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Software Licensing Terms

Privacy and Cookies

We may change this privacy notice from time to time by updating this page.

What information do we collect?

When you use this website, we may collect the following information:

  • the areas of the website that you visit
  • information about your computer, such as which browser you are using, your network location, the type of connection you are using (e.g. broadband, ADSL etc) and your IP address

We do this by using cookies, which are small files that help us track how our visitors use the website and enable us to understand where we can improve your experience. If you would like to find out which cookies we use and the information they track see our Cookies Policy.

Once you submit or register information through our website we will know who you are and your activities on this website and information about you and/or your company may be recorded on our systems. For example, we may ask for personal information when you download our software including:

  • your name
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We may also collect personal information from telephone calls and/or other correspondence with you.

What do we do with the information we collect?

The information we capture is used for various purposes. The main purpose is to provide you with our services (whether available via the website or offline). We also use the information for:

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We would like to provide you with information about our services and other information which we think you may find interesting. We may send you such information by post, email and/or telephone, unless you have asked us not to do so.

We will not provide your personal information to other organisations for marketing purposes without your explicit consent.

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Who do we share this information with?

We may share your personal information with companies acting on our behalf who will only use the information to provide that service. However, we will retain control of your data and any third party service provider that we use must act in accordance with our instructions. We may also share your personal information with a purchaser or potential purchaser of our business.

In some circumstances, we may have to disclose your personal information by law, because a court or the police or other law enforcement agency has asked us for it.

How to get copies of or amend the information we have collected

You may request details of the personal information that we hold about you under data protection laws. If you would like a copy of the information held about you please write to us at oasys@arup.com or at: Data Protection Officer, 13 Fitzroy Street, London, UK, W1T 4BQ. Please note that we may charge a small £10 administration fee for information requests.

If you think any information we have about you is incorrect or incomplete, please email us as soon as possible. We will correct or update any information as soon as we can.

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Data Security

We are committed to ensuring that your information is secure. In order to prevent unauthorised access or disclosure we have put in place suitable physical, electronic and managerial procedures to safeguard and secure the information we collect, including locked cabinets, electronic password protection and pass card access to buildings.

If at any point you suspect or receive a suspicious communication from someone suggesting they work for Oasys or a website claiming to be affiliated with Oasys, please forward the communication to us or report the incident by email to oasys@arup.com or in writing to Oasys, 13 Fitzroy Street, London, UK, W1T 4BQ as soon as possible.

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Website Terms and Conditions

The contents of this web site are protected by copyright and other intellectual property rights under international conventions. No copying of any words, images, graphic representations or other information contained in this web site is permitted without the prior written permission of the webmaster for this site.

Oasys accepts no responsibility for the content of any external site that links to or from this site.

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Software Licensing Terms

Terms and Conditions of Purchase

The full conditions of purchase and maintenance for all Oasys software are set out in the Oasys Software Licence and Support Agreement. All prices are subject to TAX at the current rate.

Prices and specifications are subject to change without notice – please ask for a written quotation.

Although every care has been taken to ensure the accuracy of all information contained herein, the contents do not form or constitute a representation, warranty, or part of any contract.

Superseded Versions of Terms and Conditions

Oasys keeps copies of all superseded versions of its terms and conditions.

Maintenance & Support Services

Twelve months support and maintenance is included with most products. Thereafter maintenance is typically 20% of the current sales price.

An annual maintenance service is available for most programs after the first year.

This service includes:

  • telephone/fax/email/web based support
  • free software updates available via internet download
  • personalised output header for many products

Frew FAQs

Find the answer to frequently asked questions from existing users.

Most popular FAQs

Yes, now it is possible to print all the output stages in Frew using batch plotting.

This problem was due to a bug which was fixed in Frew – 18.2 Build 1 (Release 8).  Batch plotting was revised for Frew 19.0.

This problem (nonsense values for strut forces) was due to the data entered in groundwater table for two of the stages. Two peizometer data entries on the same side of the wall were specified at the same level. This error can be overcome by giving a slightly lower elevation for the second record.

Screenshot of error

You can apply a prestress using Frew. Please refer to strut section of the Frew help file to know more about how it is done. You can model any nodal load acting at certain angle by entering a strut with prestress and zero stiffness.

All FAQs

Version Details Fixed in
17.8.6 and earlier Single precision calculations could lead to inaccuracy, usually indicated by bending moments occurring below the wall. All later versions
18.1 build 5 MEFP and undrained pore pressures together could give erroneous results 18.1.7
18.1 build 5 Partial factors not applied correctly when passive softening also used 18.1.10
19.0 Incorrect results when water table at top node and undrained pore pressures
19.0 Odd results when Kr set incorrectly for undrained material
19.0 Surcharges, Kac and Kpc not correctly applied for stability calcs
19.0 Factors on UDL and strip loads incorrectly applied 19.1
19.1 UDL not applied in stability calc, if carried out immediately after data input

See the Change Log for other minor fixes.  This table lists major fixes which may have affected results in earlier versions.

Non-convergence at any analysis stage will halt the analysis and output will only be available up to the failed stage.

If the lack of convergence is in Stage 0, this is often due to the application of a UDL at ground level.  This creates a numerical anomaly at the top node, because in Stage 0 the wall has not yet been inserted.  Try moving the load to a level between the top and second node.

For later stages, try increasing the number of iterations, if the iteration progress messages indicate that the errors are reducing.  The number of iterations can be edited in the Convergence Control dialog.

The reason for this is explained in the Help file topic :

Detailed Processes in Frew -> Creep and Relaxation

You should apply wall relaxation instead of manually changing the wall EI and this will correctly model the change from short to long term wall stiffness, and you’ll see the effect on the moments and deflections.

You just need to copy the bitmap to the Windows clipboard first.  Once it’s there, Paste will put it on the titles dialog.

If the wall elements are very short and stiff, the program will not compute the stresses / bending moments accurately from the displacements. The problem can usually be overcome by increasing the distance between nodes. Also please make sure that spacing between the nodes does not vary greatly(max spacing to min spacing ratio should be typically limited to  around 2).

This problem was exhibited In one example with a spacing of 0.2 m between most of the adjacent nodes, with occasional spacing of 0.1 m. If the spacing was increased to around 1 m, this problem does not seem to occur.

This problem was particularly severe in pre-17.8.6 version of Frew (and DOS Frew) which had lower precision calculations.

In the undrained stages – drop the “data” pore pressures completely out of the undrained material – if they are absent, the effective stress check should be bypassed.

Frew 19.0 and later versions deal with this automatically and this error should no longer occur.

The preload is merely a load that is applied to the strut before a Stage is analysed. The final strut load for that Stage will consider that preload, but adjust the load in the strut in order to maintain equilibrium in the model.
To use the passive softening feature, there must be undrained material at the current excavated level.  Once this is the case, the option will become available.  You then set the level of the softening surface.  The undrained strength of the material will vary from zero at ground level to the specified “global softening” percentage at the softening surface, then continue at that percentage below.  
Frew and other similar programs make a number of assumptions and simplifications in modelling the relatively complex situation of staged construction of a retaining wall.   These assumptions include, for example:-         
  • Neglecting or simplifying the likely effects of wall friction
  • Simplification of the action of structural supports (by treating them as springs fixed at one end) Very early versions of Frew considered only a “smooth” wall, which would tend to overpredict displacements.
  • Consideration of vertical shear on the wall was added in the early 1990s and significantly improved the results when compared with finite element analyses.
However, some overprediction can still be observed. Other points which are thought to be relevant to this are:-          
  • In the initial stages the ground may exhibit higher stiffnesses which are not represented by the linear elastic stiffnesses used in the program-
  • The ground may be partially saturated and have its strength and stiffness enhanced by suction It is difficult to give an estimate of the amount of over-prediction, given the variability of each individual site and local conditions.
Frew does compare well with similar programs and with finite element analysis, and various illustrations can be found in the literature.  There are some comparisons published in Ciria report C580, for example.

This can be found in the Frew help manual under topic Method of Analysis-> Total and Effective Stress -> Undrained to Drained Behaviour  and Undrained to Drained Example.

For automatic calculation of undrained pore pressures, specify a material from which to obtain effective stress parameters for each undrained material.

 Or to effect a manual switch from undrained to drained behavior without using Frew to calculate the undrained pore pressures automatically refer to the help topic:

Detailed Processes in Frew -> Undrained to drained behaviour – Manual Process

If you want to model pre-stress alone, then the stiffness is set to zero. In this case, the strut force will not be affected by the wall movement. If the stiffness is also entered, then the strut force will change due to wall movements.

The “Set problem limits” option was moved to hang off the “Graphics” menu, along with other aspects of graphics control. Please see “Output -> Graphical Output” in the online help.

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