Settlement calculation using Excel spreadsheet

[Matthewxt]

I am looking for spreadsheet programs to calculate soil settlement. Is there anyone has spent your valuable time and effort to develop such programs?

 

[STVU]

Coduto's "Foundation Design" book has a nice table format that you can follow easily. It is best to do long hand method for several months, till you get a feel of what the output range will be, prior to using spreadsheet. Otherwise, how would you spot 1.5" settlement from 3.0" one?

You have to be able to say-"It can't be right" or "Makes sense"

Using spreadsheets by others, also will make you copy their built in errors without knowing it. Besides, for computing stresses, did the spreadsheet designer use Westergaard or Bousinnesq? What about if you have layered soils or crust over soft subsoils-are those spreadsheets still applicable? Try longhand and then develop your own later.

 

[msucog]

agreed...do it by hand for a while then generate your own. it's extremely difficult to develop an all-in-one spreadsheet for every possible scenario...so consider developing a few different pages for particular scenarios you encounter. all it takes is one assumption about someone else's spreadsheet to be incorrect and the numbers could be way off.

but it is nice once you've developed on that can do calcs for several different locations based on the condition you set up. i've found that even with a well developed spreadsheet, you often must make minor adjustments to the spreadsheet for something specific to the job. but once it's set up for the project and checks out with a few hand calcs, you can quickly evaluate several different scenarios.

 

[Mccoy]

Also Mayne & Poulos, 1999, give a table format for calculating settlements with a spreadsheet, pretty neat:

P.W. Mayne and H.G. Poulos, Approximate displacement influence factors for elastic shallow foundations, ASCE J Geotech Geoenviron Eng 125 (1999) (6),

 

[oldestguy]

I used the Hough Bearing Capacity Index method to assign a figure to any kind of soil, granular or cohesive. You then can write a program to use for any soil types or mixtures.

You can compute this Index by using lab consolidation tests as usual, or you can use the Hough chart relating this index to blow count for different soil types Of course assumptions along the way may be rough.

I note that the LRFD design manuals use the Hough method as part of their procedures. I believe the Ohio DOT has adopted it also.

Unfortunately his original paper back in 1959 (ASCE SM4 Journal #2135)"Compressibility as the Basis for Soil Bearing Value" is not in any available WEB site that I know of.

His text book :"Basic Soil engineering" also is out of print.

In general if has been found the chart relating to blow count results in conservative settlement results by a factor of 2.