Static structures (e.g. – buildings) – With component having discrete prestressing means – Anchorage
Reexamination Certificate
1999-04-28
2001-02-13
Kent, Christopher T. (Department: 3635)
Static structures (e.g., buildings)
With component having discrete prestressing means
Anchorage
C052S704000, C052S707000, C052S749100
Reexamination Certificate
active
06185886
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to fixing elements for reinforcement connection with a secondary action, especially for earthquake-resistant securement.
Reinforcement rods are frequently used to strengthen building structures using a hardenable composition in the drill hole. It has proved a disadvantage that, during the lifetime of the fixing, large cracks occur in the concrete, especially in the event of shock loading, such as during an earthquake, and the anchoring can fail.
Fixing elements are known which consist substantially of a threaded bolt, an expansible sleeve and an expander body with expander cone that can be drawn into the expansible sleeve. The expansible sleeve has longitudinal slots, which allow the expansible sleeve to expand as the expander body is drawn in. These fixing elements are generally set in an undercut drill hole with which the expanded sleeve forms an interlocking fit.
European patent document EP 0 455 952 Bi describes a fixing element for fixing in a substrate affected by momentary shock loading, such as that occurring during an earthquake. To avoid failure of a fixing in the event of shock loading, in this case a bolt and a complementary expansible sleeve are proposed. The expansible sleeve has two expanding portions, the first cylindrical portion having the smallest diameter of the expander cone and a second conically widening portion having the largest diameter, the continuation of which is cylindrical. It has proved to be a disadvantage of the known fixing element that in the event of shock loading considerable axial slippage occurs, and the component becomes loose, so that a new fixing element has be used following the overloading. Furthermore, mounting in an undercut is complicated, because the undercut has to be prepared, and for many applications is too expensive.
An anchor stud for a synthetic resin adhesive is known, having a shank that has several cones arranged in the axial direction european patent document (EP 0 356 425). This known anchor stud is set in the drill hole by means of a hardenable composition. This known anchor stud is not suitable as a replacement for a reinforcement rod, since only the proper standardized reinforcement rods permit a reinforcement connection.
SUMMARY OF THE INVENTION
The invention is based on the problem of producing a fixing element for a reinforcement connection with a secondary action, especially for earthquake resistant securement, which can be manufactured economically and permits uncomplicated and secure anchoring.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a fixing element for reinforcement connection with a secondary action, which element is set in a drill hole by means of a hardenable composition, wherein in accordance with the inventive feature, the reinforcement rod is provided with one or more conical sleeves, and the conical sleeves are of a segment-shaped construction.
Because the reinforcement rod is provided with one or more conical sleeves, and the annular gap between the drill hole wall and the reinforcement rod is filled with a hardenable composition, when subjected to shock loading the hardened mortar shell is pressed by the conical sleeve against the drill hole wall and the anchoring is maintained. The construction of the reinforcement rod according to the invention and mounting thereof by means of a hardenable composition provides a system for a reinforcement connection that withstands cracks, with which different anchoring depths are possible. To facilitate sliding of the conical sleeve in the mortar shell, a dry film can be disposed on the surface of the segments.
In the event of sustained shock loading, cracks occur in the concrete. To ensure a safe reinforcement connection in this case, the reinforcement rod is additionally provided in its upper region with a plastics material sleeve, so that a non-adhering, low-friction surface is produced and the reinforcement rod is able to slide up subsequently as required, and the mortar shell formed is pressed by the conical sleeve against the wall of the drill hole. This embodiment is especially suitable for reinforcement connections having relatively short anchoring depths. Instead of a plastics material sleeve, the reinforcement rod can be provided with a coating agent. Coatings of wax-like synthetic polymer, polytetrafluoroethylene, silicone polymer or galvanically applied coverings have proved suitable. An other option is to sheathe the reinforcement rod in a deep-drawn, rigid plastics material sleeve. Other means can also be employed to achieve the low friction value.
For prolonged shock loading, the formation of cracks is additionally accompanied by damage to the concrete as well, so that parts of the concrete, particularly in the upper region, break off. In that case, a longer anchoring depth is recommended. The segment-form construction of the conical sleeve enables reinforcement rods of different diameter to be used.
REFERENCES:
patent: 1333880 (1920-03-01), Stine
patent: 5170606 (1992-12-01), Popp
patent: 0 356 524 B1 (1992-09-01), None
patent: 0 455 952 B1 (1993-11-01), None
Braun Axel
Gruen Juergen
Schaetzle Joachim
Weber Christian
fischerwerke Artur Fischer GmbH & Co. KG
Kent Christopher T.
Striker Michael J.
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