WARNING OF "ZERO SPECTRAL ACCLERATION ENTERED FOR MODE 1 TO 6"

i have prepared a model, where I am getting the warning of "Zero spectral acceleration for mode 1 to 6. besides this, there are warnings of instability. I have thoroughly checked the model for any modeling...
ram concept - stiffness of overlaying beams

I'm trying to analyze a waffle slab by modeling ribs using orthogonal beams cross passing each other (please see the snip). All beams have the same priority (5) and the slab has priority (1), does the...
STIFF parameter comments in AISC 360-16

I m using STIFF parameter comments in AISC 360-16. How can I check the distance between transverse stiffeners is adequate in the plate girder design? In TracK 2 results unable to find out.
RAM Elements 2023 Update - Shell Stiffness and Flexible Diaphragms

With the latest RAM Elements update, it is possible to independently define bending and membrane releases and stiffness modifiers. I played with this new feature a bit today to mimic flexible diaphragm...
Which method does staad pro follow stiffness matrix method or finite element method?

Which method does staad pro follow stiffness matrix method or finite element method? Pls inform regarding frame and plate elements which method is considered for their analysis.