A self-stressing shape memory alloy (SMA)/fiber reinforced polymer (FRP) composite patch is disclosed that can be used to repair cracked steel members or other civil infrastructures. Prestressed carbon FRP (CFRP) patches have emerged as a promising alternative to traditional methods of repair. However, prestressing these patches typically requires heavy and complex fixtures, which is impractical in many applications. This disclosure describes a new approach in which the prestressing force is applied by restraining the shape memory effect of nickel titanium niobium alloy (NiTiNb) SMA wires. The wires are subsequently embedded in an FRP overlay patch. This method overcomes the practical challenges associated with conventional prestressing.

A self-stressing shape memory alloy (SMA)/fiber reinforced polymer (FRP) composite patch is disclosed that can be used to repair cracked steel members or other civil infrastructures. Prestressed carbon FRP (CFRP) patches have emerged as a promising alternative to traditional methods of repair. However, prestressing these patches typically requires heavy and complex fixtures, which is impractical in many applications. This disclosure describes a new approach in which the prestressing force is applied by restraining the shape memory effect of nickel titanium niobium alloy (NiTiNb) SMA wires. The wires are subsequently embedded in an FRP overlay patch. This method overcomes the practical challenges associated with conventional prestressing.

An anchor system for fiber reinforced polymer (FRP) material having an outer casing including a linear inner profile portion; and a non-linear inner profile portion, both on an inner surface of the outer casing. The anchor further having a wedge configured to be housed by the inner profile of the outer casing, the wedge including: a linear outer profile portion configured to mate with the linear inner profile portion of the outer casing; a non-linear outer profile portion configured to mate with the non-linear inner portion of the outer casing, both on the outer surface of the wedge; and an inner gap formed in the wedge and configured to receive the FRP material.

A composite sucker rod (12) has a tension rod (16) formed of a carbon fiber reinforced phenolic material and a support sleeve (18) formed of aluminum. The support sleeve (18) extends around the tension rod (16). A compressive preload is applied to the support sleeve (18) and a corresponding tensile preload is applied to the tension rod (16). The tensile preload reduces compressive loads applied to the tension rod (16). The compressive preload and the tensile preload are applied by differences in coefficients of thermal expansion of the materials from which the support sleeve (18) and the tension rod (16) are formed, and exposure to well temperatures. Opposite terminal end sections of the tension rod (16) have exterior peripheries (62) which are formed to define compound progressive radii provided having indentions (64) and protuberances (66) which fit in cooperative relation with formed surfaces of clamping members (34, 36) of end fittings (14) having profiles (38) to secure the end fittings to the tension rod (16).

A pre-stressed cast concrete structure comprises embedded fibrous reinforcing tendons in tension. The fibrous reinforcing tendons each comprises a plurality of continuous non-metallic fibers extending substantially the entire length of the tendon. A system for pre-stressing a cast concrete structure includes a mold for containing concrete, fibrous reinforcing tendons, chuck assemblies associated with the reinforcing tendons and a tensioning mechanism. When cured, the concrete rigidly surrounds the reinforcing tendons such that the reinforcing tendons are maintained in tension. The chuck assemblies have a plurality of jaws that contact the reinforcing tendons in a manner to resist damage to the fibers.

A pregrouted PC steel material (10) includes a 19-wire-twisted PC strand (1), a pregrouted layer (2) disposed on an outer periphery of the PC strand (1), and a sheath (3) configured to cover an outer periphery of the pregrouted layer (2). A filling resin (4) is filled between steel wires (side wires) (1b, 1c, 1d). Since the filling resin (4) does not exude to the pregrouted layer (2) before tensioning of the PC strand (10), an operation of tensioning the PC strand (1) is not hindered by curing of the pregrouted layer (2). In contrast, since the gap between the steel wires is reduced when the PC strand (1) is tensioned, the filling resin (4) flows out (exudes) from between the steel wires to the pregrouted layer (2) to cure the pregrouted layer (2) only after the reduction.

In the process of the invention for producing concrete components, carbon fibers which have been prestressed by means of tensile stress or tensile-stressable fibers of at least one textile structure comprising carbon fibers are embedded in a concrete matrix. At least one textile structure comprising carbon fiber bundles is laid in a mold. The carbon fiber bundles are inserted, in each case at a distance from one another, into two accommodation elements which are arranged at two diametrical end faces of the mold and can be connected on the end walls of the mold or thereto through openings so that hollow spaces within the accommodation element are filled with a rapid-curing viscous composition having a mineral basis or a rapid-curing polymer. After curing of the composition or of the polymer, tensile forces act on one or both accommodation element(s) in the longitudinal direction of the carbon fiber bundles at at least one end face by means of a tensioning device. While the tensile forces are acting, the interior of the mold is subsequently filled completely with viscous concrete. After curing of the concrete, the tensile forces on the prestressed carbon fiber bundles are largely transferred to the cured concrete and the concrete component can then be removed from the mold.

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).

A joint exhibits high tensile strength. The 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. The joint can be used to construct a sucker rod for an oil well, or it can be used in other applications. The joint can support high tensile loads, over long distances, while occupying a very narrow tubing bore.

A method for producing a three-dimensional construction material component preferably having at least one curved surface. A plurality of spacers are arranged in a formwork. A textile reinforcement is supported on the spacers, such that the textile reinforcement has a defined position within a formwork interior of the formwork. A tensile force is applied via a tensioning device to the textile reinforcement in at least one tension direction. Construction material is introduced into the formwork interior and surrounds the textile reinforcement. The construction material is then hardened, wherein the tensile force is maintained during the hardening. During this process, the spacers are integrated into the construction material component. The tensioning device has at least one clamping unit for clamping an end portion of the textile reinforcement between two clamping surfaces. The clamping surfaces are provided on clamping insert bodies, which are of a plastic material of a defined hardness.