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.

Teng's curve
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> SEFI General Discussion
View previous topic :: View next topic  
Author Message
Site Admin
Site Admin

Joined: 21 Feb 2008
Posts: 548
Location: Phoenix Webtech Pvt. Ltd. Mumbai [

PostPosted: Thu Jan 02, 2020 2:13 pm    Post subject: Reply with quote

From rex_alfred

Dear All,

Thanks for the detailed discussion on base pressure calculation of footings subjected to biaxial moments.
In the search for a good paper for implementation of linear soil pressure method with redistributed base pressure, i came across few interesting papers.

1. Determination of Base Stresses in Rectangular Footings under Biaxial Bending - Günay ÖZMEN
2. Analysis of Eccentrically Loaded Rectangular Footing Resting on Soil – A Numerical Approach - Jignesh V Chokshi
3. Analysis of isolated footing subjected to axial load and high biaxial moments and numerical approach for its solution - Bijay Sarkar

These papers have already been extensively discussed in this thread.

I would like to add one more paper discussing the same subject through a different methodology derived from basic concepts.

4. New Iterative method to Calculate Base Stress of Footings under Biaxial Bending - Ibrahim Aydogdu

In my opinion, the method discussed by Aydogdu is by far the simplest to implement on computer.

The stress equation considering that all points of footing are at compression.

Stress equation = F/BL + Mz/Iz*x + Mx/Ix*z

This stress equation becomes the equation of Neutral Axis (NA) plane when stress is zero.

The paper alters this stress equation by adding coefficients a, b, c for stress due to axial load, moment about z axis and moment about x axis respectively.

Stress equation = a*F/BL + b*Mz/Iz*x + c*Mx/Ix*z

The iteration starts with a=1, b=1,c=1, and intersection points of NA with footing edges are calculated if there is tension in the footing.

The force is calculated by double integration of stress equation.
The moments are calculated by multiplying the forces with the corresponding lever arms.

At the end of every iteration the calculated resistance by soil (F*, Mx*, Mz*) are compared to the loads (F, Mx, Mz) applied. If the difference between resistance and force are within allowable limits. The plane formed by the assumed a, b, c is the actual NA plane. Else the iterations are continued by altering a, b, c and thus changing the position and orientation of NA plane.

This method is independent of the shape of the contact area of footing.

I felt like updating the thread with this nice  paper published in 2016.

Hope it is useful for the community.

Wish you all a very happy year 2020.

Rex Alfred
Back to top
View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger
Display posts from previous:   
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> SEFI General Discussion All times are GMT
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9
Page 9 of 9


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