One of the crucial issues in designing rigid joint of beam with I section to HSS column, is the necessity of the continuity plate presence at the joint place.
Up to now three common methods of stiffener installation have been used. In the next part we will explain how to execute these methods.
All methods of stiffener connections have important technical and executive drawbacks. These are the most important ones:
  1. too much welding and weakening of the section,
  2. long execution time,
  3. difficulty in execution 
  4. wasting materials.
Through diaphragm connection
Through diaphragm connection
Through diaphragm consists of two stiffener plates in the connection place which passes through the column and divides it into three pieces. After the installation of diaphragms, columns will be re-installed and re-welded in their positions.
 
Internal stiffener connection
There are several methods for execution of internal stiffener:
  • Cutting one face of column (to access the weld).
  • Using of robotic welders.
Internal stiffener connection
 
External stiffener connection
External stiffener connection
In this kind of connection, stiffener (as plates around the column) is designed in such a way that in addition to fully-transfer the forces resulted from beam to column bend, it prevents column local crippling too.