www.sefindia.org

STRUCTURAL ENGINEERING FORUM OF INDIA [SEFI]

 Forum SubscriptionsSubscriptions DigestDigest Preferences   FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups  RegisterRegister FAQSecurity Tips FAQDonate
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log in to websiteLog in to websiteLog in to websiteLog in to forum 
Warning: Make sure you scan the downloaded attachment with updated antivirus tools  before opening them. They may contain viruses.
Use online scanners
here and here to upload downloaded attachment to check for safety.

scale in response spectrum

 
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> SEFI Web Site Problems/ Login/Registration Issues
View previous topic :: View next topic  
Author Message
Rameshwar Prasad
SEFI Member
SEFI Member


Joined: 25 Feb 2010
Posts: 16

PostPosted: Wed Oct 20, 2010 7:49 pm    Post subject: scale in response spectrum Reply with quote

hello everybody, i am trying to design a steel multi storey car parking. i am trying to do a response spectrum analysis for the same. i have two doubts :
1. along with response spectrum case why do i have to add the self weight cases. and should i add the selfweight cases in all the three directions.
2. what should be the scale i have to enter beside X Y and Z in response spectrum load case. if i add 1 i am getting a very huge base shear.
Back to top
View user's profile Send private message
Yogesh.Pisal
General Sponsor
General Sponsor


Joined: 18 May 2008
Posts: 406

PostPosted: Thu Oct 21, 2010 4:49 am    Post subject: Reply with quote

Dear Friend,

This topic has been discussed number of times on SEFI. You can search previous discussions for more detailed information. I will try to give the clarification briefly for your ready reference.

Genearally, in response spectrum analysis, we need to define two parameters
    a. Mass Source
    b. Spectral Acceleration

Mass Source -
Here, we have to consider the mass which will vibrate during earthquake. Hence, it becomes mandatory to define selfweight also.

Spectral Acceleration -
Here, we use to define response spectrum. Refer IS 1893 Part 1 for codal response spectrum. Code has suggested some normalizations (scale factors) for response spectrum which we need to consider while defining response spectrum in STAADpro.
- Direction Scale in STAADpro is (Z / 2) x (I / R)
- Scale factor in STAADpro is used for further scaling of response spectrum. Here, you can define (Vb'/Vb >= 1).

Let me know, if you have some further doubt.

Regards,
Yogesh Pisal
Back to top
View user's profile Send private message
Rameshwar Prasad
SEFI Member
SEFI Member


Joined: 25 Feb 2010
Posts: 16

PostPosted: Tue Oct 26, 2010 8:53 am    Post subject: thank you Reply with quote

hello sir thank you very much for your prompt reply. i understood the expalanation given by you regarding mass inclusion..
but regarding spectral acceleration the directional scales would be the same in both the directions as Z/2 and I/R  values do not depend on direction..
Back to top
View user's profile Send private message
Yogesh.Pisal
General Sponsor
General Sponsor


Joined: 18 May 2008
Posts: 406

PostPosted: Tue Oct 26, 2010 11:01 am    Post subject: Reply with quote

Dear Friend,

You are right. (Z/2)x(I/R) does not depend on direction, hence this value will be same not only in 2 horizontal directions but also in vertical direction.

Regards,
Yogesh Pisal
Back to top
View user's profile Send private message
Rameshwar Prasad
SEFI Member
SEFI Member


Joined: 25 Feb 2010
Posts: 16

PostPosted: Tue Oct 26, 2010 2:43 pm    Post subject: Equivalent static method Reply with quote

thank you very much sir.... sir if you dont mind..can you give me your e mail id. i have designed a building using equivalent static method..i will send it to you.. can you please tell me whether its  correct or not.
Back to top
View user's profile Send private message
Yogesh.Pisal
General Sponsor
General Sponsor


Joined: 18 May 2008
Posts: 406

PostPosted: Wed Oct 27, 2010 4:26 am    Post subject: Reply with quote

Dear Friend,

You can mail me on

alltimepisal@yahoo.co.in

But it is always better to post your STAAD file on SEFI forum itself. This way others can also give their views.

Regards,
Yogesh Pisal
Back to top
View user's profile Send private message
Rameshwar Prasad
SEFI Member
SEFI Member


Joined: 25 Feb 2010
Posts: 16

PostPosted: Wed Nov 10, 2010 7:31 am    Post subject: EQSM Reply with quote

hello sir,

I am uploading the staad commands in notepad sir . please tell me whether the procedure i followed is correct or not. i have tried to analyze a multi story structure having given seismic loading using equivalent static method
Back to top
View user's profile Send private message
sukanta.adhikari
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 713

PostPosted: Wed Nov 10, 2010 10:27 am    Post subject: Re: EQSM Reply with quote

Dear Er. Rameshwar,

I have seen ur STAAD file,

My observation are.

1) Application of load ,ie, Dead load and Live load is not complete.

2) Plate modelling is done for floor slab...the size of plate element is 6mx6m..It is better to mesh the plate into sizes 0.5mx0.5m.

3) Another alternative is instead of plate  I will suggest..model the slab as flexible diaghpragm by applying floor load..and if at all u want to take the advantage of rigid diaghpagm action use master slave command.

4) I have attached a STAAD file in which I have carried out Equivalent static method...Please follow the link..

http://www.sefindia.org/forum/viewtopic.php?t=8628

5)Please ensure that u design by IS 13920 since u have used response reduction factor as 5 and ur building falls in zone IV.



Regards,
S.Adhikari


Rameshwar Prasad wrote:
hello sir,

I am uploading the staad commands in notepad sir . please tell me whether the procedure i followed is correct or not. i have tried to analyze a multi story structure having given seismic loading using equivalent static method
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> SEFI Web Site Problems/ Login/Registration Issues All times are GMT
Page 1 of 1

 

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum


© 2003, 2008 SEFINDIA, Indian Domain Registration
Publishing or acceptance of an advertisement is neither a guarantee nor endorsement of the advertiser's product or service. advertisement policy