This application is a cognate application claiming priorities of three applications, we hereby submit one complete specification combining the contents of Patent Application Nos.: 202221053066 dated September 16, 2022; 202321033696 dated May 12, 2023; & 202321052559 dated August 04, 2023.

TECHNICAL FIELD

[1] The present invention relates to a system and a method for joining precast elements and more particularly, to a precast elements, sleeves, a system and method therefore.

BACKGROUND

[2] Precast construction is a type of construction in which the already casted/built/ confected elements are assembled and joined on site instead of building the elements such as walls, columns, beams, slabs, 3D modules, pillars and the like on-site. An important aspect of this type of construction is joining these precast elements on site strongly and accurately. Current state of art for example patent publication numbers WO2017187451 and W02019186600 disclose the systems and methods for joining precast elements that include the mechanisms in which two precast elements having hollow sleeves positioned therein are placed adjacently and a bar is translated from one element to other through the hollow sleeve. In the next step, the wet mix of grouting material is mixed and poured/ pumped on site and inserted in the sleeves to fill the sleeves and gaps. However, care is required to be taken in the filling and the installation so as to assure that the hollow sleeves are adequately filled with the grouting material as the alignment of precast elements, insertion of the bar and grouting the sleeves and gap to perfection in the structure are crucial tasks. Further it is observed that even if the whole surface of the bar gets covered by the grouting material, the grouting material bonded over the portion of bar in the gaps between the precast elements may give way in adverse situations like earthquake where the walls get subjected to cyclic loading in combination of shear and bending loads in the absence of additional confinement around the bar in the gap.

[3] Thus, there is a need for an effective and optimized configuration by means of a product and a system for joining precast elements that ensures strong connection between the precast elements with assurance of the uniformly strong bond and confinement throughout the length of the bar, including the gap between the elements.

SUMMARY OF THE INVENTION

[4] In one aspect, the present invention provides a system for joining at least two precast elements, the system comprising a first connection sleeve for positioning in a first precast element. Said first connection sleeve has a rebar movably positioned inside the first connection sleeve. The rebar is movable from the first connection sleeve to the second connection sleeve for joining the first precast element to the second element. A second connection sleeve positioned in a second precast element. Said second connection sleeve has a cover cap of a hollow cylindrical body with a collar at one end portion thereof and at least one through hole configured on a body slidably positioned inside the second connection sleeve. Said cover cap has a length greater than a distance between the first precast element and the second precast element for covering the portion of the rebar between the gap of the two precast elements to form strong uniform bond throughout the length of the bar, including the gap between the precast elements. Each connection sleeve includes: an aligner plate attached at first end portion of the first connection sleeve and second connection sleeve; at least one engaging link engaging the first connection sleeve and second connection sleeve to the inner frame thereby securing the connection sleeves and transferring tensile/ bending/ shear stress of connection sleeves to the inner frame of the precast elements; and a sensing indicator removably connected on each connection sleeve configured with the precast elements for indicating completion of the grout filling process in the connection sleeves after moving the rebar from the first connection sleeve to the second connection sleeve. The sensing indicator is a hollow element having an opening. The hollow body includes a ball having a diameter larger than the diameter of the opening. Each connection sleeve include at least one support plate passing through the connection sleeves. The support plate has at least one holder configured thereto, an engaging link passes through the holder of the support plate for engaging the connection sleeves with the inner frame.

[5] In another aspect, the present invention provides a connection sleeve comprising an aligner plate attached at first end portion of the connection sleeve. A sensing indicator is removably connected on the surface of the connection sleeves at second end portions thereof for indicating completion of the grout filling process in connections sleeves and acts as an inbuilt shuttering system. The connection sleeve comprises a rebar movably positioned inside the connection sleeve, or a cover cap having a hollow cylindrical body with a collar at one end portion thereof and at least one through hole configured on a body is slidably positioned in the connection sleeve.

[6] The present invention provides a precast element comprising a plurality of first connection sleeve and/or a plurality of second connection sleeve placed in predefined manner.

[7] The present invention provides a method for manufacturing precast elements, the method comprising the steps of: preparing an inner frame by fixing vertical and horizontal bars in a mould plate of the precast element; marking center points for positioning at least one first connection sleeve and/or at least one second connection sleeve in the mould plate; placing the connection sleeves in the inner frame at the pre-defined positions; fixing the connection sleeves to the inner frame; fixing a plug on the mould plates by nut bolt/ magnet/ welding; positioning the first and connection sleeves pre-fixed with the aligner plates in the precast element; placing a tube over the access hole of the first connection sleeve to access the bar from the outer surface of the precast elements; placing another tube over the second end of the connection sleeves for connecting sensing indicator; attaching duct tape over the various joints to avoid leakage of cement slurry to go inside the connection sleeves; closing end portions of the first and second connection sleeves with aligner plates and keeping the outlets of the tubes outside the surface of the inner frame; casting the precast elements by pouring concrete in the mould and curing the mould until the concrete gains strength. In alternative embodiments, fixing the connection sleeves to the inner frame comprises the following steps: positioning at least one support plate through the connection sleeves; and passing the engaging link through a holder of the support plate and the inner frame thereby fixing the connection sleeves to the inner frame.

[8] In yest another aspect, the present invention provides a method for joining at least two precast elements. In the first steps a first precast element having a first connection sleeve and a second precast element having a second connection sleeve are positioned opposite to each other having a gap therebetween such that an aligner plate of first connection sleeve and an aligner plate of second connection sleeve are aligned with each other. In the next step, a rebar positioned in the first connection sleeve is moved to the second connection sleeve upto a predefined location in the second connection sleeve. In the next step, a cover cap placed in the second connection sleeve is moved from the second connection sleeve towards the first connection sleeve such that a collar of the cover cap touches side of the adjacent precast element the aligner plate of the first connection sleeve. In the next step, a mix of grouting material is introduced in the gap from top side of the elements in the gap till a sensing indicator indicate completion of the grout filling process in the connection sleeves and hollow space between the rebar and the cover cap. In the last step, the grout filled in the first and second connection sleeves, the hollow space between the rebar and the cover cap and gap and forming a strong bond with the rebar and the sleeves and cover cap thereby joining the precast elements. BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[9] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference features and modules.

[10] FIG. 1 illustrates a cross sectional view of a system of joining precast elements having connection sleeves in accordance with an embodiment of the present invention;

FIGS. 2A and 2B illustrate a perspective view and front view of a first connection sleeve of FIG. 1 placed in the precast element of the system in accordance with an embodiment of the present invention;

FIGS.3 A and 3B illustrate a perspective view and front view of a second connection sleeve of FIG. 1 placed in the precast element of the system in accordance with an embodiment of the present invention; and

FIG. 4 illustrates a perspective view of joined connection sleeves of the system of FIG. 1 in accordance with an embodiment of the present invention;

FIG. 5A illustrates an exploded view of first connection sleeve of the system of FIG. 2A and 2B in accordance with an embodiment of the present invention;

FIG. 5B illustrates an exploded view of second connection sleeve of the system of FIG. 3A and 3B in accordance with an embodiment of the present invention;

FIG. 6 illustrates front views of a grout sensing indicator of the system in accordance with an embodiment of the present invention;

FIGS. 7A and 7B illustrate a perspective view and front view of a second connection sleeve of the system in accordance with another embodiment of the present invention; and FIGS. 8 A and 8B illustrate a photographic view and a front view of the precast elements during method of joining precast elements.

[11] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[12] In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure may be practiced without these details.

[13] One skilled in the art will recognize that various implementations of the present disclosure, some of which are described below, may be incorporated into a number of systems.

[14] However, the systems and methods are not limited to the specific implementations described herein. Further, structures and devices shown in the figures are illustrative of exemplary implementations of the present disclosure and are meant to avoid obscuring the present disclosure.

[15] Furthermore, connections between components and/or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.

[16] References in the present disclosure to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in an embodiment” or “in an implementation” in various places in the specification are not necessarily all referring to the same embodiment or implementation. [17] Referring to FIG. 1, a system (300) for joining precast elements in accordance with an embodiment of the present invention is shown. The precast elements to be joined with each other include at least two precast elements i.e. a first precast element (100) and a second precast element (200). The system (300) includes at least one first connection sleeve (10) placed at a predefined location in the first precast element (100) and at least one second connection sleeve (20) placed at a predefined location in the second precast element (200). It is understood here that number of the first and second sleeves (10, 20) may vary as per the height and size of the precast elements (100, 200). In accordance with the present invention, it is understood here that in case of more than two precast elements (100, 200) are joined with each other, the precast element positioned between the two elements includes both the first and second sleeves (10, 20) placed therein.

[18] In accordance with an embodiment, the first connection sleeve (10) is positioned in the first precast element (100) and the second connection sleeve (20) is positioned in the second precast element (200). A rebar (30) is movably positioned inside the first connection sleeve (10). The rebar (30) is movable from the first connection sleeve (10) to the second connection sleeve (20) for joining the first precast element (100) to the second element (200).

[19] The first and second connection sleeves (10, 20) include an aligner plate (11, 21) attached at first end portions of the first connection sleeve and second connection sleeve (10, 20). The connection sleeves (10, 20) include at least one support plate or holdfast (12, 22) passing through the connection sleeves (10, 20). The support plate (12, 22) has at least one holder (122, 222) configured thereto. The support plate (12, 22) is turned and moved along the spiral threading of the connection sleeves (10, 20) up to the desired location.

[20] At least one engaging link (15, 25) engages the first connection sleeve (10) and second connection sleeve (20) pass through the holder (122, 222) of the support plate (12, 22) for engaging the connection sleeves (10, 20) with the inner frame (50). In alternative embodiment, a holding frame (14, 24) are fixed to the inner frame (50) of the precast elements (100, 200). The engaging link (15, 25) passes through the holder (122, 222) of the support plate (12, 22) and engages into the holding frame (14, 24). The engagement of the engaging link (15, 25) with the holding frame (14, 24) secures the connection sleeves (10, 20) and transfer tensile/ bending/ shear stress of the connection sleeves (10, 20) to the inner frame (50) of the precast elements (100, 200). In alternative embodiment, the first connection sleeve (10) and the second connection sleeve (20) can be directly connected to the inner frame (50) also.

[21] In accordance with alternative embodiment of the present invention, referring to FIG. 6, a sensing indicator (16) is removably connected at a second end of the connection sleeve (10) and (20). The sensing indicator (16) is a hollow element having an opening (160). The hollow body includes a ball (162) having a diameter larger than the diameter of the opening (160). The sensing indicator (16) indicates completion of the grout fdling process in connection sleeves (10) after moving the rebar (30) from the first connection sleeve (10) to the second connection sleeve (20) and acts as an inbuilt shuttering system. As the grout completely fills the sensing indicator (16), the ball (162) moves towards the opening (160) and blocks the opening (160) thereby indicating completion ofthe grout filling process.

[22] In accordance with the present invention, the aligner plate (11) of the first connection sleeve (10) has at least one access hole (110). The access hole (110) provides access to the rebar (30) positioned inside the first connection sleeve (10) for moving the rebar (30) from the first connection sleeve (10) to the second connection sleeve (20). The rebar (30) is moved from the first connection sleeve (10) to the second connection sleeve (20) using a driving mechanism that drives the rebar (30) from one sleeve to another. The rebar (30) can also be moved through the second sleeve (20) by pulling the same by wire connected thereto through the second open end ofthe second sleeve (20).

[23] It is to be noted here that the connection sleeves (10, 20) are secure due to a plug (112, 212) removably attached to the aligner plates (11, 21), support plates (HSR) (12, 22) and engaging links (15, 25) or HSR bars secured to the holding frame (14, 24) or links at the time of pouring the weight of concrete on the connection sleeves (10, 20). The system becomes leak proof/ water tight as the concrete slurry does not enter the sleeves by any ingress routes by provision of the plugs (112, 212) fixed to the aligner plate (11, 21). The outlet hole is at a higher level than the top of sleeve level.

[24] In accordance with the present invention, referring to FIGS. 2A and 2B the first connection sleeve (10) comprises an aligner plate (11) attached at first end portion of the first connection sleeve (10), the aligner plate (11) has an access hole (110) for accessing the bar (30); and at least hole is configured on the surface of the first connection sleeve (10) at second end portion thereof. The First connection sleeve (10) includes at least one support plate (12) passes therethrough. The support plate (12) facilitates engagement of the at least one engaging link (15) with the inner frame (50) thereby securing the connection sleeves (10) and transferring tensile/ bending/ shear stress of connection sleeves (10) to the inner frame (50) of the precast elements (100). A rebar (30) is movably positioned inside the first connection sleeve (10). The inner surface of the aligner plate (11) has a protrusion for keeping the rebar (30) at slightly elevated location while moving from the first connection sleeve (10) to the second connection sleeve (20).

[25] In accordance with the present invention, referring to FIG. 3A, 3B and 6, the second connection sleeve (20) comprises an aligner plate (21) attached at first end portion thereof; and at least hole configured on the surface of the second connection sleeve (20) at second end portion of thereof. The second end of the connection sleeve (20) includes a sensing indicator (26) removably connected thereto. The sensing indicator (26) is attached to the connection sleeves (10, 20) by an another tube attached to the end portions of the connection sleeves (10, 20). The sensing indicator (26) indicates completion of the grout filling process in connections sleeves (20). The sensing indicator (26) is a hollow element having an opening (260). The hollow body includes a ball (262) having a diameter larger than the diameter of the opening (260). The sensing indicator (26) indicates completion of the grout filling process in second connections sleeve (20) after moving the rebar (30) from the first connection sleeve (10) to the second connection sleeve (20) and acts as an inbuilt shuttering system. The second connection sleeve (20) includes the support plate (22) passes therethrough. The support plate (22) facilitates engagement of the at least one engaging link (25) with the inner frame (50) thereby securing the connection sleeves (20) and transferring tensile/ bending/ shear stress of connection sleeves (20) to the inner frame (50) of the second precast elements (200).

[26] Referring to FIG. 3A, 3B and 7A, 7B, a system for joining two precast elements (100, 200) in accordance with another embodiment of the present invention is shown. In accordance with this embodiment, at least one of the first and second connection sleeves (10, 20) and preferably the second sleeves includes a cover cap (60) slidably positioned therein. The cover cap (60) has a cylindrical hollow body with a collar (61) at one end portion thereof and has a length greater than the gap between the two adjacent precast elements. It is understood here that the cover cap (60) has a profile matching the profile of the second connection sleeve (20). The cover cap (60) includes at least one through hole (62) positioned thereon at a predefined location. The cover cap (60) covers the portion of the rebar (30) between the gap (40) of the two precast elements ( 100, 200). After moving the rebar (30) from the first connection sleeve (10) to the second connection sleeve (20), the cover cap (60) positioned in the second connection sleeve (20) is moved from the second connection sleeve (20) towards the first connection sleeve (10). As the cover cap (60) touches the aligner plate (11) of the first connection sleeve (10), a hollow space gets formed between the rebar (30) and the inner profile of the cover cap (60) which gets filled by the grouting material that enters the hollow space through the though hole (62) while filling the grouting material in the gap (40).

[27] Referring to FIG. 1-8B, in another aspect, the present invention provides a method for joining two precast elements. In first step, a first precast element (100) having a first connection sleeve (10) and a second precast element (200) having a second connection sleeve (2) are positioned opposite to each other having a gap (40) therebetween such that an aligner plate (11) of first connection sleeve (100) and an aligner plate (21) of second connection sleeve (200) are aligned with each other. In the next step, a rebar (30) positioned in the first connection sleeve (10) is moved to the second connection sleeve (20) upto a predefined location in the second connection sleeve (20). In the next step, the cover cap (60) is moved from the second connection sleeve (20) towards the first connection sleeve (10) such that the collar (61) of the cover cap (60) touches side of the adjacent precast element the aligner plate (11) of the first connection sleeve (10). In the next step, a mix of grouting material is introduced in the gap (40). The grout mix is introduced from top side of the elements in the gap (40). The grout fills the bottom portion of the gap (40) and then moves into the first connection sleeve (10) and the second connection sleeve (20) by moving in upward direction against gravity. In this step, the grouting material also enters the hollow space between the rebar (30) and the cover cap (60) through the through hole (62). In the next step, the first and second connection sleeves (10, 20), the hollow space between the rebar (30) and the cover cap (60) and gap (40) completely filled with grout are let dry. After drying, the grout hardens and forms a strong bond with the rebar (30) and the sleeves (10, 20) and cover cap (60) thereby joining the precast elements (10, 20).

[28] The present invention provides a method for manufacturing precast elements (100, 200), the method comprising the steps of: preparing an inner frame (50) by fixing vertical and horizontal bars in a mould plate of the precast element ( 100, 200); marking center points for positioning at least one first connection sleeve (10) and/or at least one second connection sleeve (20) in the mould plate; placing the connection sleeves (10, 20) in the inner frame (50) at the pre-defined positions; fixing the connection sleeves (10, 20) to the inner frame (50); fixing a plug (112; 212) on the mould plates by nut bolt/ magnet/ welding; positioning the first and second connection sleeves (10, 20) pre-fixed with the aligner plates (11, 21) in the precast element; placing a tube over the access hole (110) of the first connection sleeve (10) to access the bar from the outer surface of the precast elements (100, 200); placing another tube over the second end of the connection sleeves (10, 20) for connecting sensing indicator (16, 26); attaching duct tape over the various joints to avoid leakage of cement slurry to go inside the connection sleeves (10, 20); closing end portions of the first and second connection sleeves (10, 20) with aligner plates (11, 21) and keeping the outlets of the tubes outside the surface of the inner frame (50); casting the precast elements (100, 200) by pouring concrete in the mould and curing the mould until the concrete gains strength. In alternative embodiments, fixing the connection sleeves (10, 20) to the inner frame (50) comprises the following steps: positioning at least one support plate (12, 22) through the connection sleeves (10, 20); and passing the engaging link (15, 25) through a holder of the support plate ( 12, 22) and the inner frame (50) thereby fixing the connection sleeves (10, 20) to the inner frame (50). The distance between the two consecutive connection sleeve (10, 20) depends on structural design requirement, approximately it can be from 100mm c/c to 750mm.

[29] It is understood here that the rebar (30) is moved from the first connection sleeve (10) into second connection sleeve (20) by the driving mechanism through an access hole (110) or by a wire. The rebar (30) is moved into the second connection sleeve (20) such that half portion of the rebar (30) remains in the first connection sleeve (10) and half portion of the rebar (30) remains in the second connection sleeve (20). The grouting material is introduced in the gap (40) till it is expelled from the at least one hole configured on the connection sleeves (10, 20) or till the sensing indicators (16, 26) attached at a second end portion of the connection sleeves (10, 20) indicate complete filling of the first connection sleeve (10) and the second connection sleeve (20).

[30] In accordance with an embodiment, a connection bay can be defined as when viewed in cross section, (FIG. 1) the portion between inner frame (50) in which a connection sleeve is planned for and that a minimum clear distance is to be maintained inside a connection bay. In presence of links/ ties or both, it is tied to the main bars on outer faces of the master stirrups which define that connection bay. In no case should the links/ ties be tied inside of the connection bay. Hence, the tie the links/ ties are tied on the upper face of the top master ring of the connection bay and on the bottom face of the lower master ring of the connection bay. There is no specification of the diameter of the master ring or link/ ties. This may be as per the structural designer’s calculation. Non-Connection Bays are those portions in the cross section of the wall, between any two successive master stirrups in which connection sleeves are not planned or are absent. Neither is there any specification for minimum clear distance inside these bays nor is there any requirement of tying the links/ ties on the outer face of the master rings, etc.

[31] In accordance with an embodiment, the bars (15, 25) required for the holdfast cum supplementary reinforcement (HSR) are availed by the contractor from his site. The advantages of keeping this in contractor’s scope are as below. The lengths and the diameters are suitably designed so these rebars (30) can be availed from the “wastage bars” from the cutting lengths of standard bars as well. The wall sizes may vary and also the other factors determining the detailing of the HSRs such as Thickness of wall, Clear Cover, Main bar diameter, Stirrup diameter, and hence its not prudent to have so many variables dictating product dimensions. Due to the varying factors the contractor can rather easily issue cut bend drawings for the HSR bars and use them as per the prevailing conditions. The design of the HSR bar is such that it can also be tweaked to adjust the exact conditions by hammering the bars to match the tying point on the links/ ties. If required, the HSR bars can also be connected directly to the main bars of the walls.

[32] Advantageously, as the head of the rebar (30) is in a bullet nosing shape; therefore it doesn’t obstruct with the serrations of the second connection sleeve (20) and thus tolerance factor and smooth passage of the rebar (30) from the first connection sleeve (10) to the second connection sleeve (20) is taken care of. Also, the rebar (30) has a colored marking in the center which indicates that the sufficient length has been passed from one precast element to another.

[33] In alternative embodiments, a specially designed key is inserted into the access opening cum grout outlet and attached to the drive mechanism on one end and the other end of the key is attached to the drive device. In the next step, when the rotation of the drive device is activated, the key also rotates and therewith the main drive wheel of the gear is also set into rotation, thereby again setting the connecting bar into a translation motion therefore moving itself from donor to receptor. While in motion, the bullet shaped nosing design goes smoothly along the inside of the receptor without obstructions. In the next step, the bar of the required length is passed till the colored marking is seen in the gap, which determines successful stage completion. In the next step, a specially designed adhesive is sprayed on each wall side and on a fabric/ thin steel plate and for the same width for the height of 2m of the wall and then after waiting for a predetermined time, the fabric/ steel sheet is applied on the wall at the gap and followed by grouting. In the next step, the fabric/ thin steel plate is removed, and buffing/ grinding is done in order to make the joint look clean. In alternative embodiments, the usage of sprayable adhesive together with fabric/thin steel sheet also takes care that no leakage takes place from the joint even if there are offsets between the walls, which is a very difficult to achieve in conventional shuttering and also, the adhesive and the fabric/ thin steel sheet is sufficient to take the load of the grout head.

[34] The system (300) of the present invention consumes the least amount of grout within Tolerance limits to avoid chances of mismatch. The system of the present invention requires the least count of holes openings on the finished wall surface. The system can be used in horizontal as well as vertical casting and left-right compatible design due to rotatable grout outlets and T shaped emergency access hole. This system is compatible for any thickness of wall from 150mm to 400mm or even beyond.

[35] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.