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January 2, 2014

How does RISAConnection design HSS columns with Shear Connections?

In RISAConnection v4.0, for the Wide Flange Beam Shear Connection to HSS Column, there are three connection types:

  • Shear Tab
  • Double Clip Angle
  • End Plate

The Shear Tab connection can be designed as either welded directly to the face of the tube, or inserted through a slot in the tube as a through-plate. While using a through-plate can be prohibitively expensive, it does eliminate the need to check the column for Punching Shear and Flexural Plastification. Therefore if these limit states are failing in your RISAConnection model try enabling the through-plate option. The design of the weld is made easier with the through plate by eliminating flexure on the weld since the moment due to eccentricity can be resolved as a couple of longitudinal forces on the welds.

HSS Shear Connections 01

The Double Clip Angle and End Plate connections required some code interpretation on behalf of RISA’s engineers. One major issue with connection design is that most engineering papers and example calculations ignore the presence of axial force (and sometimes even eccentricity) in shear connections. RISAConnection considers both axial forces and eccentricity for all shear connections, which has necessitated the “filling in of gaps” in the design code.

Consider the connection below, which features an axial compression in the beam:

HSS Shear Connections 02

In this case, RISA draws a parallel between the way the clip angles attach to the face of the column, and the way an HSS branch would attach to the face of an HSS chord in a truss. By using this comparison the column can be checked for Wall Plastification and Shear Yielding (punching) caused by the axial compression, using the dimensions of the clip angles in place of the branch dimensions.

HSS Shear Connections 03

The moment due to eccentricity cannot be ignored either. When the chord/branch analogy is applied to this connection the column can be checked for Wall Flexural Plastification and Sidewall Local Yielding where the moment capacities are compared against the net moment caused by both horizontal and vertical eccentricities on the connection.


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This entry was posted by RISA News on Thursday, January 2nd, 2014 at 8:45 am and is filed under Technical Solutions. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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