Dyckerhoff & Widmann Aktiengesellschaft

Rochling Haren Kg

Thomas Herbst

Lorenz Schnitzler

Urs Kellner

Dieter Jungwirth

Otmar Langwadt

Reinhard Klockner

Hans-Peter Von Allmen

Berthold Bolmer

Lorenz Schitzler

Harald Heimsoth

Anton Lugering

Konrad Spang

Hartmut Von Grolman

A corrosion-protected support element for a soil anchor or a rock anchor or a pressure pile includes a support member which is provided with a tubular casing. The hollow space between the support member and the casing is filled out by a hardening material, for example, cement mortar. The tubular casing is a plastics material tube, for example, of PE, which extends over the entire length of the support member. The plastics material tube has the same cross-section over its entire length. In the region of force-transmission between the support member and the bore hole in which the support element is placed, the plastics material tube is deformed at spaced-apart locations to deviating cross-sections having different transverse extensions.

Corrosion protected support element for a soil anchor or a rock anchor,

An anchoring arrangement for use in underground mining or foundation work or as a reinforcing element for concrete includes a rod-shaped tension member of composite fiber material which has, over at least an anchoring portion thereof, a helically extending external thread with ribs formed by impressing valleys in the tension member. An anchoring member having a corresponding internal thread can be screwed onto the tension member. For obtaining a radial pressure on the tension member as a result of a wedge effect, the angle of inclination of the sides of the thread relative to the longitudinal axis of the tension member is smaller than 45.degree.. The thread preferably is a fiat trapezoidal thread. In an anchoring member which is stiff relative to circumferential tensile forces, the flat angle of inclination of the sides of the thread increases the radial pressure acting on the tension member, which leads to an increased effect into the depth and a higher resistance to shearing. The anchoring member may have a changing circumferential tensile stiffness over the length of the threaded engagement with the tension member, so that the anchoring member can expand at the point of highest stress concentration, with the result that a change in length of the tension member may occur.

Arrangement for anchoring a rod-shaped tension member of composite fiber

An anchoring device for a tension member of an earth- or rock anchor, where a support element transmitting the tensile force is arranged between an anchoring element undisplaceably connected with the tension member and an anchor plate abuttable against a support base, the support element includes a cylindrical hollow body surrounding the anchoring element, whose inner wall has in its lower region projections protruding inward beyond its inner contour, against which the anchoring element abuts in a force-transmitting manner with partial regions of its cross-sectional area. If a predetermined tensile force is exceeded, the support element and/or the anchoring element can plastically deform in the region of their inter-engaging surfaces, so that a relative displacement occurs in axial direction. Distance or spacer pins are provided in a head plate placed upon the tension member for visual indication of the relative displacement, which after contact with the surface of the hollow body exit upwards from the head plate.

Anchoring device for the rod-shaped tension member of an anchor,

A rod-shaped tension member formed of fiber reinforced composite material is utilized as an anchoring rod in foundation and mining construction, or as a reinforcing member in concrete and prestressed concrete construction. At least, in an axially extending region where it is to receive an anchoring member, such as a rod, the tension member has a continuous helical thread formed of alternating ribs and recesses. The anchoring member has a corresponding thread so that it can be screwed onto the tension member thread. An intermediate layer is provided between the threaded regions of the tension member and the anchoring nut, and is formed of a material affording large plastic deformation relative to the tension member when slight stress increases occur at overload conditions. Accordingly, between the threads on the tension member, and the nut, the plastically deformable intermediate layer has a strength less than that of the fiber reinforced composite material whereby it is subject to compression, acting transversely of the rod. As a result, stress peaks in the tension member are avoided by the plastic deformation of the intermediate layer.

Anchoring arrangement for a rod-shaped tension member formed of fiber

An anchoring device, such as a rock anchor, includes an anchor rod with force transmission ribs projecting outwardly from its outside surface. An anchor nut is in threaded engagement with the rod and has at least an axially extending portion formed of a material having lesser strength than the material of the rod. The anchor nut has at least two axially extending portions spaced apart by cuts through the nut, which cuts extend transversely of the nuts central axis. The portions follow one another in the central axis direction with at least the portion closer to the body into which the anchor rod extends having the lesser strength. The nut portions are dimensioned so that the portion closer to the body loses its force locking engagement with the ribs on the rod and its threads shear off when a predetermined load is exceeded. The nut portions are interconnected by narrow webs remaining after the cuts are made in the nut separating the portions. The webs cannot transmit the anchor force when the predetermined load is exceeded, and, therefore, they act as breaking points with the two portions moving toward one another and closing off the cuts. The closure of the cuts is visible and signals that the predetermined load has been exceeded, accordingly, steps can be taken to secure the stability of the body into which the anchoring device is inserted.

Anchoring device, such as a rock anchor

For the installation of an anchor member at a location below a water level through a retaining wall into a soil formation for supporting the wall, a drill mount is pivotally mounted about a horizontal axis on a retaining member secured to the wall. The drill mount can be pivoted between a drilling position inclined downwardly toward the wall and an upwardly extending loading position where the drill mount is accessible above the water level. A cable line secured to the drill mount pivots it between the drilling and loading positions. A drilling machine is displaceable on a sliding carriage along the drill mount. A drilling tool inserted into the drilling machine is used to drill an opening through the wall. Subsequently the drilling tool is replaced by a borehole pipe and the pipe is driven through the wall opening into the soil formation. With the borehole pipe inserted, an anchor member can be placed into the pipe and by withdrawing the pipe and grouting around the anchor member at the same time, the installation of the anchor member can be completed.

Method of and apparatus for installing an anchor member below water

A tension member for use as a rock anchor or the like has a plurality of steel wires embedded in a tubular member with a central bore and formed of a hardenable plastics material, such as a synthetic resin. The outer surface of the tubular member is profiled such as in the manner of a screw thread so that an anchor member can be threaded on to the tubular member. The steel wires are arranged symmetrically around the axis of the tubular member for carrying the load transmitted by the tension member. If there is a displacement of the rock anchored by the tension member then both the tension and shearing stresses acting on the wires can cause individual wires to be displaced from the tubular member into its central bore. As a result, the flexibility of the tension member is increased and the most highly stressed wires can move out of the tubular member into its central bore.

Tension member for a rock anchor or the like

A prestressed grouted anchor has a portion of an axially extending prestressed tension member grouted in a receiving material while the remaining portion of the tension member extends from the grouted portion. The remaining portion is separated from the grouted portion at a selected breaking point by reducing the tensile strength of the tension member as the result of exposing it to the action of heat, such as developed in an exothermic chemical reaction. If the tension member is prestressed and the resulting elastic elongation is maintained during the heating action with the elongation being greater than the elongation required under the heating action for effecting the severing of the tension member, then with progressive heat the tensile strength of the tension member is reduced and the elastic elongation progressively changes to plastic elongation with the tension member finally severing automatically at the selected breaking point.

Method of and device for severing a tension member in a prestressed

An anchoring apparatus for insertion into a borehole in a rock stratum for supporting the rock surface or wall, such as in a rock tunnel or rock excavation, includes a tension member in the form of an axially elongated steel rod with force transmission ribs on its outer surface and an anchoring element, such an anchoring nut, engageable with the rod. The anchoring element has an inside surface with inwardly extending projections and the adjacent flanks on the projections form grooves within which the force transmission ribs engage. The anchoring element is formed of a higher strength material than the rod. When a predetermined axially extending tension force acting on the rod is exceeded, relative movement takes place between the anchoring element and the rod. The flanks on the projections on the anchoring element in contact with the ribs on the rod shear off a portion of the ribs contacted. Accordingly, while the predetermined force is exceeded, the shearing action proceeds and affords a sliding anchoring effect between the rod and the anchoring element.

Apparatus for anchoring rock and the like

A temporary anchor for securing part of a structure to the earth includes a tension member made up of at least two complementary shaped parts forming a regular shaped exterior. One or more ribs are formed on the exterior peripheral surface of each part so that it can be engaged within a settable grout material when it is inserted into a borehole formed in the earth. A spacer member is positioned between facing surfaces of the tension member parts and holds them in spaced relation along the length of the parts within the borehole. The spacer member is removable from between the parts when they are anchored in a grout substance so that the parts can then be removed by exerting a pulling force on them. The dimension of the spacer member between the facing surfaces of the parts is at least equal to the dimension of the ribs outwardly from the parts, whereby upon removal the spacer member leaves an open space within the borehole sufficient for the part to move inwardly with its rib being fully displaced from the grout substance for removal of the part out of the borehole.

Removable tension member for a grout anchor

For their protection against corrosion, cables of high-strength steel wires, principally for use as tension members for post-stressable earth anchors or rock anchors, are treated with a corrosion protection material and furnished with a tubular sheathing member. In order to be able to surround completely all wires (3, 4) of the cable (2) with corrosion protection material, according to the invention the interior open spaces between the individual wires of the cable are in a first work operation filled with corrosion protection material, and in a second work operation immediately thereafter, when the strand is inserted into the tubular sheathing member, the annular interior open space between the cable and the tubular sheathing member is filled with corrosion protection material. For this purpose, the corrosion protection material is brought into a state of low viscosity and is kept in that state while the interior open spaces are being filled up, whereas afterward it passes over into a state of high viscosity. By this means, not only is the complete filling of the central channels between the interior wire (3) and the exterior wires (4) and consequently a complete protection of also the central wire (3) against corrosion achieved, but also it is assured that the annular space between the cable and the tubular sheathing member is filled completely with corrosion protection material.

Process for manufacturing a protection against corrosion for cables of

A profiled tensioning rod or combination of rods is provided at the end which is to be inserted into the bore hole of a rock, with a corrosion protective tube formed in three parts, an anchoring part adapted to extend over the greater portion of the anchored end of the rod, a 'free steel part' adapted to extend over the (initially) unconnected part of the anchoring rod which extends into the bore hole and a junction part to which the other two parts are connected. The junction part extends beyond the periphery of the other parts of the tube and is large enough to prevent any substantial flow of cement outwardly from the space between the anchoring part and the bore hole. The free steel part of the tube contains a deaerating conduit so that when the rock formation is stabilized after the various borings, etc., the free steel part of the bore hole may be cemented.

Corrosion protected tensioning member for a prestressable anchor in

A removable press anchor is formed of a tubular sheathing with a traction element carried for longitudinal movement within the sheathing. An anchor body is releasably connected to the traction element and is embedded in a press body which is formed by pressing in hardening material. The anchor body is formed of glass fibers so as to be destructible by cutting forces extending transverse to the longitudinal axis thereof and able to absorb large forces in the direction of its longitudinal length and only small forces in the direction transverse to its longitudinal length. In one embodiment, the anchor body is formed as a pressure member, and in a further embodiment it is formed as a traction member.

Removable press anchor with destructible anchor body

Anchoring rods which have one end thereof secured in a bore hole of the earth or rock by surrounding cement are sometimes made more secure in the earth by one or more devices which surround different parts of the buried portion of the rod and have means for supplying additional cement at high pressure thereto to crack a portion of the surrounding cement and press additional cement into the earth adjacent the area of the device thereby forming a bulge in the anchoring cement. This disclosure relates to a device of this type which, however, has an elongated body of elastic material with a longitudinal slit or opening adapted to surround the anchoring rod and be retained thereon at the desired site and which body contains an opening or channel spaced from the rod-surrounding opening or slot substantially parallel to the latter which defines a distribution channel and has an orifice therein which is ordinarily covered by the body of the device. Under pressure, however concrete will pass out of the orifice and to the outside of the device to crack the surrounding concrete.

Device for the discharge of compression material in the production of

The disclosure relates to an anchoring device adapted to hold one end of a to-be-stressed linear member within the bore hole of an earth formation. The anchor device has a tubular body surrounding and retaining a section of the linear member and has a compression channel extending along the circumferential portion of the body. The compression channel being open to the outside of the tubular body through a substantial part of its intermediate length to form a distribution channel. Means are provided for feeding hardenable material under pressure to the regions outside the device to compress the earth surrounding the bore hole. The body is covered with a sleeve of elastic material encompassing the body to normally cover the open part of the distribution channel.

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Wessling, Germany

Thomas Herbst