US3552076A - Concrete form - Google Patents

Abstract

A SELF-SUPPORTING CONCRETE FORM OF RIGID, LOW-DENSITY FOAMED PLASTIC ADAPTED TO BE LEFT IN PLACE TO PROVIDE INSULATION FOR A WALL FORMED OF A PLURALITY OF SUCH FORMS WHCH HAVE BEEN FILLED WITH CONCRETE. THE FORMS HAVE VERTICAL CAVITIES EXTENDING THERETHROUGH AND LONGITUDINALLY EXTENDING CHANNELS SO AS TO PROVIDE VERTICAL COLUMNS OF CONCRETE INTERCONNECTED BY INTEGRAL HORIZONTAL CONCRETE BEAMS.

Description

- Jan 1971 w. K. H. GREcaoRl4 I 3,552,075

CONCRETE FORM Filed oct. 24'; 196e l s sheets-Sheet 2 w. K; H. GREGoRl CONCRETE FORM Jan. '5, 1971 t. 6 Sheets-Sheet 3 .0. ..U..O....O.

FIGA

W.v K. H. GREGORI CONCRETE FORM Jan. s, 1971 v 6 Sheets-Sheet A Filed om'. 24, 196e 311.51971 I MGR'EGQRI 3,552,016

CONCRETE FORM Filed o'c';V 24,-]1968 s sheets-sheet s leo p I 75 A |52 I 86 /lso 6 Sheets-Sheet 6 Jan. 5,1911 w. K. H. GREGORI h CONCRETE FORM Fileaocx. 24, 196e 'ooo l f MOOOi W55 O O 0.5:'

Nt f E United States Patent Office Patented Jan. 5, 1971 ,523 Int. Cl. E041) 2/20; E04c 2/20 U.S. Cl. 52-309 10 Claims ABSTRACT F THE DISCLOSURE A self-supporting concrete form of rigid, low-density foamed plastic adapted to be left in place to provide insulation for a wall formed of a plurality of such forms which have been filled with concrete. The forms have vertical cavities extending therethrough and longitudinally extending channels so as v`to provide vertical columns of concrete interconnected by integral horizontal concrete beams.

This application is a continuation-in-part of U.S. patent application Ser. No. 580,912 filed on Sept. 21, 1966, now abandoned; which in turn was a continuation-impart of patent application Ser. No. 569,908 filed Aug. 3, 1966, now abandoned.

This invention is related to a concrete forming system.

In known concrete structures various forming systems are used to hold wet concrete in place until cured. These forming systems have a number of parts. The parts are made of different materials such as steel, aluminum, cement, cinder, wood, ber glass, paper, plastic and plastic foam. For example plastic coated plywood forms having a metal or wood frame and steel snap ties and steel wedges may be used. These combinations of different parts and materials create a forming system which performs only one function that of holding wet concrete in place until set. Skilled labour is required to erect this type of forming system resulting in high cost of construction. Removal of forms requires time and delays other trades such as plumbers and electricians. Furthermore if concrete is poured when the temperature drops below freezing it is necessary to provide temporary enclosures, heating and insulation. In addition the tie wires or snap ties create thermal bridges in the wall.

The prime object of this invention is the provision of a concrete forming system comprising one piece which is fromed from a single material.

Another object is the elimination of thermal bridges.

A further object is the provision of self-supporting form which does not require bracing, tie wires or shoring.

Another object is the provision of a form which eliminates the need for heating and temporary insulation when concrete is poured at low temperatures. Furthermore the concrete cures under ideal conditions and reaches design strength in a shorter period thereby allowing construction to proceed more quickly.

A further object of the invention is the provision of a form which is left in place to perform the function of permanent insulation and a vapor barrier on both sides of the concrete in the wall. It is therefore unnecessary to provide temperature steel to take up the stresses created by a temperature differential between the inner and outer faces of the wall.

Another object is the provision of a forming system comprising units molded by machine so as to provide a high degree of accuracy at low cost so that the form can be quickly erectedrby unskilled workmen.

A still further object is the provision of a form which provides a base for a great variety of wall finishes such as plaster gypsum board, ceramic tiles and plywood panels.

This invention provides a concrete form which includes two spaced transverse `walls extending from one longitudinal wall to the other to form a rigid structure defining a hole between the walls, the walls being of foamed polymeric material, and at least one pair of corresponding edges of the transverse walls being inwardly spaced from adjacent edges of longitudinal walls so as to provide a longitudinal beam of concrete integral with a column of concrete in the hole when concrete is poured into a plurality of assembled forms.

In the drawings which show preferred embodiments of the invention,

FIG. 1 is a perspective view of three building units in accordance with this invention;

FIG. 2 is a top plan view of a corner unit;

FIG. 3 is a sectional end elevational view of a wall incorporating building units in accordance with this invention;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3;

FIG. 5 is a top plan view of molded building units or blocks in accordance with this invention for use in building walls;

FIG. 6 is a perspective view of the building unit of FIG. 5;

FIG. 7 is a sectional view of a wall structure made from building unit of FIG. 5;

FIG. 8 is a section taken along the line 8 8 of FIG. 7;

FIG. 9 is a form similar to that of FIG. 6 for use in building walls;

FIG. 10 is a top plan view of the form of FIG. 9;

FIG. ll is a fragmentary end View showing the tongue and groove joint provided between two forms of the type shown in FIG. l0; and

FIG. 12 is a side elevational view of the form of FIG. 9.

The permanent insulating form unit 10, according to FIG. 1, comprises two longitudinal walls 11 and two transverse end walls 12 and partition walls 13 within the unit 10 which divide the space formed by the longitudinal and transverse walls 11 and 12 into six compartments 14. Transverse walls 12 and partition walls 13 are recessed on top and bottom at 15 to form beams 19 (FIG. 3) through the entire wall of a given structure. Recesses 16 in transverse walls 12 and partition walls 13 shown in FIG. 1 are provided to hold horizontal steel reinforcing rods 17 (FIGS. 3 and 4) in place without tying. The units 10 are made from foamed polystyrene and are placed in layers and bonded with a water and frost resistant binding material o'n all joints to prevent penetration of air and water. The superposed permanent insulating form units 10, when filled with reinforced concrete 18 by hand or machine, create a reinforced concrete wall with insulation on two sides. The recesses 15 in the two transverse walls 12 and in the partition walls 13 are located on top and bottom of the unit 10 which enables the unit 10 to be reversed.

As shown in FIG. 1, the building unit 10 is preferably provided with interior and exterior side panels 26 and 27 respectively secured thereto as by adhesive or the like. The interior wall surface 26 may be gypsum wall board for example, and the exterior wall 27 may be impregnated fiber board. These panels provide extra strength as well as providing a surface for painting or plastering.

If gypsum board is used, the joints between panels may be taped in the conventional manner.

It will be noted that the side panels 26 and 27 are offset with respect to the wall of the building unit so as to provide an overlap with adjacent building units, thus facilitating aligning of the building units. The units may be provided with a finish coat of stucco, thin veneer brick 28, conventional brick-29 or any suitable weather resistant decorative material, as shown in FIG. 3.

It will also be appreciated that the building units 10 may be fabricated in various sizes including floor to ceiling panels for use in homes or other smaller structures.

In FIG. 2, a corner unit is shown for use in conjunction with the wall unit 10. The corner unit 50 includes spaced apart side walls 51 and 52, end walls 53 and 54 and partition walls 55. The partition walls 55 have the same vertical dimensions as the partition walls 13, described above, and are provided with recesses 16 to receive the horizontally extending reinforcing steel 17. Panels 58, 59, and 61 of gypsum board, fiber board or the like are provided on the side walls 51 and 52 in the same manner as the panels 26 and 27, described with reference to FIG. l.

It will be appreciated that although the wall form unit 10 is described and illustrated as having interior and exterior side panels 26 and 27 secured thereto, the form unit 10 can be prefabricated without the side panels. However, if no side panels 26 and 27 of gypsum board or the like are provided on the form unit 10, the edges of the longitudinal walls should be adhesively secured to the mating edges of adjacent wall form units to prevent seepage of the liquid concrete. Whereas, in the case of the form unit 10, gluing is not essential.

The use of expanded beads of polystyrene or expanded polystyrene foam provides a number of advantages. These advantages include its lightweight and good dimensional stability under varying temperature and moisture conditions. The expanded polystyrene beads are also capable of being formed to very close tolerances required to provide smooth interior and exterior walls. A further advantage is that of being resilient to provide waterproof joints between adjacent wall building units. The weight of the form causes the horizontal joints to seal due to the resiliency of the foamed plastic.

The use of plasterboard as the interior side panel form 26 of the wall form 10 also provides important advantages. The plasterboard is inexpensive, fire resistant and possesses the necessary rigidity to withstand the hydrostatic pressure of the uncured concrete. It has been found in actual practice that concrete can be poured to a height of several feet without damaging the wall form.

The advantages of a left in place form which not only provides insulation but also provides semi-finished or finished interior and exterior surfaces are quite obvious. Shoring, tie wires, and removable forms are not required, thus resulting in a great saving in labour as well as saving transportation costs for moving forms to and from the site and the cost of cleaning and storing forms. Furthermore, as insulation and plasterboard are prefabricated preferably by machine before being moved to the site, there are savings in labour required to install these materials and little or no labour is required to clean up the building site after the forms are in place. Ordinarily, a certain amount of cleaning up time would be required after installation of each of the two materials.

Furthermore, although the plasterboard increases the weight of the form, a certain amount of weight is desirable to hold the form in place until the concrete is poured. It has also been found that the exterior panels may be formed of asbestos board to improve the fire resistance of the form.

In FIGS. 5 and 6 a modified concrete form 70 for use in wall structures is shown. The form is molded of expanded polystyrene beads and comprises two longi 4 tudinal walls 71 and 72 and integral transverse end walls 73 and 74. Integral partition walls 75 define four substantially cylindrical bores or holes 76 extending through the form 70. The shape of each hole 76 is such that four planar surfaces are interconnected at their ends by arcuate surfaces, thereby increasing the strength of the form without greatly decreasing the load bearing cross section of concrete filling the hole 76. A substantially semi-circular indentation 77 in each of the end walls 73 and 74 and the partition walls 75 provides a longitudinally extending channel 78 interconnecting the holes 76. As shown more clearly in FIG. 8, the channel 78 also interconnects the bores of adjacent similar form units 70.

It will be appreciated that, due to the provision of concrete columns of maximum cross section interconnected by horizontal beams, a wall of great load-bearing capacity is created through the use of extremely lightweight forms requiring a minimum of labour. The forms enable the concrete to cure under ideal conditions and decrease the uncertainties of pouring concrete in winter.

The resulting wall is not as heavy as a solid concrete wall due to the voids created by the polystyrene foam and thus the size of foundations or footings may be reduced accordingly.

The holes 76, due to their substantially cylindrical configuration, improve the ability of the form to withstand the hydrostatic pressure of the wet concrete. The surface area of the junction between the side walls 71 and 72 and the partition walls is increased, thereby improving the strength of the form. It will be noted that the holes 76 are tapered to facilitate releasing the form 70 from a mold. A more important feature of this taper is that it serves to keep the form from floating on the concrete, as concrete is poured into the form. The hole which in this example is l0 in diameter tapers half of an inch.

A wall constructed of building units 70 is shown in FIGS. 7 and 8 and comprises a preassembled panel 80 of units 70 secured together by larger sheets of building material 82 and 83 secured to the outer surfaces of the side walls 71 and 72. The panel 82 is material adapted for exterior use such as wood siding and the panel 83 is preferably plaster or plasterboard. In the embodiment shown a wire mesh 85 or the like is secured to the outer faces of the units 70 and plaster is applied to the wire mesh before the concrete is poured.

Reinforcing steel rods 86 extending vertically and horizontally within the holes 76 and channels 78 respectively, to provide additional strength are conveniently secured together during assembly of the panel 80 as by welding, wire ties or the like.

It has been found that the strength of the form 70 is greatly increased by molding the expanded polystyrene as opposed to cutting with conventional tools and securing pieces so cut with adhesive. The reason for the increased strength is that a skin is formed at the surface of the beads which increases the tensile strength by approximately 35 percent.

An alternative concrete form for use in constructing walls indicated generally at in FIGS. 9 and l0 is similar to the form 70 of FIG. 5. The form 150 is molded in one piece of expanded polystyrene beads and comprises two longitudinal walls 151 and 152 and two integral transverse end walls 153 and 154. Three integral partition walls 155 and the end walls 153 and 154 define four substantially cylindrical bores or channels 156 identical to the hole 76 described with reference to FIG. 5. An arcuate indentation in each of the end walls 153 and 154 and the partition walls 155 provides a longitudinally extending channel 158 interconnecting the bores 156.

Similarly, the underside of the form 150 is provided with a longitudinally extending channel 158a of semicircular cross section whereby, in use, a horizontally extending concrete beam is formed in the space provided by the associated channels 158 and 158a of two forms 150 when one form is placed on top of the other.

It will be noted that the top, bottom and end edges of the wall 151 and 152 are provided with tongues 160 or grooves 161 to mate with grooves and tongues of adjacent similar forms 150. The tongues and grooves have a taper of about to provide a more water tight joint.

It will be noted that the end walls 153 and 154 are :provided with ribs 154a adjacent their side edges and that ,the tongues 160 and grooves 161 at the ends of the form V150Y are provided on these ribs 154:1, thus ensuring that mating tongues 160 and grooves 1'61 adjacent blocks 150 will not be prevented from fully engaging by engagement of the major surfaces of the end walls 153 and 154;

The tongues 160 and grooves 161 provide for accurate alignment of the form vertically as well as horizontally. This alignment of the forms is facilitated by the accuracy which can be maintained in molding the forms 150'of expanded beads of polystyrene.

The walls 153, 154 and 155 are provided with recesses 165 similar to the recesses 16 described with reference to FIG. 1 to hold horizontal reinforcing steel inplace without tying. The recess 165 taper inwardly so that the portion V166v of the wall supporting the steel has a very small surfacearea. This is an advantage because the reinforcing rod will thus be more completely enveloped in concrete.

The vertically disposed reinforcing steel in theform 150 in conveniently held in position Iby a strap 17() having depending pointed portions 171 adapted to be embedded in the longitudinal walls 151 and 152. Indentations 172 centered with respect to the holes 156 are provided in the tongue 160 to receive the-straps 170. The verticalreinforcing rods extend through apertures 173 providedfin the strap 170. Dovetail grooves 175 provided in the side walls of the form serve as plaster keys.

In use,.aj irst course of form units 150 are positioned onla footing (not shown) containing vertical dowels extending `into". the` holes 156. The holes 156 are then filled with concrete to the height of the recesses 165 and the concrete in each hole is vibrated. Horizontal reinforcing is laid, and vertical reinforcing rods about 58" long are inserted into the wet concrete approximately 12".'

A secondcourse of form units 150 is installed by slipping them over the vertical rods and aligning theA holes 156 in the first and second courses, Two additional courses, including horizontal reinforcing, may then be installed before lling the second and third courses and the remaining space in the first course with concrete. Building of the wall ,is then continued three form unit courses per pour (approximately 4 feet).

When form units, in accordance with this invention are used belowf ground, it is recommended that two coats of plaster and a bituminous coating be applied on the exterior face. t

The form units 150 have a length of 4 feet and are 16" high. The width of the form varies to suit the loadfbearing requirements. It has been found that blocks having cores of 6, 8c and 10 inches in width provide a reasonable range of sizes for structures up to approximately 10 stories in height.

Expandable beads of polystyrene known as Pelaspan, is a preferred material. This material is manufactured in the form of small beads of granules contain-ing an expanding agent. These particles are expanded in a mold by the application of heat to the desired shape. Pelaspan, because of its ability to be molded, provides arideal material for molding this plastic building component. Furthermore, Pelaspan has desirable properties such as light weight, high strength to weight ratios, ideal surface 4to carry plaster, low moisture absorption and good insulating properties.

The expandable polystyrene beads are pre-expanded to the desired density (approximately 1f1/2-2 lbs. per cubic foot) before being placed in the mold. It is also recommended that a self-extinguishing type of polystyrene bead 'be used in the. molding of the forms to provide a more tire-resistant structure. Typical values of the material are shown below:

TYPICAL VALUES Above values are obrained from lab molded samples in the density range specified.

Other expanded polymeric materials may be used provided that the desired tensile strength can be obtained without adversely affecting the insulation value and weight of the form. The material must also be capable of being molded to the desired shape. Examples of such alternate materials are polyurethane foam or a foamed polymeric material sold under the trade name Polcat by Neoteric Chemical Systems Limited.

I claim:

1. A self-supporting concrete form of foamed polymeric material molded in one piece and capable of containing liquid concrete without additional shoring or transverse tie wires, said polymeric material being of uniform low density 'throughout so as to be resiliently deformable, said form including two spaced longitudinal walls terminating adjacent to and substantially co-extensive with two spaced transverse end walls, said end walls extending from one longitudinal wall to the other to form a sufficiently rigid structure for holding liquid concrete, at least one partition wall intermediate said end walls and dening holes extending through said form, each said hole being vertically disposed when said form is in use and tapering toward a smaller cross-section at its lower end, corresponding edges of said transverse walls and said partition wall being inwardly spaced from adjacent edges of said longitudinal walls so as to provide a longitudinal beam of concrete integral with a column of concrete in each said vertical hole -when concrete is poured into a plurality of assembled forms and a recess in a lower edge of each longitudinal wall and a projection provided on an upper edge of each longitudinal wall so that proections and recesses of superimposed similar forms cooperate to position said forms, said polymeric material being deformable `to provide a seal thereby minimizing seepage of concrete between forms.

2. A concrete form as claimed in claim 1 wherein said transverse walls are inwardly curved so as to provide a longitudinal beam of at least partly curved cross-section.

3. A concrete form as claimed in claim 1 wherein said walls are shaped to provide each said hole with a substantially circular cross-section.

4. A concrete form according to claim 1 wherein said corresponding edges of said transverse walls have notches in which longitudinally extending reinforcing rods can be positioned.

5. A concrete form as claimed in claim 1 formed of integrally molded expanded beads of polystyrene.

6. A concrete form as claimed in claim 1 wherein the thickness of said end walls is approximately half the thickness of said partition wall.

7. A self-supporting concrete form of foamed polymeric material molded in one piece and capable of containing liquid concrete without additional shoring or transverse tie Wires, said polymeric material being of uniform low density throughout so as to be resiliently deformable, said form including two spaced longitudinal walls terminating adjacent two spaced transverse end walls, said end walls extending from one longitudinal wall to the other to form a sufficiently rigid structure for hold- 7 i ing liquid concrete, at least one partition Wall intermediate said end walls and defining holes extending through said form, each said hole being vertically disposed when said form is in use and tapering toward a smaller crosssection at its lower end, corresponding edges of said transverse walls and said partition wall being inwardly spaced from adjacent edges of said longitudinal walls so as to provide'a longitudinal beam of concrete integral with a column of concrete in each said vertical hole when-concrete is poured into a `plurality of assembled forms anda recess in either the lower or upper edge of each longif tudinal wall, a projection provided on the other of `said lower or upper edge of each longitudinal wall to match said recess, projections provided on the end edges of longitudinal walls and recesses provided in' end edges disposed,

on opposed end edges of said longituinalnwalls, so that projections and recesses of assembled `formsco-operate to position said forms, said polymeric material being deformable to providea seal thereby minimizing seepage of concrete between forms. n

8. In a wall structure, a plurality of molded 'form blocks of foamed synthetic plastic material having a substantially uniform low density, each said block having two spaced longitudinal walls terminating adjacent two transverse end walls, at least one partition wall intermediate said end walls, said end walls and partition wall extending from one longitudinal wall to the other to form a sufficiently rigid structure for holding liquid concrete and defining vertical holes extending through said form, each said-hole tapering toward a smaller cross-section at its lower end, upper and lower edges of said transverse walls and said partition wall being inwardly spaced from adjacent edges of said longitudinal walls so as to provide a longitudinally extending beam of concrete integral with columns of concrete in said vertical holes and a projection being provided along an upper edge of each longitudinal wall and a recess' being provided along a lower edge of each longitudinal wall so that projections and recesses of superimposed forms co-operate to position said forms, said projections being compressed in said recesses to minimize seepage of liquid concrete, similar projections being provided along end edges of longitudinal walls and recesses along` opposed end edgesl of f' each of said form wher'eby projections andrecesses on the ends of ad-A jacent-similarforms lco-operate to' provide a substantially weather-tight joint. i i

9. In a wallstructur'e as claimed'in'c'laim 8 said synthetic plastic material being expandable beads of poly-l styrene'.v

10. In a wall structure as claimed in claim 8 said end walls being of a thickness approximately one-half the thickness of said partition wall.

References Cited 1 VUNITED sTArEs PATENTS 1,154,546

JOHN E. MURTAGH, Primary Examiner U.S. Cl. X.R.

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