The joint face distance is the distance from centerline of joint to the face of the support of a beam or a column element. It is sometimes referred to as the panel zone. Since there may be negligible deformation in this zone, analysis based on centerline-to-centerline dimensions of such members may overestimate the actual deflections of the structure. Criteria > GeneralCriteria > Analysis provides a feature to account for the effect of this area of little or no deformation by allowing the user to specify that the joint face distance or a portion of it be considered a "rigid end zone". The rigid end zone is then assumed to be infinitely rigid. Member forces are always output at the face of the joint whether or not rigid end zones are considered.

Since rigid end offsets reduce the effective length of a member, only the length of the flexible part of the member is taken for stiffness calculations. The stiffness matrix is then transformed to a coordinate system at the joints [Ghali and Neville, 1989] (see Reference 7, in Section 3.7).

Since the panel zone may actually deform to some degree, considering the full joint face distance as the rigid end zone may underestimate the deflections. Criteria > General provides a feature for specifying a reduction factor for the rigid end zone length. This can be helpful to realistically model a member’s effective length that will not underestimate the actual deflections.

Member forces are always output at the face of the joint when rigid end zones are considered. For analysis runs where rigid end zones are neglected, RAM Frame gives users an option to print or display the results either at the joint centerline or at the face. RAM Frame does not consider rigid end zones for braces and walls.