Method and apparatus for repairing post-tensioned concrete

Abstract

An end cap secured to a tubular member for use in repairing post-tensioned concrete, including a first segment, a second segment, and a third segment. The first segment has a first end and a first opening, where the first segment is substantially cylindrical in shape. The second segment is substantially frustoconical in shape. The third segment has a second end and a second opening and is substantially cylindrical in shape. The second segment is disposed between and integral with the first segment and the third segment. A cavity is formed by the first, second, and third segments, where the first end is arranged to be secured to a tubular member and at least one cable is disposed longitudinally within the cavity.

Description

FIELD OF THE INVENTION[0001]The invention broadly relates to a method and apparatus for repairing post-tensioned concrete, and more particularly, to an end cap secured to a tubular member used during the splicing and coupling of post-tensioned concrete repairs.BACKGROUND OF THE INVENTION[0002]Post-tensioned concrete is widely used in building structures as it provides a light, structurally efficient, durable solution for the construction of commercial office buildings, residential apartments, high-rise condominiums, and mixed-use facilities such as hotels and casinos. Post-tensioned concrete is also utilized frequently in the elevated concrete decks and sometimes in the ground floor slabs of condominium structures, including the associated parking garages. Longer, thinner slabs result in greater design flexibility and require less reinforcing steel to achieve the same strength as other methods of construction. Additionally, post-tensioned concrete greatly reduces the floor-to-floor ...

AI Technical Summary

Benefits of technology

The present invention is an end cap for repairing post-tensioned concrete structures. The end cap is secured to a tubular member and includes three segments: a first segment, a second segment, and a third segment. A cavity is formed within the end cap, with at least one cable disposed longitudinally within it. The first and second segments are connected and the third segment is disposed between and integral with the first and second segments. The end cap can be made of plastic or any suitable material known in the art, and the method of installing it includes steps for cutting openings in the concrete, installing temporary anchor devices, cutting and replacing cables, securing the end cap to the tubular member, and stressing the cables after installation. The technical effect of the invention is to provide an improved method for repairing post-tensioned concrete structures with a reliable and efficient end cap that allows for easier installation, replacement of cables, and stressing of the cables after installation.

Problems solved by technology

Many early post-tension installations did not include corrosion protection of the steel anchorage and cable ends.

As a result, penetration of moisture through the concrete often results in the corrosion of the post-tension cable, anchor, and wedges.

The presence of corrosion can have a substantial impact on the structural integrity of the post-tension system.

Additionally, a post-tension cable can be compromised when types of restoration, renovation, or remedial work are being performed on a post-tensioned reinforced structure.

Moreover, post-tension cables can also be compromised when the original construction was performed poorly or maintenance of the exterior of a building is not performed on a regular basis.

In any of these situations, the ends of the cables at the edges of concrete are allowed to corrode, and without proper maintenance, the corrosion can advance to the point where cables or end anchors fail.

Due to the extremely high force in the cables, removal of the concrete behind the anchor and bars can cause a significant failure of the slab.

As a result, replacement of deteriorated anchors requires de-tensioning of the affected cable.

The lock-off location is generally two to three feet from the edge so that the cable forces can flow or be redirected around the opening with a risk of a concrete failure.

One problem with using a pocket former is that because pocket formers were not designed to be used as end caps, they do not tightly fit the PVC and can shift, allowing concrete to potentially enter the cavity.

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