The Merge Member command is used to automatically join members to create a single member.  This command can be used to merge more than a single member at a time.  Members to be joined into a single member are found by searching the current selection for all members that are of the same section type, a collinear, are rigidly connected and are off the same component type .To join members in a structure

§    Select the members to be merged

§    Choose Merge Members  from the Advanced submenu in the Geometry menu

Groups of members that meet the above requirements will then be merged into a single member. In most cases the distributed loads applied to the merged member will also be merged to form continuous loads along the member. The user should carefully review the design properties of the merged members.