Method for recovering the structural efficiency of existing framed buildings and corresponding framed buiding

Abstract

Method for recovering the structural efficiency of existing framed buildings (100) made of reinforced concrete or steel, comprising a frame (111) formed by a plurality of first horizontal structural elements (112) and second vertical structural elements (113), wherein the method comprises the creation of at least one dissipation device (10).

Description

FIELD OF THE INVENTION

[0001] The present invention concerns a method for recovering the structural efficiency of civil or industrial framed buildings, made of reinforced concrete or steel, as well as the buildings thus recovered, which may no longer be suited to effectively counteract / contain seismic actions. The method also allows to improve the building's overall static behavior.BACKGROUND OF THE INVENTION

[0002] It is known that framed buildings are buildings in which stress resistance is entrusted to frames consisting of beams and pillars made of reinforced concrete or steel, interconnected with each other in correspondence with nodes.

[0003] The construction of new buildings requires a design that follows design, execution and testing principles from the beginning, in order to guarantee the required performance in terms of mechanical resistance and stability over time. In the same way, existing buildings may also require interventions aimed at refurbishment and, even before that, improvement / adaptation due to a potential seismic action in order to comply with the requirements of current legislation.

[0004] An essential requirement is to guarantee the resistance of the structure to a seismic action through the adoption of specific measures aimed at guaranteeing characteristics of ductility for both the structural elements and also the building as a whole. In particular, buildings should be equipped with dissipative structural systems that guarantee the necessary rigidity and resistance, according to current legislation.

[0005] Problems of this type are currently solved by building partitions rigidly constrained to the structure's pillars, but also ribs with a reinforcing and counter-thrust function which are external to the building. These solutions become "shear walls", triggering the onset of further problems. These solutions are also bulky and often difficult to implement.

[0006] Document JP2001 317215 A describes a method for strengthening the seismic resistance of an existing building, in which one purpose is to build a new wall in a space surrounded by pillars and beams without generating noise, vibrations or dust. In addition, this document teaches to increase the intrinsic resistance of structural elements that are lacking in the event of a seismic event, by creating a connection core by welding connection bars to the outside of the circumferential surface of a steel pipe. This solution is complex and difficult to install, and not very effective in terms of improving anti-seismic performance.

[0007] There is therefore the need to perfect a method for recovering the structural efficiency of existing framed buildings, and a corresponding framed building, which can overcome at least one of the disadvantages of the state of the art.

[0008] To do this, it is necessary to resolve the technical problem of improving the behavior of existing framed buildings in which the structural frame is made of reinforced concrete or steel, but which are lacking in the event of a seismic action.

[0009] One purpose of the present invention is to perfect a method that allows to recover the structural efficiency of existing framed buildings in a simple and effective manner, and at low costs.

[0010] Another purpose of the present invention is to perfect a method as disclosed above, which allows to achieve compliance with current legislative requirements by carrying out a small number of limited additional works to the existing structure.

[0011] Another purpose of the present invention is to carry out an intervention that allows the existing structure only small or very small displacements, which still allow it to remain within the elastic field as much as possible, even in the event of seismic events.

[0012] Finally, a fundamental purpose is to make an existing framed building with recovered structural efficiency usable.

[0013] The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.SUMMARY OF THE INVENTION

[0014] The present invention is set forth in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

[0015] In accordance with the above purposes and to resolve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, the method according to the present invention for recovering the structural efficiency of framed buildings comprising a structural frame made of reinforced concrete or steel formed by a plurality of first and second structural elements, respectively horizontal, such as beams, and vertical, such as pillars, comprises the creation of at least one dissipation device according to the following steps: a drilling step, in the case of a reinforced concrete frame, in which at least one hole is made in each of the four contiguous structural elements defining an aperture or mesh between them; a preparation step, in which corresponding connection members are inserted and fixed inside the holes, or connection members are welded to the elements of the steel frame; a formwork step, in which a "rebar cage" metal framework is arranged between a first shuttering and an opposing second shuttering, which are arranged to temporarily close the aperture or mesh and define, between them and with the four structural elements, a closed volume; a filling step, in which the closed volume is filled with a concrete cast, at least partly embedding the connection members, the hardening of the concrete cast forming a rigid body anchored to the frame by means of the connection members which define corresponding constraints, the volumetric shrinkage of the concrete cast leaving a small, verging on extremely small, contour hollow space between the rigid body and the structural elements, wherein this hollow space allows for very small rotary displacements between the existing structure or frame and the rigid body, and once the cast has fully cured, a dismantling step that provides the removal of the shutterings.

[0016] Thanks to the presence of the rigid body, created in limited, studied and specific positions of the framed structure, the meshes of the existing frame, in the event of oscillations due to seismic events, will impact against the rigid bodies, effectively bouncing in the opposite direction to that imparted by the oscillation, albeit only for the very small ranges allowed.

[0017] The shape of the rigid body will be essentially the same as that of the aperture or mesh in which it is inserted, peripherally spaced apart from the beams and pillars by a minimum contour hollow space that is created by the phenomenon of concrete shrinkage.

[0018] It should also be noted that the connection members define "hinged" constraints between the rigid body and the frame, which are capable of allowing a rotation, albeit minimal, in both directions, clockwise and anticlockwise, of the rigid body inside the aperture or mesh.

[0019] In accordance with another aspect of the present invention, before the filling step there can be provided and carried out a further preparation step, during which a layer of an elastomeric material could be applied along the perimeter contour of the aperture.

[0020] In accordance with another aspect of the present invention, the rigid body is a solid plate or slab.

[0021] According to a variant of the present invention, the rigid body could also be supplied as a pre-fabricated body or element.

[0022] In accordance with another aspect of the present invention, the rigid body can be provided with at least one optional through aperture, if necessary reinforced with a sufficiently resistant metal frame around its contour.

[0023] In accordance with another aspect of the present invention, the connection members between the existing structure and the rigid body have a first portion inserted and fixed in the holes and a second portion protruding from the holes and embedded in the rigid body, wherein during the preparation step a tubular element is associated with the second portion, the tubular element being shorter than the latter.

[0024] In accordance with another aspect of the present invention, the second portion protrudes from the tubular element for the embedding in the rigid body with a length equal to approximately 60-80 times its diameter.

[0025] In accordance with another aspect of the present invention, the diameter of the tubular element is at least twice a diameter of the connection member.

[0026] In accordance with another aspect of the present invention, the connection members are installed with a downward inclination comprised between 2% and 3% with respect to the horizontal plane. In one example embodiment, this inclination is of approximately 2.5%.

[0027] In accordance with another aspect of the present invention, the terminal end of the second portion is straight or bent.

[0028] The present invention also concerns a corresponding existing framed building with structural efficiency recovered by means of the method disclosed here. The building comprises a frame formed by a plurality of first and second structural elements, respectively horizontal and vertical, and at least one dissipation device disposed between four contiguous of the first and second structural elements defining an aperture or mesh between them, wherein the dissipation device comprises a rigid body disposed in the aperture and a plurality of connection members at least partly embedded in the rigid body, and by means of which the rigid body is hinged to the first and second structural elements, between the rigid body and the first and second structural elements there being defined a contour hollow space.DESCRIPTION OF THE DRAWINGS

[0029] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein: fig. 1 is a schematic view of a frame of a building in which a dissipation device has been created, according to the method for recovering the structural efficiency of the present invention; fig. 2 is an enlarged view of fig. 1 in which the dissipation device is better visible; fig. 3 is a variant of fig. 2; fig. 4 is another variant of fig. 2.

[0030] We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

[0031] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

[0032] With reference to fig. 1, this schematically shows an existing framed building 100 with structural efficiency to be recovered, for civil or industrial use.

[0033] The framed building 100 comprises a frame 111, made of reinforced concrete or steel, with a load-bearing function, formed by a plurality of horizontal first structural elements, called beams, 112 and vertical second structural elements, called pillars, 113. The beams 112 and pillars 113 are made of reinforced concrete or steel.

[0034] The framed building 100 also comprises foundations 114 connected to the frame 111 or defining an extension thereof into the ground.

[0035] The frame 111 can be of the multi-story type with any number of stories whatsoever, for example seven stories as shown in fig. 1.

[0036] The frame 111, whether made of reinforced concrete or steel, can constitute both the external elevations of the building 100, as well as the internal load-bearing parts thereof.

[0037] The method for recovering the structural efficiency of existing framed buildings 100 made of reinforced concrete according to the present invention comprises the "on site" creation, according to the steps described in detail below, of at least one dissipation device 10 between four contiguous structural elements 112 and 113 defining a usually rectangular aperture or mesh 115 between them. The dissipation device 10 allows to limit any deformations of the frame 111 upon the triggering of an action of seismic acceleration, or one of a different nature, on the building 100.

[0038] As better shown in figs. 2-4, the aperture or mesh 115 in which the dissipation device 10 is created is defined as the empty space between two facing beams 112 of consecutive stories, and between two adjacent pillars 113 of the same story of the frame 111.

[0039] The number of dissipation devices 10 that are created and their position within the frame 111 depends on the specific design requirements. For example, the dissipation device 10 can be installed in correspondence with an aperture or mesh 115 located on a facade wall of the framed building 100 and / or on an internal wall, so-called bracing wall.

[0040] The dissipation device 10 comprises a rigid body 11 and a plurality of connection members 12 at least partly embedded in the rigid body 11 and by means of which the rigid body 11 is constrained to the frame 111, in particular to the beams 112 and the pillars 113.

[0041] The connection members 12 define "hinged" constraints between the rigid body 11 and the frame 111 capable of allowing a rotation, albeit minimal, in both clockwise and counterclockwise directions, of the rigid body 11 within the aperture or mesh 115.

[0042] The shape of the rigid body 11 is essentially the same as that of the aperture or mesh 115 in which it is inscribed, spaced apart perimetrically with respect to the beams 112 and pillars 113 by a minimum contour hollow space F. This minimum contour hollow space F will be, once the cast has cured, the result of the natural shrinkage of the concrete cast.

[0043] The contour hollow space F essentially determines a joint that constitutes the "collision" interface between frame 111 and rigid body 11, in correspondence with which the effect of the vibrational energy, for example caused by an earthquake, is dissipated, since the two structures in conflict, that is, frame 111 and rigid body 11, have very different inertias.

[0044] Purely by way of example, the contour hollow space F can have a thickness comprised between about 0.4 mm and about 1 mm. Therefore the aperture or mesh 115 will remain substantially blind.

[0045] According to some embodiments, the contour hollow space F can remain empty.

[0046] Any problems of weather water infiltration, only for the exterior walls, will be resolved with traditional solutions typical of the building industry, and therefore with suitable construction details. Optionally, during the production phase, a layer S of elastomeric material, for example neoprene or other suitable material, can be arranged in the contour hollow space F, the function of which is to rigid-plastic calibrate the contrast between the conflicting rigid body 11 and frame 111, fig. 4, which thus also configure an energy dissipating mechanism. At the same time, the rigid body 11 will also act as a limiter of the displacement of the original frame, and will therefore obtain the consequent reduction of the specific tensile stresses also along the entire development of the beams 112, due to the effect of the continuity within the limit of the "technical expansion joint", as well as in the pillars 113, due to the effect of the modification of the interlocking degrees in all type 112-113 nodes, which are also within the limits defined by the structural length within the same technical joint.

[0047] The use of the layer S of elastomeric material is advantageous because it could be replaced, over time, in the event of degradation.

[0048] The layer S, as stated, could for example be made of an elastomeric material such as neoprene or suchlike.

[0049] The rigid body 11 can consist of a sheet or plate, preferably made "on site" as a cast of cement conglomerate reinforced according to the executive structural project.

[0050] According to a variant of the present invention, the rigid body 11 can also be supplied as a prefabricated element made of reinforced concrete.

[0051] The rigid body 11 can be made as a solid body, figs. 2 and 4. Optionally, the rigid body 11 can be provided with a through aperture 13, for example, preferably central as shown for example in fig. 3, of any shape whatsoever. The aperture 13 can have a technical function, for example to graduate the inertia of the rigid body 11, and / or an aesthetic function, for example to define a window hole.

[0052] The aperture 13 will be reinforced, if necessary, with a contour frame 14.

[0053] The creation of the dissipation device 10 comprises the following production steps.

[0054] A drilling step, in which at least one corresponding hole 116 is created in each of the structural elements 112 and 113 defining the aperture 115. The holes 116 are made on the contrast faces of the structural elements 112 and 113 that will go against the rigid body 11 to be made. If the existing load-bearing frame, and the corresponding structural elements 112 and 113, consists of elements made of steel instead of reinforced concrete, then drilling will not be carried out, instead head welds of the connection members 12, such as pins or bayonets, would be performed so as to guarantee the firm connection between the frame and the rigid body, that is, between structural elements 112 and 113 and connection members 12.

[0055] The holes 116, for example four in number, can preferably be made in correspondence with, or in proximity to, the center lines of the four structural elements 112, 113 of the frame 111. In any case, the position and number of holes 116 is established according to the needs of the specific structural project.

[0056] In a subsequent preparation step, corresponding connection members 12 are inserted and fixed inside the holes 116.

[0057] The connection members 12 can be pins or rods with an adequate diameter D1 which are anchored, in a known manner, in the holes 116. The anchoring in the holes 116 can occur, for example, by using anti-shrinkage mortars and / or resins. As stated, in the event the frame is made of steel, head welds will be performed between the connection members 12 and structural elements 112 and 113.

[0058] According to some embodiments, the connection members 12 will be made of metal material, for example steel, preferably stainless.

[0059] Once installed, the connection members 12 have a first portion 12a inserted into the holes 116 and a second portion 12b protruding from the holes 116 toward the aperture 115. The second portion 12b of the connection members 12 will serve for the subsequent anchoring to the rigid body 11.

[0060] During the preparation step, a tubular element 16 can be associated with the second portion 12b of the connection members 12, the tubular element 16 being shorter in length than the second portion 12b. The tubular element 16 is fitted onto the second portion 12b of each connection member 12.

[0061] The tubular element 16, preferably made of rigid plastic, is installed provided with a blind flange on the side of the rigid body 11, so that the connection member 12 reaches the rigid body 11 but the concrete is prevented from rising up into the tubular element 16.

[0062] The tubular element 16 is also provided with a discharge aperture, for example a hole of, for example, approximately 4 mm, in the lower part, to allow the draining of condensate water that may form in the segment.

[0063] The tubular element 16, as will be explained below, is installed with a downward slope and in such a way as to allow those minimal deformations of the connection member 12 in order to make the "hinge" effect between the elements 112 and 113 and the rigid body 11 effective.

[0064] The second portion 12b of the connection member 12 is therefore protruding from the tubular element 16 for the embedding into the rigid body 11 with a length L equal to about 60 times its diameter D1, in any case preferably between about 60 times and about 80 times its diameter D 1, please see fig. 2 by way of example.

[0065] This length L, set in the rigid body 11, will have to guarantee, through the steel-to-concrete adhesion resistance, the normal and shear forces that the connection members 12 will have to withstand.

[0066] The diameter D2 of the tubular element 16 can preferably be at least about 2 times the diameter D1 of the connection member 12.

[0067] Furthermore, the length of the tubular element 16 is equal to at least 18 times the diameter D1 of the protected connection member 12.

[0068] According to some embodiments, the tubular elements 16 can be made of rigid plastic material, preferably with a smooth internal surface.

[0069] According to some embodiments, the connection members 12 can be installed with an inclination comprised between 2% and 3%, for example about 2.5%, relative to the horizontal plane. It is preferable that at least the connection members 12 that insist on the pillars 113, rather than being horizontal, be installed with a downward slope of at least about 2.5%. This slope promotes the drainage of the condensate water toward and into the rigid body 11.

[0070] According to some embodiments, the terminal end of the second portion of each connection member 12 can be straight (figs. 2 and 4) or bent, for example hook-shaped to guarantee sealing through iron-concrete adhesion (fig. 3).

[0071] Subsequently, a first step of unilateral formwork of the aperture 115 is carried out, during which a first shuttering (not shown in the drawings) is arranged to temporarily plug the aperture 115, and subsequently a metal framework (not shown in the drawings) is positioned in the structure, suitable to act as a structural framework for reinforced concrete, for the subsequent concrete casting. This framework, according to the specific project, will suitably function both "in the plane" and also "outside the plane".

[0072] A second step of unilateral formwork of the aperture 115 follows, during which a second shuttering (also not shown in the drawings), opposing the first shuttering, will be arranged to close the aperture or mesh 115.

[0073] The first and second shuttering, together with the structural elements 112, 113 defining the aperture or mesh 115, delimit a closed volume that will subsequently be filled with concrete.

[0074] After the second formwork step is completed, a filling step is performed, which provides the concrete cast of the expected thickness.

[0075] Optionally, before the last formwork step, an additional preparation step can be considered, during which, if necessary, the layer S will be applied along the contour of the aperture 115 so as to fill the hollow space F.

[0076] In the step of filling the aperture or mesh 115, the concrete is cast into the closed volume. The closed volume is completely filled with concrete, which partly embeds the connection members 12 together with the tubular elements 16 fitted thereon.

[0077] Concrete is used in the filling step that is prepared according to a recipe that allows to obtain certain mechanical characteristics that will define, in succession, other parameters to be taken into account such as, primarily, the extent of the shrinkage, in addition to the resistance class of the cast and any other suitable and necessary characteristics.

[0078] The volumetric shrinkage of the concrete is a natural variation in volume that the casting undergoes during the setting and hardening step, caused by the progressive elimination of water that is no longer necessary for the chemical phenomenon, but is still contained in the cement conglomerate.

[0079] This shrinkage, which represents an extremely important element on which the principles of efficiency of the solution object of the present application are based, allows, as stated, for an essential, even if minimal, movement of the pre-existing structure with respect to the rigid body or bodies, allowing to achieve the effect of limiting the consequences of seismic actions on the frame of the building, whether this is made of reinforced concrete or steel.

[0080] After a certain waiting time, at the end of which the cast has reached so-called "curing" forming the rigid body 11, a dismantling step is carried out which provides the removal of the two shutterings.

[0081] During curing, as stated, the concrete tends to shrink so that the contour hollow space F is created along the entire perimeter of the aperture 115. The contour hollow space F determines a spacing between the central rigid body 11 and the structural elements 112, 113 that form the contour. This spacing, together with the anchoring of the rigid body 11 to the frame through the connection members 12, which determine corresponding hinges, allows the rigid body 11 to rotate in the vertical plane, even if very little, clockwise or counterclockwise with respect to the frame 111, realizing a dissipative system and therefore limiting the displacements of the frame 111, both localized and distributed, which are caused by the seismic action, and therefore reducing the stresses acting on the building 100.

[0082] The creation of one or more dissipation devices 10 thus also allows to reduce, even considerably, the overall displacements of each story of the framed building 100. This prevents complete oscillations from occurring, thus leaving the already existing frame 111 statically prepared for the sole function for which it was originally designed, always subject to timely verification.

[0083] The operation of the dissipation device 10 described heretofore is based on the interaction of two load-bearing structures, the frame 111 (large in size but with small point inertias) and the rigid body 11 (small in size but with very large point inertias), which with their inertial differences can achieve the desired results. Upon the occurrence of any acceleration, and therefore of the displacement that results from the impressed movement, the frame 111 at the contour of the rigid body 11 begins to deform according to its physical-mechanical-geometric characteristics, thus colliding with the rigid body 11 which, since it has its own different physical-mechanical-geometric characteristics, but above all a very large inertia, allows the frame 111 to 'bounce' off it, dissipating energy and also limiting the period.

[0084] The travel, or deformation, which the frame 111 is prevented from undergoing will depend on the size of the joint at the contour and on the inherent quality of the materials that interact when they collide.

[0085] Therefore, the maximum total displacement of the frame 111 as a whole will be greatly reduced through the introduction of the dissipation devices 10, with expected distribution and number, the size of the joints at the contour, the nature and quality of the materials as a function of the project requirements.

[0086] As a result of this, since the displacements and therefore the total final deformations have been reduced, the backlash forces will also be reduced, and so will the internal stresses of the individual elements of the original structure. There is therefore no need to reinforce many parts of the existing framed building 100, with a consequent saving in the total cost of the works that need planning.

[0087] It is clear that modifications and / or additions of parts may be made to the method and to the existing framed building with recovered structural efficiency as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims.

[0088] It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of a method for recovering the structural efficiency of existing framed buildings and corresponding framed building, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

[0089] In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

1. Method for recovering the structural efficiency of existing framed buildings (100) comprising a frame (111) made of reinforced concrete or steel, formed by a plurality of first and second structural elements (112, 113), respectively horizontal, such as beams, and vertical, such as pillars, comprising the creation of at least one dissipation device (10) according to the following steps: - a drilling step, where, only in the case of structural elements made of reinforced concrete, at least one hole (116) is made in each of the four contiguous structural elements (112, 113) defining an aperture or mesh of the frame (115); - a preparation step, in which corresponding connection members (12) are inserted and fixed inside said holes (116), or connection members (12) are welded to the structural elements (112, 113) in the event the frame (111) is made of steel; - a formwork step, in which a metal framework is arranged between a first shuttering and an opposing second shuttering, which are arranged to close said aperture or mesh (115) and define, between them and with said four structural elements (112, 113), a closed volume; - a filling step, in which said closed volume is filled with a concrete cast, at least partly embedding said connection members (12), the setting and hardening of said concrete cast forming a rigid body (11) anchored to said frame (111) by means of said connection members (12) which define corresponding constraints, a volumetric shrinkage of said concrete cast determining a contour hollow space (F) between said rigid body (11) and said structural elements (112, 113), wherein said contour hollow space (F) allows for very small displacements between the existing frame (111) and the rigid body (11), and a dismantling step that provides the removal of said shutterings, in which said connection members (12) are configured to define hinged constraints between said rigid body (11) and said frame (11) to allow a rotation, albeit minimal, in both clockwise and anticlockwise directions, of the rigid body (11) inside the aperture or mesh (115).

2. Method as in claim 1, characterized in that before said filling step a further preparation step is carried out, during which a layer (S) of an elastomeric material is applied along the contour of said aperture (115) and inside said contour hollow space (F).

3. Method as in claim 1 or 2, characterized in that said rigid body (11) is a solid plate or slab made of reinforced concrete.

4. Method as in claim 1 or 2, characterized in that said rigid body (11) is provided with at least one through aperture (13) and optionally reinforced with a suitable contour frame (14).

5. Method as in any claim hereinbefore, characterized in that during said preparation step a tubular element (16) is associated with a second portion (12b) of said connection members (12) which protrudes from said holes / welds (116).

6. Method as in claim 5, characterized in that said second portion (12b) protrudes from said tubular element (16) for the embedding in said rigid body (11) with a length (L) equal to approximately 60-80 times its diameter (D1).

7. Method as in claim 5 or 6, characterized in that a diameter (D2) of said tubular element (16) is at least twice a diameter (D1) of said connection member (12).

8. Method as in any claim hereinbefore, characterized in that said connection members (12) inserted in said second structural elements (113) are installed with a downward inclination comprised between approximately 2% and 3% with respect to the horizontal plane.

9. Method as in claim 5 o 6, characterized in that a terminal end of said second portion (12b) is straight or bent.

10. Existing framed building (100) with recovered structural efficiency comprising a frame (111) formed by a plurality of first and second structural elements (112, 113), respectively horizontal and vertical, and at least one dissipation device (10) disposed between four contiguous of said first and second structural elements (112, 113) defining an aperture or mesh (115) between them, wherein said dissipation device (10) comprises a rigid body (11) disposed in said aperture or mesh (115) and a plurality of connection members (12) at least partly embedded in said rigid body (11) and by means of which said rigid body (11) is constrained to said first and second structural elements (112, 113), between said rigid body (11) and said first and second structural elements (112, 113) being present a contour hollow space (F) obtained from the phenomenon of concrete shrinkage, said contour hollow space (F) being configured to allow for small displacements between the existing frame (111) and the rigid body (11).

Images