Response Spectrum Analysis as per IS1893 in Staad Pro. V8i (Dynamic Analysis)
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- เผยแพร่เมื่อ 23 ก.ค. 2024
- Response Spectrum Analysis as per IS1983 in Staad Pro. V8i
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Response Spectrum Specification as per the Indian IS:1893 (Part 1)-2002 Code for Dynamic Analysis
Methodology
The design lateral shear force at each floor in each mode is computed by STAAD in accordance with the IS: 1893 (Part 1) -2002 equation 7.8.4.5c and 7.8.4.5d.
Qik = Ak*fik*Pk*Wi
STAAD utilizes the following procedure to generate the lateral seismic loads.
1. User provides the value for Z/2*I/R as factors for input spectrum
2. Program calculates time periods for first six modes or as specified by the user.
3. Program calculates Sa/g for each mode utilizing time period and damping for each mode.
4. The program calculates design horizontal acceleration spectrum Ak for different modes.
5. The program then calculates mode participation factor for different modes.
6. The peak lateral seismic force at each floor in each mode is calculated.
7. All response quantities for each mode are calculated.
8. The peak response quantities are then combined as per method (CQC or SRSS or ABS or TEN or CSM) as defined by the user to get the final results.
Soft Storey Checking
For details on the Soft Storey Checking option, see the chapter detailed in Section 5.31.2.5 Definition of Lateral Seismic Load per Indian IS:1893 (Part 1) -- 2002 Code.
Great Video, Thanks Civil Digital for uploading
Amazing Walk through, i have been searching for the RS analysis on the web for months without any progress, and boom civildigital to the rescue.. !!
The explanation is at the best... Thank you so much for making such a useful one.
The way of teaching is perfect. Great work Sir...!!!
Thank you so much for your remarkable efforts...
Very nicely explained with references. Very useful.
Well Presented. Crystal Clear!
THIS IS VERY GOOD INITIATIVE BY YOU...A VERY-VERY THANKS TO YOU
nice video!! u v taken vry great effort... Really very helpful vid..... thanks a lot....!
thanks a lot, really helpful video and Easy to understand dynamic analysis, keep it up. it will be more use full if add geometry of model with dimensions
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GREAT ... VERY NICE EXPLANATION .... VERY USEFUL
Amazing man, you Rock!
So Thanks fo the so helpful video and explanation
Extremely good video. Please upload video on model generation, response spectrum analysis for building resting on sloping ground say 40% slope.
got a help from this video...keep it up guys...
thank you sir...it helps a lot....
hello sir. thank you very much for the video. very helpful. I want to ask something, if i input custom spectrum value (T vs Acc in "g" unit), should i use the scale factor 9.81 to convert g unit to m/s2 (SI)? Thank you very much.
Thanks, very good information through this video, keep it up - I have query in load case 2- ie result shows all forces and moments as positive, how to account these for design ?. do you have some more video on this.
thanks to video staad...
Really Easy to understand.
Hello sir,
Is there requirement of defining seismic load cases before live load and dead load as it was in Static seismic analysis using response spectrum method?
Nice Explanation of the method and very helpful too. sir, what shall be the difference if I wish to analyse an equipment foundation using same method from analysis to design (up to provision of reinforcement)?
Sir, I have one question in Load case details under Load case 1 you have added all the live and dl of slabs what about self weight of columns and beams ????
do you have any tutorial on stack design, guyed wire and self supported structure.
thanks for reply. but while defining response spectrum data we need to define code, and doing that there isn't any UBC code in drop down list. in that case shall i go to custom option??and in this option how we enter the UBC input data which is actually not matching. pls clarify
I have a query...
when calculating the live load, the floor range given was 0 to 11 of 2kN/m, but in ground floor we don't consider Live load can you pls explain...
Thanks Sir!
Can you please explain how to design the reinforcement of the structural elements using the Earth quake analysis results ?
Is it possible to have more base shear with response spectrum than static method ? Some codes do not have modal response parameter factor (i/r)
vy nice.. gud work.. the videos are vy helpful.. thank u
Thank you for your feedback..
Thank You Brother
thank you.. share to your friends too.
Dear sir. Would you please explain to me the value that input to X direction in table of response spectrum X = (Z/2)x(I/R) = 0.036. Normally I always input 1.0 for this parameter.
Thank you so much!
Great work done by you. Very useful. Can you please upload the staad input file of this RS Analysis. I have repeated this analysis on my computer but results are slightly different. Want to understand why.
is it possible to get storey drift in response spectrum analysis of building??
Hello, Its great video to understand response spectra. But i have doubt if we want to perform response spectra in X and Z direction so , i think we have to apply loads only in that two direction for response spectra load case. please reply..
Hello sir, really helpful video. Easy to understand. Great work. Can you also provide video for how to design a structure with shear wall and its dynamic analysis?
instaBlaster
Sir please , should we always apply I/R factor and why its applied? To compere with the static analysis,or it is essential factor for any dynamic response spectrum despite the static analysis
sir, if give diaphragms then we should define reference load case (as mass load) , then under the mass load we have to give selfweight, member loads, floor loads in all directions X,Y,Z with positive sign it seems, my doubt was same pattern we are giving in Response spectrum case also, so if we give in reference load case shall I skip in response spectrum case or is it compulsory to provide both in reference load case and response spectrum load case??
Should the response spectrum be added in all the three directions??
Sir, can you please upload the video regarding Pushover Analysis in Staad Pro, and please do tell me how I can carry out time history analysis without extracting input file?
sir...why i can't run the analysis results for storey drift??i'm trying to follow your video,but the results does not include the storey drift..
Can u please explain the same process for an elevated circular tank
While applying seismic weight shouldn't we take (1) Dead load & (0.25/0.3) Live load, instead of whole Live load assigned in Load Case 1. Pls correct me if I'm wrong.
Can u share one model with response spectra analysis in all three direction with cqc method and how to interpret the results ?
How to take 12 kn /m2 as a dead load?
Hi can you make a video for dynamic analysis of machine bed or turbo generator
will upload as soon as possible.
I followed exactly as u did, but in the staad output, i don't get the Multiplying Factor (Vb/VB) and therefor i have no way of determining the scaling factor. i thought maybe its because of different staad version, but again when i downloaded ur staad file and analyze, it shows a note saying Multiplying factor (Vb/VB) is of some value. where do u think i am going wrong?
Please tell us load combination for Response Spectrum method
i have negative response spectrum story drifts why ? can you help please
My result says like this...
Story drift cannot be calculated for the response spectrum load case.Response spectrum computes joint displacements that represents maximum magnitude of the response quantity that is likely to occur during the seismic load. Any response quantity like story drift, torsional irregularity, etc should be calculated from actual displacements of each mode considered during the analysis. The response quantity from each mode should be combined using modal combination to get the maximum magnitude of that response quantity.
Whats the solution for this?
Should be the response spectrum load case of seismic type?? because u have selected none
Thankyou..
How to add pvc water tank load?
Can you provide the video regarding time History analysis?
sir can you please tell me why we have used all loading in +ve direction
specially in floor load loading direction should be in the -ve direction
+Akshay Kothiyal yes why has he taken all the loadings in +ve direction..when it should have been in the -ve direction.....even for the self weight ... (confused)
Hello Sir! very worth watching and thank you for sharing the precious knowledge. One doubt is that In Static analysis while defining the seismic definition, EQ load cases must be put first ,otherwise error may pop up. But in Response spectrum analysis you have created as usual DL and LL case first and then response spectrum load case. Here why there is no error? Please explain this Sir.
Can you provide the STAAD analysis through"Time history"analysis?I will be higly grateful...
Nice one
Thanks u
please give a video showing load combination with response spectrum load
Hi, Thanks for uploading such an understandable video, would you mind pls let me know how can i use UBC or any other local code instead of IS. kindly response..
whatever the code be, the basic approach remains the same..you just need to understand the method first. Just open up some other code and try doing. its not that difficult as you think it is, and verify the results with some worked out examples..
sir can i replace SRSS method and use CQC method and the remaing procedure same as in video.
yes, you can do that.
Why only load applied in X direction 0.036
hello sir!
Can you tell me how to give more no. of modes, if 6 modes are not sufficient? 'cause as per Clause 7.8.4.2, IS 1893 part 1, the no. of modes in the analysis should be such that the sum total of modal masses of all modes considered is at least 90% of the total seismic mass" . but in my analysis, it is only 78%. So what to do to give command for more no. of modes?
Select "Commands" from Menu Bar, under the drop down menu, select "Miscellaneous" sub option, then select "Cut off mode shape", then enter your desirable mode shapes.
Ezhil Aaron that doesn't works ...
my pleasure..you can use the comment box to ask any doubts.. and share to your friends..
Acceleration scale after X value in response spectrum how to calculate
thanks for a very helpful video. Couple of questions...
1. Why is the dead load value so big. I didnt see the brick loading being applied in the model . for seismic load i think the brick load being dead load should be applied 100% . or does the applied dead load includes brick load as well ??
2. as questioned earlier by Akshay , wht abt the signs?
thnks again for the well presented video.
+aarakshya kandel Dead load value will depend on the actual brick loads and codal loads. Values assumed here are only for demonstration purpose.
what if I don't get the total modal mass greater than 90 % of total seismic weight? how to consider number of mode shapes? do reply as it is very crucial for me.
It maybe too late but i ll try to ans it lol. In toolbar select COMMANDS> MISCELLANEOUS>CUT OFF MODE SHAPE. hope this will help
Even on changing number of modes....it is not increasing to 90...
Thats really fine, but is it possibe to show how to calculate response spectrum analysis in manual procedure.
+Venkatesh Nemala Please mail me, i will give you the reference doc.
+MrFanfinn thank you very much for your reply. i will check it.
Can you elaborate on time history method of dynamic analysis using staad ..thanks
Time History Analysis In Staad Pro v8i - Structures under Seismic Accelerations check out this link for time history analysis
Hi Sir
periode must be cheked
Help me sir plzz
can you please share your email id for more information regarding the above analysis?
namgay, can you paste the warnings if you are getting any, or paste here the description that you are getting instead of the NOTE.-" " . you can zip and mail me ur STAAD file to admin @civildigital. com
like
7 years ago ... Eh ? Our loss
change the file name bro pls... IS1893 not IS1983
Thanks for pointing it out. It was a typo.