CSI SAFE - 25 Concrete Slab Short term and Long term Deflection Calculations
Deflection:
the action or process of deflecting or being deflected.
The deflection distance of a member under a load is directly related to the slope of the deflected shape of the member under that load, and can be calculated by integrating the function that mathematically describes the slope of the member under that load.
)))))) Short and Long term deflections
Three types of deflections are available, including:
1. Elastic Deflection
2. Immediate cracked deflection
3. Long-term cracked deflection accounting for creep and shrinkage
For Elastic Deflection
Section uncracked used
Load Combination = 1D (Dead) +1L (Live) +1SD (Super Dead)
)) For Immediate (Short term) cracked deflection
Section cracked used
Load Combination = 1D (Dead) +1L (Live) +1SD (Super Dead)
)) For Long term deflection
Section cracked used (with creep and shrinkage)
Load Combination (Sustained)= 1D (Dead) +0.25 L (Live) +1SD (Super Dead) → we consider 25 % live load as sustained load.
But with doing so, we are missing with rest of 75% live load deflection.
For Accommodation of 75% live load
Long term Deflection Combination
= (1D +0.25 L +1SD {with C & Sh}) +[1D +1L +1SD] -[1D +0.25L +1SD]
)) Allowable Deflections:
Immediate Deflection = Span /360
Long term deflection = Span /250
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Very informative video
Very informative again. Thanks
@civilmdc
4 жыл бұрын
THANKS Dear,
Thanks for the video lesson. Can you tell me the value of the section modifier for the beam elements in this model? thanks
its really good session! For checking long term deflection what is the value of modulus of rupture to be used ?
Hi thanks for your greet work,do you have full design project (safe+autocad) in your course ???
For L/360 is immediate deflection due to Live Load only as ACI code mentioned
Thanks for the video lesson, how can i consider the effect of creep and shrinkage in global analysis
Mr hussein you used the 7500mm distance. For flat slab with perimeter beam but without internal beam what distance to be used? Most specially when the distribution of columns is not in line due to arch considerations....
Thank you
@civilmdc
3 жыл бұрын
Welcome 😇
Thank you for making helpful video. Please make a video on edge and corner footing design.
@civilmdc
4 жыл бұрын
Thanks Dear. Noted your point
Sir, can I do the same short and long term analysis in ETABS??? Thank you.
Thank you for your work. One inquiry I would like to put about stiffness modification factors for slab you took in this exercise. I mean when we check the option non-linear cracked for immediate cracked deflection , what value the software picks ?? Or stiffness modification factor is 1
@maroma36
3 жыл бұрын
same question
Sir make a video how to design retaining wall and to apply soil pressure on wall. Sir I also watch your video on udemy
Why you used the same Load case om both immediate and long term deflection? For L/360 is immediate deflection due to Live Load only. Correct me pls. If im wrong.... 🤟
Sir make a video how to assign non uniform shell load on wall and slab
when you imported model in safe from etabs/sap, were the stiffness modifier already added in them? I mean if i have assigned modifiers in my etabs model and then i import it in safe, will the stiffness modifiers also be imported. Do I have to remove then to get elastic deflection?, and reassign them for longterm deflections?
@Thamirjabar
3 жыл бұрын
You are importing a floor and not the whole model from Etabs, for the purpose of carrying out a design for this specific floor. I believe that, since Safe is calculating the short-term and long-term deflections, taking into account shrinkage and long term creep, you do not need to apply stiffness modifiers and therefore set all modifiers to 1.0 for all cases.
Thank you for your video, but can u tell me how did you chose the load combination? depend on what ??? Thanks again!
@civilmdc
4 жыл бұрын
These combinations are given on the official website of CSI Knowledge base
@NHTL2101996
4 жыл бұрын
@@civilmdc can you send me the link ? So many tag in website 😂😂
@civilmdc
4 жыл бұрын
@@NHTL2101996 here is the link wiki.csiamerica.com/display/safe/Cracked-section+analysis
@NHTL2101996
4 жыл бұрын
@@civilmdc tks so much 😊
M hussein. When exported file from etabs for the load cases i include loads and load_Above. Pls correct me if im wrong tnx
@civilmdc
3 жыл бұрын
Correct
Hello brother, I have an issue with CSI safe, so many times , after running the model nothing happens, I mean no result will come up. I am facing this issue so many times Please can you tell me how to solve this problem. Thanks...
@civilmdc
3 жыл бұрын
Go to option. And change ... To graphics mode... Then It will show ... everything...
@civilengineeringwitharas4776
3 жыл бұрын
@@civilmdc did not work, the issue is not related to the graphics, the issue is the model will not run. this problem is only encountered in SAFE 2016. it is ok in SAFE 2014
@civilmdc
3 жыл бұрын
@@civilengineeringwitharas4776 dear Download SAFE Software from www.civilmdc.com, It has the lifetime license.... And I am also using that one.
@civilengineeringwitharas4776
3 жыл бұрын
Thank you very, Finally I solved the problem by changing the solver, I am using 64bit system, selecting 32 bit solver is completely solved the issue. Thanks again...
Spanish subtitles in your videos please