KR20150121191A - Reinforcement, structure and method for underground reinforced concrete constructions - Google Patents

Abstract

The reinforced concrete structure comprises reinforcements (1, 11) made of a plurality of elongated longitudinal members (2, 12) of fibrous material or of a similar material and arranged substantially parallel to one another in at least one predetermined direction do. The elongate longitudinal members are coupled to one another by coupling members 3, 13 of fiberglass or are formed by strips of flexible polymeric material. The metal and / or synthetic fibers are mixed with the concrete matrix to provide a shear strength to the structure, making it possible to substantially reduce the number of coupling members 3, 13.

Description

TECHNICAL FIELD [0001] The present invention relates to a reinforcement structure, a structure and a method for an underground reinforced concrete structure. BACKGROUND OF THE INVENTION 1. Field of the Invention [0002]

The present invention relates to reinforcements, structures and methods for making underground reinforced concrete constructions.

The present invention has been developed, but not limited specifically, to the construction of tunnel walls and shafts during excavation operations.

Excavation of tunnels by excavating machines (of which "tunnel boring machines" (TBM) are well known) usually install excavation machines from reinforced concrete shaft structures designed to include the ground around the tunnel entrance launch. Shafts are conventionally constructed by concrete diaphragms of a shape that tends to be parallel hexahedrons, or are formed of circular piles driven into the ground prior to commencing tunnel excavation, and are excavated and cast on the field ground.

 Excavation machines are usually moved at the ends of the tunnel through pre-built shafts. Moreover, it is very common to provide similar ventilation or approach station shafts or other reinforced concrete structures and diaphragms along the path of the tunnel as excavation operations progress.

One of the major challenges to be faced is the passage of TBM through reinforced concrete diaphragms or structures that are reinforced by these steel bars and rods to withstand the loads and bending moments imposed by the surrounding ground. Reinforced concrete is very difficult to actually break due to the additional strength provided by the iron bars and the inherent ductility of the iron bars, which prevents almost all excavating machines from passing through these structures.

For this reason, reinforcement techniques for concrete structures that do not prevent the passage of excavation machines have been introduced in recent years. In this technique, also known as "soft-eye" openings, the steel reinforcement is replaced with a fiberglass reinforcement in the area through which the excavating machine passes the concrete structure. It is known to produce a "soft-eye" having a plurality of longitudinal members formed of glass fiber bars which are joined by a plurality of ties suitably formed with respect to the geometry of the underground structure, .

The use of fiberglass reinforcements in reinforced structures for the construction of tunnels facilitates the work of excavation machines which can be excavated when encountered with materials of similar compressive strength, such as rocks and unreinforced concrete It proceeds at speeds above the speed of the machines.

Fiberglass typically has a higher tensile strength than an iron, but is much more fragile, causing longitudinal degradation of the polymeric resin when the glass fibers are broken. These properties are considered when producing concrete constructions with fiberglass reinforcements, and for this reason the number of longitudinal members, particularly ties, is greater in conventional reinforced concrete constructions with similar strength steel reinforcements Much more. For simplicity, the fiberglass longitudinal members and the frame formed by the ties for reinforcing concrete or cement are denser than conventional similar frames formed by steel longitudinal members and ties.

The foregoing is a disadvantage when using fiberglass reinforcements in reinforced concrete structures, which are relatively costly due to the large number of longitudinal members and ties required to achieve satisfactory strength. This financial cost is particularly disadvantageous for operations that are intended to be temporary, such as temporary underground works that are destroyed when the excavating machine passes through the structures.

Also, fiberglass reinforcements are relatively more complex to manufacture than conventional steel reinforcements. Steel bars can easily be deformed to produce ties of desired sizes even during cold weather, whereas fiberglass ties have to be preformed at the time of manufacture, resulting in higher costs for mass production, more complex problems, Occurs. That is, the fiberglass reinforced cage or frame is assembled in the same manner as a similar steel cage or frame, with the main difference that fiberglass ties can not be bent, welded in the field, and ready at the factory. This makes it more difficult to manufacture, transport and install concrete structures that are complicated in construction and reinforced with fiberglass reinforcements, especially when building underground structures.

The present invention suggests solving these and other disadvantages of the prior art by means of reinforcements, structures and methods for strong underground structures that are easily manufactured and relatively economical.

In order to achieve the above-mentioned objects, the present invention relates to reinforcements, structures and methods for underground reinforced concrete structures having the features set forth in the appended claims.

In one embodiment, a reinforcing material, cage, frame or framework of a material of fiberglass or of similar strength and brittleness is formed by a plurality of longitudinal members, preferably a smooth or wrinkled outer surface, Which are arranged and joined by a plurality of coupling members, the plurality of coupling members being preferably substantially transverse to the direction of the fiberglass bars so that the reinforcement can be squeezed for conveyance But it is not necessarily the case.

The reinforcement may also include a limited plurality of relatively rigid coupling members, such as ties or the like, made of fiberglass to provide a reinforcement having only a predetermined geometry. In other words, ties do not have basic structural functions and do not take an important part in the calculation of the strength of underground structures. The small number of fiberglass ties makes it much less difficult to construct reinforcements than in the prior art where a very large number of rigid ties are used. Concretes cast to include fiberglass reinforcements contain a certain amount of metal and / or synthetic fibers that provide significant shear strength to the concrete, particularly for large surface areas. Surprisingly, this kind of concrete reinforced by fibers does not prevent the excavating machines from easily penetrating the concrete structure and damaging the structure even when the fibers are metal. In addition, the fiber glass bars forming the longitudinal members of the reinforced concrete structure of the present invention themselves provide excellent bending strength as a result of the longitudinal continuity of the glass filaments in the bars. The reinforced concrete structure is provided with shear strength by including metal and / or synthetic fibers in the cement aggregate.

The flexible tie members are preferably made of strips of polymeric material made by bundles of very strong synthetic fibers contained within a strong and durable polymeric sheath.

Additional features and advantages of the invention are set forth in the following description of an embodiment made with reference to the accompanying drawings, given purely by way of non-limiting example only.

1 is a schematic perspective view of one embodiment of a fiberglass reinforcement for making a file for an underground reinforced concrete structure;
Figure 2 is a schematic perspective view of a further embodiment of a reinforcement for making a subdivision plate provided with a "soft-eye ";
Fig. 3 is a diagrammatic view of a cross-section of a subdivision plate containing "soft-eye" obtained by the reinforcement of Fig.

Figure 1 is a schematic perspective view of one embodiment of a glass fiber reinforcement (1) for making piles for an underground reinforced concrete structure. The fiberglass reinforcement 1 comprises a plurality of glass fiber longitudinal members 2 spaced substantially apart from one another and extending parallel to one another and arranged in a manner substantially similar to known metal longitudinal members used for reinforced concrete structures . The longitudinal members 2 are held in place by the coupling members 3 which are spaced apart from one another, in particular in comparison with known reinforcements. The coupling members 3 may be attached to the longitudinal members 2 by means of bindings, clips or the like, or may be coupled by adhesives or other similar means.

The coupling members 3 can also be made of glass fiber, whereby the reinforcement 1 can be formed in a predetermined geometric shape, for example in the cylindrical shape shown in Fig. 1, or in any desired shape, 2 and as shown in Fig. 3, for the construction of walls or diaphragms. In this case, the reinforcement is preferably manufactured in the factory and then transported to the place of use of the reinforcement.

In an alternative embodiment, the coupling members 3 are made of strips of polymeric material made from a bundle of high strength synthetic fibers contained in a strong, durable polymeric sheath. One example of a strip particularly suitable for use is a strip known as ParaWeb ( ^TM ) manufactured by Officine Maccaferri SpA which is used in the ground reinforcement portion. The use of the flexible coupling members 3 means that the reinforcements can be squeezed by bringing the longitudinal members 2 in close contact with each other to facilitate the transport of the longitudinal members from the manufacturing site to the site of use. The strips used for the fabrication of the coupling elements 3 enable the longitudinal members 2 to come into close contact but prevent the relative displacement of the longitudinal members 2 in the axial direction. That is, the strips used as the coupling members 3 are preferably flexible (not necessarily) in a plane substantially transverse to the axial direction of the fiberglass bars so that the reinforcement can be squeezed for conveyance Can then be easily brought to the desired geometry by simply moving the longitudinal members 2 in the transverse direction to the maximum extent permitted by the strips used as the connecting members 3 .

The longitudinal members 2 may preferably have a diameter of greater than about 28 mm (not necessarily) and preferably less than about 42 mm (but not necessarily). Although the preferred sizes of the longitudinal members 2 depend on the particular design of the underground structure to be built, the use of smaller diameter longitudinal members provides a subterranean structure with the necessary strength to withstand the forces exerted by the surrounding ground It will be appreciated that these longitudinal members are less advantageous because they have to be provided in relatively large numbers. Longitudinal members with larger diameters than indicated have a higher stress as much as the stress imparted by the fibers closest to the outer surface to the glass fibers closest to the center of the cross section of the bar, And is therefore less desirable. This problem generally results in a relative reduction in the strength and efficiency of glass fiber bars having larger diameters as compared to bars having smaller diameters.

Figure 2 is a schematic perspective view of a "soft-eye" structure with reinforcement 11 substantially similar to the reinforcement of Figure 1, but also includes longitudinal members 12 formed by elongate fibrous glass bars The outer surfaces of the bars are smooth, preferably corrugated, spaced apart, parallel to each other and joined by the coupling members 13. As described above, the coupling members 13 may be rigid, or preferably flexible, such as, for example, fiberglass ties using polymeric strips of the type described above.

The fiberglass reinforcement 11 acting as a soft-eye can for example be fastened by means of bindings 17 to a conventional steel reinforcement 18 formed by the longitudinal members 15 of the steel and the ties 16 of steel (10). The height D of the fiberglass reinforcement 11 without the steel reinforcement 10 is at least equal to the excavation size of the TBM, as will be described in detail below.

As can be seen from the schematic cross-section of Figure 3, the reinforcement 11 during use is formed by using the concrete aggregate 21 comprising the reinforcement 11 (and the soft-eye, steel reinforcement 10) ), And reinforcements of underground concrete structures (20) built by known techniques in underground construction at excavation on the ground (T).

According to a particular feature, the concrete aggregate 21 comprises a plurality of metal and / or synthetic fibers therein. Examples of such fibers are those known by the trade name Wirand ( ^R ), manufactured by Officine Maccaferri SpA. The metal and / or synthetic fibers are randomly distributed because the metal and / or synthetic fibers are mixed with the concrete when the concrete is in a fluid state. The fibers are contained within the concrete aggregate to provide a concrete aggregate with a shear strength sufficient to eliminate or at least substantially reduce the need for transverse reinforcement ties in the fiberglass reinforcement 11. [

The construction of the building using the reinforced concrete according to the present invention follows a procedure which is not different from the procedure normally used for the underground reinforced concrete buildings, and it is particularly simple for a person who is not specially trained in the use of the present invention to carry out the construction in the building site .

Fiberglass bars which form the longitudinal members 2, 12 in each of the above-mentioned reinforcements 1, 11 are prefabricated. The coupling members 3, 13 can be made of fiberglass and the coupling members are pre-fabricated in sizes and dimensions that are standardized or adjusted with a special design in which coupling members are used. In any case, the relatively small number of coupling members 3 means that the manufacture of the coupling members is relatively economical even when adjusted to a particular design.

For example, using the polymeric strips described above, in embodiments where the coupling members 3, 13 are flexible, the fabrication of reinforcements of geometric shapes and sizes that are also tailored to a particular design, The fabrication of the reinforcements 1, 11 is facilitated by the ability to cut the strips, such as coupling members, to size the reinforcements and squeeze the reinforcements so that they can be transported to the use site for construction of the reinforcements 1, It is especially economical and advantageous.

By placing the longitudinal members (2, 12) in a predetermined geometrical shape first in the building site and fastening them to the coupling members (3, 13) when the reinforcements are rigid, or by maintaining the reinforcements in place, By expanding the previously compressed reinforcements when the members 3, 13 are formed of flexible members, for example the above-mentioned polymeric strips, or members functioning in a similar manner, the reinforcements 1, 11 ) Are prepared.

After the excavation section is formed by known methods on the ground T, for example, a cylindrical reinforcement 1 is inserted into the excavation section to form a pile, for example, Is inserted into the excavation section to form the soft-eye of the diaphragm or shaft for launching the TBM. Concrete, which is then prepared on site or manufactured far from the manufacturing plant or brought to the site by a concrete mixer, is injected into the excavation section. The concrete aggregate is generally mixed with known types of metal and / or synthetic fibers, for example in the name of the present applicants, of the type disclosed in the patent specification EP 0 475 917. The fibers may be mixed with the concrete according to the methods disclosed in publication < RTI ID = 0.0 > WO 2011/015966 < / RTI > After the concrete is cast and cured, the construction of the underground structure is completed.

The building provided in this way is characterized by the compressive strength of the building provided by the concrete, the bending strength of the building provided by the fiberglass longitudinal members, and the shear strength of the building provided by the fibers substantially contained in the concrete matrix . Another important feature of the structure is that it can be easily penetrated and removed by an excavating machine, especially TBM, during the work to make the tunnel. This makes the invention particularly advantageous for the construction of temporary tunnel walls and TBM launching shafts. The use of fibers mixed with concrete makes it possible to substantially reduce the number of coupling members for longitudinal members without compromising the strength of the overall structure. By reducing the number of coupling members, the time required to couple the coupling members to the longitudinal members is also proportionally reduced accordingly, so that the lifetime is typically reduced as the excavation operations are designed to remove the structures It provides major cost savings on the construction of short structures.

When the coupling members used have flexibility, the construction costs of the structures having different geometric shapes, possibly adjusted to a special plan, such as storage and transportation costs, are also reduced.

It is recognized that the principles of the present invention remain the same and that embodiments and constituent details may be varied and broadly described without departing from the scope of the present invention, Will be.

Claims (8)

As a reinforced concrete structure,
A reinforcing member made of a plurality of elongate longitudinal members (2, 12) of fiberglass or similar material and arranged substantially parallel to one another in at least one predetermined direction and coupled to each other by coupling members (3, 13) And water (1, 11), wherein the metal and / or synthetic fibers are mixed with a concrete matrix,
Reinforced Concrete Structures. The method according to claim 1,
Characterized in that the elongate longitudinal members (2, 12) of the fiberglass have a pleated outer surface,
Reinforced Concrete Structures. 3. The method according to claim 1 or 2,
Characterized in that the elongated longitudinal members (2, 12) have a diameter greater than about 28 mm and not greater than about 42 mm,
Reinforced Concrete Structures. 5. Reinforcement for reinforced concrete structures according to any one of claims 1 to 3,
(2, 12) of fiberglass or similar material arranged substantially parallel to one another in at least one predetermined direction and coupled to each other by flexible coupling members (3, 13) doing,
Reinforcement for reinforced concrete structures. 5. The method of claim 4,
The flexible coupling members (3, 13) comprise a strip of polymeric material made from a bundle of high strength synthetic fibers contained in a polymeric cover,
Reinforcement for reinforced concrete structures. The method according to claim 4 or 5,
The elongated longitudinal members (2, 12) are connected to respective metal longitudinal members of a metal reinforcement for the production of a "soft-eye"
Reinforcement for reinforced concrete structures. Use of a reinforced concrete structure according to any one of claims 1 to 3 for the construction of temporary underground structures in the construction of excavation works such as tunnels and the like. As a method for constructing an underground reinforced concrete structure,
- made of a plurality of elongated longitudinal members (2, 12) of fiberglass or similar material and arranged substantially parallel to one another in at least one predetermined direction and being joined together by coupling members (3, 13) (1, 11), which is ring-
- preparing an excavation section on the ground (T)
- inserting said reinforcement (1, 11) into a ground (T) excavation,
- filling the ground excavation with concrete (21) to include reinforcement (1, 11), metal and / or synthetic fibers mixed with concrete.
A Method for the Construction of Underground Reinforced Concrete Structures.

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