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Geo Struct Sparks LLC

When Mononobe-Okabe Equation Doesn't Work


Errata on Paper

Posted by geostructsparks on 24 July, 2010 at 9:26

There is an error in the version of the paper to be published online and in the paper proceedings version for the Toronto Conference.  Equation 10, which computes the mass or weight of the soil wedge, has four additive terms.  Each term should include gamma, or the unit weight; it is missing from one of the terms.  This is corrected in the version available for download from the "Parameter Guide" page as of the date of this entry.  This hopefully should be obvious to anyone using the paper since the units have to be consistent.

WASP Conference Paper Accepted

Posted by geostructsparks on 4 March, 2010 at 20:23

Our paper on "Active Wedge Analysis of Seismic Pressure for Retained Slopes" has been accepted for the 9th US National/10th Canadian Conference in Earthquake Engineering has been accepted.  This conference is in July 2010 in Toronto, Ontario.  It provides a summary of the methodology and equations, and benefits of using this alternate method.

A preconference copy of the paper can be reached by the link in the start of the parameter guide.

WASP 1.0.1 License Available

Posted by geostructsparks on 30 November, 2009 at 9:40

The WASP program is finally available for sale!  The last 2 to 3 weeks have been taken up with learning or trying to learn how to make the purchase work on the web.  There have been a number of obstacles thrown up, which I think we have finally overcome.  Its not elegant, but hopefully it works.  With this task completed, I intend to focus on writing up the online help.  I will have screen shots of the program up in the "About WASP" page in a day or two.


The odyssey started about 4 years ago, when I first prepared WASP on a spreadsheet.  I wrote WASP towards the end of a specific project (more later) because I could not find a wedge analysis in online sources or in literature that was reasonably cost effective to check the seismic active pressure (I did see a Culmann Analysis module available for $3000!).  While I have continued to search and not find anything particularly applicable, there may be some codes out there that do the same thing.  We hope that with the added bells and whistles (being able to observe on screen the predicted failure wedge, incorporating displacement-based design into the analysis) we have made this program a useful tool for design that you will find cost-effective to purchase.  When we started Geo-Struct Sparks 8 months ago, essentially to license this software, we determined that we would develop the spreadsheet into a standalone program.  Thanks to Chris Cortopassi provided excellent programming services.