EP2342856B1

EP2342856B1 - Device for connection between prefabricated beams and columns

Info

Publication number: EP2342856B1
Application number: EP09736581.1A
Authority: EP
Inventors: Giovanni Avanzini; Andrea Trestini
Original assignee: Point Srl
Current assignee: POINT Srl
Priority date: 2008-09-30
Filing date: 2009-09-30
Publication date: 2015-04-15
Anticipated expiration: 2029-09-30
Also published as: ITVR20080109A1; IT1391215B1; WO2010037775A2; EP2342856A2; WO2010037775A3

Description

Technical Field

The present invention relates to a device for connection between prefabricated beams and columns.

Background Art

Today, multi-story columns which have casting discontinuities at the portions between stories are used to provide the joints between columns and beams in prefabrication in the construction sector.
In solutions of this type, the column is constituted by a plurality of reinforced-concrete segments which are mutually spaced longitudinally and are mutually connected, at their respective ends, by rebars that protrude from such reinforced-concrete segments.
During assembly, the ends of the beams, also generally made of reinforced concrete, are engaged by resting on the faces that are directed upward of the segments that constitute the column, and any space left free between the segments is filled with a concrete casting, so as to complete the joining of the beams to the column.
US 6,058,669 discloses a rigid connection between the reinforcement of the beams and the rebars that protrude from the segments of the columns, so as to provide, in the nodes of the structure, hyperstatic couplings which are particularly useful if the building is designed to withstand seismic actions.
Although it is valid in principle, the solution outlined above has a criticality caused by the fact that in the points of discontinuity of the column there is a flexural deformability that makes it difficult to transport and install.
Another known solution uses a continuous column which has, at the portion between stories, through openings in which connecting elements that protrude from the ends of the beams are designed to be accommodated.
Although this solution makes the transport of the columns and their installation less problematic, it has the drawback of requiring that during production the beams are provided with such connecting elements, which are generally constituted by metallic inserts which are partially embedded in the casting.
In order to solve the drawbacks noted above, this same Applicant filed, on 6 December 2005, Italian patent application No. VR2005A000154 related to a device for connection between columns and beams in which, along the extension of the column, there are, on opposite sides, respective resting ledges, on which end portions of a respective beam are to be engaged. In a region of the column located above the resting ledges there is a through opening that runs substantially parallel to the longitudinal extension of the beams.
JP 2002 294858 A discloses a concrete column member having a plurality of beam members connected thereto in a manner as defined in the pre-characterizing portion of the appended claim 1.
GB 2 027 785 A discloses a connection between a pillar and beams of prefabricated concrete, comprising a pillar having a through-passing aperture at a connection point, and beams provided with metal bolts which are longitudinally dispaceably mounted in metal tubes and which extend into the aperture and are supported therein, after which the aperture is filled out with concrete. Above the beams there is provided a cover coating of cast concrete provided with reinforcment members.

Disclosure of the Invention

The aim of the present invention is to provide a device for connection between prefabricated beams and columns that is capable of eliminating or at least reducing drastically the drawbacks noted above.
Within this aim, an object of the invention is to provide a device for connection between prefabricated beams and columns that is reliable in use and extremely flexible.
Another object is to provide a device for connection between prefabricated beams and columns that allows to reduce significantly the installation times of columns and beams.
Another object of the invention is to provide a device for connection between prefabricated beams and columns in which the joint between the columns and the beams ensures higher resistance to any seismic actions.
Another object of the invention is to provide a device for connection between prefabricated beams and columns that is capable of ensuring easy and practical transport of the various structural components and in particular of the beams and of the columns.
In accordance with the invention, there is provided a device connecting prefabricated beams and columns as defined in the appended claims.

Brief description of the drawings

Further characteristics and advantages of the invention will become better apparent from the following detailed description of some preferred but not exclusive embodiments of a device for connection between prefabricated beams and columns according to the present invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is an exploded perspective view of a multi-story column associated with a plurality of beams;
Figure 2 is a sectional view, taken along a substantially vertical plane of arrangement, of a device for connection between columns and beams according to the invention;
Figure 3 is an enlarged-scale view of a detail of the cross-section of Figure 2 related to the region of connection between the beam and the completion casting;
Figure 4 is a sectional view, taken along a substantially horizontal plane of arrangement, of a device for connection between columns and beams according to the invention;
Figure 5 is an enlarged-scale view of a detail of the cross-section of Figure 4 related to the region of connection between the beam and the completion casting;
Figure 6 is a view, partially in phantom lines, of a column along a plane that is substantially perpendicular to the plane of arrangement of the cross-section shown in Figure 2, in which, for the sake of greater clarity, the beam and the completion casting have been omitted;
Figure 7 is a perspective view of the longitudinal end of a beam.

Ways of carrying out the Invention

In the exemplary embodiments that follow, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.
Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.
With reference to the figures, the present invention relates to a device, generally designated by the reference numeral 1, for connection between a column 2 and beams 3 which are prefabricated.
The connection device 1 comprises, along the extension 100 of the column 2, at least one pair of resting portions, in particular a pair of resting ledges 4a, which are arranged on opposite sides with respect to the direction of longitudinal extension 100 of the column and are designed to be engaged, by resting and at least during installation, by an end portion 5 of a respective beam 3.
At a region of the column 2 that is formed above the pair or pairs of resting ledges 4a, 4b there is at least one through opening 6, which runs substantially parallel to the longitudinal extension 101 of the beams 3.
The through opening 6 is designed to accommodate means 7 for connection between the column 2 and the beams 3 which are arranged on opposite sides with respect to the through opening 6.
According to a particularly important aspect of the present invention, the through opening 6 is extended over a greater height than the height of the beams 3.
In greater detail, the connection means 7 comprise a completion casting 8, which passes at least partially through the through opening 6 and is designed to connect stably each beam 3 to the column 2 and accordingly the beams 3 arranged on opposite sides with respect to the through opening 6.
The connection device 1 further has a connecting body 9, which is arranged above a surface 8a that is directed upward of the completion casting 8 and passes at least partially through the through opening 6 in order to mutually connect the surfaces 3 a that are directed upward of the beams 3.
In particular, the connecting body 9 is designed to pass through the portion of the through opening 6 that lies above and higher than the upper surface 3a of the beam 3 and accordingly above the completion casting 8, which as shown has its upper surface at the same height as the upper surface 3 a of the beams 3.
Advantageously, the connection means 7 comprise a connecting reinforcement frame 10 between the beam reinforcement frames 11 of each beam 3 that is arranged on opposite sides with respect to the through opening 6.
The connecting reinforcement frame 10 can be constituted for example by a plurality of connecting bars 12 and is designed to cross the respective through opening 6 and to be embedded in the completion castings 8.
Conveniently, the connecting body 9 is adapted to provide a so-called structural screed, the functionality of which will be described in greater detail hereinafter.
In greater detail and with particular reference to the embodiment shown in Figures 2 and 3, at least one auxiliary reinforcement body 13 is inserted in the thickness of the connecting body 9 forming the structural screed and runs substantially parallel to the main longitudinal direction 101 of the beams 3.
As shown in the exploded perspective view of Figure 1, it is possible to form, along the extension 100 of the column 2, two pairs of resting ledges 4a and 4b, which are arranged in pairs on opposite sides with respect to the direction of longitudinal extension 100 of the column 2 and are designed to be engaged by resting by an end portion 5 of a respective beam 3.
It appears evident that in this case each pair of resting ledges 4a and 4b is arranged on opposite sides with respect to a respective through opening 6.
However, nothing prevents, as is further evident from the description, the connection device 1 from having only two resting ledges 4a and accordingly a single through opening 6 formed along the extension of the column 2.
Conveniently, the beams 3 have, at their end portion 5 designed to rest against the respective ledge 4a, 4b, a longitudinally extended recess 14 in which the concavity is directed upward.
In particular, the recess 14 has a transverse dimension that substantially corresponds to the transverse dimension of the through opening 6, and is designed, during the production of the connection device 1, to be filled at least partially by the completion casting 8.
According to a further important aspect of the present invention, the beam reinforcement frame 11 comprises at least one bar which has a respective threaded end portion 11 a, which is associated stably with a sleeve 15 which is threaded internally and can be engaged by a respective end portion 12a of a respective connecting bar 12, which forms at least part of the connecting reinforcement frame 10.
The internally threaded sleeve 15 is embedded at least partially in the beam 3.
Advantageously, the through opening or openings 6 are provided by a tubular box 16, which is embedded within the column and optionally connected stably to a reinforcement frame 17 of the column.
The auxiliary reinforcement 13 arranged inside the connecting body 9 is, in particular, for connection between brackets 18 that protrude from the upper surface 3a of the beams 3 arranged on opposite sides with respect to the through opening 6.
The method for installing the connection device 1 according to the present invention is as follows.
The column 2, which has, along its own longitudinal extension, the through opening or openings 6 and the resting ledges 4a (and optionally 4b) arranged below the respective through openings 6, is prepared vertically.
Then the end portions 5 of the beams 3 are rested on the respective resting ledges 4a, 4b arranged on opposite sides of a respective through opening 6.
The connecting reinforcement frame 10 is arranged so as to at least partially cross in a longitudinal direction the through opening 6.
With particular reference to the illustrated embodiment, the threaded end portions 12a of the respective connecting bars 12 that provide the connecting reinforcement frame 10 are screwed into respective sleeves 15 embedded at least partially in the beam 3.
This operation is evidently very easy with respect to a connection by welding, which in the specific case might entail, if not performed according to best practice, the risk of compromising the static strength of the device 1 for connection between the beams 3 and the column 2.
At this point, the recesses 14 and the lower volume of the through opening 6 are filled with the completion casting 8, embedding within the completion casting 8 the connecting reinforcement frame 10.
Advantageously, the completion casting 8 completely fills the recesses 14 and accordingly its surface directed upward is arranged at the same height as the upper surface 3a of the beams 3.
A free region accordingly remains between the upper surface of the completion casting 8 that passes through the through opening 6 and the top of the through opening 6, and the connecting body 9 arranges itself inside such free region.
In particular, for the provision of the connecting body 9, the auxiliary reinforcement frame 13 is arranged above the upper surface of the completion casting 8 and so as to pass through such free region.
Conveniently, the auxiliary reinforcement 13 is coupled to the brackets 18 that protrude from the upper surfaces 3a of the beams 3.
The presence of the connecting body, which in practice provides a structural screed which is arranged above the beams 3 and cooperates with the connection device 1 allows, for an equal height of the beams 3, to have a larger portion of continuity between the beams and the columns, with an evident advantage in terms of structural and anti-seismic performance.
It has been found that it is particularly advantageous to use, as a material for providing the completion casting 8, a material known by the acronym UHTC (Ultra-High Performance Concrete), such as the one marketed by Lafarge S.A. under the trademark DUCTAL.
This material has two main characteristics that are particularly important in the specific application: first of all, its behavior is ductile and it withstands large deformations prior to failure, differently from traditional concrete, which has a fragile behavior and fails with small deformations.
Moreover, differently from traditional concrete, it also withstands significant traction stresses.
All the characteristics of the invention indicated above as advantageous, convenient or the like may also be omitted or be replaced with equivalents.
The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.
In practice it has been found that the invention has achieved the intended aim and objects in all of its embodiments.
In particular, it has been found experimentally that the device for connection between columns and beams according to the invention remains intact up to high load values, being truly ductile.
Moreover, even after intense stresses, the column remains monolithic and the hinges form at the ends of the beams and therefore outside the cross-section of the column.
In practice, the materials used, as well as the dimensions, may be any according to requirements.
In particular, it has been found that it is particularly advantageous to provide the tubular boxes 16 and the reinforcement frames in general by using high-performance steels, such as for example the steel known commercially by the acronym HPS (High Performance Steel).
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A device (1) for connection between prefabricated beams and columns comprising, a column (2) and prefabricated beams (3), and along the extension of said column (2), at least one pair of resting portions (4a, 4b), which are arranged on opposite sides with respect to the direction of longitudinal extension (100) of said column and are engaged, by resting, by an end portion (5) of a respective beam (3), at a region of said column (2) formed above said at least one pair of resting portions (4a, 4b) there being at least one through opening (6), which runs substantially parallel to the longitudinal extension (101) of said beams (3) and accommodates means (7) for connection between said column (2) and said beams (3), said opening (6) extending over a greater height than the height of said beams (3), said connection means (7) comprising a completion casting (8) which passes at least partially through said through opening (6), and a reinforcement frame (10) passing through said through opening (6) and being embedded in said completion casting (8), characterized in that said completion casting (8) having an upper surface at the same height as the upper surface (3a) of said beams (3) such that a free region remains between the upper surface of the completion casting (8) that passes through the through opening (6) and the top of the through opening (6), and a connecting body (9) being provided which is arranged inside said free region above the surface that is directed upward of said completion casting (8) and which passes at least partially through said through opening (6) and mutually connects the upward-facing surfaces (3a) of said beams (3), and said reinforcement frame (10) being connected between reinforcement frames (11) of the beams that are arranged on opposite sides with respect to said at least one through opening (6).
The device for connection between prefabricated beams and columns according to claim 1, characterized in that said connecting body (9) is adapted to provide a structural screed.
The device for connection between prefabricated beams and columns according to claim 2, characterized in that it comprises, within the thickness of said connecting body (9) that forms said structural screed, at least one auxiliary reinforcement frame body (13) that runs substantially parallel to the main longitudinal direction (101) of said beams (3).
The device for connection between prefabricated beams and columns according to claim 1, characterized in that it comprises, along the extension of said column (2), two pairs of resting portions (4a, 4b) which are arranged on opposite sides with respect to the direction of longitudinal extension (100) of said column (2) and are designed to be engaged by resting by an end portion (5) of a respective beam (3).
The device for connection between prefabricated beams and columns according to claim 4, characterized in that said beams (3) have, at their end portion (5) designed to rest against the respective resting portions (4a, 4b), a longitudinally elongated recess (14) in which the concavity is directed upward, its transverse dimension corresponding substantially to the transverse dimension of said through opening (6), said recess (14) being designed to be at least partially filled by said completion casting (8).
The device for connection between prefabricated beams and columns according to claim 1, characterized in that said reinforcement frame (11) of the beam (3) comprises at least one bar which has a respective threaded end portion (11a) which is stably associated with an internally threaded sleeve (15) which can be engaged by a respective end portion (12a) of a respective connecting bar (12) which forms at least part of said connecting reinforcement frame (10), said threaded sleeve (15) being at least partially embedded within said beam (3).
The device for connection between prefabricated beams and columns according to claim 1, characterized in that said at least one through opening (6) is provided by a tubular box (16), which is embedded within said column (2) and is connected stably to a reinforcement frame (17) of the column.
The device for connection between prefabricated beams and columns according to claim 3, characterized in that said auxiliary reinforcement frame (13) provides a connection between brackets (18) that protrude from the upper surface (3a) of the beams (3) arranged on opposite sides with respect to said through opening (6).