The release of RISA-3D Version 19 includes the introduction of Yield-Link® Moment Connections, developed in conjunction with Simpson Strong-Tie®.
The Yield-Link® moment connections are precision-made to meet the tough demands of structural steel construction. From building owners to engineers, to contractors and fabricators, the Yield-Link’s state-of-the-art fuse technology and design tools save everyone time and money — while providing a connection that keeps structural steel buildings strong and safe.
The Yield-Link® moment connections are available in three stem thicknesses, 1/2", 3/4" and 1" and come packed in a kit with the necessary accessories including the buckling restraint plates and spacers. Additionally, the connections are completely bolted at the jobsite and all field bolting is approved as snug-tight with the exception of the Yield-Link-to-beam flanges and sloped-beam application.
Within RISA-3D these connections can be specified as Member End Releases for steel moment frames. To specify, click on the ellipsis button next to either the I or J release to open the Set Member End Releases dialog.
The Simpson Yield-Link® release code is located at the bottom of the dialog and when enabled the user can specify the desired Yield-Link® from the dropdown. When choosing a specific Yield-Link® to use, the nomenclature for the definition of the release is as follows:
Where YL4 represents the Yield-Link® stem thickness in eighths of an inch (ex. 0.5” = 4 x ⅛”) and 2.25 is the width of the yield link (in inches).
During the specification of the Yield-Link®, additional geometry checks will also be performed in order to ensure that the Yield-Link and beam are compatible. These checks include:
Beam Flange Thickness
A few additional things to consider when using Yield-Links in RISA-3D:
Yield-Links® must be defined on Hot Rolled Steel, Wide Flange, Beam members only.
Wide Flange shapes must be W12 thru W36
The minimum permitted beam depth is W12 for YL4 series, W16 for YL6 series, and W24 for YL8 series
If a Yield Link® is defined at only one member end, the other end cannot be Fully Fixed or Custom Releases.
If a Yield Link® is used at both ends, the Yield-Link® specified must be the same.
Once the Yield-Link® member end release is defined, the software will automatically calculate the rotational stiffness of the connection to be used in the solution using the following equations:
With the Yield-Link® defined, the wireframe model shows the member end release condition applied. The display looks the same as custom end releases in the Mz direction, which is the same direction where the Yield-Link® rotational stiffness is applied.
The solution for the model can now be run and the results for the member design, taking into account the Yield-Links® can be evaluated. To do so, select the beam and open the Detailed Report to see the Yield Links® included as the I/J releases.