SLAB ANCHOR ENCAPSULATION ASSEMBLY

Description

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application 63/698,714, entitled “Slab Anchor Encapsulation Assembly,” filed on Sep. 25, 2024. The contents of this priority application are incorporated by reference herein in their entirety.

FIELD

Exemplary embodiments relate to an apparatus for installing multi-strand post-tension systems. Specifically, exemplary embodiments relate to anchorages and grouting assemblies as used in such multi-strand systems.

BACKGROUND

Multi-strand post-tensioning systems are used in a wide variety of applications. Conventionally, such systems are used for all types of slabs in buildings, bridge decks, and similar applications. Typically, a plurality of strands are placed so as to extend through ducts. The ends of the strands which extend outwardly of the ducts are placed into anchorages. The strands are stressed and locked-off individually. The post-tensioning of such systems enables slab deflections and cracks under severe service conditions to be kept under control. This permits larger spans and thicker slabs to be used. The reduced materials and labor results in lower costs and faster construction. Additionally, there can be indirect savings on foundations, columns, walls and vertical surfaces.

In normal use in such existing multi-strand post-tensioning systems, the ends of the strand will extend through separate holes formed in an anchorage body. Typically, a plastic trumpet will interconnect the anchorage body to the flat tendon-containing duct. The strands will extend through tapered holes formed in the anchorage body. Normally, the strands will be angularly offset from one another as they extend through the anchorage body.

After installation, wedges are placed around the exterior of each of the outwardly extending strands. A jack is used so as to stress the strands. The wedges will remain in contact with the strands during the stressing operation. After the jack has sufficiently stressed the strands, the pressure in the jack is released so that the wedges automatically seat in the conical holes of the anchor head.

After the strands are wedged into the holes of the anchor, it is then necessary to grout the interior of the anchor and the interior of the duct. In order to facilitate the grouting of such duct, a grout hole is machined into the body of the anchor. Under existing systems, a hole is drilled and tapped through the body of the anchor so as to communicate with the interior of the duct. After the hole is machined and tapped, a special fitting is installed so as to connect a grout tube with this hole. The grout tube is then free to pass grout into the interior of the duct so that grout can be used to fill the interior of the duct and to solidify on the interior of the duct. Normally, the drilled and tapped hole in the anchorage body extends transverse to the tendon-receiving passageways so as to open on a top surface of the anchorage body. After the grout is pumped into the interior through this machined hole, the grout tube must be removed from the fitting and the hole should be sealed.

Unfortunately, the forming of such a grout hole makes the anchor very expensive. Under conventional circumstances, the anchor is made of a cast metal. The machining and forming of the grout hole on such anchorages is a time consuming and expensive operation. Often, the machining operations required so as to form the grout hole can double or triple the cost of the anchor body itself. As such, a need has developed in which to provide a grout hole on such multi-strand post-tensioning systems which is less expensive and easier to use.

FIGS. 1-3 illustrate a conventional prior art anchor as used in a multi-strand anchorage system. It can be seen in FIG. 1 that the anchor body 10 has a flanged back surface 12 which extends to an interior tendon-receiving passage 14. Grout hole 16 is formed through one of the gussets which extend from the tendon-receiving passage 14 to the flanged anchor body 12. As can be seen in FIG. 3, the grout hole 16 is drilled and tapped so as to receive the threaded fittings of a grout tube. FIG. 2 is a side view of the anchor body 10. In FIG. 2, it can be seen that the flanges 12 of the anchor body 10 extend outwardly from a central tubular area 18. The tendon-receiving area 14 is formed on the interior of the tubular area 18. FIG. 3 shows this prior art system as taken across lines 3-3 of FIG. 1. In particular, it can be seen that the grout hole 16 is formed in the surface 20 of the anchor body 10. The grout hole 16 includes a threaded area 22. The threaded area 22 is adjacent to the opening 24 on the surface 20 of the anchor body 10. The threaded area 22 includes female threads which are suitable for receiving the male threads of a fitting of a grout hole. Typically, the threaded area 22 is formed initially by drilling a hole into the surface 20 of the anchor body 10 and then tapping the hole. A curved passageway 26 will extend from the threaded area 22 so as to open at outlet 28. Outlet 28 serves to deliver grout to the tendon-receiving area 14 of the anchor body 10. The curved passageway 26 is typically formed in the casting of the anchor body 12.

As can be seen in FIGS. 1-3, the formation of the grout hole 16 is a rather complicated matter. Initially, steps must be taken so as to properly form the curved passageway 26 during the casting of the anchor body 10. After this curved passageway has been formed, then it is necessary to carry out machining operations so as to form the threaded area 22. These machining operations are quite complicated and time consuming. Finally, after the machining operations are completed, it will be necessary to threadedly affix a grout tube to the threaded portion 22 of the grout hole 16. In many circumstances, the threaded fitting on the grout tube will not properly align with the threads 22 on the grout hole 16 so as to create an improper connection between the grout tube and the anchor plate 10. This can cause the improper and leaking transmission of grout to the tendon-receiving area of the anchor plate 10.

In addition to the costs of forming the threaded area 22 on the anchor plate 10, there is an additional cost of forming a threaded fitting on the end of a grout tube. Normally, a metal threaded fitting is affixed to the elastomeric grout tube. The formation of the threaded fitting and the attachment of the threaded fitting to the grout tube is often a costly and time consuming proceeding. As such, a need has developed in which to form a grout tube which includes the necessary structure so as to allow the grout tube to be properly affixed to the grout hole of the anchor plate.

These and other deficiencies exist.

SUMMARY

Exemplary embodiments include an assembly, having an anchor body including a tendon-receiving area and a grout passage extending through a center of the anchor body; and a grout cap having a threaded grout hole extending through a center of the grout cap; and a blockout that is configured to be located between the grout cap and the anchor body.

Exemplary embodiments also include an assembly having an anchor body including a tendon-receiving area and a grout passage, the grout passage being located at a center point of the anchor body and of the tendon-receiving area and extending through the anchor body; a grout cap having a centrally located and threaded grout hole extending therethrough a center portion; and a trumpet assembly that is configured for securement on one end to the grout cap and the anchor body and on an opposite end to a duct.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate a fuller understanding of the various embodiments, reference is now made to the attached drawings. The drawings should not be construed as limiting the various embodiments, but are intended only to illustrate different aspects and embodiments.

FIG. 1 is an end view of an anchor of a prior art multi-strand anchorage system.

FIG. 2 is a side view of the anchor of the prior art multi-strand anchorage system.

FIG. 3 is a detailed and enlarged view taken across lines 3-3 of FIG. 1 of the anchor and grout tube connection of the prior art multi-strand anchorage system.

FIG. 4A illustrates a front perspective view of an exemplary embodiment with a bare anchor.

FIG. 4B illustrates an exploded perspective view of the exemplary embodiment with a bare anchor.

FIG. 4C illustrates a front view of the exemplary embodiment with a bare anchor.

FIG. 4D illustrates a top view of the exemplary embodiment with a bare anchor with a formboard.

FIG. 4E illustrates a front view of the exemplary embodiment with a bare anchor with a formboard.

FIG. 4F illustrate a cross-sectional view of the exemplary embodiment with a bare anchor with a formboard.

FIG. 4G illustrate a cross-sectional view of the exemplary embodiment with a bare anchor.

FIG. 5A illustrates a front perspective view of an exemplary embodiment with an encapsulated anchor.

FIG. 5B illustrates an exploded perspective view of the exemplary embodiment with an encapsulated anchor.

FIG. 5C illustrate a cross-sectional view of the exemplary embodiment with an encapsulated anchor with a formboard.

FIG. 5D illustrate a cross-sectional view of the exemplary embodiment with an encapsulated anchor.

FIGS. 6A and 6B illustrates a top view and a side view, respectively, of an anchor body according to exemplary embodiments.

DETAILED DESCRIPTION

Exemplary embodiments will now be described in order to illustrate the various features. The embodiments described herein are not intended to be limiting as to scope, but rather are intended to provide examples of the components, use, and operation of the various embodiments.

It is an object of exemplary embodiments to provide a post-tensioning system which allows for the easy attachment of a grout tube to the anchor plate.

It is another object to provide a post-tensioning system which eliminates the need for machining operations on the anchor plate casting.

It is another object to provide a post-tensioning system which eliminates the need for forming and attaching fittings to the grout tube.

It is still another object to provide a post-tensioning system which simplifies grouting procedures, reduces costs, and eliminates unnecessary equipment.

Referring to FIGS. 4A, 4B, and 4C, a slab anchor encapsulation assembly 100 according to exemplary embodiments is depicted for use in a post-tension concrete system. The assembly 100 has a series of components as depicted including mounting bolts 102 (of which there are two as depicted), grout cap 104, blockout 106, bare slab anchor 108, which is a bare anchor, mounting thread inserts 110 (of which there are two to accommodate mounting bolts 102), trumpet or trumpet assembly 112, duct seal ring 114, duct connector clamp 116 (which has two halves), duct connector clamp slides 118 (of which there are two), and duct 120. Optional weld-in grout port 122 and optional snap-in grout port 124 may be included as depicted. The grout cap has a grout tube 126 formed therein. The two duct connector clamp slides 118 serve to secure the duct connector clamp 116, as can be seen, for example, in FIG. 4A.

Referring to FIGS. 4D and 4E, a view of the assembly 100 is shown with a formboard 128 attached via bolt 130 to the blockout 106. This formboard may be used in a pre-pour configuration to provide containment of grout and concrete.

Referring to FIGS. 4F and 4G, a cross-section of the assembly 100 is shown in two states. First, in FIG. 4F is the cross-section with the formboard and blockout. Second, in FIG. 4G is the cross-section with the grout cap in place (that is, as shown in FIG. 4A, for example) taken along the same line as shown in FIG. 4D. These figures also provide dimensions for reference in inches[mm].

The weld-in grout port 122 provides direct grout passage into the trumpet assembly when such functionality may be required for specific applications or installation conditions. The grout tube 126 extends through the grout cap and facilitates the flow of grout through the system, connecting the external grout supply to the internal grout passages of the assembly such as the grout passage 604 in the slab anchor as described below with respect to the slab anchor of FIG. 6A. The snap-in grout port 124 may further facilitate grout flow into the assembly. The threading of the grout tube 126 may enable the grout tube to be capped after grout is input to the assembly. A threaded cap may be used.

Referring to FIGS. 5A and 5B, a slab anchor encapsulation assembly 200 according to exemplary embodiments is depicted. The assembly 200 is similar to assembly 100, except it uses an encapsulated slab anchor. Assembly 200 includes mounting bolts 202 (of which there are two as depicted), grout cap 204, an encapsulated blockout 206, encapsulated slab anchor 208, mounting thread inserts 210 (of which there are two to accommodate each mounting bolts 202), trumpet or trumpet assembly 212, duct seal ring 214, duct connector clamp 216 (which has two halves), duct connector clamp slide 218 (of which there are two), and duct 220. Optional weld-in grout port 222 and/or option snap-in grout port 224 may be included as depicted. The grout cap has a grout tube 226 formed therein. The two duct connector clamp slides 218 serve to secure the duct connector clamp 216, as can be seen, for example, in FIG. 5A.

The front view of FIG. 4C is equally applicable for this embodiment also (of course, with the element reference numbers replaced with those for this embodiment and using an encapsulated anchor instead of a bare anchor).

Referring to FIGS. 5C and 5D, a cross-section of the assembly 200 is shown in two states. First, in FIG. 5C is the cross-section with the formboard. Second, in FIG. 5D is the cross-section with the grout cap in place (that is, as shown in FIG. 5A, for example) taken along the same line as shown in FIG. 4D. These figures also provide dimensions for reference in inches[mm].

The weld-in grout port 222 provides direct grout passage into the trumpet assembly when such functionality may be required for specific applications or installation conditions. The grout tube 226 extends through the grout cap and facilitates the flow of grout through the system, connecting the external grout supply to the internal grout passages of the assembly such as the grout passage 604 in slab anchor as described below with respect to the slab anchor 300 of FIG. 6A. The snap-in grout port 224 may further facilitate grout flow into the assembly. The threading of the grout tube 226 may enable the grout tube to be capped after grout is input to the assembly. A threaded cap may be used.

FIGS. 6A and 6B depict a slab anchor 300 in a top view (FIG. 6A) and a side profile view (FIG. 6B). This slab anchor 300 may be used in assembly 100 and/or 200 (108 in FIGS. 4A and 208 in FIG. 5A). In exemplary embodiments, the slab anchor 300 may be an encapsulated anchor. In certain embodiments, it may be a bare anchor.

As can be seen in FIG. 6A, for example, there are four ports 602 to receive the ends of the anchor strands (i.e., the tendons). In this embodiment, there are four such strands. In certain embodiments, there may be more or less ports to accommodate different tendon configurations. In the various embodiments, mono-or multi-strand tendons can be used. Anchor wedges may be received in these ports during tensioning operations. Central to the strand ports is a grout passage 604. Spaced apart on either side of the grout passage are two holes 606 to receive the mounting bolts (102 in FIGS. 4A and 202 in FIG. 5A). These holes allow passage of the mounting bolts into the mounting thread inserts in the trumpet (110, 112 in FIGS. 4B and 210, 212 in FIG. 5B).

As depicted in the Figures, there is shown the improved anchor plate/grout tube arrangement as used in the post-tension system according to exemplary embodiments. The various embodiments include a refined orientation of the grout hole of the anchor plate and also an improved grout cap for covering the anchor plate. The grout cap has a threaded grout tube formed therein (126 in FIGS. 4A and 226 in FIG. 5A), for example, to allow attachment of a grout tube thereto. The grout tube 126/226 allows for the passage of grout into the tendon-receiving area of the anchor body though the grout passage 604 and into the trumpet assembly. The grout tube and the grout passage are coaxial so as to form a straight passage into the center of the strands, as held by the anchor plate. As can be appreciated, the strands flatten into a fan-shaped linear pattern along the length of the trumpet (moving away from the anchor plate) and eventually into the duct.

The snap-in grout anchor adaptor (124 in FIGS. 4B and 224 in FIG. 5B) may be used to further guide the grout passage and allow for a complete seal. The weld-in grout port (122 in FIGS. 4B and 222 in FIG. 5B) may be used to provide direct grout passage into the trumpet, if required. To provide for a liquid tight seal on the end portion of the assembly, o-rings may be used to form a seal between the grout cap and the block out as well as between the anchor plate and the trumpet. Other suitable seals may be used in various embodiments.

The anchor plate may be a steel anchor plate having a surface adjacent to the tendon-receiving area as shown in FIGS. 6A and 6B, for example. In various embodiments, other suitable materials may be used for the anchor plate. In conventional practice, multiple strands or tendons will extend into area. In exemplary embodiments, there are four such strands.

Suitable materials may be used for the various components of the assemblies 100 and 200 such as various metals, plastics, and combinations thereof.

Advantages of exemplary embodiments over existing systems include: a smaller profile grout cap/blockout, a longer (trumpet length), screw/bolt insertion from end rather than having to secure washers/nuts on a threaded end projecting from assembly, the grout tube is routed into center of strands which are terminated in a square rather than fan pattern, and the assembly uses a square pattern arrangement on the wedge plate for strands (i.e., a square pattern vs. linear or fan pattern. There is also no need to machine a grout hole or any other structures into assembly as it all comes pre-fabricated and ready to use. The configuration provides a better seal on over the anchor to allow the grout to fully set. Additionally, various embodiments include a weld-in grout port on trumpet and/or a snap-in grout anchor adaptor.

Although various embodiments have been described herein in the context of a particular implementation in a particular environment for a particular purpose, those skilled in the art will recognize that its usefulness is not limited thereto and that the various embodiments can be beneficially implemented in other related environments for similar purposes. The embodiments should therefore not be limited by the above description, method, and examples, but by all embodiments within the scope and spirit as claimed.

Further, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The terms “a” or “an” as used herein, are defined as one or more than one.

Various embodiments have been described with references to the accompanying drawings. It may, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the various embodiments as set forth in the claims that follow. The embodiments and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.