RE: Wind Loading for Open Structures

Please refer to the following wiki

communities.bentley.com/.../2042.staad-pro-load-generation-faq

Applying the wind load to a group should work for Open option as well. For example define a group consisting of specific members

START GROUP DEFINITION
MEMBER
_LEFT_FACE 1 4 6 9 12 14 27 28 32 33
END GROUP DEFINITION

Now apply the open structure wind loading to the group using the editor
LOAD 4 LOADTYPE None TITLE LOAD CASE 4
WIND LOAD X 1 TYPE 1 OPEN MEMB _LEFT_FACE