Modeling Aspects of Steel Trusses and Warehouses in Autodesk Robot: A Comprehensive Guide

[@calvoh9715]

This is the best channel to learn a software, i wish i could subscribe 1000 times. I don't understand how DECODE has many subscribers but the way he teaches softwares is purely user interface not how you teach it, that is, how the software behaves, thinks, operates, correcting the errors and making the software behave as you want it in the analysis. Kudos man.

[@CivilEngineeringEssentials]

Thanks a lot for the comment ^_^ It encourages me a lot to give it my all. Well, in my opinion, it is more important to understand why things happen rather than to understand how to do things ^_^

[@WaqasKhan-r6r9u]

So much knowledge in a single video. So grateful to you for this. Would definitely recommend this channel to others for learning structural engineering in RSA.

[@joharyramarolahy842]

Thanks for your insight on my inquiry, as you answered most of it ( my question is not as clear as it should be), but you led me on the way, as far as trusses are concerned I think you have to design fixed bracing when stabilizing in Robots because of the assumptions made by the software itself(hence there will always be a type 2 instability during analysis). I was just bugged by a theoretical rule that the bracings connections have to be pinned to avoid moments transfer in the elements wich is not realistic as you mentioned in your answer. Again thank you for sparing some time on my doubts. Keep up the good job CEE Team!!!

[@CivilEngineeringEssentials]

Most welcome. Happy it helped you 👍 Stay tuned for more content, and plz suggest this channel to ur friends

[@niisarpei3676]

Kudos 💯 Sir. I am always learning new things from your tutorials and understanding how the software behaves. For my truss depth, I usually stick to span/12-18 and truss bays not greater than truss depth and not less than 900mm I love how you model instabilities into your models and later correct them for our learn sake The instability issues in RSA coupled with the GUI is what puts a lot of new users and beginners off or in a steep learning curve. I’d personally investigate for myself, however I wish you could later in subsequent tutorials unless it’s an advance tutorial, consider applying member offset to the purlins since in reality the purlins sits atop the trusses and the roof braces beneath the top flange of the top chord. The use of member offset tool is tricky to new users including myself. Kindly throw some light on it Thank you Sir Enjoy your weekend. Regards.

[@CivilEngineeringEssentials]

Thanks for your comment, I am really happy you enjoy those videos. Your span to depth ratio does make sense. I personally stick to such ratios too. However, I wanted to mention a referenced suggestion from the AISC as there is also an educative element in the videos. As for instabilities, as you have noticed, yep, usually stabilizing structures is a challenging task, and I want in those videos to tackle those challenges head-on so that others benefit from the thought process, rather than modelling a perfect structure with no flaws. As for member offsets, I will keep it mind. Bracings are indeed connected eccentrically from the center of the truss chords, and would contribute to the torsional forces when loaded horizontally. It is a technical topic, I will explain it as soon as I can. Thanks again and regards, CEE

[@niisarpei3676]

@@CivilEngineeringEssentials keep up the good work sir .

[@sothattheng8624]

Thanks for your sharing! your VDO is very useful for young Engineer like me learn how to use Robot program.

[@CivilEngineeringEssentials]

Glad you liked it. Stay tuned, there is a much deeper video about the same topic coming up next week. if you like it, help share the word by recommending this channel to your friends. It helps a lot. Regards, CEE

[@walshi2292]

Very nice simple and clear thanks

[@CivilEngineeringEssentials]

most welcome. Glad you liked it.

[@mwangibenson5199]

i think if you have 4 released members intersecting robot may give an instability warning but this worked out very well for you

[@CivilEngineeringEssentials]

Yep. Actually, this video is what encouraged me to do a full series to explain all aspects in detail 👍

[@mwangibenson5199]

@@CivilEngineeringEssentials great & good job

[@toumsid]

Excellent video

[@CivilEngineeringEssentials]

Most welcome. Stay tuned to more videos. There is a "Industrial Warehouse design series" at the moment on this channel, check it out Regards, CEE

[@fredthe52]

I very good clear explanation I like it thanks man.

[@CivilEngineeringEssentials]

Glad you liked it. Stay tuned for more videos.

[@vukvukanic1095]

Instructive video. Just to note, purlin deformation shape is incorrect when using "Deformation" to view it at 29:44. You can clearly see that they look like continuous beams at the top chord supports. I'm not sure why this is, but using "Exact deformation for members" seams to show the correct shape.

[@CivilEngineeringEssentials]

Great observation. As far as I know (and I am not 100% sure here) just showing deformation gives an approximate cubic polynomial for the deflection shape regardless of what the ends of an elements actually are. Thank you very much for the comment, it will definitely help future viewers. All the best, CEE

[@mikeotiz3610]

can you draw the truss in Y direction?, using the truss library you have used. When i try the truss automatically orients in X direction.

[@CivilEngineeringEssentials]

Sorry for the late reply. Of course, First, open the truss library, (Geometry -> Structure -> Insert from Structure Library -> Truss) Once the window pops up, you can see on its right side something called (Dimensions, More, Sections, Insert) If you go to the (Insert) Section, You can determine the angles alpha beta and gamma Alpha is the rotation around x Beta is around y, Gamma is around z. So if you want to flip your truss to be in y, you have to rotate the entire structure around the z axis, so try gamma 90 or 270. Hope it helped. CEE

[@anannurdin1883]

is there any video verifying om concrete frame? i keep getting error when designing analysis RC Frame

[@MatheusRibeiro-oi2yn]

Hi, first, thanks for all of your videos, helped me a lot to start in Robot :D I'm having a problem trying to model a cantilever truss. I'm getting really highs deflections values and i can't understand why. Have you already modeled something similar? Thanks adv.

[@CivilEngineeringEssentials]

I did not model a cantilever truss yet, but that is an interesting idea to cover. Still, a piece of advice for you is to imagine the truss as being a steel I-shaped beam (not joking, I am serious) You know that the beam's inertia is affected by: 1) the height of the beam 2) The flanges of the beam With this analogy, you can understand that the deflection of the truss is going to be affected by the height of the truss and the upper and lower chords of the truss. Try it out and tell me what you got. Regards, CEE

[@lokmen__]

Would offsetting the purlins above the trusses solve their intersection problem with the bracing?

[@CivilEngineeringEssentials]

Not really. But "Compatible Nodes" would. There is a video on this channel explaining this.

[@jasonRhawt]

I have a situation where I had to cut the existing diagonal and bottom chords truss and just keep the top. I then added two channels back to back attached to the top chord but robot keeps saying its overlapping how do I solve this?

[@CivilEngineeringEssentials]

First of all, if you click on the error itself, it will highlight where the two bars are overlapping. On the other hand, you cannot draw a double channeled LLBB section by simply drawing two lines. You have to choose the section from your section database (there exists combined Leg-Leg Back to Back LLBB) sections, as far as I know, and apply it on ONE bar only. Hope it solves the issue. Regards, CEE

[@joharyramarolahy842]

Hi Dr CEE, I'm coming accross a project with trusses rn and I remembered this video you made ( yes stabilizing Trusses are a nightmare), I would like to ask you if you kept the bracing unreleased then assume they are subjected to bending moments? I tried to release them with multiple configuration ( as far as it is a Truss Wharehouse not a frame one) and i can't get to stabilize it! I made an assumption made on that : -the bracing have to be unreleased due to the abscence of members able to take on the rotation of the trusses , Am I on the right direction or totally misunderstanding the problem ? Sorry to take you back to an old video. Thanks for the quality content.

[@CivilEngineeringEssentials]

No problem, you can always take me back to any video. The problem with "Trusses" in RSA is that they are basically assuming that all the connections at the truss nodes are "ball and socket" elements. Meaning, zero moment resistance. Now of course those resist moment. One trick we use in real life is actually to have the lower chord and upper chord be 1 singular element, meaning it will carry moments. Try that, also, you would need to x-brace the three principal planes, XY, YZ and ZX. As I usually say, stabilizing trusses is a nightmare, not because it is a challenge in reality (detailing), but because the calculation model we are using is a little bit "too simplified". Still, I think I did not answer your question sufficiently. So here is what I want to say - please write another comment if I still did not manage to answer it, I will definitely check it again. Coz if you reply, sometimes I do not get a notification -: If two members are being braced, the bracings are usually released because: A) the bracing can carry moments (so it has a section that is sufficiently stiff) B) the braced element (the one that is being braced) can carry moments as well C) the connection between the bracing and the braced transfers moment So yes, theoretically (not talking about practical stuff), you can decide to release or un-release anything, but this will have a reflection as I mentioned in A B C. Regards CEE

[@sultanabulteif8592]

Why you didn't do any offset ?

[@CivilEngineeringEssentials]

I simplified the analysis a little bit. Since I assumed the purlins are simply supported, the differences are minimal. There is a longer explanation of offsets in the following videos: kzbin.info/www/bejne/nXTNlISIgbtrmNU&ab_channel=CivilEngineeringEssentials

[@BA-gp7sr]

Why did we model the truss using a a building design ? why didnt we use the 3rd frame desgin instead ?

[@CivilEngineeringEssentials]

Hi there, thnx for your question It's just a force of habit. Actually, Building Design provides you with slightly different members than 3D frames, but are the same nontheless. There is a full series on Warehouses. You can find it here: kzbin.info/aero/PLmw2x4fCMxg6qLYDAEfGVQ_sm2tgQAdGc Regards, CEE

[@aymanammar150]

thanks for your fantastic video I have one question where is the code parameter for this model?

[@CivilEngineeringEssentials]

Hi there, Most welcome. For that model, I used the American AISC code. Default parameters. Regards, CEE

[@aymanammar150]

@@CivilEngineeringEssentials thanks for your interest but I did not see any code parameters in this video can you tell me the timestamps for code parameters ?

[@CivilEngineeringEssentials]

@@aymanammar150 I mean, the only thing that was done is to choose the code from the job-preferences. I had a video about settings codes before. That is why those infos were not shown in this video. Regards, CEE

[@aymanammar150]

@@CivilEngineeringEssentials do you willl share this video with us or not

[@llLawkll]

Thank you for those epic tutorials, they are really helpful. i have a question regarding a steel frame i recently designed. it was a single column with 2 beams one in X direction one in Y directions, the column was a Square hollow section (SHS) and the beams were both small universal beams. the beams were obviously connected to the column and released to pin, since the connection is a fin plate welded to column and bolted to beam (thus pinned), and the column had a fixed base. i still got the instability warnings, all deflection and force and moment diagrams were good, no excessive numbers. and i tried nodal horizontal forces on the column and it was still deflecting normally. but i never knew how to get rid of the instability errors, and everything was fine. Question is, can we ignore the stability issues when everything checks out? even with horizontal forces? and why do you think in such scenarios would i get instability even though the base of column was fixed? Structure type was 3D Frame by the way.. Thanks.

[@CivilEngineeringEssentials]

Hello there, First off, thanks for the amazing comment. It encourages me to give it my best. Second: from what I understand, it seems you have modeled a 2D frame in a 3D structure type. The instabilities can be ignored since moments and deflections are good. However, of course this is not the answer you wanted ^_^ so allow me to elaborate, when you open 3D frames, Robot will consider the third dimension even if nothing is added there. meaning, robot will check also if the structure can "deflect, rotate, move" in the third dimensions, and warn you about it. Even if you do not have any loads in that dimension, a warning is still issued. That explains why the result checks out but the software seems to "freak out" Furthermore, another common type of "harmless" instability I face is the instability in the rx direction. if you release a beam from both sides, you are releasing its ability to rotate (allowing the rotation). if you check the 3D release, I think you would find rx ry and rz (I do not really remember, it depends). Releasing both rx's from both ends of the beam is an instability. Because you are allowing the beam to rotate around its own axis (kind of like what happens in the drive shaft of a car, if we ignore the fact that no rectangular HSS drive shafts exists ^_^) I hope that the answer sheds light onto your question. Feel free to follow it up in case I was not clear enough with that regard. I already recorded the video for Today's Friday. But I will try keep your instability in my mind for the next video. If the opportunity arises, I will elaborate on it. Regards CEE

[@llLawkll]

@@CivilEngineeringEssentials well explained, thank you, your information is much appreciated.

[@CivilEngineeringEssentials]

Great ^_^ if possible, help this channel by suggesting it to your friends and increase the reach by subscribing to it. Regards, CEE

[@DouglasBarreto-q7o]

EXCELENT¡¡

[@CivilEngineeringEssentials]

Most welcome. Stay tuned for more content. Also, if possible, please suggest this channel to your friends.

[@jasonRhawt]

I are the point of releases? and what is a moment release?

[@CivilEngineeringEssentials]

Moment release means that you ssume two elements to be connected in such a way that does not create any moment transfer It is basically a reflection of what the designer intends to design.