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Winter 2009
Dear Colleague:

These quarterly newsletters are intended to keep you informed of changes to Retain Pro and give pointers for its use This is our 13th. All previous issues can be retrieved from our home page by clicking on NEWSLETTERS. There is valuable information in them, particularly the Technical Topics sections.

Over 10% of our over 4,000 users are not getting these newsletters because they have not updated their email address. It's easy to update. Just go to our Support page and click on Change email address.

New Release 2007Q is now available

A new update, release 2007Q, is now available. Click "Yes" when prompted to check for updates (version 2007 only). Alternatively, you can retrieve it from Settings → AutoUpdate, or download it from It contains minor clarifications and enhancements which are described on our Support page under Maintenance Announcements.

How's the economy affecting your firm?

We've been running a survey on our home page but it is now outdated with changing economy events. To see how you're doing now, we're resetting the responses back to zero and hope you will record your updated outlook for 2009. The four questions for how your firm foresees the remainder of 2009 are: More work, About the same as 2008, Significantly less work, or Drastically less. The results can be viewed, and will be interesting!

The just-ended survey gave the following results:
More work19%
About the same as 200822%
Significantly less than 200830%
Drastically less29%

Participate, and let's see how things look for 2009!

New edition of Basics of Retaining Wall Design coming!

The current 7th edition is SOLD OUT. Look for a fully revised and expanded 8th edition, with more design examples, to be available about May 1st.

Technical Topics

Think seismic factors are too high?
So do we, and most of you. Granted, we have not had the "big one" yet, but considering the lack of evidence of seismic damage to retaining walls during the earthquakes we have had here is California, the current code requirements can impose significant and unwarranted costs to owners. There has been some action to loosen the requirements, particularly in Los Angeles City and County. For more on this and what you can do, see the Fall, 2008 newsletter, and comments on our online user forum (access from our home page).

Seismic kh factor
The kh seismic factor for entering into the Monnobe-Okabe equation for determining KAE for seismic earth pressure is obtained by kh = SDS / 2.5 per IBC 1802.2.7, and also cited in NEHRP and CBC '07. Some geotechnical engineers give the seismic force as a "multiplier" of the retained height. For example, Pseismic = 0.5*20*H*H, and suggest an inverted triangle pressure distribution for the seismic pressure. The multiplier "20" is obtained from (KAE - KA)*(effective soil density) and therefore dependent upon knowing the phi value of the soil. Be cautious when using the multiplier because it can vary significantly for varying backfill slopes. We recommend asking the geotechnical engineer for the soil phi value, then choosing the Rankine Method and inserting the phi value. The resulting KAE and KA values will be slope adjusted and will then be displayed on the seismic screen and conform to the Mononobe-Okabe equation.

The most common tech support question
We get many questions asking why, when they try to install Retain Pro on another computer, they get a message: That license has already been used. Here are three reasons it appears, and the solutions:

  1. The user has already used his/her allowed number of activations (4 or 12). In this case one computer with Retain Pro must be deactivated to free it for another activation. To do this follow instruction #8 on Installation Procedures posted on our home page (
  2. Anti-virus software was not turned off during installation. If company policy prohibits this, use [Manual Activation] which is accessed by Settings > Licensing. You then email us the codes displayed and we will email back an unlocking key.
  3. You may have a network license which allows only one installation which must be on to your server. You will get the above message if you try to install on a separate computer, or to a network license. For server installation follow #2 on Installation Procedures (
If the problem persists, email details to Remember that if you have a small office license with four allowed activations you can always upgrade online to twelve allowed activations.

Requesting technical support

If you email us for tech support ( please include your name, company, phone, and you must include your registration number (RP-xxxxxxx). If we do not respond within two business days please resend. If you leave a phone message please give your company name and phone number first -- and clearly.

Suggestions and comments.

If you have suggestions, comments, or a technical item to contribute, we want to hear from you. Email me at


Hugh Brooks, PE, SE
Retain Pro Software

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