Tension Only member with initial axial capacity

Question

Hello to all, 
 In reality horizontal braces (or vertical brace, beam, etc) that is design for tension only resist "some" axial compression capacity. 
 Is there a way that this axial compression capacity can be input in STAAD? 
 
 For example, a horizontal brace design for tension lets say, L100x100x10 has an axial compression capacity of 120kN. (based on your calculation, tables, experience etc) 
 Then what you will do is to input this 120 kN axial compression capacity of member that is design for tension only. 
 Case 1: If STAAD output force is more than 120kN, then the member will change its axial compression capacity to zero (tension capacity remains) 
 Case 2: If STAAD output force is less than 120kN, then the member will have both axial compression and tension capacity. 
 
 Thanks

Sye · Answer

Capacity cannot be input. This is calculated by the software and is based on the design parameters input by the user. For the scenario you mentioned, it would be more appropriate to specify these as TRUSS members which can take tension as well as compression. In that case the member will be checked by STAAD.Pro for both TENSION and COMPRESSION. If the member passes the code check, you automatically know that the actual force in the member is less than the capacities in compression/tension.