PURPOSE: A steel pipe assembly is provided to improve the strength of a steel pipe roof by using a lower support plate and an upper support plate. CONSTITUTION: A steel pipe assembly comprises an assembly body(10), plural plate supports(23), and plural pipe supports(40). The assembly body comprises a steel pipe(11), a lower support plate(14), and upper supporting plate(15). An opening(11a) is formed in the steel pipe. The lower support plate has the length section same as the steel pipe. The plate side of the lower support plate is formed to be perpendicular to the opened side of the opening. The lower support plate is connected to the lower side edge of the opening. The upper supporting plate has the width and length sections same as the lower support plate. The upper supporting plate is connected to the upper edge of the opening to be parallel to the lower support plate. The plural plate supports are installed in the inner space of the assembly body to support the upper support plate about the lower support plate. The plural pipe supports is mounted to the inner space of the assembly body and the steel pipe in the other side of the plate supports.
