Consider a rigid scaffolding tube, fixed at the bottom using the Scaffolding Nodal Support and loaded by both a moment and a force.
Verification Example 000055 | 1
Number of Nodes | 4 |
Number of Lines | 2 |
Number of Members | 2 |
Number of Load Cases | 1 |
Dimensions | 1.64 x 8.2 x 4.1 feet |
Program Version | 5.04.00 |
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The member hinge nonlinearity "Scaffolding N | phiy,phiz" allows you to simulate an inserted scaffolding tube joint.
The design of cold-formed steel members according to the AISI S100-16 / CSA S136-16 is available in RFEM 6. Design can be accessed by selecting “AISC 360” or “CSA S16” as the standard in the Steel Design Add-on. “AISI S100” or “CSA S136” is then automatically selected for the cold-formed design.
RFEM applies the Direct Strength Method (DSM) to calculate the elastic buckling load of the member. The Direct Strength Method offers two types of solutions, numerical (Finite Strip Method) and analytical (Specification). The FSM signature curve and buckling shapes can be viewed under Sections.
The member hinge nonlinearities "Scaffolding - N phiy / phiz" and "Scaffolding Diagram" enable the mechanical simulation of a tube joint with an inner stub between two member elements.
The equivalent model transfers the bending moment via the overpressed outer pipe and after positive locking additionally via the inner stub, depending on the compression state at the member end.
The modal relevance factor (MRF) can help you to assess to which extent specific elements participate in a specific mode shape. The calculation is based on the relative elastic deformation energy of each individual member.
The MRF can be used to distinguish between local and global mode shapes. If multiple individual members show significant MRF (for example, > 20%), the instability of the entire structure or a substructure is very likely. On the other hand, if the sum of all MRFs for an eigenmode is around 100%, a local stability phenomenon (for example, buckling of a single bar) can be expected.
Furthermore, the MRF can be used to determine critical loads and equivalent buckling lengths of certain members (for example, for stability design). Mode shapes for which a specific member has small MRF values (for example, < 20%) can be neglected in this context.
The MRF is displayed by mode shape in the result table under Stability Analysis → Results by Members → Effective Lengths and Critical Loads.