Modeling as shell finite elements

[aksualigurbuz]

take it easy everyone. I had a few questions. I would be very happy if I could get an answer. 1- What exactly does it mean to model curtains as shells. What happens if I do not model the panels as shell finite elements?.. What effects will occur? What will be the effect on the columns? (connecting columns) 2- In new building designs, do basement curtains also have shell finite elements? Will we model as elements? 3-Why do we model as shell finite elements? 4- In retrofit projects, will we model the curtains in the existing structure as a shell or without it? Why? 5-Are we going to model only the ones above the basement floor as shell finite elements among the existing[/b] in retrofit projects? Shall we model separately for the basement and upper floors (shell or normal) 6- In retrofit studies, we will model new rigid shears on the existing rigid shears? reinforcement curtains may come. In this case, should the existing rigid curtain be demolished and rebuilt, or should it be left as it is? If we are going to leave it, will the existing panel be considered as a shell? Or will the curtain (on the basement floor) that will be built instead be considered as a shell (new reinforcement curtain)? take it easy everyone. Maybe an answer you give will answer a few questions. It seems like I'm confused. Thank you...

 

[HakanŞahin]

Re: modeling as shell Curtains can be modeled as shells and rods. If you think the curtain in your building will act like a rod, you can model it as a rod. In finite element analysis, the width and length of the element in the plan must be small enough to be negligible compared to its height in order to accept a rod. However, the plan length of the board curtains can be much higher than the height. Therefore, basement walls should be modeled as shell finite elements. Let's examine the picture below: P01 is modeled as a shell and divided into finite elements. P02 is modeled as a rod. See how P01 is connected to S1 and S2. S1 and S2 elements are divided into as many parts as the number of finite elements, and the finite elements from S1 and S2 are connected via rigid arms. Now let the elements P01 and P02 have spaces. The P01 element will automatically see the gap. If you do not model the P01 element as an acceptance, you cannot enter a single piece. You need to divide it into parts to model the space. (Two pieces on the left and right and a beam in between) To sum up:

1-What exactly does it mean to model curtains as shells. What happens if I do not model panels as shells?.. What effects will occur? What is the effect on the columns? (connecting columns)

a. There is not much difference between modeling/not modeling panels close to the column size as shells b. As the panel size gets larger, it is more appropriate to model as acceptance c. Panels with voids are shells d. It would be the most realistic solution to model the panels with beamless raft systems and/or between the columns, especially in basement perimeter or basement curtain systems, as shells and to solve the superstructure-foundation interaction.

2-Should we model basement floor curtains as shells in new building designs?

Yes

3-Why do we model as shells?

Don't do it anyway There is nothing wrong with you.

4-In retrofit projects, shall we model the curtains in the existing structure as a shell or without it? Why?

You can decide according to the solution of your current project. There is not much difference between modeling or not modeling the panels as shells.

5-Of the existing curtains in retrofit projects, we will only model the ones above the basement floor as shells? Separately for the basement and upper floors. Are we going to model (shell or normal)

The answer to this depends on how you want to set up the panel/bar system. The establishment of the 3D model will be with differences as in the pictures I have attached as an example.

6-New reinforcement curtains can be placed on the existing rigid curtains in strengthening works. In this case, should the existing rigid curtain be demolished and rebuilt or should it be left as it is? If we are going to leave the existing panel shell Or will it be considered as a replacement curtain (in the basement) or a shell (new reinforcement curtain)?

You don't need to demolish the existing curtains if their strength is sufficient. The answer to this depends on how you want to install the panel/bar system. Good work

 

[aksualigurbuz]

Re: modeling as shell Ok thank you very much...

 

[eissenhover]

Sir, you explained the subject very well, but I have a question. I modeled a simple frame. I modeled two of the curtains as shells and did not model the other two as shells. I got results just like in the images you shared. For example, there was a rigid connection between the shell element and the column. However, when I examined the reinforcement drawings, the same reinforcement detail appeared for all curtains. that is, when I saw the image of the rigid connection between the shell curtain and the column, I expected that there would be a difference in the reinforcements, but there was no difference between the shell curtain and the rod curtain. If the equipment is the same, where is the difference? ok, there is a difference. such as rigid connection etc. but after the equipment is exactly the same, the difference in the image has no meaning. I'm confused, I'll be happy if you explain, thank you

 

[HakanŞahin]

sir, you explained the subject very well, but I have a question. I modeled a simple frame. I modeled two of the curtains as shells. I did not model the other two as shells. I got results just like in the images you shared. But when I examined the reinforcement drawings, the same reinforcement detail was found for all curtains. In other words, when I saw the image of the rigid connection between that shell curtain and the column, I expected that there would be a difference in the reinforcements, but there was no difference between the shell curtain and the bar curtain. OK, there is a difference in the image. It's like a rigid connection, etc. But after the equipment is exactly the same, the difference in the image seems to have no meaning. I'm confused, I would be happy if you could explain, thank you

Hello, There are minimum design and drawing conditions applied to the curtains. Account even if the effects are different, if the system works at minimum, the curtains are regulated. Due to the minimum reinforcement requirements, the reinforcements are the same and the reinforcement details are the same. The more complex the frame model, the more the design values begin to differ.