Dyckerhoff & Widmann Aktiengesellschaft

Johann Wlodkowski

Dieter Jungwirth

Oswald Nutzel

Lorenz Schnitzler

Alto Mannhart

Josef Renoth

To form a radially outwardly extending bulge in a steel wire strand made up of a plurality of individual wires, the strand is compressed along an axial length so that the individual wires deform radially outwardly and in spaced relation to one another. Compressive force is applied to one end of the strand and the strand is anchored at an axially spaced location from the end. A tubular member with a cylindrically shaped inside surface forms a limiting boundary for the outward movement of the individual wires. The tubular member is located between the end of the strand and the location where it is anchored. The end of the strand and the tubular member are rotatably supported. Each individual wire extends along an angular path about the axis of the strand between the end of the strand and the anchor location.

Method of and apparatus for forming an outwardly projecting bulge in a

In a recoverable form for use in the region where a tendon is anchored in a prestressed concrete component, a part is provided for forming a cup-shaped recess in the concrete surface. The part contains an axially extending passage through which a tendon extends. The part is formed of rubber or a rubber-like material and is constructed so that its outer surface extending in the direction of the passage arches outwardly away from the passage when a compressive force is applied to the part in the axial direction of the passage.

Recoverable form part for use in the region where a tendon is anchored

A multiple part tapered collar for use in a wedge anchoring system for a tendon in a structural concrete member usually consists of three coextensive elongated parts combined to form an axially extending annular component. The inner surface of the collar bears against the surface of the tendon, for instance, a wire, rod or the like, and its outer surface contacts the surface of a frusto-conical bore in an anchoring member. A groove is formed along the axial length of the outer surface of at least one of the parts of the collar for passing neat cement or a similar substance for enclosing the tendon. As a result, openings through the anchoring member, which are expensive to form and tend to clog, are unnecessary.

Multiple part tapered collar for a tendon anchorage system

The formwork for a concrete structural member includes a recoverable formwork part. This recoverable part has an axially elongated sheath which closely encloses a tendon over a relatively long portion of the length of the sheath. A cup-shaped part formed integrally with the sheath is arranged to form at least a portion of a recess in the concrete member. When assembled on the formwork, one end of the sheath is arranged to be located within the concrete when it is poured and the other end is located on the exterior of the formwork. The cup-shaped part is located intermediate the ends of the sheath and just inside the formwork. A member is engageable with the sheath for attaching it to the formwork.

Recoverable formwork part for forming the anchoring location of a tendon

In a system for anchoring a tendon extending through a structural concrete unit, an anchoring member is located at the outside surface of the concrete unit and has a frusto-conical passage through which a tendon passes as it extends outwardly from the concrete unit. A cap fits over the outer surface of the anchoring member and forms a closure over its frusto-conical passage. The cap is shaped so that it has an inwardly projecting portion which seats against the outer ends of wedge parts securing the tendon within the passage in the anchoring member. The projection on the cap exerts a compressive force holding the wedge parts in place. Further, during construction of the concrete unit, the cap can secure the wedge parts against displacement.

System for anchoring a tendon in a structural concrete unit

For use in prestressed concrete structures, an arrangement is provided for interconnecting serially arranged longitudinally extending bundles of prestressing tendons. Each bundle passes through a separate section of the structure with the sections being poured one after the other. The ends of a bundle extending through a first poured section are secured centrally within an anchorage member. The ends of the following bundle in the next section are secured to the same anchorage member in an annular part radially outwardly of the centrally secured ends of the first bundle. From the anchorage member, the tendons in the following bundle converge inwardly to a point spaced from the anchorage member where they are enclosed within a tubular sheathing in a normal close spacing. The end of the sheathing is trumpet shaped, diverging toward the anchorage member. The end of the trumpet shaped section closer to the anchorage member, is spaced from the anchorage member so that a longitudinally extending section of the tendons in the following bundle is directly enclosed by concrete when the second section of the structure is poured.

Growing community of inventors

Munich, Germany

Johann Wlodkowski