DE202010010749U1 - Concrete, slidably designed and fatigue-free head construction for anchoring tension elements on cyclically stressed components - Google Patents

Abstract

Einbetonierbare, slidably trained and fatigue-free head construction for anchoring tension members on cyclically stressed components, characterized in that with the nut (9) and the thread on the tension element (1) an adjustable movement joint (a) between the load introduction plate (2) and the shim ( 6) is present.

Description

Technical area

The Invented head construction belongs to the technical field of construction. With the new head construction tension elements can for securing preferably cyclically stressed components anchored.

State of the art and technical problem

Anchorages for securing components consist in principle of a head construction, a tension element and a force introduction element outside of the component. If the fuse is directly in the ground, come after valid DIN 1054 Ground anchors or tension piles for use.

Ground anchors require a minimum preload and thus carry additional loads in the component to be secured, the carrying capacity and fitness for use. at an additional backup results in additional burdens, for which the building was originally not designed has been. Due to these additional loads can deformations be generated or additional stresses etc. in the Buildings arise that can not be absorbed without damage. This then results in biased anchors not being used can. Cyclic shares in the total load plays in the case of ground anchors due to the high prestressing of the anchoring system and the stiffness distributions on the system mostly a subordinate one Role.

In the case of tension piles in the ground, even with cyclic load fractions of 20% of the characteristic pile resistance, significant deterioration in the structural behavior can occur. In addition, pile load capacities under cyclical loading below the groundwater level can not be clearly assessed without test loads. However, the comparably high load cycles for a necessary test load are difficult to realize on the construction site. With regard to possible changes in position of piles are according to applicable DIN 1054 Regular monitoring of cyclic poles is recommended. The advantage of pile constructions compared to pre-stressed ground anchors, however, is that no additional loads are introduced into the existing building structure.

Both above-mentioned anchoring methods have clear limits of use, which is an application for anchoring tension elements on cyclically stressed Components, especially in retrofit measures, z. B. in shipping locks or components to be secured in the tidal area, but also in other areas, significantly reduce.

Troubleshooting

The Problem solving consists of development and design the head detail for anchoring a tension element for securing of cyclically stressed components with the result that fatigue-relevant Shares of stresses from cyclic deformation not be transferred to the tension element. This is done by the arrangement of a movement joint with adjustable distance at the transfer point between the traction element head and the component to be secured. The tension element thereby only takes the total static load in the fractured state including all collateral in the then occurring large shifts. The prerequisite is that the component is the much smaller Take cyclic load components in use without the involvement of the anchor elements or that only such a fraction of the cyclic load is transmitted, which can be safely received by the anchoring structure.

example

A existing lock chamber wall, by the changing water level in the lock chamber is cyclically stressed and deformed, must in the limit state for extremely high groundwater levels behind the lock chamber wall against tipping later be secured (see drawing). The subsequent building security is done by a tension element, which in the bottom with a grout body is anchored. The anchoring of the tension element in the area of the lock chamber takes place with the newly developed head construction. As tension element comes a steel bar with thread ribs, preferably made of reinforcing steel, for use. In addition to the required structural safety receives the chamber wall a concrete header to ensure the durability of the Lock chamber wall to increase. For an example description the head construction will be the ones shown on the drawing Components named as follows:

1

tension element with thread ribs

2

Load transfer plate

3

Outer plain bearing sleeve

4

mortar bed

5

Corrosion protection compound

6

shim

7

pipe

8th

Inner plain bearing sleeve

9

mother

10

Inner steel cap

11

Outer steel cap

When mounting the head construction, the load introduction plate ( 2 ) in a mortar bed ( 4 ) plane parallel to the shim ( 6 ) and connected by a dowel construction with the lock chamber wall. The size of the load distribution plate ( 2 ) is selected depending on the existing quality of the used concrete.

In order not to transfer the cyclic load caused by the lock operations to the anchoring structure, the new head construction incorporates a slide bearing. Due to the arrangement of the slide bearing, the chamber wall can be freely displaced by horizontal movements of the chamber wall by means of locking processes via the tension element anchored in the floor ( 1 ) slide back and forth. The plain bearing consists of the outer plain bearing sleeve ( 3 ) and the inner plain bearing sleeve ( 8th ). Preferably, the plain bearing sleeves are made of plastic and have a round cross-section. The outer plain bearing sleeve ( 3 ) is fixed to the load introduction plate ( 2 ) connected. The inner plain bearing sleeve ( 8th ) is passed over the pipe ( 7 ) and firmly connected with him. The pipe ( 7 ) is to the shim ( 6 ) is welded on during assembly via the tension element anchored in the ground ( 1 ), so that the inner plain bearing sleeve ( 8th ) through the outer plain bearing sleeve ( 3 ) to be led. The space between pipe ( 7 ) and tension element ( 1 ) is coated with anticorrosion compound ( 5 ) completed.

Due to the wall movement due to the water level changes in the lock chamber caused in addition to the bearing displacements and low bearing rotations. Therefore, the plain bearing sleeves are installed with a minimum clearance. In the example mentioned, the plain bearing sleeves ( 3 ) and ( 8th ) formed with an annular gap of 2.5 mm. As a result, a bending stress of the tension element due to the cyclic wall deformation is excluded.

With the mother ( 9 ), the required by statics movement joint width (a) is set. This determines, from which groundwater level behind the lock chamber wall and associated wall deformation, a frictional connection between the load introduction plate ( 2 ) and shim ( 6 ) and the wall by the tension element ( 1 ) is held.

The mother ( 9 ) after setting the movement gap width (a) preferably with a weld fixed to the shim ( 6 ) connected. The inner steel cap ( 10 ) is used to protect the tension element ( 1 ) and the mother ( 9 ) close to the shim ( 6 ) screwed. The through the inner steel cap ( 10 ) and shim ( 6 ) formed cavity with corrosion protection compound ( 5 ) completed.

The outer steel cap ( 11 ) serves as a lost formwork in the manufacture of the facing shell and provides with the distance (a + b) to the inner steel cap ( 10 ) the required free deformation of the wall safely. Next prevents the outer steel cap ( 11 ) the rotational movement of the shim ( 6 ) and thus an unplanned loosening of the mother ( 9 ).

By the simple retrofitting with the tension element and the fatigue-free Head construction can the lock chamber wall even at high groundwater levels secured in the limit state against tipping and a costly New construction to be avoided.

advantages

By the new head design is cyclical To secure stressed components with non-prestressed tension elements.

The activation of the tension element as a function of the component deformation can be achieved by the distance between shim ( 6 ) and load introduction plate ( 2 ) and the resulting movement joint individually and simply with the mother ( 9 ) and the thread on the tension element ( 1 ).

First in the limit state of carrying capacity and correspondingly large Part deformation is the tension element over the head construction activated. This causes a cyclic stress on the head construction, of the tension element and the joint between injection body and soil in use significantly reduced or avoided.

The full load capacity of the head structure and the tension element can without diminishing the allowable voltages due to cyclic stresses and resulting material fatigue be used.

in the Use state, the components to be anchored not such. B. in prestressed injection anchors by biasing forces additionally charged.

By the free possibility of displacement between tension element and anchoring component can the quality of anchoring on the side facing away from the component side of the tension element by conventional acceptance tests to be controlled.

Becomes the head construction is concreted, the full function of the Displaceability between tension element and the component to be anchored receive.

All Components of the new head construction are commercially available, sturdy and durable and can with usual equipment be incorporated in the construction industry.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - DIN 1054 [0002]
• - DIN 1054 [0004]

Claims (8)

Einbetonierbare, slidably trained and fatigue-free head construction for anchoring tension elements on cyclically stressed components, characterized in that with the mother ( 9 ) and the thread on the tension element ( 1 ) an adjustable movement joint (a) between the load introduction plate ( 2 ) and the shim ( 6 ) is available. Head construction according to claim 1, characterized in that the shim ( 6 ) firmly with mother ( 9 ) connected is. Head construction according to one of the preceding claims, characterized in that the load introduction plate ( 2 ) on a mortar bed ( 4 ) is placed and connected via drilled dowel construction firmly connected to the component to be anchored. Head construction according to one of the preceding claims, characterized in that in a round opening in the center of the rectangular load introduction plate ( 2 ) the outer plain bearing sleeve ( 3 ) and fixed with the load introduction plate ( 2 ) connected is. Head construction according to one of the preceding claims, characterized in that between the outer plain bearing sleeve ( 3 ) and the inner plain bearing sleeve ( 8th ) there is an annular gap. Head construction according to one of the preceding claims, characterized in that the inner plain bearing sleeve ( 8th ) over the pipe ( 7 ) is pushed and firmly connected to this. Head construction according to one of the preceding claims, characterized in that a distance (a + b) between outer steel cap ( 11 ) and inner steel cap ( 10 ) is available. Head construction according to one of the preceding claims, characterized in that by the width of the outer rectangular steel cap ( 11 ) a twisting of the rectangular shim ( 6 ) is prevented.