Square tube and square truss structure has the advantages of overlapping shear and form centers, good torsional resistance, large bending stiffness and beautiful appearance of the composed structure. Therefore, it has been applied more and more. However, China has not done enough research and application work in this area, and there is no special specification for the design of square tube and square joist structure, and there are few design materials in this area. Introduction of joist; Joist: a structure made of rods connected with each other by hinges at both ends. The truss is a flat or spatial structure consisting of straight rods with triangular units. The truss members mainly bear axial tension or pressure, thus making full use of the material strength, saving material, reducing weight and increasing stiffness when the span is larger than that of a solid web beam. Overview of 12 inch aluminum square box truss equipment. The square box truss is generally 200mm wide, 200mm long, 500mm, 1000mm, 2000mm, 3000mm long, and is mainly used for the construction of spray painting backgrounds, with the advantage that the square box truss is flat compared to the round box truss and easy to operate on site. Advantages of 12 inch aluminum square box truss. The advantage of truss is that the rods mainly bear tension or pressure, which can give full play to the material, save material and reduce the weight of the structure. Commonly used are steel truss, reinforced concrete truss, pre-stressed concrete truss, wood truss, steel and wood combination truss, steel and concrete combination truss. https://www.tytruss.com/Square-Truss/290-290mm-Square-Truss.shtml