WO1998033994A1

WO1998033994A1 - Reinforcing bar splice and method

Info

Publication number: WO1998033994A1
Application number: PCT/US1998/001903
Authority: WO
Inventors: Antonius M. Kies
Original assignee: Erico International Corporation
Priority date: 1997-02-04
Filing date: 1998-02-03
Publication date: 1998-08-06
Also published as: AU6260298A

Abstract

A connection for steel of steel reinforced concrete provides a relatively short sleeve (13) which may be telescoped over one bar (20) and secured in place by a set screw (35) accessible through a transversely extending socket (30, 34). Another bar (32) may be secured in the socket, and opposite sockets and bar connections may be included. The interior of the sleeve is open at both ends for concrete paste intrusion when the concrete is poured in either a cast-in-place or precast construction. The interior of the sleeve may have surface irregularities (27) and a pressure point projection (26) opposite the set screw to keep the sleeve centered as the screw is tightened. The transverse bars are preferably secured with tapered threads either directly or through a position splice member.

Description

Title: REINFORCING BAR SPLICE AND METHOD

Disclosure

This invention relates generally as indicated to a reinforcing bar splice and method, and more particularly to a splice and method useful in steel reinforced concrete structures whether cast-in-place or precast, which facilitates the computer aided design (CAD) and detailing of the structure and the steel reinforcing of such structure.

Background of the Invention

Computer aided design (CAD) is becoming a widely used and useful tool in many aspects of the construction industry, including the design of buildings, and more particularly the design of steel reinforced concrete structures, both poured-in-place and precast.

Computer aided design approaches normally start out with elevations moving to perspectives of what might be termed a working model, which may be enhanced by animation or further enhanced to a virtual reality walk-through. The three dimensional images may be viewed from any direction, or any part through any section.

The overall structure and its components may be subject to various loadings such as wind oscillations, seismic ratings, compressive and tensile loadings; the results viewed, and materials and designs altered as a result. The criteria for each building structural component can be determined and the detailing of the component such as the frame, columns, slabs, footings, etc., can proceed apace. With 4D CAD, the contractors, suppliers, and even scheduling become involved in the design process.

Computed aided design has become a boon to architects and engineers, as well as owners. Traditionally steel reinforced concrete structures have been over designed with, for example, columns being larger than necessary, or beams or footers thicker than necessary, and containing more steel than necessarily desirable. Size in floors, columns, walls and beams in a structural frame is dead space unrentable or unusable to the owner. It is also usually not visible. Also, the larger the size, the more costly and longer construction usually takes.

Overdesign is often in part due to the lack of ready availability of materials or tools. For example, for many years in reinforcing steel construction the common splice was and in many areas still is a wire tied lap splice where the bar ends are substantially overlapped. Such overlap wire tie splices are used whether the bars are generally parallel or perpendicular, such as forming a grid. The placement of long bars in a closely spaced grid and the subsequent laying of each crossing bar is a backbreaking job. Such splices in parallel are inefficient because the bars have to overlap a significant distance and be axially offset.

Mechanical splices of several types have been developed. Some still overlap the bar ends such as seen in US Patents 5, 1 25,761 and 4,695, 1 78. Also a wide variety of mechanical butt splices have been developed which provide good tensile and compression characteristics. One of the most widely used is the well known LENTON^® reinforcing bar splice which utilizes tapered threads on the end of each bar and matching internal threads in the coupler sleeve. Another type is a CADWELD^® connector which uses cast metal inside a sleeve to lock the aligned facing deformed bar ends together. Both LENTON^® and CADWELD^® are registered trademarks of ERICO International Corporation of Solon, Ohio, USA. A wide variety of other mechanical couplers exist using plain threads or crimped sleeves for example. All such couplers are primarily limited to the aligned bar butt splice, and are designed primarily to improve the wire tied splice referred to above, which is still widely used.

Computer aided design in the detailing of the steel for steel reinforced concrete structures requires more versatility. For the designer to take full advantage of the computer design flexibilities, the splices require greater flexibilities in transferring loads both compressive and tensile, from bar to bar regardless of the alignment of the two bars.

For example, in anchors or terminations, large hooked bar ends are often employed. They usually hook around bar extending transversely, they are difficult to install, and occupy an inordinate amount of space. In dowel bar applications, the dowel bar configurations are often complex hooking or extending around one or more transverse bars. In footer/column, or slab/column, or roof/column applications, anchors and shear connectors are employed, and at such locations the reinforcing bar can get crowded, difficult to install, and overdesign and excess size usually results. In footers, slabs, and shear walls, grids are often employed. Parallel grids with overlapped wire tied intersections add volume and space.

Computer aided design particularly lends itself to bar continuity rather than overlap or wire binding. It also tends to avoid applications where bars have to be bent. Bending is costly, cannot be done to close tolerances, and makes the bar difficult to handle and install with continuity or continuation of bar from one part of a structure to another without overlap or binding. This is particularly true in the areas noted above. There are many areas where rectilinear continuous connections are desirable and useful.

In each of the above applications and many others, it would be desirable to be able to design anchors, terminations or connections which can be made quickly from one bar to another transverse bar.

Further to facilitate such designs it would be desirable to have a splice system which could be positioned quickly and easily anywhere along a first bar and have further bar or bars joined to that bar transversely, on one or both sides. It would further be desirable if the splice system could be positioned adjustably along such first bar, easily secured in position, and filled with cement paste intrusion when the pour occurs whether in a poured-in-place or precast system.

Summary of the Invention

A steel reinforcing bar for concrete construction utilizes a sleeve which may be telescoped over a bar. The sleeve includes one or more laterally extending sockets adapted to receive bar ends extending transversely to the first bar telescoped through the sleeve. The sleeve is held in place by a set screw accessible through the bottom of one of said sockets. The set screw is a recessed head screw which may conveniently be tightened by an Allen wrench through the socket.

The interior of the sleeve is open at both ends to receive concrete paste acting as grout when the concrete is poured. The set screw and at least one socket are preferably centered between the ends of the sleeve to avoid interference with such concrete paste intrusion. The interior of the sleeve may have surface irregularities and a pressure point or projection opposite the set screw to maintain the sleeve approximately centered on the bar over which it is telescoped to provide clearance for such concrete paste intrusion.

The bar received in such transversely extending sockets is preferably taper threaded although other splice systems may be employed such as straight threads, deformed sleeves, or others. The taper thread system is preferred because the bar can be secured in place with just a few turns. In situations where the bar cannot be turned, position splices may be provided having straight thread inserts with a tapered thread socket. The position splice insert is threaded on the bar and locked in place.

The splice system permits bar to be connected transversely on one or both sides of another bar with all of the connected bars being in the same plane. The sleeve of the system can quickly be positioned at any location along one bar and locked in place by quickly tightening a set screw. If necessary, the sleeve can be quickly repositioned before the pour. The flexibility afforded by the connection and system greatly facilitates the computer aided design or detailing of the steel of steel reinforced concrete construction whether poured-in-place or precast.

To the accomplishment of the foregoing and related ends, the invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Brief Description of the Drawings

Figure 1 is a perspective view of one form of the connection with a wrench tightening the set screw.

Figure 2 is a similar perspective of another embodiment;

Figure 3 is an axial section through the connection of Figure 1 ;

Figure 4 is a similar section of a somewhat modified connection;

Figure 5 is an axial section of the Figure 2 connection with bars connected on opposite sides of the sleeve; and

Figure 6 is yet another embodiment showing the use of a position splice where the bar at the bottom of the figure need not rotate.

Detailed Description of the Preferred Embodiments

Referring initially to Figures 1 and 3 there is illustrated generally at 1 0 a reinforcing bar connection in accordance with the present invention. The connection has a body shown generally at 1 2 which includes a relatively short open sleeve 1 3 and a lateral projection 14. The projection 14 is at the mid-point of the sleeve 1 3 and includes an external flatted configuration indicated at 1 6 which may be in the form of the hexagon enabling the body to be grasped with a wrench. The body 1 2 is in the form of a T with the projection 1 4 forming the stem of the T and the relatively short sleeve 1 3 forming the top. The body may be machined from a forging or a steel or ductile iron casting or pieces sawn from a cold or hot steel extrusion, for example.

As seen in Figure 3, the sleeve 1 3 is open at both ends indicated at 1 8 and 1 9 to receive in telescoping fashion a first reinforcing bar shown at 20. The bar 20 telescopes through the sleeve with some clearance. The interior of the sleeve is provided with irregularities which may be in the form of annular internal groves. As seen in Figure 3 there are internal grooves 22, 23, 24, 25 and 26 within the sleeve, the center groove 24 being somewhat wider than the grooves on the opposite ends. A projection 26 projects into such groove a radial distance greater than the ridges 27 between the grooves and such projection is directly opposite the axis of the projection 14. The projection 14 as illustrated in Figure 3 is provided with internal tapered threads 30 matching the external tapered threads 31 on bar 32. The interior of the taper threaded socket terminates in a straight threaded bore 34. The straight threaded bore opens into the interior of the sleeve 13. Within such threaded bore is a set screw 35 having a hexagonal recessed drive head 36 which is adapted to receive an Allen wrench as shown at 38 in Figure 1 .

When the set screw 35 is tightened by the Allen wrench, the tip 40 of the set screw forces the bar 20 against the projection 28 and locks the body or sleeve to the bar 20. The radial extent of the projection 26 is selected to maintain adequate clearance around the bar 20 within the sleeve so that when concrete is poured around the sleeve, cement paste intrusion will enter the sleeve providing a tough grout splice connection between the sleeve and bar 20. The projection and set screw also provide good electrical connection between the bars being joined which can be important in grounding or cathodic protection systems.

In operation, the connector or sleeve 1 3 is positioned along the bar 20 in telescoping fashion at the desired position and the set screw tightened. If it is found that the sleeve is in not quite in the right position, it can quickly be moved along the bar 20 simply by loosening and then retightening the set screw. After the sleeve is in the correct position, the bar 31 is attached with a few quick turns. When concrete is poured around the connection, either in a poured-in- place construction, or in precast construction, cement paste will enter the interior of the sleeve filling the grooves 22, 23, 24, 25 and 26.

Before describing the embodiment of Figures 2 and 5, Figure 4 illustrates an embodiment similar to that of Figure 3 but the interior of the sleeve 1 3 indicated at 44 has no surface irregularities. The sleeve nonetheless has a projection indicated at 45 opposite the tip 40 of the set screw 35 which maintains the clearance shown at 46 and 47 when the set screw 35 is tightened. The sleeve projection 14 accommodating the bar 32 is the same as in the Figure 3 embodiment. The interior of the sleeve will fill with cement paste intrusion during the pour. Referring now to Figures 2 and 5 it will be seen that the connection shown generally at 50 includes a body having a relatively short sleeve 51 which is provided with coaxial centered and symmetrical projections 52 and 53 each having the flatted external configuration shown at 54. The sleeve 51 accommodates a first steel reinforcing bar 56 in telescoping fashion which extends completely therethrough. The interior of the sleeve indicated at 57 may be plain as illustrated or irregular as in Figure 3. The sleeve is provided with a radially inwardly extending center projection 58 opposite the tip 59 of set screw 60 having recessed drive head 61 which is threaded in straight threaded bore 62 in the socket of projection 53. Again the set screw may be tightened in place on the bar 56 by the Allen wrench 38 seen in Figure 2. When the sleeve is telescoped over the bar 56 and the set screw tightened to lock the connection to the bar, both ends of the interior of the sleeve are open along such bar allowing cement or concrete paste intrusion when concrete is poured around the connection.

After being locked on the bar, if for some reason the connection is in the wrong position, it can readily be repositioned simply by loosening and then retightening the set screw.

The projection 53 is provided with the internal tapered threads 30 at the mouth receiving the matching external tapered threads section 31 of the bar 32. The tapered threads lead to the straight threaded bore 62 which opens to the interior of the sleeve 51 .

The opposite projection 52 is provided with a blind internal tapered thread section 65 receiving the matching external tapered threads 66 on the end of bar 67. In this manner it will be seen that the bars 67 and 32 are coaxially joined and the axis of such bars is also in the same plane as the axis of the bar 56. The connection can thus readily be positioned essentially anywhere along the one bar and can be used in anchors, terminations, grids, dowel bar connections or even in shear connections at column-slab intersections. It will also be appreciated that the bars need not all be the same size and that the bar telescoped through the sleeve may be larger than the bars extending transversely from the sleeve projections.

In some situations the connection cannot be made by rotating the bar to form the threaded connection. In such situation there is employed what is known as a position coupler. A position coupler is illustrated generally at 70 in Figure 6. The connection includes a body 71 forming the sleeve 72 through which telescopes the first bar 56. The axially opposite projections 74 and 75 accommodate and connect to bars 67 and 32 respectively. The bar 67 is secured in the projection 74 through the blind tapered threaded socket 65. The projection 75 however includes internal straight threads 76 in which is threaded with matching external threads a position splice insert member 77. The end or mouth of the position splice member is provided with a tapered threaded socket 78 accommodating the matching threads 31 of the end of the bar 32. Also threaded on the exterior of the position splice insert member is a lock nut seen at 79. In operation, the connection with the bar 32 will be made by rotating the position splice insert member 77 tightening such member on the non-rotating bar 32 through a wrench on the hexagonal or flatted end 80. After the position splice member is tightened on the bar, the position splice member is locked in place by lock nut 79 tightened against the end of the projection 75. This avoids any slip.

The body 71 is locked on the rod 56 by tightening of the set screw 82 through an Allen wrench inserted through hole 83 in position splice member 77. This permits the set screw to be manipulated without removing the member 77. Alternatively, the set screw may be provided axially at the bottom of the socket in the projection 74. It will be appreciated that the embodiments shown in Figures 3 and 4 may have a position socket instead of the tapered socket, and in Figures 5 and 6 both sockets may be position sockets.

It can now be seen that there is a provided a reinforcing bar connection for use in concrete construction which enables bars to be connected quickly and easily transversely to serve a wide variety of design expedients greatly facilitating the design and detailing of steel reinforced concrete structures through the ability to implement computer aided design.

To the accomplishment of the foregoing and related ends, the invention then comprises the features particularly pointed out in the claims, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

Claims

1 . A reinforcing bar connection for reinforced concrete construction comprising a sleeve adapted to telescope over a first deformed reinforcing bar, first means to fix said sleeve in a selected telescoped position along such bar while leaving both ends of said sleeve open along such bar, and second means to secure another reinforcing bar extending generally transversely of said deformed bar to said sleeve.

2. A connection as set forth in claim 1 wherein said first means is a set screw and said second means is a bar receiving socket.

3. A connection as set forth in claim 2 wherein said first and second means are axially aligned.

4. A connection as set forth in claim 3 wherein said first and second means are on the same side of said sleeve.

5. A connection as set forth in claim 4 wherein said first and second means are on opposite sides of said sleeve.

6. A connection as set forth in claim 5 including third means to secure yet another reinforcing bar to said sleeve.

7. A connection as set forth in claim 6 wherein said first, second and third means are axially aligned.

8. A connection as set forth in claim 1 wherein said sleeve telescopes over said first deformed bar with sufficient clearance so that said sleeve fills from both ends with concrete paste when the concrete is poured.

9. A connection as set forth in claim 1 wherein said sleeve is open at both ends so that the first deformed bar may project completely through said sleeve.

10. A connection as set forth in claim 1 wherein said first and second means are centered between the sleeve ends.

1 1 . A connection as set forth in claim 1 wherein said second means to secure is a threaded socket adapted to receive the threaded end of said another reinforcing bar.

1 2. A connection as set forth in claim 1 1 wherein said socket and end are taper threaded.

1 3. A connection as set forth in claim 1 wherein said second means comprises a socket projecting from one or both sides of the sleeve to receive and secure said another reinforcing bar, said first means being located at the bottom of said socket and accessible therethrough.

1 4. A connection as set forth in claim 1 3 wherein said first means and socket is substantially equidistant the ends of said sleeve.

1 5. A connection as set forth in claim 14 wherein said first means is a recessed head set screw which may be tightened by an Allen wrench through said socket.

1 6. A connection as set forth in claim 1 5 including a pressure point projection in said sleeve opposite said set screw.

1 7. A connection as set forth in claim 1 6 including surface irregularities on the interior of said sleeve.

1 8. A connection as set forth in claim 1 3 including two substantially aligned sockets extending on opposite side of said sleeve, each being adapted to receive an another reinforcing bar.

1 9. A connection as set forth in claim 1 8 including a position splice in said socket to secure said bar to said sleeve without rotation of said bar.

20. A connection as set forth in claim 1 wherein said second means is a position splice to secure a bar to said sleeve without rotation of said bar.

21 . A method of joining one steel reinforcing bar to another transversely extending steel reinforcing bar in concrete construction comprising the steps of telescoping a sleeve over said one bar, providing a transverse socket on said sleeve, and a set screw in the bottom of the socket operative when tightened to project into the sleeve, tightening the set screw against said one bar, and securing said another bar in said socket.

22. A method as set forth in claim 21 including the step of providing a projection in said sleeve opposite said set screw to maintain clearance around said one bar within said sleeve so that both ends of said sleeve along said one bar are open and will fill with concrete paste when the concrete is poured.

23. A method as set forth in claim 22 including the step of providing the interior of the sleeve with irregularities.

24. A method as set forth in claim 23 including the step of providing sockets on opposite sides of the sleeve to join at least two another bars to the sleeve.

25. A method as set forth in claim 24 wherein said sockets and sleeve have coplanar axes.

26. A method as set forth in claim 25 wherein said sockets are internally threaded and said another bar or bars are externally threaded.

27. A method as set forth in claim 26 wherein said threads are tapered.