METHOD FOR STRENGTHENING CRACKED METAL THIN-WALL ELEMENT OF SPAN STRUCTURES OF BRIDGES Russian patent published in 2018 - IPC E01D22/00 

FIELD: construction.

SUBSTANCE: strengthening method includes drilling a hole at the crack mouth, applying a solder, installing strengthening elements in the form of straps installed on both sides of the metal element, and local heating to the melting point of the solder. The hole in the crack mouth is drilled with a diameter of at least two sheet thicknesses, a paste-like solder is applied to the strap surface, and a mushroom-shaped strap is installed by inserting its stem into the hole. The clearance between the strap stem and the beam wall in the hole is 0.2-0.25 mm, the pressing force is not less than 0.2 MPa. The strap due to the solder adhesion with the base metal is involved in the joint work with the main element. Its cross section is not only not weakened, but is also strengthened by increasing the cross-section with the straps. While heating, in the hole area (the metal is expanded into the hole), additional compressive stresses slowing downing the crack development are created.

EFFECT: increasing the operational reliability of a span structure with a crack in the wall of the main beam, which extends predominantly from a seam fastening a stiffener thereto.

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