Hello Dr. CEE, You are correct, there is quite a lot to uncover on this subject; and I do think that the CEE is doing a fine job of this so far. Very nice discussion on the Global and Local stabilization. It will indeed be interesting to see how one may be able to effectively model these stabilizing assumptions into RSAP in as far as it is practically possible and in order to align the analysis and design model with “real-life” or anticipated behaviour. 12:30 Bracing connections. I agree with that most of these connection details are for the most parts “standard-off-the-shelf-details”. This is especially the case with local stabilization. I’d also like to add that the concept of bracing (stabilisation) is critical to the structure as a whole and so it (stabilization) will be as strong or as effective as its “weakest bracing connection link”. Therefore, it is very important for a user to get those bracing connection details right. 15:05 Built-up Columns. I am not sure if there is going to be an opportunity for a practical demonstration of these in RSAP somewhere on this series? I would have really loved to have such a demonstration. For me, built-up columns are not as common and I do think that it would be a good learning experience to also have a detailed demonstration of a case with build-up columns being used. This is a thought for the CEE consideration (if possible or if convenient, perhaps as an “academic example” or similar stand-alone demonstration?). Thank you for this video and I’ll see you in the next videos Regards, DK
Hi there Engr. DK, Actually, stability is one of the most important aspects to get right in modeling the portal frame. I hope I can reflect the concepts in robot (I am preparing to record a video tonight, with it being ready by tomorrow afternoon/evening). Bracing connections are kind of "meh", but for sake of completeness, I had a slide for them. As for built-up column sections (truss stuff), I had a chance once to do that. It was in a car-showroom made out of steel structures. It was made out of steel. Its height was really "high" as there was a central area open for all 3 stories to look down to (this is supposedly the grand jewel of the showroom, the latest Lexus SUV), with clear glass on all stories. Here is a "similar" car showroom from google maps: lh3.googleusercontent.com/p/AF1QipMqG63Te3iv41UyeAEIOKVIXUb7dSIiy2wLSIHk=s680-w680-h510 Note: It is only to show the front glass of the showroom, its height does not justify using built-up steel sections. Stay tuned, there is a FEM video being exported and a robot video being prepared. Next week I will slow down to my usual 2/3 video rate. This week was an exception as I had a longer public holiday, so I worked on this channel a bit more. Stay tuned, CEE
@@CivilEngineeringEssentials Thank you for the feedback, I imagine it must have been quite an experience with the central area 3-storey high columns you mentioned. This discussion does help to put a sense as to where and when such columns configurations may be more appropriate. I “see” also regarding the heights of the columns inside the “similar” dealership building that was referenced (I took a virtual tour inside the dealership showroom - Courtesy of the digital age 😊). Yes, the FEM video, what a weekend. I also had a sort-of a long weekend that is ending tomorrow. It seems that Workers’ Day (Labour Day) holiday is common to both our countries. Enjoy the holiday. I don’t really mind the video release rate adjustments every now and then. I noticed that there is order and reasoning behind your doing so; and that is fair enough for me. Keep up the good work. Regards, DK.
Hello Dr CEE Sir, I don’t know how I missed this session 4 days ago. I think the timetable for your video release has changed 😅. Anyways, I enjoyed this session. However, in the connection of the steel stanchion to the concrete stub columns via base plate, is the connection pinned because of the arrangement of the bolts only? It’s obvious the bolts where arranged parallel to the web plate of the stanchion. Would bolts arrangements parallel to top and bottom flanges mean the connection is fixed? As these bolts would be arranged perpendicular to the plane of major axis bending of the stanchion? Please clarify and thank you soo much God bless you
@@niisarpei3676 Hi there Engr. Ni, There was a slight modification last week. But I will be back to the usual weekly (almost) schedule where I release 3 videos 1) FEM video 2) Lecture in Warehouse 3) Application in Warehouse. As for the support, I understand your concern that: because of the support arrangement, one could think that the support is fixed. Because the bolts are spaced apart, and theoretically, if you have tension on the bolts of one side, and compression on the bolts of the other, you would - of course - get moment resistance. However, practically, there is a small technical difference between the support bolt and and steel connection bolts. Support bolts do connect a steel element with the soil. Now for tension to develop in the bolts of the support connection, the support itself should be held in place. This - for soil - would not be usually the case, as soil does not withstand tension. Now I see that you could say that the self weight of the foundation would provide the necessary tension, and I agree. That is the reason why I usually say: the assumption of fix vs pin is a designer choice and needs to be verified on site. Still, as I am referencing a reference in the lecture, I wanted to abide by what the reference is saying. Hope this clarifies the issue. Also, stay tuned, I will be recording some videos and would release them saturday and sunday (hopefully). Regards, CEE
Great video as always, look forward to the rest of the series. I’m designing a pipe bridge at the moment (warren truss with verticals, UC top and bottom chords, hot rolled hollow section other elements, internal framing to carry large pipes subject to quite chunky longitudinal and transverse force and moments) so any further content on trusses including detailing and connections would be greatly appreciated.
Hi there, thnx a lot for your comment. Sure thing, the video is being exported as we speak, you can expect a robot video tonight. For the truss bridge, I will definitely do this once the warehouse series concludes. It is a GREAT idea. Thnx a lot for the suggestion. Regards, CEE
Hello there dear Engineer, I am very pleased to know that you liked the series. It makes me proud and encourages me to continue this path. In case you liked it, maybe suggest it to your colleagues, it helps a lot. Regards, CEE
Thank you very much for the presentation, I am new to EC, Can you please tell me what is the latest available edition of EC 3 ? and give me reference link ? Thanks a lot....
Most welcome. It is a little bit different than ACI code. The entire ACI code has 1 release year and version. In the eurocode, different sections could have different release dates. Long story short, here are the latest version (As far as I know) EN 1993-1-1:2005 Eurocode 3: Design of steel structures - Part 1-1: General rules and rules for buildings EN 1993-1-2:2005 Eurocode 3: Design of steel structures - Part 1-2: General rules - Structural fire design EN 1993-1-3:2006 Eurocode 3: Design of steel structures - Part 1-3: General rules - Supplementary rules for cold-formed members and sheeting EN 1993-1-4:2006 Eurocode 3: Design of steel structures - Part 1-4: General rules - Supplementary rules for stainless steels EN 1993-1-5:2006 Eurocode 3: Design of steel structures - Part 1-5: General rules - Plated structural elements EN 1993-1-6:2007 Eurocode 3: Design of steel structures - Part 1-6: Strength and stability of shell structures EN 1993-1-7:2007 Eurocode 3: Design of steel structures - Part 1-7: Strength and stability of planar plated structures subject to out of plane loading EN 1993-1-8:2005 Eurocode 3: Design of steel structures - Part 1-8: Design of joints EN 1993-1-9:2005 Eurocode 3: Design of steel structures - Part 1-9: Fatigue Reference: eurocodes.jrc.ec.europa.eu/EN-Eurocodes/eurocode-3-design-steel-structures Regards, CEE
Hellor Dr. CEE, Thanks for videos. What about temperature loads ? How many degrees should we assign to model or should we ? It makes annoying consequences on the model
Hi there and sorry for the reply. I did not really look into that. But I think I should first add a video in autodesk robot basics explaining thermal effects first. So you basically just gave me inspiration for the next video. However, to kind of help you in your question: Usually thermal loads are applied as gradients, where the sun-side is hotter than the interior side. This thermal gradient causes the outside (in a sunny day) to expand more than the shady side, causing the beam to curve ever so slightly. Hope it helped somehow, Regards, CEE
@@CivilEngineeringEssentials Dear Sir, Even we apply a little temperature load , its cost are high for frame sections and restraint reactions. Is it really plausable ? Some experienced engineers say that they dont use temperature loads in their design.
Hello Dr. CEE, I was working on a project for Saudi Arabia, and the person I'm working for mentioned that we should consider the steel connection with 4 bolts to the foundation as fixed, not pinned. However, in the previous illustration, you depicted it as pinned. Could you please explain why you considered it as pinned?
Sure. The idea of "fixed vs pinned" is a discussions that is pretty much always gonna happen. So here is my personal opinion on the matter: First: the theory part: A fixed support means that 0 rotation happens at the ground level. This assumes an infinitely rigid support. A pinned support means that there is rotation. This assumes a totally free rotating support. Second: the practical part: In reality, there is no 100% rigid or 100% free support. It is always going to be a "relative issue". So since it is relative, what are the things that are relative? 1) The size of the column relative to the size of the foundation 2) The magnitude of the forces relative to the size of the foundation 3) ESPECIALLY the magnitude of horizontal and moment reactions at that foundation relative to its size. The opinion of our Saudi Colleagues is granted. Truth to be said, it is still a debated point. Ok, so why did I say "let me use pinned"? Since we established that the issue is a hotly debated topic, I went to the "more conservative" approach. But why is pinned more conservative? 1) More moments on the column (yes, it also makes the moment on beam a little smaller) 2) Columns bent into single curvature (needs extra safety when considering slenderness kl/r) 3) A structure that might have more side-ways movement, encouraging me to increase the stiffness of the columns a little. Of course, please note that, the only true way to judge if it is pinned or fixed is to do a "deeper research". The simplistic way to explain it is: Model the soil, model the foundation, apply the loads, measure the rotation, check if it is more than a certain "threshold" you put. If you want me to go deeper in the research domain, please let me know. I am more than happy to explain. Anyways, sorry again for the long reply. Regards, CEE
First of all, I would like to thank you for every single word you wrote. You are such a gentleman. Secondly, I would like to know more about modeling the soil and the foundation. I'm not sure if what I thought about is correct, but I believe you might be suggesting using software like Abaqus to model the foundation, plate, and soil. Then, we can mesh the foundation - connections, and apply the load to check the forces on each node. Is my understanding accurate?
@@aliomar6441 Hi there, so, a disclaimer first: for any practical considerations (real world applications), such a detailed analysis is not really needed for a simple warehouse. But here is the research/deeper modeling of it. Short answer: Yes, an abaqus model as you have stated would be great. Also a plaxis model. Long answer: Here is what I would expect from an MSc student to do: 1) Use plaxis/abaqus to model something called: "soil structure interaction" 2) Perform an iterative analysis. Why iterative? because the rotation at the support depends on the reaction. And the reaction depends on the rotational spring stiffness of the support, which needs the rotation, (circular) 3) Try find the equivalent rotational spring constant "a linear one" for the foundation. It means that: what is the rotation of the foundation (y-axis) compared to the applied moment (x-axis). From it, find the slope, which is the rotational stiffness of the foundation. Based on that, and on the maximum rotation, one could decide what to consider it. But of course, since we are doing some deeper analysis here, we are way past the "black and white / fix and pin" stage. For a PhD, I would go deeper to assume non-linear springs and deep foundations (something that a warehouse never needs) Also, I would consider the interaction between the stiffness of the steel column vs the stiffness of the RC foundation.
@CivilEngineeringEssentials, dear Dr., I apologize for my delayed response. Your idea is truly remarkable and has the potential to elevate the subject to a new level. Exploring (ISS) and applying its principles to the dynamic of structural systems is an intriguing concept. I've discussed this with my university advisor. Additionally, I'm contemplating delving into modeling the connections themselves, investigating microelements, and analyzing the stresses within. While I initially considered a more focused approach, I'm now convinced that every aspect of our profession ties back to the dynamics of structures. I'm eagerly anticipating further insights, especially in the realm of non-linear dynamics. Introducing non-linear damping systems and studying their behavior under seismic activity through time history analysis or evaluating wind pressures at individual nodes using CFD methods holds immense potential. There's a plethora of topics we can explore. I apologize for the lengthy comments, but I truly enjoy engaging in discussions with esteemed professionals like you.
Hello if you can leave the references of your work because I check the link in the description and I think I should pay for it , i don't mind but how we can do it ?
can you check this direct link to the file? www.steelconstruction.info/images/9/90/SBE_SS2.pdf does it work? if it does not, then I will upload it myself on my google drive. Regards, CEE
