[CIVIL NX] Truss Element vs Cable Element – MIDAS Support

Question

How are a truss element & a cable element considered?

The main differences between these elements are tabulated below :

Feature	Truss Element	Cable Element
Sag effect	No sag A truss element is generally linear and has constant stiffness.	Sag is predominant Cable elements are inherently non-linear, and their stiffness changes with the applied load. Hence, consideration of sag becomes important.
Load combinations	Superimposition is possible Linear combinations of load cases can be used to compare truss force results.	No superimposition is possible Since cable elements are non-linear by nature, the superposition of load cases is no longer valid, and the combined effect of the loads must be considered.
General usage	It is used for both cable-stayed bridges and for modeling struts and ties in general bridge structures.	It is effective in the case of cable bridges, i.e., suspension and cable-stayed bridges, where large deformation effects cannot be neglected.
Usage in cable bridges	For the preliminary design of cable-supported bridges, the cables are idealized as equivalent truss elements. The analytical model is then evaluated to verify that the truss stiffness is adequate to sustain the initial dead load.	A more detailed analysis may require modeling the cable elements. In this case, a geometric non-linear analysis must be carried out, and the cable's elastic catenary behavior is considered.