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Some beginner questions

Some beginner questions

Some beginner questions

(OP)
Hello all.

I've encountered a particular dilemma where I am unable to transpose my knowledge of structural analysis and design to the computer programs. I've used them a bit in school (undergrad), but never really got great results and therefore never really felt too confident about it.

I'm really looking to sharpen my skills so I've been messing around with ETABS and various online tutorials. The project I'm working on with this is really just a feeler, and if you look at my attached ETABS file you'll see its a bit sloppy. The main interest is the top floor (STORY3) where the goal is to add an opening in the floor for new stairs. If you look on the model, the stair opening is centered at about B5. My intent for this project was to model the existing floor (Fy=30 ksi steel, denoted by the suffix "-A" at the end of the member section), and then to create a set of Auto Select Lists to determine the best member section for approximate beam sizes that I have just ballparked so far.

This model I made here is not the entire floor, just the immediate area of interest. My goal for this is to familiarize myself more with the program, and I didn't want to model more of the floor than I needed to in order to keep the number of random variables down.

While I believe I have done this, when I run the analysis I get a number of questionable results in my shear and moment diagrams of my frame. For instance, the W16x45 beams that run between A&B and span across 3, 4, and 5 show no internal forces resulting from live load, although a uniform live load of 50 psf has been applied to the area above this slabs.

In addition to that, the distributed loads observed in the program do not correspond to the values of the uniform distributed loads applied. This makes me think that the paths of my forces is not defined correctly. How should I go about telling the programs that I want my slabs to be supported by the beams running in the x-direction, and then fed to the girders running in the y-direction which will finally be supported by the columns? I've tried setting the slabs as individual areas, one large area, changing the intersection point, and even messed with some mesh settings I don't think I quite understand.

If someone could please take a look at my file and tell me what I have done wrong I would greatly appreciate it.

I'm sorry if this is wordy and incomprehensible. I'm sure my problem is a simple one, I'm just not sure if I explained the situation well.

Here is the attached link: https://njitmikepugliese.sharefile.com/d/3648dc4e5...
Let me know if it works, I've never uploaded a file like that before.

Thanks a lot

RE: Some beginner questions

My friend, I did not check your file coz I was in rush, but to transfer the slab loading to supporting beam you have to define them as membrane in case on one way slab and shell system (along with meshing) in case of two way slab. After analyzing performed, you may verify the distribution of loads from Display< Load assigns

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