US3161703A - Method and apparatus for fabricating a roof on large concrete structures - Google Patents

Description

Dec. 1,5, 1964 J. J. WATSON 3,161,703

METHOD AND APPARATUS FOR FABRICATING A Rooi;1

ON LARGE CONCRETE STRUCTURES Filed Feb. 19, 1962 s sheets-shed 1 JAMES J Wasolv ATTORNEYS Dec. 15, 1964 .1. J. wA-'rsoN 3,161,703

METHOD AND APPARATUS FOR FABRICATING A RooF 0N LARGE CC)I\CRE'1`E STRUCTURES 3 Sheets-Sheet 2 Filed Feb. 19, 1962 INVENTOR. JAMES J. Marsan BY n TTQ/fyg Dec. 15, 1964 J. J. wATs N 3,161,703

METHOD AND APPARATUS RoR EABRICATTNG A RooE oN LARGE CONCRETE STRUCTURES Filed Feb. 19, 1962 3 Sheets-Sheet 3 34 I 36 5&9 50 33 30 m 37 35 42 2' `j Y WM 44 INVENTCR. JAMES J. WATSON TTOPIVEVS United States Patent O,

3,161,7@3 METHD AND AKPARATUS FR FABRECATHNG A RQCDF N LARGE CQNCREEE STRUCTURES laines 5. Watson, 4331 Ridgeway Drive, Kansas Qity, Mo. Filed Feb. 19, 1962, Ser. No. 174,229 6 Claims. (Cl. 264-32) This invention relates to supports for forms used in pouring massive concrete structures, and more particularly to improvements in the method and apparatus for supporting roof forms for pouring concrete roofs inplace on very large column free limited interior access constructions.

Heretofore, the method and apparatus used for supporting under or soft forms for pouring in-place massive concrete roof slabs usually required a huge complex of both Vertical and horizontal framing members reaching from the iloor of the construction up to the concrete forms for the roof and necessitated the time-consuming and expensive procedure of progressive cribbing during which shoring members were tied, cross-tied and braced. In assembling such form-supporting structures, each member was assembled individually and generally no fixed combination of members could be employed to accelerate the erection since each job required a different elevation at the top `in order to obtain the particular dimensional requirements of the subsequently poured concrete roof. After the concrete was poured, and obtained selfsupporting strength, each member was disassembled individually and often a great deal of time was required for removal due to limited access to the inside of the concrete construction. It is apparent that the method and apparatus heretofore used for supporting roof forms in large column free limited access constructions was difficult and time-consuming and added materially to the cost thereof.

The principal objects of the present invention are: to provide a method for erecting concrete roof soiit form supports in large tank-like constructions which is substantially less expensive and less time-consuming than heretofore; to provide a removable apparatus for supporting such forms which is simpler in construction and requires considerably fewer parts than heretofore; to provide such a method and apparatus wherein a working deck is maintained between the form-supporting structure and 'he tank bottom to carry workmen and materials in a convenient position for simplifying the support structure assembly; to provide such a method and apparatus wherein a plurality of circumferentially spaced pockets are formed in the construction wall to supply convenient support surfaces not requiring vertical shoring; to provide such a method and apparatus which take advantage of expandable telescopic beams for ease of assembly and disassembly within the construction interior; to provide such a method and support structure which require only a single easily removable self-stabilizing central supporting column having multiple sections for vertical sharing within the tank construction; to provide such a supporting column having a radial flange at the elevation 0f support surfaces formed in the tank wall whereby horizontal longitudinally telescopic beams may be supported at each end thereof; to provide such a supporting column having a circular platform on the top thereof forming an upper bearing ring extending above the tank wall upper edge a distance approximating the height of a frusto-conical roof to be formed, said upper bearing ring being adapted to support the inner ends of radially extending longitudinally telescopic beams supported at the other ends thereof in wall pockets, said beams forming a frustoconical frame structure adapted to supportV a concretereceiving soirlt form deck; and to provide such a method 3,l 5 L7M Patented Dec. l5, 15%64 ice and temporary structure which offers extreme simplicity in dismantling and removal through a conventional central roof opening.

Gther objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illustration and example certain ernbodiments of this invention.

FIG. l is a` cross-sectional view in elevation through a concrete sewage treating digester showing the roof softit form supporting structure in place immediately prior to the dismantling and remo-val thereof, the rear upper telescopic beams thereof not being shown for clarity of illustration.

FlG. 2 is a fragmentary perspective view of the digester of FlG. 1 with a portion of the roof broken away to show details of the roof soiiit form supporting structure and working deck.

FIG. 3 is a fragmentary perspective sectional view through the central supporting column on an enlarged scale, particularly showing the lower and upper beam bearing rings.

FIG. 4 is a fragmentary sectional View on an enlarged scale particularly showing the pockets in the digester wall for receiving and supporting the telescopic beams.

FIG. 5 is a cross-sectional view through a telescopic beam on an enlarged scale showing the locking structure for selectively locking the beams in teiescoped condition.

Referring to the drawings in more detail:

The reference numeral l generally indicates a structure known as a sewage digester which is herein illustrated as an example of one type of construction particularly adapted to benefit from this invention. The digester 1 is essentially a large partially underground tank having overall outside dimensions in the order of SO-feet in height and SO-feet in diameter. The digester 1 is characterized as being entirely of reinforced concrete 2 and, in the illustrated example, has an inverted regular frustoconical floor 3 terminating at the lowermost portion thereof in a small circular platform 4. A wall 5 extends vertically upwardly from the upper terminus 6 of the floor 3 and has an upper horizontal circular edge 7 and a cylindrical inside surface S. A circular vertically extending groove 9 is provided in the upper edge 7 between the inside surface 8 and the wall outside surface 1t) to help form an effective anchor and seal between the edge 7 and the roof 11 now to be described.

The roof 11 is a regularfrusto-conical reinforced concrete member which, after construction, is supported entirely on the wall edge 7 and has a relatively small central opening 12 therethrough, The outer rim or peripheral portion 13 of the roof 11 is generally thicker than the balance of the roof to support the increased shear loads produced as the periphery of the cone is approached. The central opening 12 in the roof 11 is surrounded by a cylindrical integral concrete ring 14.

It is to beiunderstood that the door 3, wall 5 and roof 11 are formed by any one of several conventional methods and structures, and such methods and structures will, therefore, not be referred tto in detail herein. One variation, however, in the conventional design and construction of the wall 5 in practicing the present invention is that an upper group of pockets 15 and a lower group of pockets 16 are formed in horizontally circumferentially spaced relation about the cylindrical inside surface 8 and extend radially outwardly into the wall 5. The upper group of pockets 15 and lower group of pockets 16 respectively form an upper group of ledges 17 and a lower group of ledges 18. The upper ledges 17 are adjacent the wall upper edge 7 and the lower group of ledges 18 are spaced atentos El downwardly from the upper ledges i7, as best illustrated in FIG. 4.

A removable self-stabilizing multiple section supporting column 19 is erected on the platform i of the dige-ster 1 and, in the illustrated example, when completed come prises a lower column section 2d, an intermediate column section 21 and an upper column section 22. The lower column section 2d terminates at the lower end thereof in a radially extending circular flange 23 which rests on the platform 4 and provides independent vertical stabilization for the supporting column 19. It is desirable that a layer of grout 24 be placed between the flange 23 and the platform 4 to aid in adjusting the plumbness of the lower column section 2t? and, after the grout has hardened, maintaining same in plumb. The lower column section 20 is positioned to extend axially of the cylindrical inside surface 8.

A collar 25 is assembled on the upper end of the lower column section Ztl, preferably prior to locating the section 2d on the platform 4. The collar 25 is provided with a plurality of gussets 26 preferably welded in place to add rigidity thereto and is adapted to receive a plurality of bolts 27 for securing thereagainst a flange 28 fixed to the lower end of the intermediate column section 2l.

When assembled, the intermediate column section 21 extends axially with and above the lower column section Z and :the lower and intermediate sections 2t) and 2l 1re free standing without additional support due to the plumbness thereof and the stabilizing effect of the flange Z3.

A collar 30 is assembled on the upper end of the intermediate column section Z1 preferably prior to the coniection of the section 2 with the lower column section Ztl. The collar 3i) is rigidly supported on the intermediate column section 2l by means of gussets 3l preferably welded respectively thereto and contains a plurality of :ircumferentially spaced vertically extending bores 32 adapted to receive bolts 33 extending through a flange 34 rigidly connected to the lower end of the upper column ;ection 22.

Preferably prior to the assembly of the upper column section 22 with the section 2l, a plurality of longitudinally :elescopic lower spanning shores or beams 35 are expanded and supported in the digester i as hereinafter described. l`he collar 30 has a diameter substantially greater than yhe flange 34 producing a horizontally extending lower )caring ring 36 which is positioned at the elevation of ,he lower group of ledges 18 as best illustrated in FIG. l. The beams 35 are inserted into the digester interior ',hrough the open top (in absence of the roof ll) and ex- )anded in systematic opposition into supported Contact at he inner ends 37 thereof and outer ends 38 thereof re- ;pectively on fthe lower bearing ring 36 and lower ledges i3. The beams are preferably placed in regular circumerentially spaced radial relation about the intermediate :olumn section 2li. The inner ends 37 and outer ends 38 3f the beams 35 respectively have lip portions 39 which Jrovide areas of contact with lthe bearing ring 36 and :he lower ledges l.

The beams 35 may be of any suitable longitudinally expandable type, however, inthe illustrated example, each :omprises two telescoping end members il@ and 41 of -elatively light weight plate steel and a lattice central nember 42 adapted to slidably receive the members iii and 41 at each end thereof. Eyebolts 43 adjacent each 2nd of the lattice member 42 and operably connected vith friction plates 44 permit longitudinally slidable adustment of the members 44B and di with respect to the attice member 42 to change the overall length of the :earn 35 and also provides a suitable lock between the nembers when the desired length is obtained. When he beams 53 are expanded into the desired positions, the ip portions 39 on the inner ends 37 are preferably spot velded to the lower bearing ring 36 at 45 and grout lo s placed in the lower pockets 16 adjacent the lip portions 39 at the outer ends 38 to temporarily stabilize the respective beams 35 and prevent a possible shifting out of their desired positions. Prior to the stabilizing of the respective beams 35, it is desirable that the plumbness of the lower and intermediate column sections Ztl and 2l be checked to insure the proper subsequent centering of the concrete soft molds or forms more fully described hereinafter.

A plurality of planks 47 are laid over and between the lower beams 35 to form a plank decking or working deck d adapted to conveniently support workmen, tools and material (all not shown) for completing the construction.

The upper column section 22 is assembled with the intermediate column section 2l preferably after the working deck i8 is installed. rEhe section 22 is provided with a circular platform 49 on the top thereof greater in diameter than the flange 23, collar 25 and collar 3i) and forming an upper bearing ring 5d extending above the wall upper edge 7 a distance approximating the height of the frusto-conical roof lll. A plurality of vertically extending gusset plates 5l are secured to the upper column section 22 preferably by welding and extend radially outwardly thereof in circumferentially spaced relation forming access passageways 52 with the open interior 53 of the upper bearing ring 5d. The passageways 52 extend into the interior of the digester 1 from the outside thereof. The upper bearing ring 5t) has a peripheral downwardly extending outer lip 54 welded thereto for additional rigidity and also a plurality of circumferentially spaced radial plates 55 adapted yto be secured to the respective gusset plates 5l, in the illustrated example by bolts 56. A suitable bearing block, in the illustrated example a wooden ring 57, has inside and outside diameter dimensions whereby it is adapted to rest on the upper bearing fing 50 without overlap on the periphery thereof or obstruction of the access pasasgeways 52. The ring 57 has the upper edge 58 thereof sloping conically downwardly and outwardly at approximately the same angle as the roof 11 to be formed.

A plurality of bearing blocks 59 are inserted into the upper group of pockets 15 and rest upon the upper ledges 17 thereof. The blocks 59 preferably have the upper edge or surface 6i) thereof sloping downwardly and outwardly of the diges'ter l at an angle which approximates the intended slope of the roof lll.

A plurality of longitudinally telescopic upper spanning shores or beams 6i similar to lthe beams 35 are inserted into the open top of the digester 1 and temporarily expanded into supported contact at the inner ends 62 and outer ends 63 respectively thereof on the wooden ring 57 and bearing blocks 59. As indicated in FIG. 2, when the upper beams 6l are locked into position, a frusto-conical frame structure 64' is quickly and easily produced. A plurality of supporting cross members 65 are then laid transversely of the respective upper beams dl and a soiiit form deck 66 is secured thereover in the conventional manner for producing the mold which will subsequently form :the under side of the roof il. Central opening forms 67 adapted to produce a conventional central opening of greater diameter 'than the upper bearing ring 50 are secured to the form deck do in the usual manner and suitably braced with supports 68 for maintaining the central opening forms in fixed position with respect to the form deck when-'the concrete is subsequently poured therearound. The roof outer surface forms and supports therefor (not shown) are completed in a conventional manner and the entire roof 11 may be poured as a unit or in sections as desired. Y

After the concrete in the roof 1l has reached selfsupporting strength, the dismantling of the above-described form supporting structure may proceed. ingress and egress of men, tools and materials are conveniently maintained through the open access passageways 52. Al-

though several different sequences of steps may be used in the dismantling procedure, it is generally desirable to first collapse the upper beams 61, laying same on the Working deck 48, and coincidentally therewith removing the cross members 65 and form deck 66. After removal of the central opening forms 67, the upper column section 22 may be unbolted from the intermediate column section 21 and removed axially upwardly from the digester 1 through the central opening 12. The central opening 12 then provides a convenient passageway for the removal of the upper beams 61 and form deck parts resting on the working deck 48. The progressive dismantling and removal of the working deck, lower beams 35 and the remaining sections of the supporting column 19 may then be accomplished quickly without the need for complex procedures.

It is to be understood that the invention above-described does away with the need for the expensive, timeconsuming, cumbersome, complex of vertical shoring heretofore required for similar construction jobs, and in its place provides a simple, fast and eicient structure and method which results in considerable time and labor savings. An important feature of this invention is the use of the previously formed wall or walls of the structure for carrying the roof loading at the time of pouring, thereby utilizing said walls to an immediate advantage for a function which they ultimately have to assume anyway, since in practically all building structures the walls carry at least part of the roof load and with construction similar to the illustrated example, all of the roof load. The invention is well adaptable to other shaped roofs such as flat or inverted cone constructions. The working deck may be installed at any convenient level and nds additional utility, for example, in the undercoating of the roof after the forms are removed.

It is to be further understood that While one example of this invention has been illustrated and described, it is not to be limited to the specific form, method or arrangement of parts herein described and shown except insofar as such limitations are included in the claims.

What I claim and desire to secure by Letters Patent is:

1. The method of supporting a roof soit form deck while fabricating large structures of the type in the order of about 50 feet in width and having a floor and a concrete roof and a wall with an upper edge and an inside surface, said method comprising the steps of:

(a) providing a group of circumferentially spaced members on said wall and having ledges adjacent said wall inside surface and near said wall upper edge,

(b) erecting in sections a temporary supporting rigid column in upright relation on said iioor at the vertical center of the structure with a spread of engagement of the column with the floor that the column is self-stabilizing,

(c) assembling bearing means on said column forming a supporting surface extending around and outwardly of said column at an elevation approximating the height of at least a portion of said roof,

(d) temporarily expanding a plurality of longitudinally telescopic beams into supported contact at opposite ends thereof respectively on said bearing means supporting surface and said ledges, said beams being rigid and circumferentially spaced and extending radially from the column and producing a form supporting frame structure, and

(e) laying the form deck on said frame structure, whereby the entire vertical support for said form deck is provided by said column and wall through said beams.

2. The method of supporting a roof sotiit form deck while fabricating large structures of the type in the order of about feet in width and having a oor and an at least partially surrounding wall with an upper horizontal edge and an inside surface and a generally frusto-conical concrete roof supported entirely on said edge and having a central opening therethrough, said method comprising the steps of:

(a) forming a group of circumferentially spaced integral members in said wall having ledges adjacent said wall inside surface and near said wall upper edge,

(b) positioning a lower section of a temporary multiple section rigid supporting column in upright relation on said tloor substantially at the vertical center of said structure with a spread of engagement of a base on said lower section with the oor that the column is self-stabilizing,

(c) moving additional column sections onto said lower column section and securing them in end to end alignment,

(d) temporarily assemblingV an upper column section axially of said lower column section and provided with a platform of greater diameter than said column forming a bearing ring surface above said wall upper edge a distance approximating the height of said roof,

(e) temporarily expanding a plurality of longitudinally telescopic beams into supported contact at opposite ends thereof respectively on said bearing ring surface and said ledges with said beams being rigid and circumferentially spaced and extending radially from `said bearing ring producing a frusto-conical form supporting frame structure, and

(f) laying the form deck including a central opening form of greater diameter than said bearing ring on said frame structure, whereby the entire vertical support for said form deck is provided by said column and wall through said beams and said column and beams are removable through said central opening.

3. The method of constructing the support for a roof soit form deck during the fabricating of large structures of the type in the order of about 50 feet in width and having a floor and a concrete roof and a wall with an upper edge and an inside surface, said method comprising the steps of:

(a) forming ladjacent said inside surface an upper group of .circumferentially spaced pockets having ledges located at a level adjacent said wall upper edge and a lower group of spaced pockets having ledges located at a level downwardly from said upper ledges,

(b) erecting a temporary self-stabilizing rigid supportting column in upright relation on said oor,

(c) positioning said column substantially at the vertical center of said structure,

(d) assembling lower bearing means on said column at the level of said lower ledges forming a supporting surface around and outwardly of said column,

l (e) temporarily expanding a plurality of longitudinally telescopic lower beams into supported contact at opposite ends thereof respectively on said lower bearing means supporting surface and on said lower ledges in circumferentiallyspaced relation about said column, said beams being rigid and extending radially of the column producing a deck supporting structure,

(f) laying a working deck on said lower beams,

(g) assembling upper bearing means with said column at an elevation approximating the height of at least a portion of said roof,

(h) temporarily expandinga plurality of longitudinally telescopic upper beams into supported contact at opposite ends thereof respectively on said upper bearing means and said upper ledges with said upper beams being rigid and circumferentially spaced and extending radially from said bearing means producducing a form supporting frame structure, and

(i) laying the form deck on said frame structure, whereby the entire vertical support for said working deck and form deck is provided by said column and wall through said upper beams.

4. The method of fabricating large concrete tank structures of the type in order of about 50 feet in width and having a floor and a vertically extending wall with an upper horizontal circular edge and a cylindrical inside surface and a regular frusto-conical roof supported entirely on said edge and having a central opening therethrough, said method comprising the steps of:

(a) forming said floor,

(b) forming said wall in contact with said iioor and with an upper and a lower group of circumferentially spaced pockets horizontally extending radially outwardly from said cylindrical inside `surface into said walls and respectively presenting an upper group of spaced ledges at a level adjacent said wall upper edge and a lower group of spaced ledges located at a level downwardly from said upper ledges,

(c) erecting a lower section of a temporary multiple section rigid supporting column in upright relation on said oor with a spread of engagement of the column with the door that the column is self-stabilizlng:

(d) positioning said lower column section axially of said cylindrical inside surface,

(e) assembling a collar on said column provided with a horizontally extending radial flange at the level n of said lower ledges forming a lower bearing ring,

() temporarily expanding in systematic opposition a plurality of longitudinally telescopic lower beams into supported Contact at opposite ends thereof respectively on said lower bearing ring and on said lower ledges in regular circumferentially spaced radial relation about said intermediate column section, said lower beams being rigid,

(g) temporarily securing said lower beams at points of supported contact on said lower bearing ring and said lower ledges,

(h) laying .a working deck on said lower beams,

(i) assembling an' upper column section with said column and provided with a circular platform on the top thereof greater in diameter than said column and forming an upper bearing ring extending above said wall upper edge a distance approximating the height of said roof,

(j) temporarily expanding a plurality of longitudinally telescopic upper beams into supported contact at opposite ends Vthereof respectively on said upper bearing ring and said upper ledges, said upper beams being rigid and circumferentially spaced and extending radially from said bearing ring producing a frustoconical frame structure, v f

(k) laying a softit form deck including a central opening form of greater diameter than said upper bearing ring on said frame structure,

(I) pouring concrete over said form deck forming said roof, f

(m) permitting said concrete to reach self-supporting strength,

(n) dismantling said frame structure and form deck and upper column section between said roof and said working deck,

(o) removing said frame structure and form deck and upper column section from said tank through said central opening,

(p) dismantling said working deck and lower beams,

and

(q) removing said working deck and lower beams and balance of said column through said central opening.

5. A structure adapted to support a soilt form deck tor molding a concrete frusto-conical roof on a large con- :rete tank in the nature of 50 feet in diameter and of the ype having a iioor and a vertically extending wall having in upper horizontal circular edge and a cylindrical inside surface, said frusto-conical roof after formation being iupported entirely on said edge and having a central openng therethrough, said structure comprising:

(a) an upper andra lower group of circumferentially spaced pockets horizontally extending radially outwardly of said cylindrical inside surface into said walls and respectively presenting an upper group of ledges at a level adjacent said wall upper edge and a lower group of ledges at a level spaced downwardly from said upper ledges,

(b) a removable self-stabilizing multiple section supporting column having a rigid lower section positioned in upright relation on said floor axially of said cylindrical inside surface,

(c) an intermediate rigid column section assembled axially with and extending above said lower column section,

(d) a collar on said intermediate column section provided with a horizontally extending radial flange at the level of said lower ledge and forming a lower bearing ring,

(e) a plurality of longitudinally telescopic lower rigid beams supported and temporarily secured at opposite ends thereof respectively on said lower bearing ring and on said lower ledges in regular circumferentially spaced radial relation about said intermediate column section,

(j) a working deck resting on said lower beams,

(g) an upper rigid column section assembled axially with said intermediate column section and provided with a circular platform on the top thereof greater in diameter than said column and forming an upper bearing ring extending above said wall upper edge a distance approximating the height of said roof,

(h) a plurality of longitudinally telescopic upper rigid beams supported at opposite ends thereof respectively on said upper bearing ring and said upper ledges in regular circumferentially spaced radial relation producing a truste-conical frame structure,

(i) said frame :structure being adapted to support said form deck including a central opening form of greater diameter than said upper bearing ring,

(j) whereby said frame structure and form deck and upper column section may be dismantled and removed through said central opening prior to the dismantling -and removal through said opening of said working deck and lower beams and intermediate and lower column sections.

6. A structure adapted to support a soflit form deck for molding a concrete frusto-conical roof on a large concrete tank of the type having a floor and a vertically extending wall having an upper horizontal circular edge and a cylindrical inside surface, said frusto-conical roof after formation being supported entirely on said edge and having a central opening therethrough, said structure comprising:

(a) a group of circumferentially spaced pockets horizontally extending radially outwardly of said cylindrical inside surface into said walls and respectively presenting a group of ledges at a level adjacent said wall upper edge,

(b) a removable self-stabilizing multiple section supporting column having a rigid lower section positioned in upright relation on said iioor axially of said cylindrical inside surface,

(c) an upper rigid column section assembled axially with said lower column section and provided with a circular platform on the top thereof greater in diameter than said column and forming an upper bearing ring extending above said wall upper edge a distance approximating the height of said roof,

(d) a plurality of longitudinally telescopic upper rigid beams supported at opposite ends thereof respectively on said supper bearing ring and said ledges in regular circumferentially spaced radial relation producing a frusto-conical frame structure,

(e) said frame structure being adapted to support said form deck including a central opening form of great- 975,525 er diameter than said upper bearing ring, 1,016,485 (f) whereby said frame structure and form deck and 1,584,658 column may be dismantled and removed through said 1,891,160 central opening. 5 2,7 05,359 2,901,809 References Cited by the Examiner 3,072,996

UNITED STATES PATENTS 1@ Harshbarger 25-124 Elsmere 25--124 Rutten 25-124 Iespersen 264-32 Strandberg 264-32 Ciesla 25-124 McGuire 25--1315 ALEXANDER H. BRODMERKEL, Primary Examiner.

4 10 MICHAEL V. BRINDISI, ALEXANDER H. BROD- MERKEL, Examiners.

Claims (2)

1. 2. THE METHOD OF SUPPORTING A ROOF SOFFIT FORM DECK WHILE FABRICATING LARGE STRUCTURES OF THE TYPE IN THE ORDER OF ABOUT 50 FEET IN WIDTH AND HAVING A FLOOR AND AN AT LEAST PARTIALLY SURROUNDING WALL WITH AN UPPER HORIZONTAL EDGE AND AN INSIDE SURFACE AND A GENERALLY FRUSTO-CONICAL CONCRETE ROOF SUPPORTED ENTIRELY ON SAID EDGE AND HAVING A CENTRAL OPENING THERETHROUGH, SAID METHOD COMPRISING THE STEPS OF: (A) FORMING A GROUP OF CIRCUMFERENTIALLY SPACED INTEGRAL MEMBERS IN SAID WALL HAVING LEDGES ADJACENT SAID WALL INSIDE SURFACE AND NEAR SAID WALL UPPER EDGE, (B) POSITIONING A LOWER SECTION OF A TEMPORARY MULTIPLE SECTION RIGID SUPPORTING COLUMNS IN UPRIGHT RELATION ON SAID FLOOR SUBSTANTIALLY AT THE VERTICAL CENTER OF SAID STRUCTURE WITH A SPREAD OF ENGAGEMENT OF A BASE ON SAID LOWER SECTION WITH THE FLOOR THAT THE COLUMN IN SELF-STABILIZING, (C) MOVING ADDITIONAL COLUMN SECTIONS ONTO SAID LOWER COLUMN SECTION AND SECURING THEM IN END T END ALIGNMENT, (D) TEMPORARILY ASSEMBLING AN UPPER COLUMN SECTION AXIALLY OF SAID LOWER COLUMN SECTION AND PROVIDED WITH A PLATFORM OF GREATER DIAMETER THAN SAID COLUMN FORMING A BEARING RING SURFACE ABOVE SAID WALL UPPER EDGE A DISTANCE APPROXIMATING THE HEIGHT OF SAID ROOF, (E) TEMPORARILY EXPANDING A PLURALITY OF LINGITUDINALLY TELESCOPIC BEAMS INTO SUPPORTED CONTACTED AT OPPOSITE ENDS THEREOF RESPECTIVELY ON SAID BEARING RING SURFACE AND SAID LEDGES WITH SAID BEAMS BEING RIGID AND CIRCUMFERENTIALLY SPACED AND EXTENDING RADIALLY FROM SAID BEARING RING PRODUCING A FRUSTO-CONICAL FORM SUPPORTING FRAME STRUCTURE, AND (F) LAYING THE FORM DECK INCLUDING A CENTRAL OPENING FROM OF GREATER DIAMETER THAN SAID BEARING RING ON SAID FRAME STRUCTURE, WHEREBY THE ENTIRE VERTICAL SUPPORT FOR SAID FORM DECK IS PROVIDED BY SAID COLUMN AND WALL THROUGH SAID BEAMS AND SAID COLUMN AND BEAMS ARE REMOVABLE THROUGH SAID CENTRAL OPENING.
2. 6. A STRUCTURE ADAPTED TO SUPPORT A SOFFIT FORM DECK FOR MOLDING A CONCRETE FRUSTO-CONICAL ROOF ON A LARGE CONCRETE TANK OF THE TYPE HAVING A FLOOR AND A VERTICALLY EXTENDING WALL HAVING AN UPPER HORIZONTAL CIRCULAR EDGE AND A CYLINDRICAL INSIDE SURFACE, SAID FRUSTO-CONICAL ROOF AFTER FORMATION BEING SUPPORTED ENTIRELY ON SAID EDGE AND HAVING A CENTRAL OPENING THERETHROUGH, SAID STRUCTURE COMPRISING: (A) A GROUP OF CIRCUMFERENTIALLY SPACED POCKETS HORIZONTALLY EXTENDING RADIALLY OUTWARDLY OF SAID CYLINDRICAL INSIDE SURFACE INTO SAID WALLS AND RESPECTIVELY PRESENTING A GROUP OF LEDGES AT A LEVEL ADJACENT SAID WALL UPPER EDGE, (B) A REMOVABLE SELF-STABILIZING MULTIPLE SECTION SUPPORTING COLUMN HAVING A RIGID LOWER SECTION POSITIONED IN UPRIGHT RELATION ON SAID FLOOR AXIALLY OF SAID CYLINDRICAL INSIDE SURFACE, (C) AN UPPER RIGID COLUMN SECTION ASSEMBLED AXIALLY WITH SAID LOWER COLUMN SECTION AND PROVIDED WITH A CIRCULAR PLATFORM ON THE TOP THEREOF GREATER IN DIAMETER THAN SAID COLUMN AND FORMING AN UPPER BEARING RING EXTENDING ABOVE SAID WALL UPPER EDGE A DISTANCE APPROXIMATING THE HEIGHT OF SAID ROOF, (D) A PLURALITY OF LONGITUDINALLY TELESCOPIC UPPER RIGID BEAMS SUPPORTED AT OPPOSITE ENDS THEREOF RESPECTIVELY ON SAID SUPPER BEARING RING AND SAID LEDGES IN REGULAR CIRCUMFERENTIALLY SPACED RADIAL RELATION PRODUCING A FRUSTO-CONICAL FRAME STRUCTURE, (E) SAID FRAME STRUCTURE BEING ADAPTED TO SUPPORT SAID FORM DECK INCLUDING A CENTRAL OPENING FORM OF GREATER DIAMETER THAN SAID UPPER BEARING RING, (F) WHEREBY SAID FRAME STRUCTURE AND FORM DECK AND COLUMN MAY BE DISMANTLED AND REMOVED THROUGH SAID CENTRAL OPENING.

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