The method for manufacturing an individually sheathed strand comprises: conveying a group of metal wires through a die; upstream of the die, applying a first filler product to at least a first portion of the strand; upstream of the die, applying a second filler product to at least a second portion of the strand distinct from the first portion; and extruding a plastic around the group of metal wires passing through the die, so as to envelop the group of metal wires covered with the first and second filler products in a continuous sheath formed of the extruded plastic. The second filler product has greater adhesion to the group of metal wires than the first filler product.

Provided is a method for manufacturing segments for a tower, in particular of a wind turbine, and a prestressed segment for a tower. Provided is tower ring for a tower, a tower of the wind turbine, and a wind turbine. In addition, a prestressing device is provided. The method for manufacturing segments for a tower, in particular of a wind turbine, comprises: arranging at least one prestressing element in a mold, wherein the prestressing element comprises or consists of fiber-reinforced plastic; tensioning the prestressing element; embedding the prestressing element in a concrete mass; hardening of the concrete mass into a longitudinal segment, preferably in the form of a complete longitudinal segment of a tower; removing the hardened longitudinal segment from the mold.

Self-stressing engineered composites that include a matrix containing self-stressing reinforcement that is activated by an activator that causes, in situ, the self-stressing reinforcement to transfer at least some of its pre-stress into portions of the matrix adjacent the self-stressing reinforcement. In some embodiments, the activator can be of a self-activating, an internal activating, and/or an external activating type. In some embodiments, the self-stressing reinforcement includes an active component that holds and transfers pre-stress to a matrix and a releasing component that causes the active component to transfer its pre-stress to the matrix. In some embodiments, the self-stressing reinforcement is initially unstressed and becomes stressed upon activation. Various engineered composites, self-stressing reinforcement, and applications of self-stressing engineered composites are disclosed.

The present invention provides an early warning device and a ductility control method for a prestressed FRP reinforced structure. By setting a tensioning screw, prestressed reinforcement can be converted into non-prestressed reinforcement when tensioning screw failure occurs, and the structure is still in a safe state. This can improve the bearing capacity and ductility of the reinforced structure, while the ductility can be controlled and designed, thereby resolving the problem of easy disconnection and brittle failure between the FRP and anchors, and greatly improving FRP utilization and structural safety.

A reinforcement system for anchoring tendons for structural reinforcing a structure such as a concrete structure, said reinforcement system comprises at least one anchor and at least one tendon, said anchor is adapted to fix said tendon in and/or outside said structure, wherein said reinforcement system comprises a ductility element, which is positioned in structural connection between said tendon and said anchor, said ductility element comprising weakened deformation zones being deformable so that the length of the ductility is increased or decreased in an axial direction along the length of said tendon.

A precast segmental pier reinforced with both FRP bars and steel bars according to one or more embodiments of the present application includes a footing, a segmental pier, longitudinal bars and unbonded post-tensioned tendons, characterized in that: the segmental pier is comprised of one or more precast segments , the longitudinal bars are comprised of both the steel bar and the high-strength steel bar, connecting the footing and the segmental pier together with unbonded post-tensioned tendons to form an entire pier.

In an anchorage 1 of continuous fiber-reinforced polymer (CFRP) strands that anchors continuous fiber-reinforced polymer strands 2 to concrete structures, there is provided an untwisted diameter-expanded portion 3 expanded to a diameter D2 by being radially expanded with respect to a diameter D1 of a general portion 4 of the CFRP strands 2 by untwisting any section of the CFRP strands 2 formed by stranding a plurality of element wires (20, 21) that are bundles of multiple continuous fibers, and filling and curing a time curable material 5 in a clearance among the element wires the untwisted section that is untwisted.

A joint includes a solid rod having a slit or opening into which a wedge is inserted. The rod and wedge are inserted into a fitting. The internal surface of the fitting has a contour which continuously and nonlinearly varies with distance along the fitting. The wedge has a dimension having a similar contour. The shape of the contour can be described by a polynomial of order two or higher.

A structural element for constructions comprising a structure (2) made of concrete and/or geopolymer and/or alkali activated material and at least one strip (3) made of a fibre-resin composite. Such strip surrounds at least part of said structure (2), compressing it. The strip also at least partly surmounts an external surface (20) of said structure (2).

The method according to the invention for producing a prestressed concrete workpiece is characterized in that the prestress is created by a heat treatment, wherein the concrete and the reinforcement therefor are selected in such a way that, when cooling the concrete workpiece from an elevated temperature, the heat expansion coefficient of the concrete is less than that of the reinforcement, and in that, during cooling, the concrete and the reinforcement adhere sufficiently strongly to one another if, during cooling, the concrete is hydrated at least to such an extent in order to be able to expand the reinforcement on account of the different heat expansion coefficients, and in that the concrete, together with the reinforcement, is brought to the elevated temperature in such a way that and is hydrated during cooling at least to such an extent that it is prestressed by the reinforcement after cooling.