Steel Interchange

Minimum Connection Depth

Answer

Chapter F in the AISC Specification states "The provisions in this chapter are based on the assumption that points of support for beams and girders are restrained against rotation about their longitudinal axis." That is, the Specification requires the rotational support must be provided at supports. It is common practice to provide a connection with depth at least equal to T/2, as recommended for all the framed connections in Chapter 10 of the AISC Manual, to ensure that the proper restraint is provided. It may be possible to provide the required restraint by other means, but the half-depth connection has become a de facto requirement.

Larry S. Muir, P.E.