Hello,
I have recently picked up RAM SS and have run into some issues. I am trying to design some slender columns in Ram Concrete Column, but get the following output:
Column is SLENDER
Major Axis Capacity MRdy = 0.00 kNmMajor Axis Capacity Ratio MEdy / MRdy = infMajor Axis Capacity < Major Axis Moment NOT OK for moment resistanceMinor Axis Capacity MRdz = 0.00 kNmMinor Axis Capacity Ratio MEdz / MRdz = infMinor Axis Capacity < Minor Axis Moment NOT OK for moment resistance
Does this mean that the program cannot design slender columns to the Eurocode?
Can you send your file? I am getting results in a test file for a slender column, EN codes, version 16.01.00.20. There may be a point at which the column becomes too slender to give capacity results. Secure File Upload
Done. I must say I am not particularly interested in the upper floors, as they will be done by others. I am also unsure as to the column boundary conditions in the lowest level. I want to use the Foundation Loads feature of RAM Modeller to get my reactions, but since the columns effectively only run through the slab, I don not know how to get accurate results.
I spot checked one column in your file, using version 17.00.00.93. It's slender and fails because the Effective Length factor (K factor) is 4.0. In 2-way slabs systems, it's important to assign the Effective Length factor (in the analysis mode). because the program can't properly calculate it absent beams. I assigned 1.0 as a test (not a confirmed value) and the column I originally spot checked then works fine. You might also want to review the Sidesway criteria for this file.
Answer Verified By: Asen Filkov
That's great, thank you very much! Would you be able to advise me how to assign the fixities of my columns at the lowest floor, assuming there will be piles underneath (the columns are as thick as the slab). Right now, I have pinned them at the bottom and fixed at the top and done the opposite where I have ground beams; I am not sure if this configuration gives accurate shear force reactions.
That's a judgement call, but a short column that is pinned-fixed seems reasonable. With lateral columns you can have a finer control thru the use of fixed column bases in conjunction with foundation springs (assigned in Ram Frame) if you feel that is necessary.