Mat Foundation Issue

Hello forum,

I have built a large mat foundation with dead and operating loads in the x, y and z directions.  I have entered the y-direction loads negatively to reflect a downward force.  The mat foundation is supported with piles.  I used the pile position table under the pile layout leaf to place my piles.  When I analyze the model, my pile reactions do not equal the downward force which is being applied to them.  Does anyone have any ideas on what I might be doing wrong?  I can get into more detail if anyone might have any ideas on this boondoggle.  Thanks!!

JP

  • I suggest you run the model on SFA 9.7.0.87 and check the value again. One of the errors that was fixed recently involves the soil pressure calculation for a mat that is supported on soil and piles. Here is the description from version 9.7's What's New section of the defect that was rectified.

    19. An error was present in the highest and lowest soil pressure that is reported in the calculation sheet for mat foundations if the mat is supported by a combination of soil and piles. The error was caused by the fact that the soil pressure (force/influence area) was calculated by using the force in the pile spring as the term in the numerator, instead of the force in the soil spring. This has been corrected.

    Also, requesting you to create a new post instead of appending questions on new topics to unrelated discussions like that in this thread.



  • Hello,

    I am having similar issue. I am using STAAD Tank Farm Fnd 3.sfato design a piled mat foundation and my expectation is the maximum base pressure of the mat should be very small but what I am getting looks unreasonable high and I can't to be able to reconcile the total pile reaction with the maximum mat base pressure. See the  model file attached.

  • hi to everyone, i have staad foundation 4.0, but ive got an error when i process to analyze, which this file were imported from staad pro v8i. and i have windows 7 64 bit, is my version compatible with my os? i am new to SF, is there any website that can i get some example for SF for my guide only? thankyou very much.

  • I am new to STAAD Foundation and am having a similar issue.  My project is to put a new building on a new mat foundation which is supported by existing (unevenly spaced) piles.  I want to import my building model from STADD.pro into Foundation and see how the existing piles behave.  

    I am trying to get acquainted with Foundation by following Example Problem 7.2 "Mat Foundation Example" which is included in the program's help file.  However, instead of modelling the mat foundation as supported on soil, I want to support it with user defined piles (locations and allowable capacities).  When I built this Example model, I put in a random group of piles using the "Pile Position Table" leaf, and I did not check the box for "Use Soil Spring" in the "Soil Property" leaf.  In the "Pile Spring" leaf, I have Kx = 360 k/ft, Ky = 1000 k/ft and Kz = 360 k/ft.  However, when I try to run this model, I get an error that says "No pile or soil support defined.  Stopping analysis..."

    Can anyone offer guidance on how to model a mat a supported only on piles?  

  • I need the file to have a look at what has happened to this issue. Better still, if you log in a service ticket with the technical support group, who will be looking at it with priority.

    Sudip Narayan Choudhury