Force Mechanism and Progressive Collapse of Steel Tube-coupler Scaffold Under Local Load

Abstract

The force mechanism and progressive collapse of steel tube-coupler scaffolds were studied under a local load. A distributed optical fiber system was used to conduct experiments on four different scaffold erections. The stresses of the vertical rods, horizontal rods and braces had ladder-like distributions; braces sustained most of the axial force, whereas vertical and horizontal rods sustained an axial force and bending moment. A reasonable numerical analysis strategy is established on the basis of this research and a comparison with experiments, and the progressive collapse process is simulated using ANSYS software. Horizontal rods and braces not only provide auxiliary support for the vertical rods, but also contribute to forces throughout the scaffold; internal forces pass through the two types of bar and are redistributed in each vertical rod such that all vertical rods are associated with forces in the scaffold. Braces block the spread of local collapse within the same floor while bottom horizontal rods block that from one floor to another. The addition of braces and bottom horizontal rods can therefore effectively prevent progressive collapse.