What is meant by flat slab and flat plates? The stiffness can be reduced for flat slab and walls only and cannot be reduced for solid /waffle slabs/...?
In the CSI stiffness modifier page you showed says you should use the same stiffness modifier if you want to model the out of plane stiffness of the wall. So you should use 0.7 instead of 0.25.
There is no need to use 0.7. I believe you may have misunderstood the website. In my research, I used 0.25, which means I reduced the wall stiffness by 75%, reflecting the reality that shear walls are weak in resisting out-of-plane bending. This approach is commonly adopted by engineers. If you prefer to use 0.7, that is your choice, but using 0.25 is also valid. Many engineers even use values as low as 0.1 to represent the minimal out-of-plane stiffness of walls. Additionally, the ACI code specifies reducing the out-of-plane stiffness of slabs to 0.25 but does not mention walls. This suggests that using 0.25 for walls is reasonable since they behave similarly to slabs under out-of-plane loads.
Please refer the CSIamerica page you have shown in the video and refer to the note. wiki.csiamerica.com/display/etabs/Modeling+concrete+cracked+section+properties+for+building+analysis
Certainly, ETABS can provide you with the tensile stresses of a slab. To obtain these stresses, you would need to select the shell stresses results, specifically S11, S22, and so on. It's important to understand the nature of the applied loads, whether they are gravity loads or lateral loads. This understanding helps determine which results you are interested in. For example, let's assume that a lateral load is applied to the floor in the Y-direction. In order to obtain the compressive and tensile stresses resulting from this load, you would need to check the F11 or S11 values in the shell stresses results. These values correspond to the stresses along the X-axis, which in this case represents the direction perpendicular to the applied load.
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Thanks a lot!
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ruclips.net/video/0VUqMwS4FCo/видео.htmlsi=3ICYsUkyqmPIHyP-
What is meant by flat slab and flat plates? The stiffness can be reduced for flat slab and walls only and cannot be reduced for solid /waffle slabs/...?
All types of slabs should be reduced
In the CSI stiffness modifier page you showed says you should use the same stiffness modifier if you want to model the out of plane stiffness of the wall. So you should use 0.7 instead of 0.25.
m11, m22 and m12 are the modifiers for the out-of-plane stiffness!
Yes they are but I'm saying you should use 0.7 for out of plane stiffness instead of 0.25.
There is no need to use 0.7. I believe you may have misunderstood the website. In my research, I used 0.25, which means I reduced the wall stiffness by 75%, reflecting the reality that shear walls are weak in resisting out-of-plane bending. This approach is commonly adopted by engineers.
If you prefer to use 0.7, that is your choice, but using 0.25 is also valid. Many engineers even use values as low as 0.1 to represent the minimal out-of-plane stiffness of walls.
Additionally, the ACI code specifies reducing the out-of-plane stiffness of slabs to 0.25 but does not mention walls. This suggests that using 0.25 for walls is reasonable since they behave similarly to slabs under out-of-plane loads.
Please refer the CSIamerica page you have shown in the video and refer to the note. wiki.csiamerica.com/display/etabs/Modeling+concrete+cracked+section+properties+for+building+analysis
Thanks
Welcome
Is it for ultimate limit state?
Yes for ultimate limit state
Thank you
really appreciate !
Do you use stiffness modifier for design also?
Sure
Can I output the result of compressive stress and tensile stress in slab by using ETabs ? How do I read
Certainly, ETABS can provide you with the tensile stresses of a slab.
To obtain these stresses, you would need to select the shell stresses results, specifically S11, S22, and so on. It's important to understand the nature of the applied loads, whether they are gravity loads or lateral loads. This understanding helps determine which results you are interested in.
For example, let's assume that a lateral load is applied to the floor in the Y-direction. In order to obtain the compressive and tensile stresses resulting from this load, you would need to check the F11 or S11 values in the shell stresses results. These values correspond to the stresses along the X-axis, which in this case represents the direction perpendicular to the applied load.