RAM Structural System Help

Effective Length (ℓ/L)

The Eurocode values for ℓ/L is specified by selecting the Criteria-Effective Length menu command, or on a member-by-member basis using the Assign menu. The effective beam stiffness does consider the fixity conditions and is reduced by 25% if the beam is pinned at the end (closest node) away from the joint. The beam length is considered to be the distance from the joint to the closest node away from the joint. This length is not necessarily the full length of the member but could be the distance from the joint to the location where a brace or column-from-above intersects the beam. Columns pinned top and bottom are given ℓ/L values of 1.0 in both non-sway mode and sway mode. If a column is continuous but all beams coming into a joint are pinned, then η for that end of the column is assigned a value of 0.95. This results in a ℓ/L of 4.88 for a sway column and 0.96 for a non-sway column. Knee brace columns are assigned a ℓ/L value of 1.0 in the direction of the knee brace.