The main materials used in the scaffolding and the formwork are steel tubes and bamboo braces. According the standard requirements, the steel tubes used for the couplers scaffold shall be designed for 48mmm for its external tube diameter and 3.5mm thickness. However, most of the steel tube manufacturers make advantages of the materials to shrink the thickness of the tube wall to 3.0-3.2mm in order to have more advantage in the market competition. These unqualified steel tubes when used for more than many times will have big potential risks as their tube wall will become thinner and thinner as well as its inertia torque is minimized.
One of the main reasons for the collapse of the scaffolding is the instability of the supporting braces. Most of the construction units rely more on their working experience to set the bracing supporting system rather than to make formwork design and the rigidity test. For most of the cases, many of the reclaimed scaffolds have been used in the projects, which are severely rustic or abraded, and some of them are bended or cracked at the welded joints.