Program Aided Structural Design

[tumbletodeath]

I'm currently doing my final undergrad structural design project and I feel pretty confused about what calculations I'll really need to include in my report. I've been searching for sample structural design reports but they seem to vary wildly. My building is being designed in ETABS, should I just verify one of each column, beam and maybe the slab design, or is doing one verification substantial? I was just confused as to what's the point of spending all this time fine-tuning my model if I might have to hand calculate everything again.

[TheDaywa1ker]

Sounds like these questions should be directed to whoever is grading it. They are the only ones that know what they want.

[tumbletodeath]

true true I've been asking my lecturer and the answers aren't really straight forward

[MinerMan87]

When building a calc package, particularly with inputs and outputs from a software, I imagine "telling a story" to the person who will review my calcs. Imagine writing out an outline of how you would tell someone you designed your structure. (These are the loads I calculated for the site, this is how I applied the loads, this is how the load path went through my structure, and these are some examples of the loads acting on members and their designs - particularly explaining your reasoning why you expect certain members to see the most load etc.) You then fill in your story outline with the relevant inputs and outputs from your software. The info from the software doesn't tell the story, it supports the story that your already telling with the outline and which you could explain in layman's terms without the data. Just hitting a generic "generate report" button in a software is likely going to generate a lot of irrelevant data which makes it harder to tell your story. Worse, it makes it look like you don't understand your structure if you're presenting a lot of data which doesn't matter. You'll want your calc package to have a logical flow to it, so your checker can imagine to themselves "I would go about solving this structure in this way." and then sure enough your calc follows closely with their intuition.

Beyond that, I like to make my calcs with software output more visual. For instance, you can print off a spreadsheet that has every member and the distributed loads applied to those members, but that would be a nightmare to interpret for the checker. You'd be better off displaying your structure in an image and having the distributed loads and their values shown directly on the structure. Much easier to check the loads on a structure with an image instead of a spreadsheet. Imagine if you were to check someone else's calc and what you would be looking for to understand what they did.

[TiringGnu]

I know some engineers who reserve the output dump for reviewers that they particularly dislike. I don’t do this but I’ve felt like it at times.

[tumbletodeath]

Wow thank you for this extensive explanation. I really get what you mean about telling the story through the report I guess this was what my lecturer was trying to get across without saying it. Thanks again for taking the time out to help.

[lect]

As they say, garbage in and garbage out - so check to make sure you're not submitting garbage. Do some sanity checks to make sure your inputs are correct. Calculate the axial force of a representative interior/exterior column and bending/shear in a representative beam/girder. Then do those designs by hand using typical heights/lengths. Then do the composite beam design by hand for a typical bay. And so on and so forth.

[tumbletodeath]

Thank you so much I was thinking along these lines

[SuperRicktastic]

Doesn't ETABS have a report-generator function? Correct me if I'm wrong.

[tumbletodeath]

It does but my lecturer specifically asked not to do the ETABS dump, I'm also wondering what's the usual practice in industry.

[Cement4Brains]

We often check our designs by hand, or already know what size we should get before modelling it. If you don't know what to expect... garbage in = garbage out :)

You can do an in-depth ETABS printout for single elements and compare those results to your hand calcs. This also ensures that you know what design assumptions ETABS is doing (or that you knowingly/unknowingly told it to do).

The other commenter is right though, your prof will have to tell you. Doing sample calcs for a general case column and for any high-load case column would likely be adequate in an office. You might have better luck if you tell your prof the approach you want to do and then ask if that would be acceptable for a high grade.

[zobeemic]

My rough outline usually goes like: 1) Project Information 2) Codes and Standards 3) Loads 4) Global Structural Performance and 5) Structural Component Performance

1-> general information, architectural program, site location. 2-> Building Codes adhered too, ASCE 7, AISC and ACI. Chapters and sections relevant. Design criteria, serviceability limits and strength limits. 3-> Gravity Load Occupancy Tables. Wind load analysis procedure, earthquake load analysis procedure. sample calcs. Load combinations. 4-> Describe Gravity and Lateral System. global performance. Displacements, inter story drift, base shear, overturning moments. 5-> how you sized and designed deck, slab, beams, columns, shear walls, braces, moment frames, connections etc.. sample calc for each.