US3426541A

US3426541A - Earth supporting structures

Info

Publication number: US3426541A
Application number: US624929A
Authority: US
Inventors: Carlo Chiaves
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-03-30
Filing date: 1967-03-21
Publication date: 1969-02-11
Anticipated expiration: 1986-02-11
Also published as: DE1634302A1; GB1176878A; CH459901A; DE1634302C3; ES338531A1; DE1634302B2; FR1515760A

Description

1969 c. CHIAVES I 3,426,541

EARTH SUPPORTING STRUCTURES Filed March 21, 1967 Sheet of :1

C. CHIAVES EARTH SUPPORTING STRUCTURES Feb. 11, 1969 Filed March 21, 1967 Z of 5 Sheet Feb. 11, 1969 CHIN/ES I 3,42 ,541

EARTH SUPPORTING STRUCTURES Filed March 21, 1967 Sheet 3 of 5 United States Patent 7,371/66 US. CI. 6139 Claims Int. Cl. E02d 5/20; E04b 1/344; EO lc 1/10 ABSTRACT OF THE DISCLOSURE An earth supporting structure is formed from a plurality of prefabricated re-inforced elements, each element comprising a prefabricated re-inforced concrete panel with a prefabricated re-inforced concrete tie rod for supporting the panel in an erect position, the tie rod being articulated to the panel through exposed common re-inforcing elements so that the structural element as a whole will take up relatively little space in storage and handling and will be easy to erect. A method of erecting the structural element includes supporting the panel in a substantially upright position utilizing the tie rod as a prop. With the element in such propped position final adjustment and the laying of a concrete base over the free end of the tie rod may be carried out and the exposed common re-inforcing elements covered with concrete.

The invention relates to earth supporting structures of the type which comprise a vertical wall of prefabricated reinforced concrete panels and a horizontal base which is also of reinforced concrete and which extends transversely of the bottom of the vertical wall and is connected to the panels of the said wall by means of tie rods. This base extends towards the volume of earth to be supported or confined and the space or interior angle between the base and vertical wall is filled with earth on completion of the wall.

In earth supporting structures of the abovementioned type it is known to employ flexible tie rods for interconnection of the vertical wall and base, such tie rods being formed from round sectioned iron rod encased in a sheath of plastics. This encasement is of course to prevent corrosion.

The use of such flexible tie rods is however objectionable because they bend under the load of the supported earth and thus cause the panels to incline towards this earth. In consideration of this, it has been proposed to substitute, for flexible tie rods, rigid tie rods which are in the form of reinforced concrete girders of such a size as to bend only by a negligible amount under the transverse loads which result from the weight of the filling earth.

Such girders are at present cast in situ but this causes difliculties. For instance, the girders are situated behind the vertical wall, a region which is, almost by definition, inaccessible. This region is also often dangerous owing to the possibility of land-slides. Moreover, to cast the girders, it is necessary to employ moulds of accurate size and this results in a considerable amount of timber going to waste.

In any case, whether flexible or rigid tie rods are employed, assembly of the panels is very unstable because their centre of gravity is situated close to the exposed panel face. Consequently, after the panel has been laid in a provisional substantially vertical position, it is inevitably unstable and a prop and stay tool must be employed to support it and bring it into its true vertical position. Furthermore, when rigid tie rods are employed, the period of time required for hardening of the cast concrete girders determines the time which must elapse between as- 3,426,541 Patented Feb. 11, 1969 sembly of the panels and filling of the structure with earth. As will be obvious, it would be advantageous if this latter delay could be avoided.

An object of the invention is thus to dispense with the need to cast the tie rods in situ when building a structure which incorporates rigid tie rods of reinforced concrete.

A further object of the invention is: to facilitate assembly of the panels so that they are stable when in their substantially vertical position. This will of course avoid the need to use a stay tool for supporting the panel and bringing it to a truly vertical position.

A still further object of the invention is to reduce the time period between assembly of the panels and filling of a structure which employs rigid tie rods with earth.

According to these and further objects of the invention, there is provided a structural element for forming an earth-supporting structure, the structural element comprising a panel and a tie rod which latter has one end connected to the said panel by means of an articulation and its other end free so that the rod may be hinged apart from the panel about the articulation for erection of a structure before connection of the said free end with a structure base.

Also in accordance with the present invention, a method of utilising such elements to construct an earthsupporting structure comprises the steps of arranging the element in a substantially upright position with the tie rod hinged apart from the panel and the free end of the tie rod resting on the ground, forcing a prop between the panel and an earth bank or the like, arranging the panel to stand truly vertically, casting a base on the ground, which base incorporates the free end of the tie rod, filling the space between the articulated end of the tie rod and the panel with a suitable cement, removing the said prop and filling the space formed between the panel, the base and the said earth bank With earth.

It is not essential to Wait until the cement in the region of articulation has set before starting to fill the space with earth.

Preferably, the position of the tie rod with respect to the panel is maintained by the insertion of a spacer therebetween.

In summary, the structural element of this invention includes a prefabricated re-inforced concrete panel with an exposed face, back face, and re-info'rcing elements Within the panel, a tie rod in the form of a prefabricated re-inforced concrete girder is articulated from one end of the tie rod to the back face of the panel by re-inforcing elements which are common to the panel and girder and exposed at the point of articulation so that the free end of the tie rod may articulate or pivot about the exposed re-inforcing elements from a position when the tie rod is fiat against the face of the panel to a position for the tie rod is propping the panel at an upright position. A method of forming an earth supporting structure utilizing such structural elements includes arranging an element in upright position with the free end of the tie rod resting on the ground and propping the element, truing the panel vertically by means of a prop, casting a base on the ground and incorporating a free end of the tie rod, filling the articulation space enclosing the exposed re-inforcing elements at the point of articulation, and removing the prop and filling the space between the panel and base With earth.

These and other objects and advantages of the invention will be clear from the following description, given with reference to the accompanying drawings which are by way of example and in which:

FIG. 1 is a perspective view of a structure constructed from elements according to the invention;

FIGS. 2 and 3 are side views of an element comprising a panel and a tie rod therefor in two different positions before erection;

FIGS. 4 and 5 are detail sectional views corresponding respectively to FIGS. 2 and 3, the said FIGS. 4 and 5 being drawn on an enlarged scale to show more clearly an articulation between the panel and tie rod;

FIGS. 6 and 7 are views similar to those of FIGS. 4 and 5 but show an articulation of another kind; and

FIGS. 8, 9 and 10 show three different steps in the erection of a structure utilising elements according to the invention in a method according to the invention.

The erected earth supporting structure shown in the figures is of the type having a substantially angular profile in cross section and comprises a substantially horizontal base 1 and a substantially vertical wall 2 interconnected by obliquely arranged rigid tie rods 3. The base 1 extends transversely from the bottom of the vertical wall 2 towards the earth to be supported, the space or interior angle between the base 1 and the wall 2 being filled with earth on completion of erection of the structure.

As shown, the vertical wall 2 bears on a concrete foundation bead 4, one edge of which contacts a longitudinal marginal portion of the base 1.

In accordance with the invention, the wall 2 is formed from a plurality of prefabricated reinforced concrete panels 5 each of which is of fixed width and substantially equals in height the depth of earth to be supported. The inner or uphill face of each said panel 5 is formed with a stiffening rib 6 of reinforced concrete which extends from the bottom to the top of the said panel. An end 7 of a tie rod 3, in the form of a reinforced concrete girder, is attached to each said rib 6 at about the midheight of the latter.

As indicated, the tie rods 3 are each in the form of a reinforced girder and each said rod includes reinforcements 9 therein. These reinforcements for the tie rods 3 are internally located and anchored to a respective panel 5 in order to transmit stresses thereto and to prevent tilting and slipping of the said panel as a result of the forces exerted by the earth filling and to absorb the bending moments which may arise as the earth filling settles. It is to be noted that the reinforcements 9 for each the rod 3 may be varied in number and diameter according to the height of the wall 2, the nature of the earth, the slope of the confined earth embankment, the overload on the inclination of the slope and the overload on the embankment, if any.

Also in accordance with the invention, the tie rod 3 are prefabricated together with the panels 5, an articulation 8 being provided between the end 7 of each tie rod 3 and the rib 6 on the associated panel 5. The prefabrication of the panels, the rods and these articulations will now be detailed.

The panel 5 is generally built by casting concrete in a mould that the exposed panel face faces downwards, the rib 6 being formed by the provision of suitably shaped walls in the mould. A tooth 11 is formed on the top sur face of the rib 6. During such muolding, ends of the reinforcements 9 which will be later incorporated in an associated tie rod 3 are embedded in the Concrete form ing the rib 6 on the panel 5, the remaining and major lengths of the reinforcements 9 being left exposed, and drawn out of and away from the rib 6 in a direction parallel to the latter, thereby forming a bend 10 at the region of their exit from the said rib (FIG. 4).

Upon removal of the mould from the rib 6, two plates are placed one at either side of the said rib to form a mould for casting the concrete for the associated tie rod 3. This is done while care is taken to leave the bent portions 10 of the reinforcements 9 (FIG. 4) exposed. The remaining portion of the reinforcements 9 are now embedded in the casting for the tie rod 3, this embedding being with the exception of the extreme free ends 91 of the reinforcements which protrude from the casting.

Before casting of the tie rod 3, a layer of insulating material, such as a sheet of tarred paper, is placed on the rib 6 to prevent the concrete of the tie rod 3 from setting integrally with the concrete of the rib 6.

The presence of the tooth 11 referred to above results in the formation of a matching recess 12 in the tie rod 3.

As a result of this casting procedure the bent portions 10 of the reinforcements 9, which bent portions were of course left exposed on formation of the tie rod 3, constitute the aforementioned articulation 8 between the end 7 of the tie rod 3 and the panel 5. The other end 13 of the tie rod 3 still remains free.

As best seen from FIGS. 2 and 3 and 8 to 10, a ring 14 is secured to the rib 6 close to its articulation 8 of the tie rod 3, a further ring 15 being secured to the said rib 6 towards its upper end and the top of the panel 5.

For erection of a structure of the type shown in FIG. 1, from prefabricated elements comprising each a single panel and tie rod facilitated as hereinbefore described, the tie rod 3 of each such element initially remains bent about its articulation 8 towards and against its panel rib 6 (FIG. 4).

After transport of the element to the exactly desired position, the tie rod 3 therefor is drawn apart from the rib about the articulation 8 so that its ends 13 is Well spaced from the panel and the whole rod obliquely arranged with respect thereto. This position of the tie rod 3 with respect to the panel 5 is maintained by the insertion of a spacer 16, such as a small board, between the tooth 11 and groove 12.

As a result of the hingeing of the tie rod 3, the bent portions 10 of the reinforcements 9 are straightened and this is shown in FIG. 5. It is to be here noted that the centre of gravity of the combined element formed by the tie rod 3, the panel 5 and the rib 6 at this juncture automatically displaced towards the tie rod 3 and away from the exposed panel faces.

The panel 5 is lifted by engaging one end of a cable 17 in the ring 14 and by passing the other end of the cable through the ring 15 to engage it with the hook 18 of suitable lifting gear (see FIG. 8). The panel 5 may in this way be suspended by the hook 18 in a stable and substantially vertical position and in this state be lowered onto the bead 4 so that the ends 9' of the reinforcements 9 extending from the face end 13 of the tie rod 3 rest on the ground.

When lowered into this position the panel 5 is in a condition of stable equilibrium and the cable 17 may be released therefrom.

As shown in FIG. 9, a prop 19 is now forced between the inner face of the panel 5 and the earth bank adjacent it and the said panel is so arranged as to stand truly vertically. The base 1 i now cast and this incorporates the extreme free ends of the reinforcements 9. The space between the end 7 of the tie rod 3 and the opposing surface of the rib 6 is next filled with cement mortar which is mixed with expansible substances so as to tension the reinforcements during setting. The said substances added to the mortar also serve to accelerate setting of the latter and spacer board 16 functions as a base for a mould adapted to contain this filling mortar.

After the mortar has set the inner angle of space between the base 1 and the panels 5 is filled with earth.

In order to ensure a full straightening of the portions 10 of the reinforcements 9 constituting the articulation 8, during drawing apart of the tie rod, these portions should be so curved when the tie rod 3 is bent against the rib 6, that the middle points of the curved portions 10 are aligned along a straight line parallel with the exposed face of the panel 5.

In practice, the type of articulation 8 described with reference to FIGS. 4 and 5 is recommended when the reinforcements 9 are three or four in number, and the modified embodiment of FIGS. 6 and 7 is more suitable when a larger number of such reinforcements are employed. Specific reference will now be made to these latter two figures, in which similar reference numerals are used to denote components which are seen in FIGS. 4 land 5.

As will be seen from FIGS. 6 and 7, a number of reinforcements 90 are partly embedded in the rib 6 of the panel 5 and the remaining portions of these reinforcements 90 embedded in the tie rod 3. Intermediate portions thereof are left exposed .at the junction of the tie rod 3 With the panel 5, this being arranged during prefabrication. Further reinforcements are also utilised for the tie rod 3, these being denoted 9a and bent over to form eyelets 19 which are coaxial one with another and are arranged at the end 7 of the said tie rod. Still further reinforcements 20 .are embedded in the rib 6 of the panel 5 and there form coaxial eyelets 21 which are similar to the eyelets 19.

In addition to any basic reinforcements 9, the ribs 6 are thus strengthened also by

reinforcements

20 and 90 and the rods 3 by

reinforcements

9a and 90.

The relative position of the

eyelets

19, 21 is such that separation of the tie rod 3 from the panel 5 about the articulation 8 causes the loops of the eyelets 19 to move into coincidence with the loops of the eyelets 21. The tie rod 3 may thus be retained in this separated position it a dowel 22 is inserted through the aligned eyelets 19 and 21 and a spacer 16 wedged between the aforementioned tooth 11 and groove 12 which .are again provided (FIG. 7).

By way of general explanation it is pointed out that, during erection of a structure according to the invention, the base 1 may be formed gradually as laying of the panel 5 progresses, and in this way the said base can be cast without the need to employ cranes or other lifting gear, conventional transport means being able to move in the spaces still unoccupied by the panels. Furthermore, .all the operations for erection of the structure can be carried out as formation of the base progresses, and this of course avoids any risk from storms, landslides or earth falls, all of which latter hazards can otherwise overturn the panels before they are firmly con nected with the base.

Various modifications of the invention are of course possible within the scope of the appended claims.

For instance, it is possible, after filling the clearance between the tie rods and ribs with mortar, to start at once filling the structure with earth. This is possible due to the rapid setting of the mortar with the expansive substances referred to above.

What I claim is:

1. A structural element for forming an earth supporting structure the structural element comprising:

(a) la prefabricated reinforced concrete panel with an exposed face, a back face, and including reinforcing elements within the panel;

(b) a tie rod in the form of a prefabricated re-inforced concrete girder with re-inforcing elements therein, the tie rod being articulated at one end to the back face of the panel;

(0) at least some of the re-inforcing elements being common to the panel and girder and exposed from within the concrete over a portion of the elements between an end of the tie rod and the back face of the panel; and

(d) the articulation between the tie rod and panel formed by the exposed portion of the re-inforcing elements common to the panel and girder, the end of the tie rod that is not articulated to the panel being free to allow the tie rod to hinge from the panel about the articulation from a position adjacent to the back face of the panel to a position to prop and support the panel before connection of the free end of the tie rod to a base structure.

2. A structural element as in claim 1 wherein the exposed intermediate portions of the common re-inforcing elements are initially bent and. curved so that the middle points of the exposed intermediate portions are on a straight line parallel with the exposed panel face.

3. A structural element as in claim 1 wherein at least some of the re-inforcing elements of the panel and tie rod are bent to form eyelets, one eyelet being formed by the tie rod re-inforcing elements adjiacent the articulated end of the tie rod, and one eyelet formed by the panel re-inforcing elements adjacent the back face of the panel at the articulation, the eyelets being positioned such that when the tie rod is articulated to a propping position the eyelets are aligned and a dowel may be inserted through the eyelets.

4. A method of forming an earth supporting structure utilizing a plurality of structural elements, each element including a re-inforced concrete panel and a re-inforced concrete tie rod articulated at one end to a back face of the panel through exposed re-inforcing elements common to the panel and tie rod, the panel and tie rod being prefabricated together, the method comprising the steps of:

(a) arranging at least one said element in a substantially upright position with the tie rod hinged about the articulation and extending from the panel with the free end of the tie rod resting on the ground to prop the panel;

(b) forcing another prop between the panel and an earth bank;

(0) arranging the panel to stand truely vertical;

(d) casting a base on the ground, which base incorporates the free end of the tie rod;

(e) filling a space around the exposed re-inforcing elements at the point of articulation between the end of the tie rod and the back face of the panel with cement;

(f) removing the prop and filling a space between the panel the base and the earth bank with earth.

5. A method as in claim 4 wherein the position of the tie rod with respect to the panel in propping position is maintained by inserting a spacer therebetween.

References Cited UNITED STATES PATENTS 2,941,371 6/1960 Benedict et al. 6149 FOREIGN PATENTS 165,930 5/1950 Austria. 592,575 5/ 1925 France.

37,209 1923 Norway.

JACOB SHAPIRO, Primary Examiner.

U.S. Cl. X.R. 52-169, 573, 583