At one point RAM was not calculating diaphragm forces and taking these forces to the frames from a sloped semi-ridged diaphragm. Has there been an update so that it now applies loads from a semi ridged diaphragm to the frames properly? Are there any specific settings that I need to update in order for this to happen? I know that I will need to include all of the diaphragm properties (in this case a steel deck).
Thank you.
The diaphragm forces were always calculated for sloping semirigid diaphragms. However, the way that the loads are applied can cause unintended behavior and lead to odd results. See the frequently asked question, "How do sloping semirigid diaphragms affect the analysis?" on the web page below for more discussion:
http://communities.bentley.com/Products/Structural/Structural_Analysis___Design/w/Structural_Analysis_and_Design__Wiki/ram-ss-semirigid-diaphragms
The primary sources of unintended behavior are:
1. Lateral loads and mass are always applied in the global XY plane. For sloping semirigid diaphragms, there is always a component that acts out-of-plane of the diaphragm. This can lead to large displacements and low frequencies, particularly for flexible semirigid diaphragms.
2. The in-plane stiffness of the sloping semirigid diaphragms has a vertical component. This can cause the diaphragm to act a deep beam element, particularly for large slopes, and reduce moment and shear in the beam framing.