Modeling of Basement Walls in Autodesk Robot | Part 1: Modeling Process
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- เผยแพร่เมื่อ 30 ก.ค. 2024
- Welcome to the first part of our two-part series on modeling basement walls in Autodesk Robot! In this video, we'll be taking a look into the modeling process for basement walls, providing you with a comprehensive guide to creating accurate and efficient models. Whether you're an engineer, architect, or construction professional, this tutorial is designed to help you master the art of basement wall modeling using Autodesk Robot.
We'll start by creating and editing wall elements, including defining wall thickness, height, and other key properties.
This is the first part of a two-part series, so be sure to subscribe to our channel to stay up-to-date on the latest videos. Whether you're new to Autodesk Robot or an experienced user, this tutorial is sure to provide you with valuable insights and techniques for modeling basement walls. So, let's get started!
Links:
Structure: drive.google.com/file/d/1me5Q...
Original Video watch/?ref=s...
Current Video Ideas for the Future:
- Full Structure with mesh and twisting.
- Advanced Mesh Options
- The Dynamics Series: comparative analysis between robot
- Circular Arrangement of Reinforcement
- Highway Bridge
- Watertank with non-linear hinges.
- 3D elements in Dams or soil-structure interactions
- Basement Walls and the discontinuity of loads on columns
- Influence Surfaces
- When and why modal mass is always 90% or less.
- Tie beams in normal structure.
- More details about modal participation / report?
- Masses and stiffnesses to control modes
- LL Reduction in ACI/ASCE (vertical and horizontal)
- A possible way to model columns with pressure areas
- Deeper dive into slab reinforcement.
- Raft with larger thickness and positions
- Robot - seemingly - erratic deformation when supported by beams and columns
- A way to manually “clean-up” simple mesh like the above
- Wood and Armer Moments in Slabs and their meaning
- Complex and Principle results
- Simple TBM tunnel lining analysis in robot
Timestamps:
0:00 Introduction
0:32 Quick Look on Basement Walls
1:51 Other Types of Walls
5:28 Supporting Basement Walls
9:27 Modeling
24:01 Loads
27:52 Analysis and Results
Hello CEE,
PART I
I must say that the video intros and their original videos links showing the “real-life” and/or the “overall/overview” of the concept of the tutorial of the day are a welcome addition. They help a lot to set the scene so that it is much clearer as to what the bigger picture for the day is. Thanks for these and keep these up.
The background information and key concepts lecture part of this video which covered the various types of walls, their similarities and differences, the different kinds of connections in a basement wall, the idea of an integrated column v/s a separated column, storey height v/s basement height was content rich and it was very enlightening for me. The information on these parts helps me to be able to comfortably navigate and appreciate various assumptions necessary in the modelling and design of the basement walls. Because of this information, I can be able to work with other types of basement walls beyond the exact example that was used in this video. Thank you CEE for always adopting such a holistic approach.
Question @ 09:03 - In case one decides to use the option of a separated column, would the GAP not be subject to “expansion and contraction” of the concrete on the basement walls on the LHS and the RHS of the column? Shouldn’t the gap then be filled with compressible filler materials to allow for such expansion and contraction to occur? What is the typical width of such a gap in a typically spaced columns arrangement?
I think that the “contraction and expansion” coupled with “the need to stop water and soil ingress” makes for a very challenging construction details on this GAP, what are your thoughts? In any case, would it not be inevitable that there be at least some contraction and expansion joints (gaps) in a long and continuous concrete structural element like a basement wall?
11:15 😂🤣😂, I also think that we should explore both walls and shells so that one can decide when is it more beneficial to use a wall or a shell model and visa versa. I am glad that this is the route that is being taken in this video.
13:14 Nice catch 😊 [Yes, you are correct, mathematically speaking, the “area” term in equalish areas everywhere will always cancel out, and the calculations can be effectively taken as just the number of stories x by the sustained load action, nice catch and thank you for sharing, it can be sometimes difficult to spot these simplifications when one is overwhelmed with the crunching of the numbers, it is really good to have someone like you to guide and to remind]
Question: When estimating the foundation load or “service sustained load”, are we talking about the ……“Sustained Vertical Load” which equals to the “total nominal self-weight of the building” including partitions and permanent equipment and the sustained portion of the imposed vertical loads (usually 25% to 30% of the imposed (live) loads depending on the code of practice that one is using…….?)
13:34 Video ideas suggestion for the future: I propose a deep dive video on how to properly estimate “Tangent Elasticity” Kx and Ky kN/m3 for rafts. And even how to estimate the rotational elastic coefficients HX, HY, HZ (kN*m/Deg) for elastic supports. I currently find these to be a challenge and I think that the CEE can help to unwind these life mysteries 😊. I know instead of using Kx, and Ky there was a time where a “stabilizing support” was applied in the beams on elastic ground foundation video…. how important are these factors? Can one “ignore them” and use stabilizing supports and dummy values in detailed designs?
13:50 😁😁 on the model type…you are not alone there …. Autodesk should really look at allowing users to choose a default model type that will appear all the time …. Unfortunately, I can’t say the same thing about the thickness, Mr. Editor is correct, LOL that one is all on the n000000b!!, Autodesk is innocent.
15:36 I’ll speak for myself here. I have never had any problem with the CEE balance on all the past videos. I actually prefer and like it when CEE focuses on the new.
I think the fact that CEE refers to and also links detailed and applicable previous videos for those who may not have yet watched a certain subject matter for reference is more than enough accommodation for those individuals.
Unfortunately, and like most things in life, there will always be steps and elementary knowledge that is required in order to carry out certain tasks efficiently…. one must first learn how to walk before they can run; you shouldn’t learn how to walk at a sprint running Olympics event…. [this is my opinion; anyone should feel free to disagree and express their opinions].
The comment is continued in PART II
Hi there Engr. DK,
Happy that the video got some positive feedback from you. It helps not only me, but all other viewers as well.
Indeed, the Editor started including those things whenever he starts talking about something new that is not theoretical in nature.
The background infos discussed are something I see forgotten about, only to be included in a last minute effort, causing some serious hassle.
The gap is indeed filled with expansive water repellent filler material. Still, I want to state the following: Do not do this ^_^ It is - in my humble opinion - a 1000 times better to have it an integral part rather than separating columns from walls. It is only headache. Still, true to the nature of this channel, I try to cover all possibilities.
The rule of thumb is usually 1inch. But please note that this is not a rule set in stone, as we engineers can always deal with any case that arises.
About 11:15, allow me to tell you, you gonna get an enlighting revelation in part 2. BTW, I already recorded it and finished editing it. I really really want to include your comment in it, but it is already finished editing. So please wait, part 2 is gonna hit all people hard.
About the sustained loads, yes yes yes. I 100% agree. The load is kind of similar to what you would use in earthquake loads. This is OW + sustained load + % of your live load. I missed mentioning this. To my defence, I try to be code neutral.
(Hi there CEE Editor here, I usually do not write comments but the recorder guy just plain lied to cover up his mess-up.... what a n00b).
The idea of diving deep into the foundation is something that is already overdue and should be covered ASAP, I guess I will add it into my ASAP list. thnx a lot for your suggestion. Yes it seems to be a mystery at first,, but I guess I can do some magic there.
I keep messing up my model type, only to discover after some frustration that I messed it up.
It is a challenge to be honest to kind of balance having a fast paced youtube video vs providing just enough details.. It is really a hard balancing act.
Part II cont'd
@@CivilEngineeringEssentials
Hi there CEE,
Thank you for the comprehensive feedback, I can gladly confirm that you are definitely not missing anything and that you are providing full answers [on all Parts I, II, III].
It is both a pleasure and an invigorating experience to read through your perspective and guidance.
You honour me regarding the targeting of the FE size. I want you to know that all your videos, your shared thoughts, and the shared references are a BIG BIG influence on the way that I currently approach engineering challenges. Thank you for being you, thank you for sharing your knowledge with the rest of the world.
In PART III, as far as I am concerned, you have given me LED SPORT LIGHTS and a rope out of the rabbit hole. This right here in part III is one shining example of a case in point where one can see and experience the CEE channel wisdom, patience and guidance without judgment. Thank you MJ
Here’s is to your successful exams sessions next week. Know that you have already given a lot to the CEE channel community and that you continue to give more [you have recorder part II of the basement walls video early to accommodate us] + THE COURSE 😲. It is totally ok to shift your focus to the exams, it is ok if you won’t have time to record something, you have given the community a lot to chew on at the moment, the community will be here when you return; all the best with the exams sessions.
Kind regards, DK
Excelente tu contenido, muchas gracias.
You are most welcome ^_^
PART II
18:01 😁😁, the group selection and deleting of the wall supports is working with Delete “linear” support selected. I can’t say why this did not work on your model because you seem to have also tried Delete “linear” support, I can only confirm that the very same command did work on my model. Maybe Autodesk is not so innocent after all heh?
19:05 Thank you for mentioning this important point, and for reiterating it again at 20:50, this is very much appreciated.
20:12 I am glad that you decided to go with the GAP option, it gives a practical learning chance to explore how to deal with the associated meshing challenges due to this decision and configuration.
Is making the GAP 3m-2.75m = 250mm one of the workarounds (or preparations) geared to minimise the predicted FE meshing problems, why is the size 250mm and not say 100mm or any other value? could it be because CEE anticipate the FE sizes of the mesh to be generated for the other elements to be around 250mm_ish? I also noted CEE mentioned the meshing nuance at 33:05 related to this GAP.
21:28 😂🤣😂…. I’ll just leave it as it is I don’t care…. otherwise, I would have to deal with the ceiling of that thing……. 😂🤣😂….
I think I would consider a GAP between column and basement wall if I am going for the separated column idea or if I am making an expansion/contraction joint.
Note that I still have my reservations regarding the separated column idea at the moment because of the practical difficulties which I foreshadow during the construction and during the operation of such joints.
I would like to add the following question in addition to my earlier questions that I asked at 09:03 above.
Question: With brickwork or blockwork one creates expansion and contraction joints on the brick walls and not on the floor slabs that support those brick walls. I am thinking the same concept with the basement walls having expansion/contraction joints on them and not extending through the raft foundation that supports these basement walls.
Is there ever a time where it would be practically or theoretically corrected to extend the concrete structure expansion/contraction joint through the raft foundation?
I think this would mostly be problematic for the same structure and should only be considered where one have say a relatively long building [like a school classrooms block] and decide to separate the building structure into “separate structures”. What are your thoughts? What length of concrete raft foundation would justify to consider “separate structures” and “separate raft foundations” by means of an expansion/contraction joint cutting all the way through the raft foundation?
22:04 YES, indeed I agree. I think FOCUS is good practice and it allows the videos to be manageable at under 60min. For me, the simplifications are not an issue as long as the CEE continue to remain clear on the same video as to what simplifications are being made and how a user may deal with them. This information allows a user who intend to model a full structure to be able to do so and also to be able to include or adjust their model to now include the simplifications that were missing in the tutorial since those are clearly disclosed and guidance was provided by the CEE. Thank you CEE.
27:34 that was some sleek selection of those six (6) panels to be honest ^_^
28:03 😊not cool, not sleek ^_^
28:12 Thank you for going through the detailed interpretation of the results. It really helps to reinforce and to confirm the interpretation of these results.
Thank you again CEE for such an engaging video. There is so much to learn from your videos and I am looking forward to part II of the basement wall video.
Take care and have a wonderful day
Regards, DK
Ps. I have a tangent question that I have attached as a separate PART III below. Apologies for the loooooooong comment.
Hi there Engr. DK,
I am almost 99% sure deleting using linear supports worked in the past. For some reason, it just did not work today. Conspiracy Confirmed!
Local axis direction is extremely important to have a chance in interpreting the results in a meaningful way.
OH!!! THE COMMENT IS GOOOOOOOOOLDEN!!! I wish I had not recorded part 2!!!! To my defence, I recorded earlier because I have to give some exams next week so I might not have any time to record smthn.
But that comment, this is youtube gold!!! YES, putting the FEM size to target that 250mm value or any value like 125mm is GREAT!!! YES!!! YOU ARE A GENIUS!
Exactly, about leaving it as it is, I know the practical problems of having a gap.
I tooooooooootally second your opinion of HATING the gap between column and wall. As I said in part 1, I want to cover all bases, while providing subtle (and sometimes direct) comments of how I hate a certain alternative.
My previous comment of the expansion joint is the same here. With the difference in brickwork that you might need to provide a steel mesh at the last brick so that you can connect it effectively with whatever you gonna cast on its edge, before you go with the expansion joint.
Expansion joint in rafts? I need to go to my "bat cave" and do some research to be honest. I would never "wing an answer" when I am not 100% sure. Now I know that a structural joint will cut the raft in some cases. Expansion joint? hm....
Still, I second your opinion about this being a nightmare in practice, that is why I keep hating it multiple times in the video. Still, I have to research the idea of joints in rafts. I will get back to you.
I actually lightly script my videos, but the reactions and ideas while implementin are things I come up with on camera. Crazy part is, I had to pause to do smthn and forgot to record again. Ooooh editor actually hated me for that.
Cont'd Part 3
Also, no problem, you can write as long as you want, you will always get a full answer. I still hope I did not miss anything.
I tried looking for some infos with regard to raft joints. I found this. I am not really happy but at least that is a start
www.structuralguide.com/construction-joints/
PART III
Tangent question:
1. I know that today’s video is not about shear walls, I also understand that shear walls are a different category and a totally different ballpark [CEE overview about shear walls from 04:20 on this video was very clear on this (thanks)].
2. My question is: I am modelling a four-storey residential building [Rigid RC frame structure with Columns, Beams and Slabs]. I would like to investigate an option of a structural system for this building that also have SHEAR WALLS. I intend for the shear walls to carry lateral loads (from EQ and WIND loads) on the entire building.
3. I would like to “assume” that the columns on my structure DO NOT carry any lateral loads [from EQ and WIND] and that all lateral loads (from EQ + wind loads) are being “exclusively” carried by the shear walls.
Now I also think that in reality, this assumption is not really what will happen to the real structure because as long as these elements are all connected, the loads will be distributed (like it or not) in the built structure according to the relative stiffnesses of the various connected structural members [beams, columns, slabs, and shear walls] and there is not much that will “shield” the columns from getting their share of the lateral loads irrespective of my supposed assumption?
4. Nonetheless, I have seen this assumption made in structures before. I think that in one of the previous slab series video when we were discussing about the torsion on the ribs, CEE mentioned “moment redistribution" and indicated that ….…even if a rib is not strong enough to carry torsion. The rib will not simply "explode" but would first go into the process of shifting the load to the next element, creating what is essentially a non-linear hinge…….
My similar thinking here is that even if the lateral loads (EQ + Wind loads) will in reality be distributed to the columns which I am assuming that they will not carry any of the lateral loads, these columns will “not simply explode 😊” but will shift the lateral loads to the SHEAR WALLS as I am assuming. Are these assumptions correct regarding the columns that do not carry lateral loads?
5. IF the above is correct, my next question is how do I efficiently model these assumptions in RSAP?
I am thinking of modelling the entire building frame (columns, beams, slabs, and shear walls) as usual and then I intend to assign the columns [which I am assuming to not carry lateral loads infinitesimally small values of the moment of inertia in the two orthogonal bending directions (through RSAP build-in option to reduce the element (column in this case) moment of inertia). I think analysing such a structural model will “shift” all lateral loads to the SHEAR WALLS and if the shear walls that I design using this model are capable of resisting the lateral loads, then, the assumption of the columns not carrying the lateral loads will be valid-ish. Is this correct?
6. The reason I would like to do the above is because I want to reduce the sizes of the columns and I want to use the shear walls to their maximum capabilities. What are your thoughts? Should I rather not reduce the columns stiffness and let the FE method proportion the lateral loads due to the members relative stiffness?
What about the beams? Do I need to reduce their moment of inertia or are they part of the slab “diaphragm actions” that facilitate the loads transfer to the shear walls? I think that the beams are part of the diaphragm actions and I must not reduce their stiffnesses?
I kinda feel like I am going deep into the rabbit hole here with this model and I can really use help.
Regards, DK
Continuing...
a quick glimpse on your comment reveals that you are thinking like a post-graduate researcher. This is really really cool!
Your assumption of letting shear walls carry lateral loads entirely is totally valid. In that case, you would "theoretically" release your columns. Of course, this is not really your question, so I will end-follow you.
You are simply saying that indeed there is no 100% clean release, even if you are actually not rigidly connecting the beams with columns in reality (no steel interconnection, columns cast separately from beams).
Now, the assumption of having axial elements (released) in columns is valid, but is kind of in the non-safe side. What you are thinking now, is that there is moment, so there must be some interaction diagram requirements there. And YES! it exists.
Now, first of all, the practical modeling consideration. In practical considerations, a simple release in the column is sufficient. Why? Now I need to be not code-neutral. In the ACI code, parts of the factor of safety considers accidental eccentricities and moments due to this exact interaction, so the code got me covered in that case. Pls check your code if there is smthn similar.
Going into the deeper though, how would you calculate the non-linear hinge there, and here is my take on it, please note that this is an opinion.
I would calculate two stages of the moment there.
Stage 1: column did not crack. It can carry tension. (you can ignore it if you want)
Here, this stage covers all moments between 0 and the cracking moment of your column section. This can be calculated by setting the max tensile stress in your concrete inside the column.
Stage 2: cracked section.
Here, you loose the tensile part of your concrete, and you can calculate the moment carrying capacity of your column, based on the moment applied. THIS IS A HUGE APPROXIMATION, because you are ignoring the axial force in this case. Please note, this is at least M.Sc. research stuff, where researchers would do their entire thesis on:
Simulating a beam-column connection
Having a real-life experimental model
Trying to see how the real life experimental model corresponds to their simulation
using AnSYS.
so in point 5: you can simply release your column. This is not an attempt to run away.
but wait.. psssssssssst, here is a cool thing I did back in my day, this same issue haunted me since I was a junior engineer. So what did I do?
I had 2 robot files. 1 robot file with released columns and another with rigid columns (the two extremes). I designed columns using both and the larget reinforcement ratio was used.
Now I am aware that I have an infinite combination of moments and axials (beause I can have anything between fully released vs fully rigid), but this is as close as I can get to perfection.
But to address 6, just release the columns, is good enough in my experience.
Beams need to be reduced in moment of inertia as those are flexural members, meaning that a larger part of their section is cracked.
I hope this comment is kind of a flashlight helping you to navigate those really really interesting thoughts. I remember myself contemplating similar ideas.
Once again, a huge thnx for your comment, it helps me and the viewers immensely.
Regards,
CEE