RAM Structural System Help

Frame Type Selection

One of three frame types can be specified for the design of concrete beams and columns: Ordinary Moment Frames (OMF), Intermediate Moment Frames (IMF), and Special Moment Frames (SMF). The Frame Type is selected from the Frame Type option under the Criteria menu and is applied to all the lateral members in the structure. The gravity members are always designed as OMF. Similar to the Load Combo Generator, the selection of the frame type in either the beam or column mode will change the option for both modes.

When the IMF or SMF option is selected the user has three options for the gravity dead and live load factors used to calculate the minimum shear capacity of the beams. This is due to a discrepancy between the ACI-318 99 and certain building codes such as UBC 97. Per the ACI commentary in R21.10, the ACI factors for IMF and SMF are taken from Equation 9-2 with the lateral loads ignored.