PURPOSE: To upgrade the efficiency and quality of the reinforcement assembly work by jointing reinforcements together by means of electrically insulated securing tools, and by physically preventing the reinforcement groups from forming electrical circuits.

CONSTITUTION: A strengthened plastic made clamp B is provided on the crossing portion of reinforcements 3 arranged in a construction and the reinforcements 3, 3 crossing each other are jointed together by means of the clamp B. In the clamp B, a pair of circular or polygonal cylindrical reinforcement holding pieces 4, 4 are connected together in a back-to-back manner mutually rotatably around a pin fitted through the same holding pieces 4, 4. The holding pieces 4, 4 are then turned around the pin serving a center, reinforcements 3, 3 are fitted into respective holding pieces 4, the reinforcements 3 are embraced by the holding pieces 4 by virtue of their elasticity and the reinforcements 3, 3 are jointed together at a required angle. Thus, formation of an electrical circuit caused by the reinforcement groups is prevented so as to prevent generation of induced current and reduce magnetic drag.