Geometry ribbon tab, select the
Add Beam > Add Beam Between Mid-Points tool in the Beams group.
The mouse pointer changes to the Add Beams
Click on any point along the first beam where the starting node of
the new beam will lie.
A new beam member is "rubber banded" to this
Click on any point along the second beam where the end node of the
new beam will lie.
New nodes are created on the selected beams at their
mid-points and a the new beam member connects these two new points.
Repeat steps 1 through 3 to continue adding beams.