 |
| Fall 2007 |
|
In this Newsletter
Dear Colleague:
As 2007 comes to a close, we hope it has been a good year for you, and of course we hope that Retain Pro has contributed to your "bottom line"! Although a construction slowdown is predicted next year, we notice only an increase in sales. We hope this is a sign you are busy too and will continue to be in 2008! Change in licensing systemBeginning shortly we will be adding one more step to your installation procedure. After downloading the software and after entering your Product Activation Code (PAC), you will be prompted to enter an "Installation Code". This 15 digit numeric code will be assigned to new users upon ordering. Existing users can acquire the code from our Support page. It can easily be pasted into a space provided. This added code will help us control unauthorized use of the software. Otherwise, our licensing is the same: the "Small Office License" allows installation on up to four computers per company site, and the "site license" (soon to be renamed "Network License") for installation on a server allowing up to 25 concurrent users. New monthly survey questionYou will notice on our home page a new feature: a monthly survey question on topics that we think will be interesting to see results. The results will be posted for all to view, after we get a significant number of responses. And it's fixed so no one can vote twice to "load a response". And there will be no political topics! Take a look and cast a vote. About these newslettersFor those of you who are new users, these quarterly newsletters keep you updated on what we are doing, and discuss technical issues related to retaining wall design. If you missed a previous newsletter, they are all posted on our home page. In past newsletters we've posted many topics on a range of technical issues related to retaining walls. You'll find useful information in them. Is AutoUpdate keeping you current?The latest update is Retain Pro 2007J with date 21-Dec. 2007 Still using version 2005 or earlier?You're missing many valuable new features, such as segmental retaining walls (gravity or MSE), pier foundation option, masonry option to use LRFD, water retention option, an Equation Menu to quick-solve a dozen complex equations, new user's manual with more design examples, and other improvements. Version 2007 has been updated to IBC '06, CBC 2007, and MSJC '05. Upgrade discounts begin at $195. You can download the program immediately after ordering - no more waiting. For features, a demo, and ordering click www.retainpro.com. Had a crash, bought a new computer, and can't find your PAC?No need to call us - just retrieve it from www.retainpro.com/support. You'll need your password. More segmental retaining wall vendor choicesWe've included most of the major vendors in our database, but if you want another vendor added, all we need is their current ICC Evaluation Report. From that we can enter their technical data for inclusion in an upcoming AutoUpdate. CalcTracThis feature of Retain Pro - a line-by-line trace of calculations leading to a result - was to be dropped since it is usually quicker to check a result by a hand calc than to use CalcTrac. However, many of you were adamant about keeping CalcTrac, so we are revising and updating it and hope to release a new version soon. We'd like your comments on this? Windows VistaI've switched to it and have experienced no problems - except familiarization. . When requesting technical supportIf you email us for tech support please include your name, company, phone, and your registration number (RPxxxxxxx). And if you fax a calculation report printout be sure your company name appears in the title block (you create it from the Settings screen). Technical issues
Code requirements for seismic design of retaining structures are explained in FEMA 450-2, 2003 (NEHRP Recommended Provisions). Here is a link:
http://www.bssconline.org/NEHRP2003/comments/C7.pdf Global stability primer Global stability analysis is used to determine the factor of safety against failure, either by circular rotation or wedge type failure, of the soil mass encompassing the retaining wall system. It is generally required in situations where a segmental wall - or conventional retaining wall --is combined with a slope either at the top and/or at the base of the wall, or tiered wall systems. Presence of a slope and surcharging structures on the level grade at the top of the slope may also warrant global stability analysis to determine the overall stability of the system. If the site consists of poor subsurface soils and the overall stability is a concern, the global stability may be warranted regardless of the surcharge and slope conditions at the top and bottom of the wall. Geotechnical engineers usually determine the need for global stability analysis and they perform the analysis since they will have information regarding the subsurface soils and bedrock and shear strength parameters. The geogrid reinforcement, which has high tensile strength, incorporated within a segmental wall, adds to over all resistance against shear within the reinforced zone. Should the factor safety against global stability be low, typical remedies include increasing the length of the geogrids beyond those required for internal stability of the segmental wall. Depending on subsurface conditions, soil improvement beneath the wall by adding geogrid reinforcement or by other measures may also be incorporated in the design. For global stability analysis of slopes, many methods are available (such as the Bishop Method of Slices), and analysis tools consist of published charts for simple conditions to computer programs (not inexpensive) that perform very detailed analysis of complex geometry including soils reinforcement. The cost of the computer programs vary depending on their ease of use, analysis methods incorporated, and presentation of results. Some of the computer programs commercially available, include, PCSTABL5, RESSA, and GSLOPE. Most geotechnical firms have the software to perform the investigations. Seismic design changes coming for SRWs. Rumor has it that NCMA is simplifying the application of seismic earth pressures to segmental retaining walls. Instead of the applied force being an inverted triangle/trapezoid, a uniform load is proposed. This slightly increases overturning but simplifies incremental forces up and down the wall. We'll be in contact with NCMA and report further in the Winter Newsletter. Check Load Factor and Material Data screens. It's always a good idea to check the load factors tab for a new design since you may have changed them (they are editable) and forgotten to change back. Also, on the Material Data screen be sure the values are input as you want them. For example, the IBC '06 multiplier for fm to calculate Em should be 900. Switching data between a cantilevered or restrained wall is now enabled in release 2007H. PLEASE! We MUST have your current email address! Otherwise you will miss our bulletins and these newsletters. It often happens that the person ordering the software, such as a purchasing person, uses their email address, rather than the person in the firm who should receive technical information and these newsletters. You can easily change your email address at www.retainpro.com/support. Just click: "Change email address". Have suggestions or comments? We want to hear them! Email me at hbrooks@retainpro.com. With best wishes for the holidays and a great 2008! HughHugh Brooks, SE Retain Pro Software PS: REMINDER: If you haven't upgraded to version 2007, click on www.retainpro.com and receive the discount (and your tax deduction!) by 12/31/07. NOTE: If you received this Newsletter and you are not the person in your organization who should receive it, please forward it to the appropriate person and ask him/her to go to www.retainpro.com/support and change to the correct email address.
Retain Pro Software div. HBA Publications, Inc. PO Box 826 Corona del Mar CA 92626 949-721-4099 hbrooks@retainpro.com
© 2007 HBA Publications, Inc. All Rights Reserved.
|