ETABS Tutorial 13: Determining the Correct CM and CR Coordinates for the Inherent Torsional Moments
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- เผยแพร่เมื่อ 9 ก.ค. 2024
- In this tutorial, you will receive a comprehensive explanation of the process involved in obtaining the correct locations for the Center of Mass (CM) and Center of Rigidity (CR). Also, it shows an investigation into how the inaccuracies in diaphragm mass can significantly impact the CM coordinate calculations, subsequently affecting the overall structural analysis and behavior.
The primary cause of diaphragm mass inaccuracies in ETABS lies in the modeling technique used for diaphragm assignment. Within ETABS, two primary options exist for diaphragm assignment: shell or joint. However, issues can arise, particularly when using the shell option, as not all masses lumped to the joints may be correctly selected in the diaphragm assignment process.
Moreover, assigning diaphragms from the joint option requires the removal of any pre-existing assigned slab meshes. Removing these assigned meshes from slab elements is a crucial step to ensure accurate structural modeling.
00:00 Introduction
2:23 CR for Semi-Rigid Diaphragms
3:42 Eccentricity Calculations (Using the CM and CR Coordinates)
6:41 Example 1
11:28 Example 2
13:17 Example 3
14:18 Comparing the Case Study Model to a More Accurate Model
16:00 Final Decision
You can access and download the Excel sheets by clicking on the link below:
drive.google.com/drive/folder...
GOOD EVENING SIR TAREEK, nice explantaion about torsional calculations. I had encounter calclating or checking redundancy factor. I'd be very grateful if you can record a video on step by step how to check on redundancy factor (shall we use 1.0 or 1.3), Thank you. I enjoyed so much your video series and learn a lot. :)
Thank you for the positive feedback! I'll definitely consider your suggestion for a video on checking the redundancy factor. In the meantime, using 1.3 is a safe bet for added conservatism.
Stay tuned for more content, and I'm glad you're finding the videos helpful! 😊
Can you please share an excel sheet
You can access and download the Excel sheets by clicking on the link below:
drive.google.com/drive/folders/1WWyrqs8OaJbvIjkEqigb8ki_FDQmfauO?usp=sharing
Tarek I am your big fan but is it possible you do how to read results sir as I struggle to read shell forces f11,f12 M11 and M12 how to read them there are very less youtube videos who teach you how to read results after the modelling is done Sir can you please make a video on that sir???
Hello! I'm grateful for your support, and I appreciate your suggestion. It's great to hear that you're interested in understanding how to interpret shell forces and moments (f11, f12, M11, M12) after the modeling process. I can definitely create a video guide on how to read and interpret these results effectively.