejso lines being at equal angles toeach of these components s are equally loaded. v.

The shapefofthe building in cross section cannot change appreciably since inlorderfor the Windward side of the building to be depressedguthe lee side must raise andv this isprevented byfthefcable system. Also, the dimpled surfaceof the building creates turbulent air flow over the entire surface and thereby reduces the relative effect ofthe lift forces Von the' leeV side of the building. q 1 H l,

lt will be seen from the foregoing that the present invention provides an .improved reinforced inflatable building capable of withstanding greater static and dynamic forces in which an improved cable system uniformly releaves fabric tension in all directions under all l l r end of each of the cables in each of said sections ter 'nating at groundanchors at the edge of the section conditions and prevents the building fromdeforming and twisting under wind loading.

l claim:

. 15A reinforced innatable building comprising i combination aninflatable fabric skin anchored to th ground atg' itsperiphery ,and adapted to be sel l l l l 4 l 1 supporting'upon'filling of the interior of thebuildin unit 2,3'is thenj placeclin operationandthe skin inflat'es. 51"

with air'underlpressu're, acable network overlying th outer'su'rface'of said skinr including a plurality of cable lying along first and second'intersecting sets of parallf cable lines,eachof said cable lines extending betwee lperiphfcral ground anchors. mea' ns l for rigidly clampin `the.intersecting cablestogetherat the'points of intel l V l t y section. said cable networkcomprising a number c tween the:l intersecting cables baloons outwardly to give sections interconnected at connection points. and cor nectors provided at said connection points for intel connecting the cables in adjacent cable sections. sai sections comprising a numberof cables which exten alongacable line in one of said sets through a conne( tor at alconnec'tion pointland turn to extend along cable linein the other of said sets,A each end of the c: bles in eachfof said sections terminating at 'ground ai clhorsat thevedgeof' the-section positioned at the pi riphery of thebuilding.

l 2. Afreinforced inflatable building according to claii l, whereinsaid connectors are readily detachable froi at leastgone vof the cables interconnectedthereby.

-3.'A reinforced inflatable building according to clai;

- 2,; wherein said'connectors include hook;| means ft loosely engaging=eachof the cables interconnecte 4 "L-reinforced-inflatablebu'ilding according to clai 3,. whereinsaidlkc'onnectors"include a pair of intercoi .juectedj4 hookmembers and-resilient-means position@ 4 "tonormally close the opening in each hook member allow insertion of a cable therein and to retain the cab therein.

5. A'renforced inflatable building according to clai 4, whereinsaid connectors include a bar member inte l connecting-said -hook members and means for attac ing said b ar member-.to said fabric skin.

6..A reinforced inflatable building, comprising combination an inflatable fabric skin having a recta guiar floor plan including lend sections each in the ge f 4eral vform of a truncated quartersphere, saidskin beii anchored tolthe'groundat its periphery and adaptat to'be self-supporting upon filling of the interior of t .bnilding'withairunder-pressure, a plurality of cabl arranged toform 'a cablt'fnetwork overlying the enti `-'fjout er surfacefl'of 1 the skin,A the cables-in the netwo forming only first and second sets of parallel cable lin extendingover the surface 'of the skin between peri;

l 'eralground"anchors,V said first and second sets of cal llines intersecting substantially at right angles and bei positioned at equalangles to the longitudinal axis said building, and'means for interconnecting the cab at the pointslo'f intersection.

7. A reinforced inflatable building according to cla 6`,.whereinsaid.cable network comprises a number sections interconnected at connection points a wherein connectors are provided at said connecti 4-points for interconnecting the cables in adjacent n work sections, said sections comprising a number of bles which extend along acable line in one of said s through a-connector at a connection point and turn extendalong a .cable'line in the other of said sets` e:

sitioned at the periphery of the building.

8. A reinforced inflatable building according to claim 6, wherein eachof said endl sectionsof saidskinis formed from a triangularendpanel andtworight triangularside panels. said end panel hayingftwoequal 1" sides and a base lying along the peripheral lend edge of the building, each of said side panels hayingits hypotenuse connected to one of said equal sides' of said end panel and having its base lying along ythe end portion of the side of the building.

Claims

1. A reinforced inflatable building comprising in combination an inflatable fabric skin anchored to the ground at its periphery and adapted to be self-supporting upon filling of the interior of the building with air under pressure, a cable network overlying the outer surface of said skin including a plurality of cables lying along first and second intersecting sets of parallel cable lines, each of said cable lines extending between peripheral ground anchors, means for rigidly clamping the intersecting cables together at the points of intersection, said cable network comprising a number of sections interconnected at connection points, and connectors provided at said connection points for interconnecting the cables in adjacent cable sections, said sections comprising a number of cables which extend along a cable line in one of said sets through a connector at a connection point and turn to extend along a cable line in the other of said sets, each end of the cables in each of said sections terminating at ground anchors at the edge of the section positioned at the periphery of the building.

2. A reinforced inflatable building according to claim 1, wherein said connectors are readily detachable from at least one of the cables interconnected thereby.

3. A reinforced inflatable building according to claim 2, wherein said connectors include hook means for loosely engaging each of the cables interconnected thereby.

4. A reinforced inflatable building according to claim 3, wherein said connectors include a pair of interconnected hook members and resilient means positioned to normally close the opening in each hook member to allow insertion of a cable therein and to retain the cable therein.

5. A reinforced inflatable building according to claim 4, wherein said connectors include a bar member interconnecting said hook members and means for attaching said bar member to said fabric skin.

6. A reinforced inflatable building, comprising in combination an inflatable fabric skin having a rectangular floor plan including end sections each in the general form of a truncated quarter sphere, said skin being anchored to the ground at its periphery and adaptable to be self-supporting upon filling of the interior of the building with air under pressure, a plurality of cables arranged to form a cable network overlying the entire outer surface of the skin, the cables in the network forming only first and second sets of parallel cable lines extending over the surface of the skin between peripheral ground anchors, said first and second sets of cable lines intersecting substantially at right angles and being positioned at equal angles to the longitudinal axis of said building, and means for interconnecting the cables at the points of intersection.

7. A reinforced inflatable building according to claim 6, wherein said cable network comprises a number of sections interconnected at connection points and wherein connectors are provided at said connection points for interconnecting the cables in adjacent network sections, said sections comprising a number of cables which extend along a cable line in one of said sets through a connector at a connection point and turn to extend along a cable line in the other of said sets, each end of each of the cables in each of said sections terminating at ground anchors at the edge of the section positioned at the periphery of the building.

8. A reinforced inflatable building according to claim 6, wherein each of said end sections of said skin is formed from a triangular end panel and two right triangular side panels, said end panel having two equal sides and a base lying along the peripheral end edge of the building, each of said side panels having its hypotenuse connected to one of said equal sides of said end panel and having its base lying along the end portion of the side of the building.

9. A reinforced inflatable building according to claim 8, wherein said connectors are formed to be readily detachable from at least one of the cables interconnected thereby.

10. A reinforced inflatable building according to claim 9 wherein said connectors include hook means for loosely engaging each of the cables interconnected thereby.