Abstract: A mine roof support system is disclosed having a connector. The connector has a first hole through which one end of a first roof supporting rod is inserted and a second hole through which one end of a second roof supporting rod is inserted. The first and second roof supporting rods are fastened to the connector so as to support the roof of the mine. In order to increase the bending arcs of the connector along which the first and second roof supporting rods bend without increasing the weight of the connector, the holes of the connector may be bevelled to form elliptical openings in the connector and the connector may be canted.

Abstract: To facilitate the construction of a very high structural member for use in a body of water such as at an offshore location with the structural member extending from the floor of the body of water to above its surface, tensioning members are inserted into relatively narrow tensioning ducts accessible only from the top of the structural member. The tensioning members, such as steel rods, steel wires, or steel wire strands, are provided with members for effecting a positive locking engagement in a hardenable material forming an anchored length of the tension member at the lower end of the tensioning ducts. Initially, the tension members are lowered into the lower ends of the ducts and then are grouted in the ducts by a hardenable material. After the hardenable material has set over an anchored length, the tension members are tensioned within the ducts. Next, the tensioned length of the tension members in the ducts is grouted with a hardenable material to provide a composite action with the structural member.

Abstract: A wedge anchorage for an axially elongated tension member, encased in and arranged to prestress a concrete structure, includes an anchor member with a conically widening surface where a wedge seats for securing the tension member in the tensioned state with a cap arranged to fit in locked engagement with the end of the anchor member through which the tension member extends out of the concrete structure. The cap has a cover wall extending transversely of the axial direction and spaced from the anchor member. An opening is provided in the cover wall through which the tension member extends out of the concrete structure. A spring or other biasing member is located within the cap for limiting axial displacement of the wedge when the tension member is stressed in tension. This arrangement avoids the formation of a recess in the surface of the concrete structure from which the tension member extends and the need for a filler member for sealing off the recess when the prestressing operation is completed.

Abstract: A closed ring-shaped reinforcing member for use in a concrete structure and which is stressed by annular tensile forces, such as a bell-shaped anchoring body for a prestressing member used in a prestressing concrete structure, is provided around the radially outer surface with a coating of a material which is elastically or plastically deformable under compression. The reinforcing member can deform under the action of annular tensile forces which cause it to stretch, but the presence of the deformable coating on its outside surface prevents the transfer of such deforming forces to the concrete structure, since otherwise such forces could result in the formation of cracks in the structure.