Frustoconical wedges for gripping cables are described and shown which are circumferentially divided into a plurality of complementary parts which are held in the assembled state by a retaining ring located in a circumferential recess. The wedge has a bore to receive the cable, the walls of which are helically grooved to correspond to the helical plies of the cable.

Two spaced heads carry gripping and pulling elements which clamp and tension the two lapped end sections of a cable when the heads are spread apart by linear actuators. The heads are formed with downwardly opening cable-receiving throats which enable the cable to be loaded into the tensioning device simply by placing the device over the cable.

A connector for connecting together end-to-end two sets of reinforcing tendons in a concrete structure, particularly at the junction of sections in a post-stressed structure, has respective sets of bores for the sets of tendons providing, for both sets, frusto-conical seats for gripping wedges for the tendons, and also has for one of the sets of tendons means for resiliently urging the wedges into their seats, in order to hold the tendons in place until they are tensioned. The two sets of bores may be in a gripping plate, and the resilient means in a spacing member abutting the plate.

An anchor-clamp is disclosed for clamping to a prestressing member (50) intermediate its length and over a support (68). The clamp (FIG. 1), after initial assembly, is packed in polystyrene blocks (62, 64) for shipment. At the site of use, the anchor-clamp, still in its foam package, is assembled to the prestressing member (50) and then the concrete is poured and allowed to set. After hardening of the concrete, the prestressed member (50) is stressed in the conventional way, the polystyrene package is removed from about the anchor-clamp and the clamp is operated to clamp the stressed prestressing member (50). Thereafter, the entire clamp is imbedded in concrete. When only one intermediate anchor-clamp is used, it may be clamped to the prestressing member (50) prior to the stressing of the same. The polystyrene foam package not only protects the clamp during shipment and assembly to the prestressing member but also protects the same from concrete or water when the concrete is poured and before removal of the polystyrene package. The clamp comprises a compression member (56) threaded to two tubular portions (52) of two substantially identical clamps (20, 30) arranged in facing relationship. The threading of the member (56) to the tubular portions (52) is left-handed for one of the members (52) and right-handed for the other member (52) so that upon rotation of the member (56), it will move the tubular portions (52) outwardly away from each other whereby wedge activators (44) bearing against wedges (32) drive the wedges (32) outwardly within frustoconical bore (28) in hubs (26). This outward movement of the wedges (32) causes them to move together and clamp to the outer surface of the prestressing member (50).

An apparatus for anchoring wires or stranded wires incorporating an anchor plate equipped with throughpassage bores for the wires or stranded wires, and clamping wedges associated with the anchor plate for anchoring the wires or stranded wires. The throughpassage bores possess at one end a conical recess for receiving the clamping wedges and also have a subsequently merging cylindrical section. Means are provided for applying the clamping wedges, during the mounting of the apparatus at the wires or stranded wires and during the tensioning thereof, against a press-in plate arranged in spaced relation from the anchor plate and which press-in plate is provided with holes or perforations for the throughpassage of the wires or stranded wires. The applying means retains the clamping wedges out of the their effective clamping position. The press-in plate, after tensioning of the wires or stranded wires, is displaceable against the anchor plate for simultaneously and uniformly bringing the wedges into their clamping position.