Reinforcement butt stud welding method and device therefor and repairing/expanding method for ferroconcrete structure

A reinforcement butt stud welding method comprising the steps of:

• removably mounting an earth clamp having a conductor surface perpendicular to an existing reinforcement over the periphery of the end portion of said existing reinforcement;
• mounting a ferrule on the end portion of said existing reinforcement or on the distal end portion of a stud reinforcement loaded in a stud welding gun, this ferrule having on both ends thereof mounting openings into which the existing reinforcement and stud reinforcement can be respectively inserted and inside thereof a space for a molten metal pool and also having gas release openings on the periphery of said space;
• bringing the distal end of said stud reinforcement in contact with the end surface of said existing reinforcement;
• and
• conducting stud welding in a state in which said ferrule is pressed against the conductor surface of said earth clamp.

A stud welding apparatus, wherein

• one or a plurality of guide poles are provided in a protruding condition, parallel to a drive shaft for linear driving, in front of a stud gun body;
• a ferrule contact part is formed on the distal ends of said guide poles;
• a movable body slidably provided in the middle portion of said guide poles is linked to said drive shaft;
• a stud holding tool is provided on said movable body;
• and
• a stud reinforcement mounted on said stud holding tool is disposed above the gun body or on the side thereof.

A stud welding apparatus, wherein

• a stud holding tool is provided perpendicular to a distal end portion of a drive shaft for linearly driving a stud gun body;
• a linear guide is provided parallel to said drive shaft along the upper surface or side surface of the gun body;
• an auxiliary stud holding tool is slidably provided on said linear guide;
• a ferrule contact member is provided at the front distal end of the gun body;
• and
• a stud reinforcement mounted on said stud holding tool and auxiliary stud holding tool is disposed above the gun body or on the side thereof.

A stud welding apparatus, wherein

• a linear guide is provided along the upper surface or side surface of a stud gun body;
• a stud holding tool is provided on said linear guide so that the tool can be slidably moved by a linear driving mechanism;
• a ferrule contact member is provided at the front distal end of the gun body;
• and
• a stud reinforcement mounted on said stud holding tool is disposed above the gun body or on the side thereof.

A repairing/expanding method for a ferroconcrete structure comprising the steps of:

• simultaneously cutting an existing reinforcement and concrete which are at least part of the ferroconcrete structure;
• stud welding, to the end surface of the existing reinforcement exposed on the concrete cut surface, the end portion of a stud reinforcement of the same diameter almost coaxially to obtain an extended reinforcement;
• and
• placing concrete.