How does the program identify a joint and the chord and the brace member in a joint?
The joint, the chord and the brace members are identified automatically by the program.
A joint is being considered between any two members. The program will apply the +/- 15 degree rule (refer clause 4.2.4 of the API 21st edition code) to determine the members in a plane and then determine the joint as being the intersection point of these members.
Out of the two members forming a joint, the Chord member will be taken as the one with the larger diameter and the other will be treated as a brace. In case of members with equal diameter, the one with the thicker wall will be considered as Chord Member. In case of members with equal diameter and thickness, the most horizontal member will be taken as the Chord Member.