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.

pedestal design for light pole
Goto page 1, 2, 3  Next
 
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> New Members make Test Posts
View previous topic :: View next topic  
Author Message
dubeyratnesh
SEFI Regulars
SEFI Regulars


Joined: 21 Mar 2022
Posts: 38

PostPosted: Fri Apr 01, 2022 9:13 am    Post subject: pedestal design for light pole Reply with quote

hello sir i want to design a pedestal with footing on soil having sbc 8 t/m2.pedestal is supporting 9m high light pole in an area having basic wind speed 50 m/s.
what approach we can follow to design this pedestal and footing
Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3851

PostPosted: Sat Apr 02, 2022 3:32 am    Post subject: Reply with quote

Pedestal & footing  for high mast

Wind load is predominant and substructure is designed for moment due to wind forces on high mast body.

Generally square pedestal and square shape footing for ease of reinf placement vis a vis circular one.

Footing size as also foundation depth shall be sufficient enough to provide soil weight over footing . Footing shall be checked for overturning  . Sliding may not be a problem but to be checked .

Base pressures needs to be checked considering some upliftment of footing due to wind.
e = M/W
M is the moment at base due to wind forces
W is the wt of footing + soil wt over it + wt of steel mast
The contact length X = 3*(B/2 - e)
B is the dimension of footing in direction of moment
Contact Length percentage = (X/B)*100

Contact %  can be 67% to 80% depending on FOS against OT

Max base pressure = 2*W /( X*L)
L is the dim of footing in other direction

Some designers also consider passive soil resistance relief with some FOS provided by rcc pedestal and footing
Back to top
View user's profile Send private message
dubeyratnesh
SEFI Regulars
SEFI Regulars


Joined: 21 Mar 2022
Posts: 38

PostPosted: Sat Apr 02, 2022 3:38 am    Post subject: pedestal design for light pole Reply with quote

SIR ON WHAT BASIC DEPTH OF PEDESTAL WILL BE CALCULATED OVER FOOTING.
Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3851

PostPosted: Sat Apr 02, 2022 10:50 am    Post subject: Reply with quote

Pedestal shall also be rcc in square crossection .

Pedestal is designed as vertical cantilever  from footing .

Depth of foundation for 9.0m mast may be minimum 2.5 m . But all depend on soil weight needed over footing . If foundation size is restricted , then higher depth of foundation is needed to achieve soil weight.
Back to top
View user's profile Send private message
dubeyratnesh
SEFI Regulars
SEFI Regulars


Joined: 21 Mar 2022
Posts: 38

PostPosted: Sun Apr 03, 2022 11:36 am    Post subject: Design of pedestal for electric pole Reply with quote

Thank you sir
From where we can start ? On what basis we can select hight of pedestal.? Taking factor of safety about 1.5 for overturning the hight of pedestal is coming more than 4 meter which is not feasible.a 9 meter hight pole on cyclone effected area gives more wind moment? Weight of pedestal resisting will be more? How to decide pedestal hight.further footing design?
Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3851

PostPosted: Sun Apr 03, 2022 3:45 pm    Post subject: Reply with quote

You are thinking of block foundation for light pole . I think in this case Pl think of rcc spread footing with soil over it  with rcc pedestal. The concrete block foundations are feasible for low ht light poles , but not for high mast which require spread footing with rcc pedestal.
Back to top
View user's profile Send private message
dubeyratnesh
SEFI Regulars
SEFI Regulars


Joined: 21 Mar 2022
Posts: 38

PostPosted: Mon Apr 04, 2022 3:06 am    Post subject: Design of pedestal for electric pole Reply with quote

Sir can you provide any design example of high mast from any refrence book or previous design?
Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3851

PostPosted: Mon Apr 04, 2022 4:05 am    Post subject: Reply with quote

I don't think that any ready standard design / details available , but you can search NHAI or Highways / Expressways for any ready material.

But it is a simple case of designing an isolated spread footing for Uniaxial moment. Footing need to be square as wind can blow in any direction .
Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3851

PostPosted: Mon Apr 04, 2022 4:39 am    Post subject: Reply with quote

Pl see in google search details  for standard street light pole upto 35 feet high Search P-660.pdf on Google.

Last edited by vikram.jeet on Mon Apr 04, 2022 5:40 am; edited 2 times in total
Back to top
View user's profile Send private message
vikram.jeet
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 3851

PostPosted: Mon Apr 04, 2022 5:03 am    Post subject: Reply with quote

Please see in google search for light pole design calcs , are available in net
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 -> New Members make Test Posts All times are GMT
Goto page 1, 2, 3  Next
Page 1 of 3

 

 
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