I don't really understand the purpose of what you're trying to do... But anyway, try something like this:
DATA: fieldname TYPE string.
FIELD-SYMBOLS: <field> TYPE ANY.
LOOP AT oref_struc->components ASSIGNING <gw_wa>.
CONCATENATE '<gw_itab>-' <gw_wa>-name INTO fieldname RESPECTING BLANKS.
ASSIGN (fieldname) TO <field>.
<field> = <gw_wa>-name.
ENDLOOP.
INSERT <gw_itab> INTO TABLE <gt_itab>.