Web crippling in steel members

Web crippling behavior: Web crippling failure is likely to happen when large concentrated forces are applied to thin-walled flexural members. American Iron & Steel Institute has defined four different crippling condition based on the location of failure (interior or exterior) and the number of loads involved (one or two). Figure below illustrates these conditions including Interior-One-Flange (IOF), Interior-Two-Flange (ITF), End-One Flange (EOF) and End-Two-Flange (ETF) .

Another important thing is the size and position of web openings. Nowadays, web openings are common in structural design. The crippling strength of the web depends significantly on the position and size of these openings. Figure below is related to an experimental study of web crippling. As you can see in the picture the presence of holes has caused a significant change in the amount of crippling load.

However several experimental formulas have been suggested, they are usually applicable only for a certain type and size of sections. As usual, verified finite element models can be a reliable source of prediction for web crippling stress of different cross sections. I am going to provide a video lesson soon to show you how to model the crippling behavior of steel members.