Expansible construction form and method of forming structures

APPLICATION

This application is a continuation-in-part of Serial No. 476,446 filed by the applicant on August 2, 1965 and now abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to construction forms and to methods of forming reinforced structures from flowable materials. In particular, the invention relates to 50 collapsible-extensible forms adapted to be expanded at the construction site for receiving concrete or other cementitious material in the fabrication of reinforced walls and other structures.

In most cases, forms used to support plastic con- 55 Crete or cement until hardened, are assembled at the construction site. The erection of these forms and their subsequent dismantling are costly operations and in some instances forms have failed as a result of attempts to economize. Forms must obviously have sufficient stiff- go ness and provide adequate resistance to the lateral pressures created by newly poured concrete or cement.

Many attempts have been made in the past to provide prefabricated forms for the erection of structures from concrete and other flowable materials, but such gg prefabricated concrete forms, generally fabricated from wood or steel, have been extremely expensive to manufacture, have posed storage problems, required considerable labor to erect and have been subject to high maintenance costs. Further, they cannot be employed over 70 irregular ground surfaces with out the use of additional supportive structure.

SUMMARY OF THE INVENTION

The apparatus of the invention is particularly adaptable for manufacture in prefabricated form in which it may be readily collapsed for storage and shipment and readily expanded, positioned and erected on a job side. The device of the present invention is adaptable for use in forming any type of structure, such as tapered walls, ininterior building walls of concrete or light weight fill materials, exterior building walls, garden walls, serpentine walls, and curtain walls.

The teachings of the invention are not limitted to terrestrial use since they may be applied in the erection of undersea structures, such as docks, caissons and the like because the particular nature of the expansible construction form pecularily adapts it to utilization in subaqueous applications.

In accordance with the broad aspects of the present invention, there is provided a prefabricated construction form for cementitious materials that is collapsible and is easily extended, positioned and erected on a job site, at least portions of the form providing reinforcing within the final structure. The form broadly includes opposed, collapsible-extensible side members joined together by transverse, rigid connector elements that maintain the side members in predetermined, spaced-apart relation in the extended condition and reinforce the cementitious material after pouring and setting thereof. The transverse connector means may be arranged to comprise a collapsible-extensible space frame structure that is relatively rigid when expanded and that is therefore able to span irregularities in the ground surface over which the form is erected.

There is thus provided a prefabricated form that is unusually light weight and requires no additional work at the construction site so that fabrication and labor costs are minimized. Little or no experience is required to use this form and costly errors are thereby avoided. Generally, a wall structure can be made according to the invention by first driving spaced support means into the ground. The support means may be driven by impact or augured into place but in any event, should preferably be made of non-ferrous material to prevent corrosion of the transverse elements comprising the interior framework of the form. Next, upright pilasters are attached to the support means, the form is expanded and then slid down over adjacent pilasters, spanning the distance therebetween and ground surface irregularities. Portions of the frame structure contact the pilasters and normally, no attachment, provisions, by way of welding or otherwise, are needed between the pilasters and frame structure. The final step comprises the pouring of the cementitious material. Upon setting, the side members, if made of a material, such as plastic, that is impervious to the cementitious material, are stripped away. The pilasters and transverse connectors, embedded in the final structure, provide highly effective reinforcing.

In accordance with another aspect of the present invention, non-corrodible fastener means, of plastic or the like, may be used to couple the transverse connecting elements and the side members of the form in spaced apart relation. In this fashion, in conjunction with the use of non-ferrous pilaster support means, the framework forming the internal reinforcing of the final structure, which framework will typically be steel, can be completely isolated from the ground and ambient atmosphere to prevent corrosion thereof.

Other, more specific examples of the present invention include the utilization of hingedly connected side members which are accordioned into the collapsed condition and the use of transverse connector elements hingi,751

FIG. 28 is a fragmentary side elevational view, in section, of a portion of an alternative embodiment of the present invention;

FIG. 29 is an enlarged, fragmentary side elevation view of a portion of the form of FIG. 28; and,

FIG. 30 is a sectional view of the portion of the form depicted in FIG. 29 taken along the plane 30—30.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings and, particularly, to FIGS. 1-4 thereof, there is shown a collapsible-extensible prefabricated form 10 constructed in accordance with the teachings of the invention and consisting of two collapsible-extensible side members 12 which, in one embodiment of the invention, are fabricated from any suitable, flexible plastic sheet material, such as polyvinyl chloride, “Mylar” and the like. However, it will be obvious to those skilled in the art that any suitable sheet material may be utilized in substitution for the plastic sheet material, typical examples being rubberized fabric, canvas and a wide variety of analogous fibrous and woven materials.

In addition, while the teachings of the invention are disclosed as applied to the erection of structures on the surface of the earth, as previously mentioned, the teachings can be applied with equal cogency in subaqueous applications where the side members can be so connected ₃₀ to each other that a form cavity is provided which is isolated from the penetration of the water and in which the form is erected so that the flowable material, such as concrete, or the like, may be fed into the cavity through suitable conduits or hoses and a subaqueous structure _3g erected.

Moreover, while the forms of the invention are disclosed as being prefabricated, it is conceivable that, in extremely large applications, the forms might be assembled from suitable components on the job site, and it is 40 not intended that the method of the invention be limited to the utilization of prefabricated forms.

The side wall members 12 are connected in operative relationship with each other by suitable transverse connectors 16, which, in the present embodiment of the invention, comprise rigid metallic grids having transverse wires 18 with looped extremities 20 which engage the exterior surfaces of the side wall members 12 to maintain them in predetermined spaced relationship with each other. When the prefabricated form 10 is disposed in the collapsed condition, the side wall members are folded into pleats and the connectors 16, of course, are moved into overlapping collapsed relationship.

One of the advantages of the form of the invention is that a wide variety of configurations can be imparted to the concrete structure 24 because the extent to which the form is extended determines whether the surface of the structure being formed will have a plurality of arcuate protrusions, will be flat, or will be serpentine, as best shown in FIG. 7 of the drawings.

Secured to the opposite extremities of the form 10 are mounting means 28 constituted by cages 30, which are adapted to encompass structural steel pilasters 32 whose lower extremities are mounted in concrete foundations 34. The lower extremities of the pilasters are mounted in and secured to auger-like supporting elements 36. The supporting elements 36 are preferably nonferrous and they are driven into the earth before the pilasters 32 are mounted therein. In addition to the concrete foundation 34, an elongated footing 38 may be poured simultaneously with the pouring of the concrete or other flowable material into the form 10·.

The pilasters 32 incorporate transverse connectors 42 which serve as supports for longitudinally oriented reinforcing steel 44, as best shown in FIGS. 1 and 2 of the drawings.

3,5 edly coupled in series to provide continuous, longitudinal reinforcing of the finished structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with further aspects and advantages thereof, can best be understood by reference to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view showing one embodiment of a form constructed in accordance with the teachings of the present invention;

FIG. 2 is a perspective view of a portion of the interior of the form of FIG. 1;

FIG. 3 is a transverse, fragmentary view, in section, showing the extremities of two forms, such as that shown in FIG. 1, connected together;

FIG. 4 is a fragmentary, elevation view, in section, showing the manner in which the form of FIG. 1 may be mounted on the adjacent terrain; ₂0

FIG. 5 is a fragmentary, schematic, elevation view, in section, showing an alternative embodiment of the form of the invention;

FIG. 6 is a view similar to FIG. 5 showing the same embodiment installed in a different manner;

FIG. 7 is a fragmentary, schematic, top view of another embodiment that may be used to provide a serpentineshaped wall structure;

FIG. 8 is a fragmentary, sectional view showing a stake or rod securement and support means utilized in the serpentine construction form of FIG. 7;

FIG. 9 is a fragmentary, sectional view of an alternative securement means for connecting transverse elements in the form to the side members of the form;

FIG. 10 is a fragmentary, side elevational view of another securement means;

FIG. 11 is yet another embodiment of a securement means;

FIG. 12 is an elevation view, in section, illustrating a stabilizing structure adapted to be utilized in conjunction with the form;

FIG. 13 is a fragmentary, top view of a form incorporating one type of transverse connector means for joining the side wall members;

FIG. 14 is a fragmentary, elevation view of an alternative type of pilaster having a securement bolt at its upper extremity;

FIG. 15 is a fragmentary, elevation view that shows the lower extremity of an adjustable pilaster;

FIG. 16 is a perspective view of an alternative embodiment of the form of the invention;

FIG. 17 is a fragmentary, top plan view of the form of FIG. 16 in the expanded condition;

FIG. 18 is a fragmentary, top plan view of an alternative embodiment of the form of the invention;

FIG. 19 is an enlarged, fragmentary, side elevation view of the form of FIG. 18;

FIG. 20 is a fragmentary, perspective view of another embodiment of the form of the invention;

FIG. 21 is a fragmentary, perspective view of yet another embodiment of the form of the present invention;

FIG. 22 is a fragmentary, sectional view of the form shown in FIG. 21;

FIG. 23 is a side elevation view, partially in section, of an alternative embodiment of the form of the present invention;

FIG. 24 is a transverse sectional view of the form of FIG. 23 taken along the plane 24—24;

FIG. 25 is an enlarged, fragmentary side elevation view, in section, of a portion of the form of FIG. 23;

FIG. 26 is an enlarged, fragmentary end elevation view, in section, of a portion of the form of FIG. 23 in the collapsed condition;

FIG. 27 is a transverse sectional view of a portion of the form of FIG. 23 in the collapsed condition; 75

3,555,751

The sequence of operations in following the method of the invention involves the placement of the expansible wall members 12 in predetermined spaced relationship by expanding said wall members until they are maintained in predetermined spaced relationship by the transverse _gconnectors. However, prior to this time, the auger-like supports 36 for the pilasters have been driven into the ground, the cylindrical concrete footings 34 have been poured and the pilasters attached to the supports 36.

Then the mounting cages 30 are engaged upon the jq pilasters by sliding the extended form down over the pilasters. The box-like structure of the extended form renders it self-supporting; the pilasters hold the form in the extended, erect position, the form spanning any irregularities in the ground surface. 15

If desired, an elongated footing trench 38 has been dug and the cement or concrete is ready to be poured into an elongated trough 48 which has lower edges 52 which, as best shown in FIGS. 1 and 4 of the drawings, are adapted to be inserted in the spaces between the verti- 20 cal wires of the connector means 16 for the side wall members 12. The cement or concrete can then be poured and the form is left in place until the cement or concrete has been properly cured. When the curing has been completed, the side wall members 12 are simply stripped from 25 the final structure 24 (see FIG. 4). At this time the projecting, looped extremities 20 of the connectors 16 can be utilized to affix a surface coating to the corresponding surfaces of the concrete structure 24, or can be cut off flush with the finished wall surface. The transverse con- 30 nectors 16, embedded within the cementitious structure, serve as reinforcing elements, as do the pilasters 32. Longitudinal reinforcing is provided by the horizontally extending rods 44.

Illustrated schematically in FIGS. 5 and 6 is an alter- 35 native embodiment 60 of the form of the invention in which the lower extremities of the vertical elements of the transversely oriented connectors 62 are provided with prongs 64, preferably made from a non-corrodible or nonferrous material, adapted to project into the ground for 40 added strength and stability. In FIG. 6, the transverse connectors 62 extend downwardly below the lower margin of the form into a footing trench.

Illustrated in FIGS. 7 and 8 is the utilization of the form 10 to achieve a predetermined configuration such as a serpentine shape. In such an application, elongated pins 66 are inserted in the looped extremities 20 of the transverse connectors 16 and driven into the surface of the adjacent terrain to stabilize the form 10 in the predetermined configuration. The pins 66 are removed after ₅₀setting and curing of the cementitious material.

In order to isolate the transverse connectors 16 from the ambient atmosphere and thereby retard or completely preclude corrosion of the connectors, which are typically of steel, plastic buttons 72, as best shown in FIG. 9, may ₅₅be secured to the opposite extremities of each of the transverse wires 18 of the connector means 16. The side wall members 12 are provided with corresponding openings 76 which permit the side wall members 12 to be fitted over the plastic buttons 72 and an elongated wire or θθ rod 78 to be inserted in corresponding openings 82 in vertically aligned buttons 72 to secure the side wall members to the connectors 16. The rods 78 may be single pieces extending through series of vertically aligned openings 82 in which case they may additionally provide sup- _6gport and stability in the manner described in connection with the rods 66 in FIG. 7. As an alternative, the rods 78 may comprise individual pins of short length, each inserted in a single button opening to preclude the side members 12 from disengaging the buttons. In any event, γθ the buttons serve to couple the connectors 16 and side members 12 in spaced apart relation. After the cementitious material has set, the buttons may be used as supports for surface finishing or may be sheared off flush. This mode of attachment can also be utilized to facilitate 75 the overlapping attachment of the adjacent extremities of side wall members of adjacent forms 10.

Other modes of attaching the side wall members 12 to the transverse connectors 16 are shown fragmentarily in FIGS. 10 and 11 of the drawings. In FIG. 10, the overlapping extremities of side wall members 12 of adjacent forms are secured by the insertion of elongated rods or wires 84 in corresponding loops 86 provided in the extremities of the transverse members of the mounting cage 30 and by providing a reinforcing strip 88 underlying said loops and elongated rod or wire 84. A similar construction, illustrated in FIG. 11, utilizes reinforcing washers 92 under the rod 84.

It is frequently desirable when employing very large forms, to provide stabilizing means and an example of such stabilizing means 102 is shown in FIGS. 12 and 14. Stabilizing means 102 includes a pair of stabilizing arms 104 which have their lower extremities secured to augers 106 having eccentrically positioned connecter pins 108 thereupon. Therefore, the augers 106 can be rotated to place the pin 108 in the best location for providing the maximum stabilizing effect through the stabilizing arms 104. The upper extremities of the arms are secured to a sill bolt 110 which is welded, or otherwise secured, to a pilaster 114 at its upper extremity, as best shown in FIG. 14 of the drawings. While two arms 104 are shown, only one may be necessary. In addition, stabilizing wires or cables may be substituted for the arms 104.

In an alternative embodiment 120 of the form, as best shown in FIGS. 13 and 15 of the drawings, the connector means 122 are angularly oriented, rather than located in directly transverse relationship with the side wall members 126 associated therewith. The lower extremity of the pilaster 114 is secured to an associated footing 132 by means of a sill bolt 134. The pilaster includes an elongated slot 136 that permits the adjustment of the pilaster 114 with reference to the upper extremity of the sill bolt 134 for precise adjustment of said pilaster upon the footing 132. The angular orientation of the transverse connector not only provides a triangulated space frame structure providing a relatively rigid form in the extended condition, but affords continuous, longitudinal reinforcing in the final structure.

An alternative embodiment 140 of the form of the invention is illustrated in FIGS. 16 and 17 as fabricated from accordion-pleated, corrugated paperboard, or the like. The side walls 142 are joined by transverse connector means 144 of steel grid material or the like. The transverse elements of the connectors 144 project through the side wall members 142 and are engaged by washers 146 that hold the side members 142 in place. Steel strapping 148 which is looped through bearing plates 152 serves to maintain the form in the collapsed position shown in FIG. 16. This embodiment of the form is exceedingly inexpensive to produce, yet provides the required rigidity and resistance to lateral pressure exerted by the cementitious material while in the plastic form.

Another embodiment 160 of the form of the invention, is illustrated in FIGS. 18 and 19 of the drawings and includes side wall members 162 fabricated from hingedly connected plates 164 of metal, such as heavy screen wire mesh, or expanded metal.

The plates 164 are formed with integral hinge knuckles 166. Elongated rods 168, extending through the interlocking knuckles 166, hingedly couple the plates 164 and permit the plates to be collapsed upon one another or to be moved into the extended positions as shown in FIGS. 18 and 19. The members 162 are joined by angularly oriented connector means 172 that have looped protrusions 174 on the transverse elements thereof to receive the pins 168. The result is a structure which may be easily collapsed or accordioned for transportation to the construction site and there extended for use. Also provided are auxiliary transverse connector means 178 which cooperate with the connector means 172 for stabilizing the

3,555,751 form in its expanded condition, limiting the amount of expansion, and providing added reinforcing. It is also contemplated that longitudinal limiting wires 161 having lugs 163 thereupon will be utilized to control the extent of expansion of the form 160 in a longitudinal direction.

An alternative embodiment 180 of the form of the invention is shown in FIG. 20 and incorporates a plurality of pockets 182 which have back walls 184 formed of material, such as fine mesh fabric, or other pervious material, which will permit the infiltration of concrete into pockets 182. Mosaic tiles 188 or larger tiles 190, or similar decorative elements, can be inserted in the pockets and, as the concrete is poured, it will infiltrate into the pockets to engage the rear surfaces of the tiles or other decorative elements to adhere them to the corresponding surface of the concrete structure being formed. It should be noted that the mosaic tiles are mounted on a cardboard backing 194 which can be stripped with the outer plastic film 196 which constitutes the outer side wall of the pockets.

Another embodiment 202 of the invention, is illustrated in FIGS. 21 and 22 of the drawings and includes a plurality of pockets 204 which have their front and back walls 206 and 208 formed from impervious material, such as plastic film, said pockets being adapted to receive forms 210 having decorative recesses or projections 212 formed in a surface thereof which is adapted to be juxtaposed to the inner side wall of the pocket 204 with which it is associated. As a result, when the concrete is poured, the inner walls 208 will be deflected by the concrete into conformity with the decorative projections or recesses 212 to impart a desired decorative pattern to the surface of the structure being formed.

FIGS. 23-30 shows embodiments of the present invention in which the collapsible-extensible side members of the form are carried by collapsible-extensible frame structures including hingedly coupled, transverse spreader elements formed, for example, from lengths of heavy wire.

In the specific embodiment of FIGS. 23-27, a frame structure 220 that incorporates a plurality of transverse spreader elements 222 is utlized. Preferably, each spreader element 222 is made of a single length of heavy wire of steel or similar materal formed into an angled or zig-zag pattern, as best shown in FIGS. 23 and 25. The spreader elements 222 each have horizontally extending, vertically aligned loop portions 224 at the apexes along one extremity and similar vertically aligned loop portions 226 at the apexes along the other extremity. Although the described and illustrated spreaders 222 are formed most conveniently from single lengths of wire, it will be evident as the discussion proceeds that short, angled wire components, for example, V-shaped segments, may be suitably combined to provide spreaders having overall heights that are predetermined or adjusted for utilization in a particular form structure.

The transverse spreaders 222 are assembled by bringing the loops 224 into vertical alignment with the loops 226 of adjacent spreaders. Pivot means, preferably in the form of elongated, vertical rods 228, are passed through vertically aligned sets of loops to thereby hingedly join the spreaders 222 into a composite frame structure. It will be seen that the resulting frame structure 220 can be easily collapsed, as in FIG. 27, into a compact, easily transported unit and expanded at the construction site into the extended configuration as shown in FIG. 24.

As an alternative, the spreader pivot means may be in the form of individual pins (not shown) joining together single pairs of loops 224 and 226. By making the pivot means 228 in one piece, that is, from a single length of rod or wire (and these advantages would pertain equally to the spreaders themselves), added strength, stability and reinforcing are imparted to the framework itself and to the finished cementitious wall structure. Further, in connection with the pivot means, by utilizing one-piece hinge rods 228, the rods may each be provided with a lower tip portion 230 configured to facilitate implanting into the ground, after the form is in place and before pouring, to provide greater stability. The tip portions 230 may be made of a non-ferrous material to isolate the rods from the ground and thereby retard or completely prevent corrosion of the rods and framework from that source.

The side walls of the form are defined by opposed, collapsible-extensible side members 232 suitably attached to the frame structure 220. The side members, as already explained in connection with previous embodiments, may be made of plastic sheet material; pleated, heavy duty cardboard (as in the embodiment of FIGS. 16 and 17); hingedly connected, rigid panels (as in the embodiment of FIGS. 18 and 19), or the like. In the specific example depicted in FIGS. 23—27, a flexible material such as “Mylar” plastic sheet is used.

Fasteners 234, fabricated of a non-corrodible material such as plastic, couple the frame structure 220 and side members 232 in spaced-apart relation. The spacing function performed by the fasteners 234, as already explained in connection with the embodiment of FIG. 9, is of significance because corrosion of the inner framework 220, which forms the reinforcing of the final cementitious wall structure, is thereby substantially precluded. The ultimate object is to have the framework 220, which will in most cases be constructed of steel or iron, completely embedded within the final wall structure so as to avoid exposure of any part of the framework to the ambient atmosphere or ground.

Fasteners 234 may be connected to the framework 220 and side members 232 in any suitable fashion. A particularly convenient and inexpensive technique and fastener structure are shown in the drawings. Fasteners 234, which may be molded as a single piece, comprise an inner end 236 bifurcated to receive a pair of the loops 224, 226. A vertically oriented aperture through the inner end 236 of the fasteners receives the pivot rod 228. The bifurcated inner end 236 thereby defines a horizontally disposed slot for receiving the looped portions of adjacent spreader elements and is dimensioned so that little or no frictional interference is introduced when the fastener and adjacent spreaders move relative to one another during longitudinal extension or contraction of the form.

Each fastener 234 is provided with an outer, split end 244 that projects through an opening formed in the side members 232. The outer extremity of the fastener has a peripheral groove 248 for receiving a locking or restraining element. The locking element may simply be a washer (not shown) that is pressed over the contractable, split outer end 244 of the fastener and snapped into the groove 248. As a preferred alternative, a vertically oriented rib 252, provided with vertically spaced holes may be used as the locking or restraining element. The use of ribs 252 is advantageous in that additional support is provided for the side members 232 and help prevent excessive bulging during pouring of the form. The ribs 252 may simply comprise strips of plastic or wood or the like.

The form under discussion may be made virtually any desired height and length as may be required for a particular construction project. It will be evident that the form may also be made in sections joined together to provide the required, overall length. Preferably, each section would span between a pair of spaced pilasters or column structures for connection to a foundation. An example of one such pilaster is illustrated in FIGS. 23 and 24 and designated generally by the reference numeral 260. As best seen in FIG. 23, the pilaster 260 depends from the lower edge of the form and is anchored at its lower extremity in a load-bearing member 262 driven or impacted into the ground. The load-bearing member 262 may take the form of an auger, such as that shown in connection with the embodiment of FIG. 1, or a spikeshaped element or the like which may be easily embedded or otherwise driven into the ground. As already stated, the load-bearing member 262 is preferably fabricated of

3,555,751 a non-ferrous material with the object of isolating the pilaster 260 and the framework 220 from attack by corrosion working its way up from the ground.

As shown in FIG. 23, the typical procedure in erecting the form and wall structure 'will begin with impacting the load-bearing members 262 into place in the bottom of footing holes 264. A coupling member 268 is then attached to the load-bearing member 262 and receives the pilaster 260. The coupling member 268 may typically be of some non-ferrous material and can, by way of example, be conveniently constructed of concrete or cement. Once the pilaster 260 is in place, the hole 264 is filled with concrete to provide a firm footing 270 for the form and final wall structure where the loads necessitate such foundation. For additional support, an elongated footing 272 extending between the footings 270 may be utilized although this is not necessary in all instances. The framework 220, with the side members 232 in place, is extended between adjacent pilasters, and slid over the pilasters and because of the space frame type of structure involved, will span any irregularities in the ground as shown in FIG. 23.

The form is then poured in the manner already described, allowed to cure and the side members are stripped away. The projecting ends of the fasteners 234 can either be sheared off flush with the finished wall or used as supports for carrying a finished wall surface such as might be used in the interior of a residential or office building. FIGS. 26 and 27 show portions of the form as they would appear in the collapsed condition. It will be seen that in the collapsed condition, the transverse spreaders nest to the extent that only a small acute angle exists between them.

The pilaster 260 can be of any suitable shape to slidably receive the framework 220 and securely hold it in place. The pilaster shown in FIGS. 23 and 24, by way of example, is fabricated of three vertical rods 274 interconnected by a series of cross members 276 to form a structure having a generally triangular cross-section as best shown in FIG. 24.

A great variety of wall patterns may be obtained with the form of the present invention. For example, as shown in FIG. 24, a vertically fluted wall surface is achieved as a result of the slight arcuate bulges in the portions of the side members 232 between fasteners. The protrusion of the portions of the side members between fasteners can be made greater or less depending upon the extent of expansion of the form. Other patterns may be provided by using accordion pleated side members, such as shown in FIG. 17, or side members consisting of hingedly connected rigid panels or sections such as illustrated in FIGS. 18 and 19. Likewise, a serpentine shape may be imparted to the wall, after the fashion depicted in FIG. 7, by implanting the lower extremities of the pivot rods 228 into the ground as already discussed. For additional support, the ribs 252 may also be provided with extending lower extremities (not shown) for implanting into the ground to impart greater support and stability especially where shapes other than rectilinear are desired.

The texture of the final wall surface can also be controlled by the appropriate choice of side member material. Thus, for example, the cementitious material may be made to assume an interesting and attractive surface pattern by the use of a diamond-shaped mesh material like that illustrated in connection with the embodiment of FIGS. 18 and 19. The double-wall configuration as shown in FIGS. 20-22, for receiving in the pockets thus defined a variety of decorative motifs, may also be employed with the embodiment under discussion.

After pouring the form of FIGS. 23-27, the frame structure 220 provides interior reinforcing which is continuous along the length of the wall. By “continuous” is meant a structure, which although pivotally connected at successive points, is nevertheless uninterrupted and unbroken along its length so as to provide a wall capable of resisting relatively large structural loads. The frame struc ture 220 therefore forms a continuous, triangulated space frame which is self-sustaining when set in place and additionally serves as reinforcing in the final wall. Normally, no auxiliary support devices are required to support the forms either before, during or after pouring. Additional longitudinal reinforcing can be provided, if desired, by sliding vertically-spaced, longitudinal rods lengthwise into the form before pouring.

FIGS. 28-30 illustrate an embodiment that is a modification of that shown in FIGS. 23-27 and that is better adapted for the erection of larger wall structures. In the embodiment of FIGS. 23-27, the spreaders have single turn loops at their apexes. Although this is satisfactory for most applications, the rigidity and stability of the form can be enhanced for heavier duty applications by providing loop portions with more than one turn to thereby increase the resistance of the pivot points to bending.

In the version of FIGS. 28-30, spreaders 280 are provided having looped portions 282 along one vertical extremity thereof comprising a hooked portion in the horizontal plane which defines a pair of spaced loops 284, 286. Single loops 288 may be employed along the opposite vertical extremity of the transverse spreader and upon assembly each of the single loops 288 is inserted between the mating loops 284, 286 with a vertical pivot rod 290 extending through the loop portions thus joined to form the final pivot. It will be apparent that greater numbers of helically wound loops, for example three, four, etc. may be formed at either or both vertical extremities of the transverse spreaders as may be required for sturdiness and to prevent jamming during expansion and contraction of the form and as may be demanded by the size or the utilization of the final wall. Fasteners 292, such as those already described in connection with FIGS. 23-27, but having bifurcated inner ends modified as necessary to accommodate the additional height of the looped portions may be employed.