For analyses which involve members that carry axial loads only (i.e., truss members) there are two methods for specifying this condition. When all the members in the structure are truss members, the type of structure is declared as TRUSS whereas, when only some of the members are truss members (e.g., bracing members in a building), the MEMBER TRUSS command can be used where those members will be identified separately.

In STAAD.Pro, the MEMBER TENSION or MEMBER COMPRESSION command can be used to limit the axial load type the member may carry.