What are Web Doubler plates used for in RISAConnection?

For moment connections in RISAConnection there is an option to place web doubler plates on the column web. These plates act as a reinforcement for the column web to prevent panel zone shear failure. As shown below, when the flanges of a beam in a moment connection connect to a column they form a force couple which causes the column to kink.

If the column web is too thin to handle that kink then it will fail through tearing or buckling. In order to prevent this failure on connections which have a high amount of panel zone shear you can use web doubler plates. These plates are applied directly to the web, and welded all around.

When using these plates they are considered to increase the column web thickness, which in turn increases the panel zone shear capacity significantly. As an engineer be sure to use these web doublers only when absolutely necessary though. They are very expensive to fabricate, and often a design featuring a column with a thicker web is ultimately cheaper.