US20240229460A9

US20240229460A9 - Reinforced masonry and method for carrying out such masonry

Info

Publication number: US20240229460A9
Application number: US18/491,390
Authority: US
Inventors: Marco Savoia; Maurizio Trizzino
Original assignee: St Consulting Srl
Current assignee: St Consulting Srl
Priority date: 2022-10-21
Filing date: 2023-10-20
Publication date: 2024-07-11
Also published as: EP4357558B1; IT202200021822A1; US20240133177A1; EP4357558A1

Abstract

A reinforced masonry includes at least one wall panel (M) having at least one accessible face (F) almost vertical and adjacent to a set of respective almost horizontal curb elements (C). Each curb element (C) is associated with the at least one wall panel (M). The reinforced masonry (1) includes a plurality of rod elements (3) fixed, individually or in bundles and by use of fixing material (5), within respective hollow seats (7) carried out, almost vertically and mutually spaced, at least in the accessible face (F) of the at least one wall panel (M). The reinforced masonry (1) further includes, for each seat or group of hollow seats (7), a first reinforcing element (9) fixed to portions of the at least one accessible face (F) of the wall panel (M) which are adjacent to the longitudinal development of the seat or group of hollow seats (7).

Description

BACKGROUND

The present invention relates to the field of construction concerning the improvement of earthquake resistance and/or the reinforcement of buildings with a load-bearing structure made of bricks or of reinforced concrete with bricks infill walls, and in particular it relates to a reinforced masonry and a method for carrying out such masonry.
The invention relates to a technical solution for improving the resistance to horizontal strain (e.g., seismic type) of existing brick buildings, such as those made of load-bearing bricks, and of reinforced concrete buildings with brick masonry panels, residential or industrial buildings, the improvement being obtained by operating mainly from the outside and with low-impact operations that allow the building to be kept usable during the work. In fact, it is well known that masonry buildings constructed in the past without provisions with respect to seismic actions are highly vulnerable, and that the known traditional techniques have the disadvantage of being highly invasive on the use of the building, while the known techniques considered innovative and non-invasive have the disadvantage of only partially solving the problems of vulnerability of such buildings to external stresses such as those due to seismic or flood or landslides events.
Prior art documents US 2020/362558 A1; US 2002/157344 A1 and KR 2009 0064830 refer to a reinforced masonry comprising a wall panel having an accessible face vertical and adjacent to a set of respective horizontal curb elements each one associated with the wall panel. Said reinforced masonry comprises a plurality of rod elements fixed within respective seats carried out in the accessible face of the wall panel. Prior art document KR 102 107 066 B1 refers to a reinforcing element.

SUMMARY

One purpose of the present invention is to propose a reinforced masonry in order to improve its resistance to horizontal stresses, particularly those due to seismic events. Another purpose is to propose a reinforced masonry whose architectural and aesthetic characteristics generally do not differ significantly from those of the masonry itself prior to its reinforcement.
Further purpose is to propose a reinforced masonry whose final strength characteristics can be predetermined and obtained in a way that can be modulated according to needs and contingencies, within an overall seismic improvement project.
Another purpose is to propose a method for carrying out the reinforcement of the masonry which allow the use of the building even during the implementation of such method.
Further purpose is to propose a method that can be implemented in pre-existing buildings and masonries made of brick, or other kind of building materials, load-bearing or in buildings and masonries with reinforced concrete structure and with infill made of brick walls, such as hollow or solid bricks.
Other purposes are to propose a method by which reinforcements of predeterminable strength can be made as required, in single or multi-story buildings and in specific portions or in the whole of buildings and masonries.
Another purpose of the present invention is to improve, compared with known techniques, by as much as 2-3 times the resistance to horizontal actions of masonry panels without increasing the thickness of the masonry itself.
Further purpose is to propose a method that can be implemented in a simple way to carry out the reinforced masonry even by typical workers such as those engaged in construction, moving limited weights that allow intervention with no more than two workers operating on a scaffold.
It should be noted that despite the simplicity of installation, the invention allows the reinforced masonry to reach the theoretical limit strength of the panels, which is that corresponding to diagonal compression failure.
The invention also includes specific techniques for anchoring to slab, curbs or building foundations.
The present invention can be the only intervention technique to be used in the case of buildings made entirely of load-bearing masonry, or it can be used to reinforce specific portions of a reinforced concrete building, even in conjunction with other intervention techniques.
In particular, three types of interventions are possible, similar from a technological point of view but very different from a structural point of view:

- reinforcement of solid or perforated load-bearing masonry elements, with a minimum thickness of about 15 cm, forming part of the load-bearing structure of the building or some of its parts (e.g., the stairwell);
- reinforcement of brick infill masonry panels, typically 8-15 cm thick, made outside the building and in the light between beams and pillars of a reinforced concrete structure, and making them integral with the reinforced concrete structure itself, so as to make the panels to all intents and purposes elements that cooperate in resisting horizontal strain (e.g., caused by an earthquake);
- reinforcement of large masonry panels against transverse actions, e.g., with respect to overturning verifications.

Reinforcement can be placed over the entire height of the building, modulating the number of bars for each floor according to the design and using the accessory systems listed below.
The reinforcement can also allow an improvement in the seismic performance of the building by operating only from the outside of the building and/or in the common parts, with obvious advantages from the point of view of reduced invasiveness of the interventions.
The intervention allows to improve the strength and ductility of the panels, as well as to avoid problems of out-of-plane tilting of the panels (both load-bearing and infill), without changing the stiffness of the structure in the case of load-bearing masonry, thus allowing, if necessary, to classify the intervention as “reinforcement intervention or local intervention” under the current Standards.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics of the invention are highlighted below with particular reference to the accompanying drawings in which:

FIG. 1 illustrates a schematic, partial, frontal view of the reinforced masonry object of the present invention in which two horizontal reinforcing elements are shown transparently to allow views of rearward portions of three first vertical reinforcing elements and in which any coatings, plastering or the like have been removed;

FIG. 2 illustrates a schematic, axonometric, partial view of a portion of FIG. 1 of which two cross sections, top and side, made from horizontal and vertical planes, respectively, are visible;

FIG. 3 illustrates a schematic and partial view of a horizontal cross-section of a portion of the reinforced masonry of FIG. 1 in which a coating or plaster is only partially visible;

FIG. 4 illustrates an alternative realization to that in FIG. 3 , including a holding element.

DETAILED DESCRIPTION

With reference to FIGS. 1-3 , numeral 1 indicates the reinforced masonry of the present invention comprising at least one masonry panel M, for example, consisting of a wall or portion of a wall made of solid or hollow bricks or other bricks of a building used for dwelling or industrial purposes or a retaining wall or consisting of an infill wall of a frame structure with reinforced concrete columns and beams, where such wall panel has at least one accessible face F, e.g. and preferably an exterior face of the masonry and an interior face thereof.
Such a face is usually flat and vertical but may be curved or slightly inclined.
The masonry may be without, or comprise one or more, floor curb elements C located at the height of the floors, and/or roofing and/or foundation. For example, the masonry may be without curb elements when it consists of enclosure or retaining walls.
Where present, such curb elements C are nearly horizontal and each is associated with at least one wall panel M that is closed, i.e., solid and continuous, or has a set of openings A, such as windows, doors, and the like. The masonry 1 comprises a plurality of rod elements 3 attached to the masonry individually or, if appropriate or if required by specific contingencies and/or characteristics of the masonry, in parallel bundles. Such rod elements 3 are clamped and secured within respective hollow seats 7 by means of a fixing material 5 that thereby accomplishes the so-called “grouting” of the rod elements 3 in their respective hollow seats 7. Such hollow seats 7 are carried out nearly or substantially vertically and mutually spaced apart on the accessible face F of the wall panel M.
In addition, for each hollow seat or group of hollow seats 7, the masonry 1 includes a first reinforcing element 9, elongated in shape, thin, with nearly parallel edges, and reproducing the shape of the portion of the accessible face F of the wall panel M adjacent to the longitudinal development of the hollow seat or group of hollow seats 7. In other words, the first reinforcing element 9 is firmly attached to the portions of the accessible face F located laterally to a hollow seat 7 by rejoining, that is bonding, such portions separated by the hollow seat.
The tests and trials conducted have shown excellent behavior and strength of the work described above, which, to achieve further improvement, may additionally include at least a second reinforcing element 11, each attached to a respective curb element C and to the portions of the wall panel M or wall panels M adjacent to said curb element C, e.g., the upper and lower panels to the curb itself. An intermediate horizontal portion or lower edge of the wall panel M may also include a corresponding second reinforcing element 11 attached to the respective visible face F.
The second reinforcing element 11 mutually ties the curb element C and the respective wall panels M together making the latter capable of contributing to the reinforcement of the masonry and possibly allows the intermediate and lower portions of the wall panels M to be strengthened as well.
The portions of the accessible faces of the wall panels M carrying the hollow seats 7 and the first 9 and second 11 reinforcing elements and adjacent thereto shall be either bare or devoid or deprived of any coatings, such as plaster, panels, slabs, or the like, so that the reinforcing elements first 9 and second 11 can adhere directly to the brick, cement, or concrete. If the masonry is obtained from a construction having some claddings or clothing, this will be removed in the portions indicated above for the application of the first 9 and second 11 reinforcing elements and then restored where appropriate.
The vertical development of the rod elements 3, fixed by means of the fixing material 5 in their respective hollow seats 7, generally starts from the base or foundation of the wall panel M and their respective upper ends reach to heights less than or equal to the height of the respective wall panel M or reach the upper portion of the masonry by passing through, and being fixed to, all vertically overlapping wall panels M of the masonry 1.
Each rod element 3 may have to be developed for a length even much greater than that which can be stored, transported, and easily handled, for said reason each rod element 3 may consist of one or more segments whose adjacent end portions are mutually connected and locked or secured by means of rings and/or sleeves and/or steel ties or resin-bonded banding. It is also provided that the ends of the rod elements may be provided with bonded sleeve, bonded and possibly taped “spigot” or a male and female screw connection.
As shown in the variant in FIG. 4 , the masonry may also include one or more optional holding element 13 made of fabric or glass fabric or mat or the like and having a tubular, sock or tape form.
Such holding element 13 is placed between the walls of a hollow seat 7 and respective rod elements 3, wherein such at least one holding element 13 is at least partially encased in the fixing material 5. The holding element 13 viewed in cross-section may be “U-shaped” with sides interposed between the walls of hollow seat 7 and rod element 3 or “O-shaped” in that it is wrapped around the rod element or shod around it; in either case, the fixing material 5 totally, or nearly so, impregnates or encompasses both holding elements 13 and rod element 3 and adheres to, and/or penetrates into the interstices of the walls of the hollow seat 7. The holding elements 13 are particularly useful in hollow seats 7 made in wall panels M made of perforated or hollow bricks because they improve the attachment of the rod element and prevent leakage of the fixing material 5 into the cavities of the bricks by improving the adhesion of the rod elements 3.
The invention provides that each rod element 3 can be fixed to the floor and/or roofing and/or foundation curbs by means of clamps, collars, pins, bandages, and the like secured to the curbs by means of screwed or secured with resin masonry pins.
Each rod element 3, or respective segment, is made of composite material comprising carbon and/or glass and/or aramid and/or boron and/or basalt and/or high-density polyethylene or Dineema® fibers embedded in an epoxy or polyurethane resin matrix or embedded in adhesive mortars or grout or the like. Alternatively, the rod elements, or some of them, may consist of steel bars or pipes or cables. The surface of each rod element 3 may be provided with optional gripping means, assigned to improve coupling with the fixing material 5, consisting of at least one of: adherent coating of sand or other rough material, cavities, transverse grooves or protrusions, or the like.
Each of the first 9 and second 11 reinforcing elements is fabric made of carbon and/or glass and/or other mineral or organic fibers such as aramid and/or boron and/or basalt and/or high-density polyethylene or Dineema® and the like or steel. Alternatively, the second reinforcing element 11 may be nonwoven fabric or mat of said fibers.
The fabric of the first reinforcing element 9 is preferably of a quadriaxial type and the fabric of the second reinforcing element 11 is preferably of a unidirectional, bidirectional or mat type wherein said fabrics are embedded in an epoxy or polyurethane resin matrix of the respective first 9 and second 11 reinforcing elements and adhered to the masonry 1, securing said first 9 and second 11 reinforcing elements to the masonry itself; the fixing material 5 consisting of at least one of: high-strength mortar, epoxy resin, construction adhesives also incorporating aggregates and/or reinforcing fibers.
The invention provides that the wall panels M and, if any, curb elements C together with other building elements, are of a pre-existing construction and to be reinforced, and that the other constituents of the masonry (easily identifiable as they are marked by Arabic numerals) constitute the cooperating reinforcement with panels and curbs to give the masonry the desired resistance, for example to seismic events.
The method for carrying out the masonry, which is the object of the present invention, provides the following steps:

- making, at least in a predetermined position of the at least one accessible face F of one or more wall panels M of the masonry 1, at least one vertical hollow seat 7, each having transverse dimensions equal to or slightly greater than the transverse dimensions of at least one rod element 3 of one-piece type or of multiple interconnected segment type;
- fixing the at least one rod element 3 into its respective hollow seat 7, fixing it therein by applying into the hollow seat 7 fixing material 5 in the fluid or semi-fluid state and assigned to consolidate for realizing the block or anchoring or “grouting” of the at least one rod element 3 into its respective hollow seat 7;
- fixing a first reinforcing element 9 to a portion of the at least one accessible face F of the wall panel M adjacent to both sides of the longitudinal development of the hollow seat or a group of mutually adjacent hollow seats 7.

The method further provides securing at least one second reinforcing member 11 to portions of the at least one wall panel M or wall panels M adjacent to at least one curb member C and to such at least one curb member C and/or securing at least one second reinforcing member 11 to at least one horizontal portion of the at least one wall panel M.
The method further provides securing each first reinforcing element 9 of the masonry 1 to the respective portion of the accessible face F of the wall panel M by securing a four-axial fabric thereof 9, either having a different weft or weave or lacking the latter, by application to such respective portion of a resin in a fluid state assigned to imbibe the fabric and consolidate to embed or to encase the fabric and accomplish said fixing; and it provides the fixing of each second reinforcing element 11 of the masonry 1 to its respective surface portion by blocking a unidirectional, bidirectional, or differently textured fabric or fabric without any specific texture, of said second reinforcing element 11, by application to such respective portion of a resin in a fluid state assigned to imbibe the fabric and consolidate to embed or to encase the fabric and to carry out said securing or fixing.
The method also provides removing, prior to the fixing of the first 9 and second 11 reinforcing elements, any plaster or other coatings of the portions of wall panels M assigned for said fixing. The coatings, whether of plaster, tiles, slabs, panels, or the like may eventually be applied or restored upon completion of the other steps of the method.
The method may further provide placing at least one optional holding element 13 made of fiberglass fabric or mat or the like in the form of a sock or tube or ribbon folded into place, against at least one wall of a hollow seat 7 carried out in a wall panel M made of perforated or solid brick, prior to the positioning and fixing of the respective rod element 3 into that seat by means of the fixing material 5.
The method provides making hollow seats 7 at fixed or variable mutual distances depending on the peculiarities and characteristics of the masonry and the type and magnitude of stresses to which it might be subjected by foreseeable events. It is also contemplated to make hollow seats 7 at the sides of the openings A of the masonry panels of the construction and, if necessary, to fix the second reinforcing elements to the masonry panels, not only at the curbs but also at base or intermediate areas of the masonry panels, such as above and below the openings A.
The invention provides that the hollow seats 7 with their respective rod elements 3 and the first reinforcing elements 9 can be made and fixed vertically in one or more stacked wall panels.

Claims

1. Reinforced masonry comprising at least one wall panel (M) having at least one accessible face (F) substantially vertical and adjacent to a set of respective substantially horizontal curb elements (C) each associated with the at least one wall panel (M); wherein said reinforced masonry (1) comprises a plurality of rod elements (3) fixed, individually or in bundles and by means of fixing material (5), within respective hollow seats (7) carried out, substantially vertically and mutually spaced, at least in the at least one accessible face (F) of the at least one wall panel (M), and wherein said reinforced masonry further comprises, for one or more of the respective hollow seats (7), each first reinforcing element (9) of a plurality of first reinforcing elements is fixed to a corresponding portion of the at least one accessible face (F) of the wall panel (M) adjacent to a longitudinal development of said one or more of the respective hollow seats (7).

2. The masonry according to claim 1, wherein the rod elements (3) that are fixed by means of the fixing material (5) in their respective hollow seats (7) extend starting from a base or foundation of the at least one wall panel (M) up to one or more respective heights lower than a height of a respective wall panel (M), or at least a subset of the rod elements (3) extends for an entire height of a respective wall panel (M) or of an entirety of the masonry (1).

3. The masonry according to claim 1, wherein at least one rod element (3) is constituted by one or more portions having ends that are mutually connected and blocked or fixed by means of one or more of rings, sleeves, steel bands, or resin-soaked bands.

4. The masonry according to claim 1, comprising for at least one curb element (C), a second reinforcing element (11) fixed to said curb element (C), or to the portions of the at least one accessible face (F) of the wall panel (M) or of wall panels (M) adjacent to the at least one curb element (C), or comprising at least a second reinforcing element (11) fixed to at least a horizontal portion of an edge of the wall panel (M).

5. The masonry according to claim 1, comprising at least one holding element (13) made of fabric or mat of glass fiber having a shape of a sock or ribbon, between the walls of a hollow seat (7) and a respective rod element (3), where said at least one holding element (13) is at least partially incorporated into the fixing material (5).

6. The masonry according to claim 1, wherein each rod element (3) or respective rod element segment is made of composite material comprising one or more of carbon, glass fibers, or other mineral or organic fibers, embedded into an epoxy or polyurethane resin matrix or into adhesive mortar, where a surface of each rod element (3) is provided with gripping means consisting of at least one of adherent sand coating or other rough material, cavities, transverse engravings or protrusions; each first reinforcing element (9) is made of fabric, as a quadriaxial type, and each second reinforcing element (11) is of fabric, as unidirectional or bidirectional, or is mat, where such fabric or mat is in carbon, glass fibers, or other mineral or organic fibers and are embedded into a resinous matrix of a respective first (9) and second (11) reinforcing element, and adhere to the masonry (1) fixing the reinforcing elements (9, 11) to the masonry; the fixing material (5) consisting of at least one of high-strength mortar and building adhesives, also incorporating inerts, reinforcing fibers, or both.

7. A method for carrying out the masonry of claim 1, comprising the following steps:

making, at least in a predetermined position of the at least one accessible face (F) of the at least one wall panel (M) of the masonry (1), at least one vertical hollow seat (7), each having transverse dimensions equal to or slightly greater than transverse dimensions of at least one rod element (3) of a single kind or of a kind made of several interconnected segments;

placing the at least one rod element (3) into a respective hollow seat (7) fixing it therein by applying into the hollow seat (7) fixing material (5) in the fluid or semi-fluid state for consolidation and realization of a block or anchoring of the at least one rod element (3) in its respective hollow seat (7);

fixing the corresponding first reinforcement element (9) to a portion of the at least one accessible face (F) of the at least one wall panel (M) adjacent to sides of the longitudinal development of a hollow seat or of a group of side by side hollow seats (7);

fixing at least a second reinforcement element (11) to at least a horizontal portion of the wall panel (M) adjacent to at least one curb element (C).

8. The method according to claim 7, further comprising fixing each first reinforcing element (9) of the masonry (1) to the respective portion of the accessible face (F) of the wall panel (M) by blocking a fabric of the first reinforcing element (9), quadriaxial or with different weave or without it, by applying to this respective portion a resin in the fluid state assigned to soak the fabric and to reticulate to incorporate the fabric and to make said fixing thereof; and by fixing each second reinforcing element (11) of the masonry (1) to the respective surface portion by blocking a fabric of the second reinforcing element (11), of the unidirectional, bidirectional kind or with a different weave or without it, by applying to this respective portion a resin in the fluid state assigned to soak the fabric and to reticulate to incorporate the fabric and to make said fixing thereof.

9. The method according to claim 8, comprising removing plasters or other coatings of the portions of the wall panel (M) before fixing the first (9) or second (11) reinforcing elements.

10. The method according to claim 7, comprising placing at least one holding element (13), made of fabric or mat of glass fiber having a shape of a sock or ribbon, against at least one wall of a hollow seat (7) made in a hollow or solid brick wall panel (M), before fixing the respective rod element (3) in the respective seat by means of the fixing material (5).