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.

Roof Purlins Design

 
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
rajneesh_jindal
SEFI Member
SEFI Member


Joined: 18 Dec 2010
Posts: 14
Location: Chandigarh
PostPosted: Thu May 26, 2011 6:51 am    Post subject: Roof Purlins Design Reply with quote
Hi All..
In the Design of Roof Purlins, can we design with Factored Load Combinations as 1.0*(DL+WL) considering Limit State of Serviceability, Instead of 1.5*(DL+WL).
Please Help.

Regards
Rajneesh Jindal
Back to top
View user's profile Send private message
rajancivildesign@gmail.co
...
...


Joined: 26 Jan 2011
Posts: 537
PostPosted: Thu May 26, 2011 7:30 am    Post subject: Load combination for Roof purlin Reply with quote
For analysis of roof purlin in steel truss following load combination has to be considered:
(1) 1.5 DL+1.5LL
(2) 1.12DL +1.12LL+1.12WL (increase 25% allowable stress in steel for wind load)
(3)0.9DL+1.5WL

V.M.RAJAN.
Back to top
View user's profile Send private message
rajneesh_jindal
SEFI Member
SEFI Member


Joined: 18 Dec 2010
Posts: 14
Location: Chandigarh
PostPosted: Thu May 26, 2011 8:24 am    Post subject: Re: Load combination for Roof purlin Reply with quote
rajancivildesign wrote:
For analysis of roof purlin in steel truss following load combination has to be considered:
(1) 1.5 DL+1.5LL
(2) 1.12DL +1.12LL+1.12WL (increase 25% allowable stress in steel for wind load)
(3)0.9DL+1.5WL

V.M.RAJAN.

Dear Sir

Could you give justifications for using factors 1.5 , 0.9  and 1.12..
Back to top
View user's profile Send private message
rajancivildesign@gmail.co
...
...


Joined: 26 Jan 2011
Posts: 537
PostPosted: Thu May 26, 2011 9:49 am    Post subject: Design of steel purlin load combination Reply with quote
Dear Rajneesh Jindal,
I have indicated the load combination based on my experience. Kindly refer  Table 4 of latest IS 800-2007 for correctness of the design. Generally 1.5 is used for DL+WL combination. For purlin stability check of 0.9DL+1.5WL is not necessary. For stress increase there are two methods of analysis. One is reduce the load by 25% of ultimate load and apply. Accordingly I mention 0.75*1.5 =1.12. Another method is analysis as it is and consider the interaction ratio of less than  1.0  for steel member check as 1.33. I am not expert in Steel design. Kindly comment on this issue by any expert in steel structures.

V.M.RAJAN.
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