EP3394358A1

EP3394358A1 - Anti-seismic connection joint having a slotted hole

Info

Publication number: EP3394358A1
Application number: EP16831581.0A
Authority: EP
Inventors: Giovanni BULFERETTI
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-12-21
Filing date: 2016-12-05
Publication date: 2018-10-31
Also published as: WO2017109616A1; ITUB20159737A1; MA44152A

Abstract

A mechanical anti-seismic connection joint (100) comprises a female element (10) and a male element (20), fixable to the respective structural components (110,120). The female (10) and male elements (20) are joined by a pin (30) to form a connection hinge (40) between the structural components (110,120). The pin (30) is inserted in at least one slotted hole (33) provided on a support (14) of the female element (10). The mechanical joint (100) is arranged such that the hinge (40) is provided with a damping element constituted by the pin (30) inserted in the slotted hole (33) and translatable along a trajectory (T) defined controlled by the shape of the slotted hole (33). Advantageously, the mechanical joint (100) exploits the forces generated by the earthquake to reactivate the characteristics of stability already present in the building, but momentarily made unavailable by sussultatory type shocks.

Description

DESCRIPTION

"Anti-seismic connection joint having a slotted hole"

[0001] This invention relates to a mechanical-type anti- seismic connection joint, in particular for prefabricated structures made of reinforced, pre-stressed or normal cement .

[0002] Recent seismic events have focused attention on new anti-seismic connection systems for construction, suitable to allow the structural scheme of the building and/or the structure (existing or newly constructed) to which they are applied, to adequately withstand seismic forces and absorb deformations.

[0003] In particular, an anti-seismic joint realises an adequate connection between the major structural elements of the buildings, or more generally of infrastructural constructions, essential to prevent serious damage and collapses during the earthquake. In fact, precisely due to seismic events, adjacent structural components of the same structure (components normally designed in simple support and with a significantly different seismic behaviour) are in danger of colliding with each other and falling precisely at the connection points following the "loss support". At the same time, the anti-seismic joint must always allow the free expansion of the building structure (due, for example, to seasonal temperature changes), preventing damage and cracking. In particular, since the scope of application is that of industrial buildings and constructions made of reinforced cement and pre-stressed concrete in general, it is essential that the anti-seismic joint be suitable to support adequately not only the first seismic shock, but also all subsequent shocks .

[0004] The perceived need in the sector of anti-seismic constructions and infrastructures is that of having a structural connection between the components of the building that is able to limit displacements in correspondence of support points and, in any case, prevent "loss of support" and the consequent falling of the structures.

[0005] Moreover, this structural connection must be made in compliance with current standards and also applicable on both new and existing buildings or constructions.

[0006] Moreover, such a structural connection must limit excursion in support points for the entire duration of the seismic event.

[0007] Moreover, this structural connection must be possibly simple, inexpensive, safe, durable and not require maintenance over the years.

[0008] The purpose of this invention is to resolve the problems of the known art, taking into account the needs of the field.

[0009] This purpose is achieved by a hinge-type mechanical connection joint with "damping and dissipative" function thanks to the force of friction that is generated on the contact surfaces between the various structural elements.

[0010] This purpose is achieved by a mechanical anti- seismic joint according to claim 1 below. The dependent claims describe preferred or advantageous embodiments of the mechanical connection joint.

[0011] The characteristics and advantages of the mechanical connection joint according to this invention will be apparent from the following description, given by way of non-limiting example, in accordance with the accompanying drawings, in which:

[0012] - Figure 1 shows an axonometric view of a mechanical anti-seismic connection joint according to this invention, in an embodiment variant;

[0013] - Figure 2 shows a transverse sectional view of the anti-seismic connection joint of Figure 1, obtained along a vertical plane passing through the X axis;

[0014] - Figure 3 shows a longitudinal sectional view of the anti-seismic connection joint of Figure 1, obtained along a vertical plane passing through the X axis;

[0015] - Figures 4A, 4B and 4C respectively show the position of the pin inside the shaped seat of the mechanical hinge joint, in the various phases of the seismic event;

[0016] - Figure 5 shows an axonometric view of the anti- seismic connection joint of Figure 1 in a in a further embodiment variant.

[0017] Naturally, the joint shown in the previous figures (1 and 5), suitably dimensioned, can also be applied to the supports of bridge decks on corresponding piles or for other similar applications.

[0018] With reference to the accompanying figures, a mechanical anti-seismic connection joint is indicated by reference number 100.

[0019] In normal situations (as shown in Figure 3 and 4A) , and thus in the absence of a seismic event, the horizontal structural component 120 is supported at the corresponding vertical structural component 110 on the support plane 130. On the support plane 130, there is generally present a damping slab 140, for example made of elastic material (neoprene, natural rubber or elastomers in general), metallic materials or composite materials. In many cases, however, the various structural components 120,110 are simply supported on one another (cement on cement) .

[0020] As shown in Figure 1, the joint 100 is a hinge joint comprising a female element 10 and a male element 20, each fixable to a respective structural component 110,120, for example a pillar, a pile or a wall 110 made of reinforced cement and a beam or tile 120. The female element 10 and male element 20 are fixable to the respective structural components 110,120 by means of fastening systems 90, such as screws and bolts, chemical anchors and metal bindings.

[0021] The female element 10 and male element 20 are provided with a plate 11,21 for fastening with the respective structural component 110,120. The plate 11,21 is fixable to the respective structural component 110,120 for example by means of screws, bolts and chemical or mechanical anchors 90. The plate 11,21 is provided with circular or preferably oval-shaped holes to allow a plurality of positions of the screw in the hole, so as to avoid the internal reinforcement of the structural component .

[0022] In a variant, shown in Figure 1, the plate 11,21 is, or can be, provided with lateral shoulders 28 for fixing along the sides around the structural components 110,120, for example, when such structural components do not allow the insertion of screws along the base or when the dimensions are too narrow.

[0023] The female element 10 and male element 20 are metallic components connected by means of a pin 30, preferably with threaded ends for fixing two nuts 93 that prevent their slipping off.

[0024] As shown in Figure 1, the female element 10 and male element 20 are joined by means of the pin 30 to form a connection hinge 40 between the two structural components 110,120, so that the vibratory movement generated by the earthquake occurs freely for each of the two connected parts .

[0025] In particular, the hinge 40 allows absorbing the axial and transverse stresses of the structure, and particularly of the structural components 110,120, which are caused by seismic events. Moreover, the hinge 40 allows the free expansion of the structural components 110,120 themselves due to seasonal variations in temperature and does not generate any type of interlocking at the supports.

[0026] As shown in Figure 3, the pin 30 is inserted in circular holes 32 provided in the male element 20, circular holes 32 that limit any displacement. The circular holes 32 are thus rigidly associated to structural component 120 subject to horizontal displacements (along the Z axis) .

[0027] The pin 30 is inserted in slotted holes 33 provided in the female element 10, slotted holes 33 that allow a longitudinal translation (along the Z axis), in the two directions, and within a maximum predefined excursion.

[0028] In particular, the slotted holes 33 formed in the female element 10 extend along a substantially horizontal direction (Z axis), are symmetrical (with respect to the Y axis) and have a substantially elliptical shape.

[0029] As shown in Figure 4A, the shape of the slotted hole 33 is characterised by a curved portion that extends in the upper part 35 up to the sides 36 included and by a straight (horizontal) portion in the lower part 37. The shape of the slotted hole 33 (and in particular the curved portion in the upper part 35) defines the controlled trajectory T along which the pin 30 slides.

[0030] The slotted hole 33, in its ends, is also a mechanical stop to the displacement of the pin 30 (Figures 4B and 4C) .

[0031] The mechanical anti-seismic connection joint 100 according to the invention is thus provided with a damping element in the form of a hinge 40 with the pin 30 inserted in the slotted hole 33 (provided in the female element 10) and translatable along the controlled trajectory T defined by the shape of the hole itself.

[0032] The curved portion in the upper part 35 of the hole 33 has a virtually horizontal initial trend in correspondence of the axis of symmetry (vertical Y) to facilitate normal thermal expansions, which continues (on one side and the other of the axis of symmetry Y) curving gradually towards the lower portion 37. Therefore, the larger the (horizontal) displacement of the horizontal component 120 due to seismic event, the greater is the vertical force (of traction between the two structural elements 110 and 120) generated by the joint 100 and acting on the support plane 130. Greater, therefore, is the corresponding new friction force between the structural components 120,110 precisely in correspondence of the support plane 130.

[0033] The maximum design excursion S (i.e., the maximum horizontal displacement allowed to the horizontal component 120) depends on the dimensions of the support while the entity of the resulting vertical displacement is a function of the thickness of the damping slab 140, where present.

[0034] In a purely indicative way, and for building structures of medium dimensions, the maximum design excursion S is between 10 mm and 40 mm, preferably between 20 mm and 30 mm. For viaducts and infrastructural constructions in general, the longitudinal and vertical excursion parameters will be established from time to time according to the constructional and dimensional characteristics and by the acting loads.

[0035] In fact, the shape of the slotted hole 33, and in particular the curvature of its upper portion 35, determines the entity of the crushing of the support slab 140 (when present), and in general the intensity of the compression between the structural elements 120,110 involved. Therefore, the inclination a of the displacement trajectory T of the pin 30 from the initial position (along the Y axis, as in Figure 4A) to that of maximum excursion (as in Figures 4B and 4C) varies as a function of the type of support (i.e., if this is the support slab 140 is present and the type of material used) .

[0036] Preferably, the inclination a of the controlled trajectory T of the pin 30 is the ratio expressed as a percentage between the vertical displacement (crushing) and the horizontal displacement (s) and is comprised between 5% and 40%.

[0037] For example, the inclination a of the controlled trajectory T of the pin 30 will be minimal and comprised in the order of 5% to 10% for cement on cement supports or with interposed metal slabs 140.

[0038] For example, the inclination a of the controlled trajectory T of the pin 30 will depend on the thickness s characteristic of the slabs 140 and comprised in the order of 20% to 40% for supports with interposed slabs of neoprene or similar materials. [0039] The particular curved shape of the upper portion of the slotted hole 33 is the heart of the mechanical anti- seismic connection joint 100 of this invention.

[0040] During a seismic event, the force arising from a sussultatory shock (causing a slight lifting of the horizontal component 120) causes the original "loss of support" due to a lack of friction force and generates a horizontal displacement of the horizontal component 120.

[0041] The horizontal displacement of the horizontal component 120 (and with it the male element 10, and again the pin 30 inserted in the circular holes 32 of the supports 24 provided on the plate 20) given the presence of the mechanical anti-seismic connection joint 100 (in which the pin 30 slides along the trajectory T defined by the shape of the slotted hole 33 and moves vertically downwards) results in a traction force (downwards), and thus in a new compression force between the horizontal component 120 and the vertical component 110 on the support plane 130, compression that generates a consequent new friction force that dampens and cancels the acting seismic force.

[0042] Substantially, the mechanical anti-seismic connection joint 100 according to the invention exploits, simply and dependably, the forces generated by the earthquake to reactivate the characteristics of stability already present in the building, but momentarily made unavailable by sussultatory type shocks.

[0043] The female element 10 is provided with at least two supports constituted by two distinct pairs of supports 14, protruding from the plate 11. Each support 14 is provided with a slotted hole 33 for the insertion and housing of the pin 30.

[0044] The male element 20 is provided with at least two distinct supports 24, protruding from the plate 21. Each support 24 is provided with a circular hole 32 for the insertion and housing of the pin 30.

[0045] The joint 100 connects the vertical and horizontal structural components 110,120 to each other and, at the same time, being a hinge joint, achieves a decoupling of the masses in such a way that the vibratory movement determined by seismic events occurs freely for each of the two connected parts.

[0046] In addition, the joint 100, being a hinge joint with damping element (hinge with pin inserted in the slotted hole) , is designed to allow the structure to collect both the deformations that occur slowly over time, such as thermal deformation or shrinkage, and the forces resulting from seismic type dynamic and impulsive actions. Therefore, the mechanical anti-seismic connection joint 100 is particularly suitable for single- storey or multi-storey earthquake-resistant structures, for bridge decks and in general for infrastructural constructions, in which the respective high dimensions necessarily require the presence of thermal expansion systems in correspondence of which the problem of hyperstaticity would intervene if known structural joints were applied. The joint 100, being of the hinge type, does not create any degree of interlocking in correspondence of the support of the beams 120.

[0047] Moreover, the hinge 40 of the joint 100, being particularly robust and characterised by large geometrical dimensions, guarantees the structure against all the transverse seismic forces (or, in any case, inclined) and prevents falling and/or lateral tipping of the horizontal structural elements 120. The action of the joint 100 during the excursion phase (displacement of the structural components) results in a significant damping effect and an important energy dissipation due to the sliding along the support plane 130 of the horizontal structural component 120 on the corresponding vertical structural component 110 (in the presence or not of the slab 140 of elastic material) .

[0048] For new construction works, the joint 100 is a simple, adequate and economical solution for structural connections since, through the simple installation of bushings in the structures during pouring, the installation of the joint will be reduced to only the application of bolts in already prepared seats.

[0049] Preferably, in order to improve the sliding of the pin 30 in the slotted hole 33 (and along its elliptical profile) the pin 30 is made of stainless steel and the supports 14 of the female element 10 are made of high- strength steel (for example of type 38NCD4 or similar) .

[0050] Preferably, for outdoor applications exposed to the weather such as bridges, viaducts, etc., the joint 100 is made entirely of stainless steel, including the related anchors .

[0051] In its various applications, the mechanical anti- seismic connection joint 100 according to the invention can be realised with one or more pairs of supports 14 of the female element 10 with interposed one or more supports of the male element 24. For example in case of severe conditions or in the presence of significant lateral forces, the female element 10 will have to comprise at least two pairs of supports 14, each connected by the pin 30 to corresponding supports 24 of the male element 20. For example in more simple situations, the female element 10 comprises a pair of supports 14, connected by the pin 30 to support 24 of the male element 20. [0052] For joints 100 of important structures such as bridges, etc., it is preferable to use joints provided with three or more distinct pairs of supports 14 of the female element 10 coupled to three or more distinct supports 24 of the male element 10.

[0053] The mechanical anti-seismic connection joint 100 of this invention finds application in buildings, such as industrial sheds, or on constructions or works of art constructed in the context of infrastructure such as bridges, viaducts, hydraulic plants, etc., (of new construction or already installed and in use) .

[0054] It is essential that the joint 100 allows a limited displacement with precise limits, for example of the beams 120 on the pillars 110 or on support walls of reinforced cement, or bridge decks on the corresponding piles. Since a pillar generally has indicative dimensions of about 50-60 cm in order to allow the support of two beams 120 having indicative dimensions of about 20-30 cm, when the seismic event is concluded, it is critical that the aforesaid beams, if translated, are still in a completely safe position of support on the pillar 110.

[0055] Once dimensioned and adapted, the mechanical anti- seismic connection joint 100 described above can be used for the anti-seismic connection of all the structural components in reinforced cement and pre-stressed cement buildings or in existing or new infrastructural constructions .

[0056] This invention also relates to an anti-seismic connection system comprising:

[0057] - a horizontal structural component 120 resting on a corresponding vertical structural component 110 on a support plane 130 provided or not with a dampening slab 140;

[0058] - an anti-seismic connection joint 100 wherein the slotted hole 33 allows a maximum, predefined design excursion S that is a function of the dimensional characteristics of the support and of the thickness of the slab 140.

[0059] This invention also relates to an anti-seismic connection system comprising:

[0060] - a horizontal structural component 120 resting on a corresponding vertical structural component 110 on a support plane 130;

[0061] - an anti-seismic connection joint 100 in which the inclination a of the trajectory T of displacement of the pin 30 is a function of the type of support plane 130 in the presence or not of the slab 140. For example, the inclination a is of the order comprised between 5% and 10% for cement on cement or cement on damping metal slab 140 type supports. For example, the inclination a is of the order comprised between 20% and 40% for cement on damping slab 140 supports made of neoprene or similar materials .

[0062] Innovatively, a mechanical anti-seismic connection joint 100 according to the invention creates a structural connection between the components of the building or the infrastructural construction limiting displacements in correspondence of the support points (without inhibiting them) for the whole duration of the seismic event.

[0063] Advantageously, the mechanical anti-seismic connection joint 100 prevents the "loss of support" and the consequent falling of the structures.

[0064] Advantageously, the mechanical anti-seismic connection joint 100 according to the invention exploits the forces generated by the earthquake to reactivate the characteristics of stability already present in the building, but momentarily made unavailable by sussultatory type shocks.

[0065] Advantageously, the mechanical anti-seismic connection joint 100 according to the invention is applicable both newly constructed or existing buildings or constructions. The mechanical anti-seismic connection joint 100 is particularly suitable for structures with support slabs 140 made of elastic materials.

[0066] Advantageously, the slotted holes 33 present on the supports 14 of the female element 10 in fact behave as elements of damping and dissipation of the seismic force thanks to the new friction force generated in correspondence of the support plane 130.

[0067] Advantageously, joints made of galvanised or painted steel applied in the interior of buildings and for stainless steel joints applied outside (viaducts etc.), do not need any routine or extraordinary maintenance over the years .

[0068] It is clear that one skilled in the art may make changes to the device described above, all contained within the scope of protection defined by the following claims .

Claims

1. Anti-seismic connection joint (100), comprising a female element (10) and a male element (20), fixable to respective structural components (110,120) resting on one another along a support plane (130), said female elements (10) and male elements (20) being joined by means of a pin (30) to form a connection hinge (40) between the structural components (110,120),

characterised in that the hinge (40) is provided with a damping element constituted by the pin (30) inserted in at least one slotted hole (33) provided on the female element (10), and in that the pin (30) is translatable along a controlled trajectory (T) defined by the shape of the slotted hole (33) in such a way as to create a compression on the support plane (130) and a consequent horizontal friction force.

2. Anti-seismic connection joint (100) according to claim 1, wherein the slotted hole (33) allows a longitudinal translation of the pin (30), in both directions, and within a predefined, maximum design excursion (S) .

3. Anti-seismic connection joint (100) according to claim 1 or 2, wherein the ends of the slotted hole (33) create a mechanical stop to the movement of the pin (30) .

4. Anti-seismic connection joint (100) according to any of the preceding claims, in which the slotted hole (33) extends along a substantially horizontal direction and has a substantially elliptical shape.

5. Anti-seismic connection joint (100) according to any of the preceding claims, wherein the slotted hole (33) comprises a curved portion in the upper part (35) and a horizontal rectilinear portion in the lower part (37) .

6. Anti-seismic connection joint (100) according to claim 5, wherein the curved portion in the upper part (35) has, in correspondence of the centre, a horizontal development and continues curving, symmetrically, toward the lower portion ( 37 ) .

7. Anti-seismic connection joint (100) according to any of the preceding claims when dependent on claim 2, wherein the excursion (S) is comprised between 10 mm and 40 mm, preferably between 20 mm and 30 mm.

8. Anti-seismic connection joint (100) according to any of the preceding claims, wherein the inclination angle (a) of the trajectory (T) , an inclination defined as the percentage ratio between the vertical displacement and the horizontal displacement of the pin (30), is comprised between 5% and 40%.

9. Anti-seismic connection joint (100) according to any of the preceding claims, wherein the pin (30) is inserted in circular holes (32) provided in the male element (20), circular holes (32) that limit any displacement.

10. Anti-seismic connection joint (100) according to any of the preceding claims, wherein a plate (11, 21) is provided with lateral shoulders (28) for fixing along the sides around the structural components (110, 120) .

11. Anti-seismic connection joint (100) according to any of the preceding claims, wherein the pin (30) is made of stainless steel and a support (14) of the female element (10) is made of high strength steel.

12. Anti-seismic connection system comprising:

- a horizontal structural component (120) resting on a corresponding vertical structural component (110) on a support plane (130);

- an anti-seismic connection joint (100) according to any of the preceding claims

wherein the slotted hole (33) allows a maximum, predefined design excursion (S) that is a function of the dimensions of the support plane (130) .

13. Anti-seismic connection system according to claim 12, wherein :

the inclination (a) of the trajectory (T) of displacement of the pin (30), an inclination defined as the percentage ratio between the vertical displacement and the horizontal displacement of the pin (30), is a function of the type of support plane (130),

for example, is comprised between 5% and 10% for cement on cement or cement on metal slab (140) type supports, or is comprised between 30% and 40% for supports on damping slab (140) made of neoprene or similar materials.