ES2570029B2 - Link device between micropiles and existing shoe for building overhang - Google Patents

Abstract

Link device between micropiles and existing footings for building enhancement. # This is a link device between foundations to be heated and micropiles, both of any material. With it the union between both elements is improved, usually committed to the simple friction between the surfaces of both materials. The device has a main part consisting of a shaft (1) and pressure skates (4), provisionally connected to each other by means of tying elements (8). Before being introduced into the hole in the foundation (6) to be overheated, a transition element or screw (9) is placed to connect the device with the micropile (7). The effect of exerting pressure on the walls of the hole of the foundation to be stressed is achieved by activating the device by means of a screw or pressure rod (3), operated manually or mechanically.

Description

OBJECT OF THE INVENTION

The present invention relates to a link device between micropiles and an existing shoe for overhaul of buildings, that is, for overhaul in rehabilitation works.

The device is applicable to the traditional way of executing an overhang by micropiles, drilling the flight area of the shoe, which guarantees the transfer of loads, for which means are provided that reduce the number of micropiles needed for an overhang, being applicable in all cases that may arise in buildings.

The invention is part of the technical construction sector, specifically in the field of building architecture and engineering, addressing the existing connection between micropiles and existing footings in the usual procedure of overhaul of buildings in rehabilitation works.

BACKGROUND OF THE INVENTION

In the execution of overhangs of existing building foundations, the most frequent procedure at present is the use of micropiles, since they are elements that run with little material and small machinery, which facilitates commissioning in existing buildings where space limitation It is a condition to take into account. In this system, the most unfavorable point, in the technical aspect, is at the junction between the micropiles and the existing foundation in the building. The calculation and execution procedure is approximately the following:

1. The load capacity of the micropiles is calculated, based on the resistance of the ground,

obtained from the corresponding geotechnical study. These elements are composed of a central tube, made of steel, covered with a mortar grout, which serves a double function, resistant and protective. Given their physical characteristics, micropiles are very resistant elements, since they are small steel pillars reinforced externally and internally with concrete.

2.

The second step consists in estimating the number of micropiles needed, depending on the load of the shoe that is the subject of overheating.

3.

Subsequently, the connection between the micropiles and the existing foundation is analyzed, depending on the materials that make up both, especially the second. In this sense, the Guide for the Project and the Execution of Micropiles in Road Works, the only normative reference in this field in Spain, includes a table with the last flush tension of calculation between the grout or mortar of the micropile and the pre-existing foundation.

Normally, this union is the most unfavorable point in the calculation. That is to say, the resistance of the micropiles, is penalized by the union between them and the existing shoe, where everything is entrusted to the flush effort between the concrete of the micropile and that of the existing shoe. Generally, this makes this meeting the most delicate point of an overhaul intervention, forcing the increase in the number of micropiles, with respect to those that would be necessary only due to the geotechnical conditions. On the other hand, in cases where the micropiles form a new foundation, this penalty does not occur, since outgoing rods are arranged in the micropiles, in order to improve the adhesion with the concrete of the bundle-bundle beam, which In addition, it is poured at one time, not causing the joint between pre-existing concrete and pouring in situ, in the case of overheating.

Consequently, an improvement in the strength of this joint will allow the reduction of the number of micropiles necessary for the overhaul of a foundation, which means an economic saving and the execution time of the overhang.

Some patents address the issue of piles or micropiles, such as patent ES2394578A1 "Prefabricated pile hollow for foundation", the patent

ES2317172T3 "Micropile and micropile mounting stems comprising said stems" and patent ES2394578A1 "Prefabricated hollow splicing pile for foundation", but all of them refer exclusively to the characteristics of the micropiles and do not fall into the type or characteristics of the foundation , which is what the present invention fundamentally refers to; specifically to the relationship between micropile and existing foundation.

The ES2313425T3 patent "Tower foundation reinforcement device" consists in the realization of a coated slab that reinforces the foundation in order to prevent slippage. It is therefore a different concept, specifically applied to foundations of towers, such as those composed of lattices, which usually hold the electrical networks that run through the field.

Patent ES2351097T3 "Foundation reinforcement procedure" serves to reinforce existing pylon foundations avoiding the incorporation of micropiles, an important factor in the present invention.

The patent ES2100776A1 "Total execution of any prefabricated construction in reinforced concrete", consists in the execution of prefabricated and modular reinforced concrete plates that are subsequently used in building. The aforementioned invention relates to the construction of molds for prefabricated elements, not to mention any link between the foundation elements, nor the overhauls of these, which is the basis of the present.

The ES2393003A1 patent "Embedded head for anchors in construction systems" prevents the heads of the anchors from protruding from the walls or walls, minimizing the impact on the environment. It is applicable in elements with active reinforcements, especially the anchors for securing earth containment screens. It does not allow to reduce the number of piles necessary to re-build a foundation.

There are also several Spanish utility models with similarities to the present invention, among which the ES1057773U "Threaded Pilot-micropile" model, which consists of a variant of the known piles and which is screwed on soft ground and

which aims to improve the foundation elements. Therefore, it is not a novel micropile-shoe attachment element but rather a variant of the system currently used.

The model ES1078907U "Apparatus for the overheating of a foundation" consists of an apparatus that comprises a micropile of overhang that is driven into the ground and serves as a support for the foundation. It does this by incorporating a plate on the outside of the shoe, which motivates you to have to use additional systems to ensure the proper functioning of the foundation. That is to say, the referred invention proposes to make the union between a foundation to be stressed and a pile, leaving the second one outside the first one, which penalizes the transfer of the loads between both foundation elements. In addition, in most of the cases in building, with the aforementioned system it would be necessary to reinforce the existing foundation, which would limit the proposal, to very specific cases.

DESCRIPTION OF THE INVENTION

The present invention relates to a connecting element between micropiles with the existing shoe that is subject to overhaul in rehabilitation works.

With the present invention it is intended to reduce the number of micropiles needed, since a device is designed that improves the union of the micropile with the existing shoe, object of overhaul, since it improves the transmission of loads between micropiles and shoes.

In general, in the calculation of an overhang by micropiles, the most unfavorable point is the union between them and the existing shoe. Since the union between both elements is produced by simple friction between concrete, the present invention aims to provide an improvement thereof, improving the transmission of the loads of the shoe to the micropile. To achieve this, the proposed device exerts a pressure on the walls of the hole executed in the hot shoe.

It is a metal device that is embedded in the concrete provided when executing

the final part of the micropile, so its proper behavior is guaranteed against corrosion.

This invention is intended for overhaul works of existing foundations.

5 An improvement in the transmission of loads between shoes and micropiles reduces the number of micropiles necessary for the transmission of loads between an existing building and its new foundation after overheating, which means an economic and temporary saving in the execution of a work.

Basically, the linking device object of the invention is constituted from a central and vertical axis to which are welded perpendicularly and offset 90 ° in an alternating manner, tubes of the same diameter in which other tubes connected perpendicularly to vertical surface plates are connected. roughened by its outer face, surface that will end up in contact with the concrete of the existing foundation that is subject to overhang

15 There are also wrap-around elements of the aforementioned elements, so that the coupling by plug between the tubes connected to the central axis and the tubes of the side plates, is perfectly carried out in order to facilitate the introduction into the corresponding existing hole of The shoes.

20 The device is complemented by a pressure screw that is inserted vertically through the central axis, pushing laterally the skates that form the side plates and the rods welded perpendicularly to it, so that once that pressure screw is inserted, the commented skates exert pressure on the surface wall

25 inside the hole or drilling made on pre-existing foundation concrete.

On the other hand, a transition piece is provided as a connecting element between the device mentioned above and the micropile itself, whose transition piece is formed by a grooved cylinder in its upper part to house the horizontal tubes of the

30 central axis, so that perpendicular to these grooves there are tightening screws to fix the shaft and therefore the device to the corresponding micropile.

DESCRIPTION OF THE DRAWINGS

To complement the description that will then be made and in order to help a better understanding of the features of the invention, according to a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description. where, for illustrative and non-limiting purposes, the following has been represented:

Figure 1.- Shows a vertical section view of the link device in an inoperative situation.

Figure 2.- Shows the same device represented in the previous figure but with the tied element wrapping the elements of the device, but also in its deactivated position.

Figure 3.- Shows a view like that of the previous figure but with the pressure rod inserted on the central and vertical axis of the device.

Figure 4.- Shows a perspective view of the vertical axis with the tubes welded perpendicularly and therefore horizontally to said vertical axis.

Figure 5.- Shows a sectional view of a perforation performed in an existing foundation.

Figure 6.- Shows the device in a position to be mounted on the perforation shown in Figure 5.

Figure 7. - Shows view with the device already mounted in the foundation drilling, but not yet activated.

Figure 8 shows, finally, a view like that of the previous figure but with the

link device in operative or activated situation, exerting pressure on the perforation of the foundation.

5 PREFERRED EMBODIMENT OF THE INVENTION

As can be seen in the aforementioned figures, and specifically in relation to figures 1, 2 and 3, the device can be observed in assembly and activation phases. Specifically, the assembly of the device consists in the formation of a longitudinal device, by means of

10 assembly of the parts that are detailed below and that correspond to:

-

Central axis of the device (1), composed of welded tubes. One of them is a vertical tube, which will be used to insert inside the pressure screw (3), as indicated below. This central axis is a hollow tube and

15 has an internal thread, so that the penetration of the pressure screw (3) is facilitated and guaranteed.

As the figures show, this central axis (1) has other tubes (2) perpendicular to it. Its mission is to hold the pressure skates (4), whose

20 fixing pins (4 ’) are inserted inside these horizontal tubes (2).

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The pressure skates (4) have the function of improving the adhesion between the new micropile and the pre-existing shoe.

25 The execution system consists of making a hole (5) in the existing shoe (6), with a crown drill, to subsequently execute inside the same hole for the micropile (7). Traditionally the connection between the micropile (7) and the existing foundation (6) has been entrusted to the flush effort

30 (simply friction) between the materials of both foundations. The pressure skates have two distinct parts; the first (4) is a plate, finished on a rough surface, to improve the adhesion with the material of the

foundation to be stressed. The second part of the skates are the fixing pins (4 '), formed by welded rods perpendicular to the bands (4), so that they allow their coupling with the central axis (1) of the device, when introduced into perpendicular substitutes (2).

The designed device consists of four pressure skates (4), arranged orthogonally, but the number could be increased depending on the technical requirements, preferably in pairs, so that the two opposite skates are faced, with the bars (4 ') occupying a diameter slightly smaller than the hole in the preexisting shoe. In this position, the horizontal bars (4 ’) facing each other touch.

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To achieve the activation of the device, that is, the effect of the pressure on the walls of the hole (5) carried out on the foundation (6) to be stressed, it is necessary to introduce the pressure screw (3), which when advancing through the inside the central axis (1) moves the pressure skates (4) outwards, pushing them against the inside face of the hole (5) in the foundation

(6) to reheat. The diameter of the pressure screw (3) can be used to adjust the pressure exerted on the walls of the existing foundation hole. One way to achieve different diameters is to place threaded bushings in the end holes of the vertical tube of the central axis of the device (1).

-

To ensure that the central shaft (1) and the pressure skates (4) form a single piece, they are wrapped with tie elements (8), such as wire. When advancing the pressure screw (3), push the skates (4) outwards, breaking the tying elements (8).

The commissioning procedure of the device in question comprises the following stages:

1) Execution of the hole (5) in the existing foundation (6) and in the ground, to introduce the micropile (7) inside (Figure 5).

2) When the last section of the micropile tube (7) is inserted, the device is fixed to its head, using the clamping screws (9) (Figures 6 and 7).

5 3) Insertion of the device into the hole of the foundation to be stressed.

4) Insertion of the pressure screw (3) in the central axis of the device (1) to activate the device.

10 Finally, mention that the clamping screws (9) have upper grooves (9 ’) for positioning the tubes (2) welded perpendicular to the vertical axis (1).

Claims (1)

 R E I V I N D I C AC I O N E S 1st.- Link device between existing micropiles and shoes for building overhang, constituted from a vertical body intended to be mounted on the upper end or 5 head of the micropile (7), whose upper body is expandable by means of a shaped piece of threaded rod (3) for the adjustment and pressing of the body on the hole (5) made for the purpose in the corresponding foundation (6), characterized in that the expandable body that constitutes the device that is placed on the upper end of the micropile (7) ), is constituted by a vertical and tubular axis (1) to which tubes (2) 10 are welded perpendicularly with angular offset of 90º alternately, complementing with skates (4) formed by external plates in contact with the concrete and from which they emerge perpendicular pins (4 ') housed in the tubes (2) welded perpendicularly to the constitutive tube of the vertical axis (1), the elements (1-2) and elements being linked ntos (4-4 ’), by means of wire-bound elements (8) envelopes, to maintain a 15 set suitable to be housed inside the hole (5) of the foundation (6), by setting the rod (3) by tapping inside the tube that constitutes the vertical axis (1). 2nd.- Link device between existing micropiles and shoes for building overhang, 20 according to claim 1, characterized in that the assembly formed by the elements (1-2) and (4-4 ') is mounted on the upper end of the micropile (7), through a clamping screw (9) with the grooved upper edge (9 ') for placement and positioning in that groove (9') of the horizontal tubes (2) welded to the vertical tube (1).