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.

Precompression Issue

 
This forum is locked: you cannot post, reply to, or edit topics.This topic is locked: you cannot edit posts or make replies. Thank Post    www.sefindia.org Forum Index -> E-Conferences-2008 [ Flat Slab Design issues ]
View previous topic :: View next topic  
Author Message
nitinengr
SEFI Member
SEFI Member


Joined: 29 Sep 2008
Posts: 11
Location: Vadodara

PostPosted: Fri Jan 02, 2009 12:57 pm    Post subject: Precompression Issue Reply with quote

Can any body tell me what is the criteria of P/A  for the design of the PT slab and beam systems.

As code suggest  0.86 to 2.1 N/mm2 is the limit for the precompression.

But if i keep the precompression as 0.45 or less then what is the effect on the design.

Here i m attacing a pdf which suggest in plane compression is between 125 to 500 psi (0.85 to 3.45 N/mm2).

How can we decide P/A for the structures in which no such compression is need for the tensile stresses.

so can any one give me how it comes 125 psi.

Thanks



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.
Structural_Engineer_2008_oct.690.pdf
 Description:

Download
 Filename:  Structural_Engineer_2008_oct.690.pdf
 Filesize:  875.84 KB
 Downloaded:  731 Time(s)

Back to top
View user's profile Send private message Visit poster's website
gorhemant
SEFI Member
SEFI Member


Joined: 27 Jun 2008
Posts: 11

PostPosted: Sun Jan 04, 2009 10:05 am    Post subject: Precompression Issue Reply with quote

Nitin,
The Technical Report 43 (TR43) specialised document on PT slab design also recommend Minimum Average Effective Prestress of 0.7MPa in clause 2.4.
It reads as follows
"Past experience shows that for the Pre-Compression to be effective it should be at least 0.7MPa in each direction"

You will agree with me that codes give some minimum main reinforcement criteria for flexure ,shear and torsion in structural elements (Slab/ Beam/Column). They have some back-ground studies or past experience and reasons. Similar to this the criteria of minimum average effective prestress from past experience only.

regards,
Hemant Gor


On Fri, Jan 2, 2009 at 4:57 PM, nitinengr <forum@sefindia.org (forum@sefindia.org)> wrote:
Quote:
  Can any body tell me what is the criteria of P/A for the design of the PT slab and beam systems.

As code suggest 0.86 to 2.1 N/mm2 is the limit for the precompression.

But if i keep the precompression as 0.45 or less then what is the effect on the design.

Here i m attacing a pdf which suggest in plane compression is between 125 to 500 psi (0.85 to 3.45 N/mm2).

How can we decide P/A for the structures in which no such compression is need for the tensile stresses.

so can any one give me how it comes 125 psi.

Thanks





Attachments:
Structural_Engineer_2008_oct.690.pdf




Posted via Email
Back to top
View user's profile Send private message
Display posts from previous:   
This forum is locked: you cannot post, reply to, or edit topics.This topic is locked: you cannot edit posts or make replies. Thank Post    www.sefindia.org Forum Index -> E-Conferences-2008 [ Flat Slab Design 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 can attach files in this forum
You can 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