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.

Steel Column-Base plate Anchor rods - Pedestal & Pedestal reinforcement

 
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> SEFI General Discussion
View previous topic :: View next topic  
Author Message
mjnasar
...
...


Joined: 26 Jan 2003
Posts: 60

PostPosted: Sun Oct 03, 2021 6:36 am    Post subject: Steel Column-Base plate Anchor rods - Pedestal & Pedestal reinforcement Reply with quote

Dear Engineers
Greetings

As per ACI 318 -14 chapter 17.5.2.9 if the anchor reinforcement encloses the anchor. The design strength of anchor reinforcement shall be permitted to be used as breakout strength instead of concrete break out strength

Can the reinforcement in the pedestal considered as anchor reinforcement.
( Please see typical pedestal sketch attached )


As the above pedestal reinforcement not complying with  figure R17.5.2.9a , R17.5.2.9b(attached)

thanks
Mjnasar



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.
typical Pedastal.pdf
 Description:
Typical pedestal reinforcement

Download
 Filename:  typical Pedastal.pdf
 Filesize:  25.29 KB
 Downloaded:  87 Time(s)


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.
ACI 318-14_CH17.5.2.docx
 Description:
Figures from Ch17.5.2

Download
 Filename:  ACI 318-14_CH17.5.2.docx
 Filesize:  300.26 KB
 Downloaded:  70 Time(s)

Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3205

PostPosted: Mon Oct 04, 2021 7:13 am    Post subject: Reply with quote

Just a generic view :-
Anchors are subject to axial tension - -  Anchors being embeded into  Concrete  with Vertical reinforcement bars and closely spaced lateral ties - - - Tension is  passed on to concrete through bond - - Concrete in presence of lateral ties will able to transfer tension to vertical reinf.  Thus  splitting in concrete is protected by ties aiding tensile force to transfer to vertical bars.

Each structural element has its role to play ,
Back to top
View user's profile Send private message
pvgraju
Progressive Member
Progressive Member


Joined: 07 Jun 2020
Posts: 41

PostPosted: Mon Oct 04, 2021 11:17 am    Post subject: Steel Column-Base plate Anchor rods - Pedestal & Pedestal reinforcement Reply with quote

Dear Sir,

There are some limitations such as No6 bars, distance from center line of anchor were provided in the commentary to use anchor reinforcement.

when high shear force is present concrete will tend to break out in shear. But by providing this hair pin anchor bars, by developing those bars by Ld, by ensuring suitable connection between anchor-anchor bar-concrete this shear force causing breakout will be resisted by anchor bars first.

so before concrete reinforcement comes into action. If this reinforcement is not able to absorb the required breakout force by its own strength,bond with other side of concrete then concrete break out strengh to be considered.

Connection between anchor,anchor reinforcement is to be taken care.

Regards,

P.V.Gavarraju.
Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3205

PostPosted: Mon Oct 04, 2021 3:18 pm    Post subject: Re: Steel Column-Base plate Anchor rods - Pedestal & Pedestal reinforcement Reply with quote

Dear Er PV Gavarraju ,
Since not used such hair pin anchor bars , request you to please enlighten . Is this hair pin reinf is in form of horizontal mesh with its bars having downward legs embedded Ld at periphery with Vertical reinf of pedestal.
But same role is played by lateral ties which create no. of  meshes at regular spacing in concrete mass , the difference is that ties are closed around vertical pedestal bars and are distributed in conc mass in many layers depending upon spacing of rings(Ties).


pvgraju wrote:
Dear Sir,

There are some limitations such as No6 bars, distance from center line of anchor were provided in the commentary to use anchor reinforcement.

when high shear force is present concrete will tend to break out in shear. But by providing this hair pin anchor bars, by developing those bars by Ld, by ensuring suitable connection between anchor-anchor bar-concrete this shear force causing breakout will be resisted by anchor bars first.

so before concrete reinforcement comes into action. If this reinforcement is not able to absorb the required breakout force by its own strength,bond with other side of concrete then concrete break out strengh to be considered.

Connection between anchor,anchor reinforcement is to be taken care.

Regards,

P.V.Gavarraju.
Back to top
View user's profile Send private message
pvgraju
Progressive Member
Progressive Member


Joined: 07 Jun 2020
Posts: 41

PostPosted: Tue Oct 05, 2021 5:01 am    Post subject: Steel Column-Base plate Anchor rods - Pedestal & Pedestal reinforcement Reply with quote

Dear Sir,

I referred to the ACI attachment. It seems as per research these type of bars are recommended as a shear key with some limitations such as 6No bar,max c to c spacing from center line of anchor.

In the attachment two alternatives were recommended.

1. U bar (hairpin) around anchors.These hairpins shall enclose edge reinforcement and shall be placed as close as possible to anchors.(Fig:17.5.2.9a)
2. Another one is embedded into the concrete. (17.5.2.9b)

This Ld shall be development length in tension since it resist shear by tension in bars.

Regards,

P.V.Gavarraju.
Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3205

PostPosted: Tue Oct 05, 2021 11:56 am    Post subject: Reply with quote

Thanks Engineer  Gavarraju ji ,  appreciate yr response.
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 General Discussion 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 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