THE UNION STRUCTURE OF THE GRATING

PURPOSE: A fastening structure of gratings is provided to easily fasten the gratings adjacent to each other, and prevent damage from vehicle traffic. CONSTITUTION: A fastening device(60) of gratings include a fastening bracket(20), a nut(40), and a fastening bolt(50). The fastening bracket(20) includes a first vertical plate(21), an upper plate(23), a second vertical plate(25), a fastening support plate(27), and a lower plate(29). The fastening bracket(20) fixes the four sides of the hollow frames(11) of a first and a second grating(110,110`). The nut(40) is coupled with the fastening bolt(50) so that the first and a second grating(110,110`) are fastened with the fastening bracket(20). The fastening bolt(50) includes a fastening portion(51) and a head portion(53). The fastening portion(51) is vertically coupled to the nut(40) through a first through hole(26) formed on the fastening support plate(27) and a second through hole(28) formed on the bottom plate(29). The head portion(53) is formed on the upper portion of the fastening portion(51), and is settled on the fastening support plate(27).