A structural reinforcement member is provided to be affixable to a metallic member. The metallic member defines a stress concentration section at which the metallic member is subject to loading in at least one direction such that stress is generated at the stress concentration section in at least one corresponding principal stress direction. The structural reinforcement member includes a polymer matrix composite (PMC) patch element and a bondline. The PMC patch element includes fibers suspended within a polymer matrix. The bondline is disposed to affix the PMC patch element to a surface of the metallic member at the stress concentration section such that the fibers extend along the principal stress direction.

A beam reinforcing metallic material includes a welding surface, a counter-flange-part surface, a contacting surface, a protrusion, and the like. The beam reinforcing material is a member that is made of metal such as steel for example. The beam reinforcing metallic material is not plate shaped but has a three dimensional shape. More particularly, the cross-sectional shape varies from the edge parts toward the center part in longitudinal direction. The cross section (cross-sectional area) of the center part of the beam reinforcing metallic material in longitudinal direction is larger than the cross sections (cross-sectional areas) of the both end parts. Increasing the cross-sectional area of the vicinity of the center part of the beam reinforcing metallic material allows the part that receives maximum stress to securely obtain the flexural strength when the beam reinforcing metallic material is fixed to the beam.

A beam is an H-shaped steel having flange parts above and under a web part. A through hole is formed on web part to let pipes and the like pass through. A ring beam reinforcing metallic material is disposed through hole. A beam reinforcing metallic material is disposed along the upper and lower flange parts at positions away from the through hole. The beam reinforcing metallic material on the front surface of the web part (opposite side of a flange of the ring beam reinforcing metallic material). The beam reinforcing metallic material in a direction in which a counter-flange surface of the beam reinforcing metallic material faces the flange part. A contacting surface is in contact with web part and is fixed to the web part with a welded section. At this time, the welded section is formed up to the height to which an angle varying part is covered.

A laser welding repair device includes a laser oscillator, a laser head that condenses laser light from the laser oscillator to irradiate a repair portion, a temperature sensor that detects a temperature distribution of a steel material irradiated with the laser light, and a control unit. The control unit sets a spot diameter of the laser light to be less than 3 mm, moves the laser head and enlarges a heat input area to check for a crack in the heat input area, the heat input area being formed by irradiating the steel material with the laser light, and controls the laser head to irradiate a region where a temperature detected by the temperature sensor is equal to or less than a mechanical melting temperature of the steel material. Where a welding is performed in a flat position, the crack can be easily and reliably erased without causing burn through.