Retaining Wall Analysis Program

WALLAP Version 6.09
Copyright Dr D.L.Borin  2026
Distributed by Geosolve, London, UK
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Retaining Wall Analysis Program  -  WALLAP   Version 6.09
Revision  A60.B78.R61                                              May 2026
Bug fix
WALLAP Version 6.08 introduced an error in the calculation of seismic pseudo-dynamic loads, this bug has been corrected. Note that this was a conservative error that overestimated the pseudo-dynamic load only, any quasi-static and all non-seismic analyses are unaffected.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.09
Revision  A60.B77.R61                                       October 2025
License system update
Added support for Keylok dongles. 
Revised Help for Moment of Inertia of Walls and Single Piles 
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Retaining Wall Analysis Program  -  WALLAP   Version 6.09
Revision  A60.B77.R61                                             April 2025
Bug fixes
Corrected the prop force sign convention (+ve to the right; -ve to the left) and also the display of "Slack" as appropriate in Shear Force and Bending Moment tables.

New features 
Additional data warnings for soft layers below toe of wall (Subgrade Reaction)  or lower rigid boundary rigid boundary (2DFE).
The Turbo option for Wedge Analysis now offers a default Turbo Factor (2)
Additional advice on specification of wall friction
Soil properties: Compatible Earth Pressure Coefficients
Full explanation of "Compatible Earth Pressure Coefficients" and further simplification of the input of soil strength parameters and earth pressure coefficients. The Notepad facility and EC7 formula will be selected automatically when any of the analysis options requires "Compatible Earth Pressure Coefficients"
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Retaining Wall Analysis Program  -  WALLAP   Version 6.09
Revision  A59.B77.R61                                        January 2025
Bug fixes
Wedge Analysis - unusual active wedge mechanisms. 
Where there is soft cohesive soil and/or a steep slope, or a heavy surcharge at ground level, set back from the wall, critical active wegdes may have a shallow exit angle at the wall. In such a situation, wall friction is kinematically implausible. The program will now automatically ignore wall friction in these cases.

Single Pile Analysis
The previous release introduced an error that meant that the right hand side soil type could not be edited while in single pile mode.  This has been corrected.

New features 
Soil Properties 
In the soil properties menu there is a new layout to simplify the input of Ka/Kp directly or as functions of φ and δ.

Soldier Pile Wall Analysis. 
Output has been redesigned to include results both per unit length of wall and per pile.

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Retaining Wall Analysis Program  -  WALLAP   Version 6.09
Revision  A59.B77.R60                                         August 2024

Bug fixes
Anchor Free Length.  
Errors in graphical display in certain cases have beeen corrected. Tabulated values were correct.

Summary output for slack props.
Version 6.08 (October 2023) introduced an error in the Summary output for slack props.
Slack props were shown with negative force values instead of "Slack". Bending moments 
and all other results were correct.

Wedge Analysis.  
Correction of several graphical display errors including  
 a) Strata display in reverse berms.
 b) Display of stable wedges in high cohesion soils

New features 
New parameter in Surcharge definition 
The new parameter, "Surcharge Type" clarifies the distinction between Surcharges which are:
1.	Structural surcharges at or below Ground Level (The original basic type of surcharge)
2.	Soil surcharges which represent Soil Fill.
3.	Structural surcharges on top of Soil Fill
Surcharge data from previous versions is interpreted and saved in the new format.
Data saved by Version 6.08 in the new format will, as far as possible be understood by previous versions.

Single Pile Analysis. 
Output has been redesigned.  For piles loaded at multiple orientations, the tabulated output shows envelopes of shear, bending and displacements at each stage. 
For each stage there is a Critical Orientation, the orientation of the maximum bending moment, for which full details are shown.

Steel Sheet Pile Section Data
Steel Pile Section data has been fully updated including new tables of Ultimate Moment Capacity for the range of Steel Strengths and Classes of Steel Section
Data for older discontinued sections can still be referenced.

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Retaining Wall Analysis Program  -  WALLAP   Version 6.08
Revision  A57.B76.R60                                      February 2024

This was an intermediate release. The cumulative revision list as of August 2024 is given above.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.08
Revision  A56.B75.R60                                       October 2023

Bug fix
Revised Turbo option for speeding up Wedge Analysis
The Turbo option in Version 6.07 could lead to erratic pressure profiles. The revised option allows for a more controlled adjustment of the number of nodes omitted from the limit pressure profiles.

New features 
WEDGE ANALYSIS
Display of wedge mechanisms
The graphical display of results now includes an additional option to view the critical active and passive wedges at each node elevation. This gives important insight into the effect of surcharges, weak strata and berg geometry on potential failure mechnisms.

ANCHOR & STRUT GRAPHICS
Graphical output now makes a distinction between the portrayal of Struts and Anchors. Struts are shown on the excavated side, Anchors are shown embedded in the soil with an arrow on the outer face of the wall to indicate the force on the anchor plate. The data values of Strut and Anchor (free) lengths are shown to scale. Strut and Anchor inclinations are shown according to the data values.

ESTIMATED MINIMUM REQUIRED ANCHOR FREE LENGTH
Free anchor length is the unbonded part of an anchor in the active zone which may be part of a failure mechanism. There is no simple rule for estimating the position of all the relevant failure mechanisms. However the Wedge Analysis option provides exactly this information taking account of strata geometry and surcharge loads.

Version 6.08 introduces a new calculation which looks at the point of intersection of each anchor with the relevant active wedge mechanism at each stage. Codes of practice disagree as to the proper rule for determing to what depth the wedges should be considered. WALLAP adopts a simple rule based on the point at which passive pressure exceeds active pressure i.e. a point below which there is no tendency for the wall to fail by forward movement.

Estimated Minimum Anchor Free lengths are indicated on the graphical output at each stage and tabulated in the summary results.

PROP LOAD SIGN CONVENTION
According to context, we use two different sign conventions for loads applied applied to the wall
1.	When looking at the Bending Moment and Shear Force distribution in the wall, prop loads (or other loads applied to the wall) are regarded as Positive to the Right and Negative to the Left.
2.	In the Prop Force summaries:
     Compression in a Strut is Positive
     Tension in an Anchor is Positive

SURCHARGES
Structural surcharges on top of a Soil Surcharge
Version 6.06 (August 2018) introduced Soil Surcharges which allow the user to model fills of any profile. However there was no option to place a Structural Surcharge on top of the "fill", such as a train on a railway embankment.

Verison 6.08 introduces just such an option which, in conjunction with the Wedge Analysis allows more accurate modelling of potential failure mechanisms and Limiting Active pressures.

Short surcharge correction factor
"Short surcharge" means a surcharge which is short in the direction parallel to the wall. 
The correction is only relevant when calculating active and passive limit pressures by the Wedge Analysis option. Originally, the Wedge Analysis (based on a 2-dimensional slope stability calculation) took no account of the length of the surcharge; short surcharges were treated as if they were infinitley long. The errors were on the safe side and warning messages were given. The most severe errors might have occurred, for example, in the case of a heavy crane base adjacent to the wall.

WALLAP 6.08 introduces a refinement to the rather simple correction first introduced in 
Version 6.07

BERMS
Reverse Berms
Version 6.08  introduces the Reverse Berm which slopes upwards away from the wall. WALLAP's built-in calculation of passive limit pressures for Normal  Berms (sloping down away from the wall) does not work for Reverse Berms. You must specify the Wedge Analysis option to deal with reverse berms, either active or passive. A new Data Error message enforces this rule.

Modify berms by filling
Version 6.08 introduces the option to modify both Normal Berms and Reverse Berms by filling.
Each fill layer can have a different soil type

NON-LINEAR MODULUS PARAMETER
The program now offers a default value for the Non-linear Modulus Factor “L” 

IMPROVED HELP

2DFE and Subgrade Reaction options
Discussion of the relative merits of the 2DFE and Subgrade Reaction options has been expanded with specific advice on when to use them.

“Unable to calculate a FoS”
There are more detailed explanations of the specific reason for this message in each case.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.07
Revision  A55.B74.R58                                        October 2020

Bug fix
Batch Analysis did not always work properly.
Sometimes not all the files in the folder were analysed.

New features
Improved analysis of Short Surcharges.
WALLAP 6.07 introduced a correction factor to take account of the finite length of a short surcharge as compared with an infinite long surcharge when calculating active and passive
limit pressures by the Wedge Analysis method. This correction has been further improved 
- see above.

Notes files
An important new facility to enable users to keep track of their data and results.
A Data file can now have an attached Notes file. The Notes filename is chosen by the User and is specified in the Titles section of the WALLAP data. Notes files are fully formatted and can include graphics.  Notes files are intended for recording:
    Aims and objectives of a set of analyses,
    Main assumptions and sources of information,
    Key results, observations and conclusions.
The same Notes file can be shared by several data files.

Help feature when viewing results
Right-click on blue underlined text to link to the associated Help Topic

Prop forces at each stage  (horizontal components)
Stage   --- Strut no. 1 ---
 No.       at elev. 0.00   
         kN/m run  kN/prop 
  3       25.48     25.48  
  4       24.35     24.35*
  5       23.25     23.25*
  6       22.14     22.14 
  * Indicates that the total force shown is the sum of the force in the prop plus a force applied at the same elevation which may represent  temperature load or other forces which are part of the prop load. Force components are listed in the detailed results for individual stages.	

Knowledge Base 
The previous collection of Example Data files has been expanded and is now called the Knowledge Base. Data files are linked to an accompanying Notes file (see above). A search facility allows the user to find all data files associated with a group of search key words entered by the user.

File Open Menu - Recently used files 
The option for re-opening recently used data files has been greatly improved. It now offers 2 levels of file history;  the last 15 folders and the last 15 files from within each folder. 

Wall properties - Moments of Inertia of Pile Sections
When editing the 'Moment of Inertia' there is a Help option (press <F1>) which brings up a list of Sheet Pile sections. There is now an option to choose the way the list is arranged - either by Section Name (as at present) or by  I-value.
This makes it much easier to see all the pile sections of similar I-value.

Soldier Pile data entry
Stiffness (EI) of Soldier Pile sections is now in terms of EI per pile (and not per m run). The equivalent value (per metre run) is displayed automatically.

There are now lists of Universal Columns and Universal Beams for use as Soldier Piles to assist in the selection of Soldier Pile sections as described above for sheet piles

Keeping track of Users on a Network License
The latest Network licensing system can display a list of all the current User and Computer ID's.

Improved facilities
Copying marked text from Results listings
When Viewing Results there is an improved facility for copying marked text
(to clipboard) from the Summary, Detailed Results and Data Listing. There is
a copy option in the (right-click) popup menu or simply type Ctrl C

Berm calculation
Improved smoothing of passive pressures calculated by the WALLAP berm method (not Wedge Analysis)

Integral Bridge. Special Soil Parameters.
There is now a direct link from the main Soil Properties input to the tables of additional properties required for Integral Bridge analysis. 

Change Wall Stiffness  and Yield Moment
The Construction Stage "Change EI of Wall" has been reorganised. Changes of EI and Yield Moment are are no longer defined in a single stage. Old data files are automatically adjusted (creating an additional stage as necessary) and a warning message is issued.
The Stage Ouput titles are correspondingly clearer.

Negative effective stress error message 
The improved message states precisely where the error has occurred.
     "Negative vertical effective stress on Left  (Right) side at elev 1.23"

Stiffness Matrix Storage
Stiffness matrices are generated as part of the 2D Finite Element analyses. 
The matrices are stored in files of file type
        .01L, .02L etc    and  .01R, .02R etc
Saving the files in this way saves time during repeated analyses of the same or similar data.
Matrix files used to be stored indefinitely in the data folder unless manually deleted by the user. Now they are stored in a sub-folder (\Matrices) of the data folder and are automatically culled (by WALLAP) as follows.
    1. All matrix files more than 2 months old
    2. All matrix files whose parent data file is has been deleted.
The user is not notified of matrix file deletion for the following reasons:
    1. The files are of no use except by WALLAP.
    2. If a data file is re-analysed after its matrix files have been deleted, then WALLAP will 
        simply re-create them with a one-off cost of a small amount of extra computation time.
The benefit is that it keeps your hard disk a bit tidier!

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Retaining Wall Analysis Program  -  WALLAP   Version 6.06
Revision A52.B71.R56                                        March  2019

New features
Improved Contents layout in WALLAP Help file  
New, simplified installation procedure for Network installations and Short Term licenses.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.06
Revision A52.B71.R55                                      January  2019

Bug fixes
A bug was introduced in the previous revision (A52.B70.R55, August 2018).
There were errors in the calculation of Active pressure limits by the Wedge Analysis method.
Coulomb values were used instead of Wedge values in some cases. There was no significant effect 
on results except for cohesionless sloping backfill modelled as surcharges, where the backfill slope 
is greater than phi. Data Warnings have, in any case, always been issued in such cases.
Users of Revision A52.B70.R55 have been notified.

False data error messages concerning "Negative modulus values....". Results were not affected
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Retaining Wall Analysis Program  -  WALLAP   Version 6.06
Revision A52.B70.R55                                          August 2018

New features
Additional parameters for Strut and Anchor definition
All props are now defined explicitly as either "Struts" or "Anchors".
All props are defined explicitly as being installed on the "Left" or "Right" side of the wall.
The "Tension permitted" flag (struts only) is now applied strictly according to which side the strut is installed.  Previously it was assumed that all struts were installed on the right side of the wall. When old data files are read, the user is prompted to select values for the missing parameters. Default values are prompted by the program.

New sign convention for strut forces
In connection with the new Strut parameters (above) the tabulated output employs a new sign convention for prop forces. The sign is defined according to the context:
a) In tables of bending moments and displacements (individual stages):
The sign of the total prop force (including any load applied at the same elevation) 
is defined in accordance with the general (WALLAP) convention for forces acting 
on the wall   i.e. a force acting to the right is positive.

b) In tables of forces for individual props:
   The sign of the total prop force (including any loads applied at the same elevation) is 
   defined in relation to the prop
   i.e. positive for compression in a strut (equivalent to tension in an anchor).

Tension in struts
The criterion for "tension" in struts is now based on the total sum of strut force plus any 
applied loads at the same elevation.

Number of Decimal Places in tabulated values of displacement
By default, displacements are show to 3 decimal places i.e. 1 mm if working in metres
It is now possible to select 4 or 5 decimal places.
The Decimal Place option is found under the Format tab on the WALLAP desktop.

Integral Bridge design
The recent new faciliy for Integral Bridge design has been modified:
a) Revised and improved iterative procedure for calculation of Kp*
b) More automated data input sequence; improved data checking and error reporting

Revised messages and warnings
In "View Results" mode the tabulated results now inlcude links to the help system. 
Click on the highlighted blue underlined text to see further explanation of the output.

The graphical representation of Surcharges now distinguishes between the two 
main types of surcharge:
a) Surcharges which represent fill and are associated with a soil type.
    Soil surcharges are always shown at true height at the same vertical scale as other 
    strata. An envelope is drawn round the soil surcharges to indicate the fill ground level. 
    Soil surcharges are shown in brown.

b) Surcharges which represent applied loads e.g.structural and traffic loading.
    Large non-soil surcharges may be shown with limited height i.e. not to scale.
    Non-soil surcharges are shown in red.

Output options menu
There is an additional caption in the Output options menu:
      REPORT CREATION:  STAGE OUTPUT SELECTION OPTIONS

Limit State factored results in Excel report files
Factored values of Bending Moment and Shear Force are now included in Excel reports
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Retaining Wall Analysis Program  -  WALLAP   Version 6.06
Revision A50.B69.R53                                       February 2017

Additional warning messages
Flow below the toe of the wall
The Warning message about Flow below the toe of the wall has been extended to include situations where the Effective Toe elevation has been changed by modifying the wall stiffness (EI value) 
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Retaining Wall Analysis Program  -  WALLAP   Version 6.06
Revision A49.B69.R53                                     February 2017

Bug fixes
Single Pile analysis with loads at various orientations. 
Minor inconsistencies in the printed results for Critical Orientation

Error when Excavation level is at the toe of the wall.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.06
Revision A49.B68.R52                                     January 2017

New features
Integral Bridge Loading. This is a major new feature. There is a new type of Construction Stage to model the repeated loading due to seasonal temperature changes in Integral Bridge decks. It offers a highly automated way of implementing the design requirements of:
BSI publication PD 6694-1:2011 May 2011
"Recommendations for the design of structures
subject to traffic loading to BS EN 1997-1:2004"

Single Pile Analysis with loads applied at various orientations
This new option allows you to specify Horizontal Loads, Applied Moments and Rotational Restraints acting in different orientations (horizontal directions).  Applied loads, moments and rotational restraints now have an additional parameter - "Orientation". WALLAP carries out a series of analyses with forces resolved in a range of directions to discover which orientation of the resolved forces produces the most critical result governing design.
Geosolve is grateful to Aspin Consulting Ltd for suggesting this new option and for their comments during development.

Batch Analysis
The Batch Analysis option allows you to initiate the analysis of several data files in one run. All data files in the current folder are analysed without interruption. The usual warning messages requiring a response are suppressed.  
The Batch option appears in the "Titles" menu. Having selected the Batch option, the calculation is initiated in the usual way by clicking the Analyse button in the Main Menu.

Wedge Analysis for Active and Passive Limit Pressures
The Wedge Analysis calculation is more robust. The active and passive limit pressures have been smoothed to avoid steps in the pressure diagram where there is no change of soil type.

The new "Turbo" facility significantly reduces the time taken for Wedge Analysis. The Turbo facility is optional in order to facilitate comparison with the old slower method. The faster calculation means that Wedge Analysis can now be used routinely in conjunction with the Strength Factor method for factor of safety calculation. This combination was previously discouraged on account of the immense amount of time taken.

Wedge Analysis option for Seismic Stages only
There is a new option to cut down on analysis time when Wedge Analysis is only required for Seismic Stages. Under Factor of Safety options see the new item
                       Wedge option for Seismic Stages only

Change of terminology in referring to the Left and Right sides of the wall.
Up till now we have referred to the left side of the wall as the "Active" side and the right side of the wall as the "Passive" side. The use of the terms Active and Passive has been rationalised. Active and Passive are now used only when referring to the stress state in the soil; Active when creating a disturbing force, Passive when providing a resisting force.
The analysis is now symmetrical in all respects. WALLAP will now carry out the Factor of Safety calculation whether the wall is tending to fail from Left to Right or from Right to Left.

Report creation
The creation of reports containing large amounts of graphical output has been speeded up considerably.

Bug fixes
Uplift water pressures under a base slab in conjunction with the Wedge Analysis option were not correctly analysed. Fixed.

There was an error in the creation of additional nodes when an Initial Pore Pressure Profile was defined which included pore pressure points above Ground Level.

Unexcavated ground (i.e. excavations of limited width) was NOT modeled in the Wedge Analysis. This may have led to the underestimation of passive pressures in some cases. The effect was on the safe side and is not likely to have been significant.

Error in data listing 
           'Partial factor on Permanent Variable loads'  (!)
     has been corrected to 
           'Partial factor on Variable Unfavourable loads'

There was a bug in the data entry for defining a change of EI of the wall. Error messages relating to changing EI for part of the wall (only) were displayed when changing EI for the whole wall.
.
Additional warnings and messages
There was no warning that you must choose the 2D FE analysis option if a Yield Moment has been specified for the wall.

There was no warning that Relaxation of bending moments can only occur if the EI of the wall is decreased. 

Warnings about FLOW below the toe of the wall have been added to the Summary output. Previously they only appeared in individual stage output.

The Help menu now offers an option to look for a more recent version of the software on the Geosolve website and warn you if your version has been superseded.

The Help menu now offers an option to download the latest version of the User Guide.

The Strut Force Summary sometimes included a redundant message concerning the summation of strut forces when no such forces were present.

There are clearer messages emphasising the limited applicability of the Normally Consolidated Cohesionless model.

The caption of the Soil Modulus (Spring Stiffness) column in the tables of active and passive pressures now make a proper distinction between 2D-FE and Subgrade Reaction values.

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Retaining Wall Analysis Program  -  WALLAP   Version 6.05
Revision A45.B58.R49                                              April 2013

Bug fixes
Improved warning messages when entering new wall properties.
Removal of I/O error messages during extra security check.
Active and Passive limits legend on earth pressure results repositioned.     
Mended overflow error in 2DFE when excavation was at toe level.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.05 
Revision A44.B58.R48                                   November  2012

Reorganisation of ULS options
The two alternative interpretations of ULS Design Approach 1, Combination 1 have been reorganised.

   Combination 1A     has been re-titled "Combination 1"
                                 This is the (more or less) standard interpretation of Combination 1

    Combination 1       has been re-titled "Combination 1 (Alternative)"
                                 The Geosolve advice note on EC7 sets out the thinking behind this 
                                 approach

For most situations it is still advised that one need only consider the SLS situation and ULS DA1 Combination 2  unless surcharges and applied structural load are very significant. See the WALLAP Help messages for further advice.

New feature
Design Factor on calculated Bending Moments and Strut Forces
Some Limit State options require the calculated bending moments and strut forces to be factored in order to obtain design values. You now have the option to specify this factor. It does not affect the WALLAP analysis itself but the Design Factor is applied to the calculated values to obtain design values. The Detailed Results for individual stages show only the calculated values but the Summary Results show both calculated and factored values.

Soil Properties Source file
It is now possible to edit the Datum Elevation of imported Soil Types.  All other soil properties can only be edited from within the Source File itself - as before.

Revised presentation of Strut Forces
Where there is an applied force and a strut at the same level, the Strut Force summary now shows the net force plus a comment concerning the components of the net force.

Bug fixes
Load category was not always initialised.
Excel spreadsheet output files are now named according to Excel version (XLS or XLSX).
Mended problems with network installations where the user did not have write access to the WALLAP folder.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.05 
Revision A41.B56.R46                                            July   2012

Bug Fix
Partial Factors of Safety on Young's Modulus were not actually applied during the analysis. The effect on Bending Moments and Strut Forces will not have been very great - almost always less than 10%.

Minor Revisions
Improved annotation of Limit States associated with Water Pressure profiles in the edit menus.
The graphical display of surcharges in the data now inlcudes the effect of Partial Factors.

Error reporting
A new error reporting system facilitates the generation of email reports of Run Time errors to Geosolve.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.05 
Revision A41.B55.R44                                           June  2012

Minor Revisions

Chinese Windows
Difficulties in viewing results and creating reports have been resolved

Error messages
There was an annoying error message when starting WALLAP 6.05 for the first time.

Older data files
There were errors when reading data files generated by WALLAP 5.03 and earlier. (superseded July 2007)

Limit State Analysis
Additional option for user-defined Limit States 
There were errors in the default/recommended partial factors on applied loads.
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Retaining Wall Analysis Program  -  WALLAP   Version 6.05 
Revision A38.B55.R43                                            May  2012

New features

Limit State analysis
WALLAP now offers a limited facility for the automatic application of Partial Factors of Safety relevant to Limit State design as required by Eurocode 7. From a single set of data SLS and ULS  analyses can be carried out by simply selecting the appropriate Limit State. Partial factors are applied to  

Soil strength 
Soil Modulus
Surcharges 
Loads 

You can also specify alternative water pressure profiles for  Moderately Conservative (SLS) and Worst Credible (ULS) conditions.

Worst case excavation levels (overdig) are not adjusted automatically and must be applied manually by the user as they are not amenable to automatic factoring.

Soldier Pile Walls can now be analysed without the need to scale the passive earth pressure coefficients manually. The advice previously given in Appendix K is now redundant and a new option has been introduced under "Wall Properties" to specify a "Soldier Pile Wall".

Soil Properties Source file
This facility allows you to use a set of Soil Properties defined in a separate data file. This is a convenient way of sharing a standard set of soil properties between all the WALLAP files of one project.

Removal of a highly stressed strut
When a highly stressed strut is removed it is useful to be able reduce the load in stages. This can now be done using the new Strut Removal option which allows you to remove the strut and replace it with an equivalent load. You then apply increments of load in the opposite direction until the nett load is reduced to zero.   
      
Increased Data Capacity

Maximum No. of Data Items	New limit
Version 6.05	Old limit
Version 5.04	
Strata on either side of wall	100	40	
Soil types	100	40	
Struts and anchors	80	40	
Loads and Moment Restraints applied to the wall	80	40	
Surcharge loads	80	40	
Pore pressure profiles	40	20	
Pore pressure points per profile	40	20	
Construction stages	120	80	
Nodes (calculated by WALLAP)	120	80	

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Retaining Wall Analysis Program  -  WALLAP Version 5.04      
Revision A36.B53.R41                            9th November 2011

Bug Fixes
The Arching calculation has been simplified to make it more robust and faster. Calculated wall pressures and bending moments may be slightly higher in some cases.

Some machines with Asian Language support are unable to read the output files. An attempt has been made to fix this problem.

New features
Load applied at the same elevation as a strut
When a load is applied at the same elevation as a strut you have the option to suspend the effect of the strut spring during the application of the load. Details are given in the Help topic 

"Temperature stresses and other loads in Struts/Anchors"

There are new data examples to illustrate the different cases.

Excavation elevation
Excavation elevation can be equal to current Ground Level. This allows the specification of a series of berm excavations where the elevation of the top of the berm does not change.

The minimum permitted Element Length is only adjusted automaticaly if it was already equal to the recommended value.
       
Seismic calculation
 The Quasi-static force which is based on the retained height now includes an adjustment for the case of a passive berm i.e. the "retained height is estimated as if the excavation level is somewhere between the top and the bottom of the berm.

Output and reports
Active and Passive limit pressures are plotted on the earth pressure diagrams.

There is now an option to plot boundary conditions on data graphics in reports.

Report graphics can be plotted in colour.

Progress bar
A brief stage description of the current stage is displayed in the progress bar during the calculation.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A36.B52.R41                              28th February 2011

Bug fix
This bug fix is only relevant to network installations
A recent Microsoft security patch places restrictions on viewing Help (CHM) files that are stored on a network drive. On accessing the Help facilities one might see the message 

               This page cannot be displayed 

This revision circumvents the problem without the user taking any action. On detecting network execution the application makes a copy of the Help file on your local hard drive and accesses it from there.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A36.B51.R40                              6th February 2011

Bug fix
1. An error was introduced in the previous release (Revision A36.B50.R40) in regard to the Seismic  Analysis. The effect of this was to cause the program to assume a constant value of 0.333 for the line of action of the quasi-static force in seismic loading stages. The value entered by the user was ignored.  The line of action of the pseudo-dynamic force was treated correctly. 

2. Revised calculation of the trapezoidal pressure distribution  of seismic forces (Revision A36.B50.R40).
     An extra node is now introduced at the newly calculated "equivalent excavation level"
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A36.B50.R40                          30th November 2010

Bug fixes
Revised treatment of a moment load at the same elevation as a rotational restraint as described in the box below. 

Moment loading via floor slabs which also provide rotational restraint. 
In WALLAP  Version 5.01  Revision A11.B26.R18  (Dec. 2002)  a new facility was introduced which permitted the application of structural moments at the same elevation as an existing rotational restraint. This facility was  intended to be used for modelling the common situation where a floor slab or bridge deck (encastré into the wall)  is subject to live loads which cause moment loading in the wall. 

This new facility created a special case. Where the applied moment was at the same elevation as an existing rotational restraint, the effect of the rotational restraint was suspended during the application of the load.  
It is now realised that this modification was introduced mistakenly. There is no reason to disable the rotational restraint in any circumstances. Re-examination of some actual cases of deep excavations with stiff slabs shows that the errors are unlikely to be serious in practical circumstances.
Further details are given in the WALLAP Help system	

Error in Wedge Analysis when surcharges were placed on top of fill.

Improved calculation
Revised treatment of a horizontal load at the same elevation as a strut. See Help messages for details

Revised calculation of the trapezoidal pressure distribution of seismic forces. Where a berm is present an estimated equivalent ground level is used and its value is displayed in the results in the "Assumptions" section.

Tension is ignored in the Wedge Analysis method for calculating limiting active pressures. A one time message is displayed during the analysis if this rule has been invoked.

Revised algorithm for choice of relaxation factors to improve convergence in Displacement and Bending Moment calculation.

Help file
The Help file is now in CHM format.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A35.B49.R39                                    21st May 2010

Bug fix
There were errors in the last release with the following combination of options and soils data:
             Wedge Stability option 
             Wall friction

Submerged berms
The previous warning message has been removed as the calculation is now known to be reliable.

Apologies to all users for any inconvenience caused.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A34.B48.R39                                   27th April 2010

Bug fix
Overlapping surcharges were not accumulated properly when using the wedge stability option.

Improved features
Improved calculation of active and passive limits by the wedge stability method for cases including berms, submerged berms, limited width excavation and surcharges at ground level.

Improved calculation of active and passive limits by the wedge stability method for cases including wall friction.
 
Improved calculation of passive resistance of submerged berms (when not using the wedge stability option).

Improved display of limited width excavation combined with berms and surcharges at ground level.

The  Notepad Facility for calculating Ka and Kp  values from phi and delta is now shown automatically when the analysis options require compatible values of phi, delta, Ka and Kp

The help facility for Steel Pile section properties now shows moment capacities for both Standard and Higher Grade steel. The table inlcudes:
	Ultimate moment capacity
Allowable moments for temporary works     ( partial FoS = 1.35 )
Allowable moments for permanent works    ( partial FoS = 1.50 )
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A32.B47.R38                           17th December 2008

A horizontal Load applied at strut level is applied as if the strut is not present. This allows you to model thermal stresses in struts properly. If you need to apply a horizontal load at a strut elevation and the load is from a source unconnected to the strut then you should apply the load at an elevation which is slightly different from the strut elevation. 

Bug fixes
Minor changes to avoid "negative effective stress" errors in certain marginal cases.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A31.B45.R37                           13th December 2007

Bug fixes
1. "Factor all soil strengths" could be accessed in View Results mode. 
2. Very long path names were not properly displayed in the title box and error messages
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A30.B45.R36                            8th November 2007

Bug fix in new feature - 
Option to define the Yield Moment of the Wall
There was an error in the checking of wall moments against the yield limit. The message "Yield moment already exceeded at stage nnn" was sometimes given when no yield limit had been set. The calculation terminated prematurely. All errors would have been on the safe side.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A30.B44.R36                             16th October 2007

New feature
Option to define the Yield Moment of the Wall
This new feature allows you to define a Yield Moment for the wall (pile). This represents the ultimate capacity of the wall in bending. If the bending moment reaches the limiting value the wall continues to deform at constant moment i.e. the wall is assumed to be fully ductile.

You define the value of the Yield Moment in the Wall / Pile properties. This value applies to the whole height of the wall. If you wish to define different values of yield moment for different parts of the wall then you use the Construction Stage "Change EI of the Wall" which offers you the option of defining a Yield moment to go with the new EI value.for a limited part of the wall. For Single Pile Analysis you can also define the Diameter of the new pile section.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A28.B42.R35                                     6th July 2007

Bug fix in new feature - 
Wedge stability analysis for calculating active and passive limit pressures
Further minor errors have been corrected. 
1) The combination of wall friction and water pressures produced errors in limit pressures
2) The combination of seismic forces and submerged ground produced errors in limit pressures
3) Wall friction was modelled but wall adhesion was not - results for cohesive soils with wall adhesion may have been in error.
4) Calculations in imperial units  (lb,feet) for very deep walls were in error due to numerical overflow.
Advice: All calculations using the Wedge Calculation combined with 
    a) wall friction and water pressures
    b) seismic forces and submerged ground
    c) cohesive soils and wall adhesion 
should be repeated.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A27.B39.R35                                  26th April 2007

Version 4 data files can now be read by version 5.04.
Improved speed of calculation for Wedge Calculation with Strength Factor method
Uniform terminolgy for Seismic analysis options. Adjustment of Limit Pressures is always referred to as "Quasi-static" analysis.
Minor changes to verification of network installations.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A25.B37.R33                                14th March 2007

New features
1) Wedge stability analysis for calculating active and passive limit pressures (see 17th January 2007 below)
2) Seismic analysis.  There is a new type of construction stage which applies seismic loading.

Revised calculation
When the EI value of the lower part of the wall is reduced to a negligible value, the FoS calculation takes account of the reduced effective depth of the wall.

Bug fix in new feature - 
Wedge stability analysis for calculating active and passive limit pressures
Further minor errors have been corrected. 
   1) FoS by the Strength Factor method - values of FoS were overestimated.
   2) Passive berms: passive resistance was slightly overestimated.
Advice: All calculations using the Wedge Calculation combined with Strength Factor method or Berms should be repeated.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A25.B36.R33                              7th February 2007

Bug fix in new feature - 
Wedge stability analysis for calculating active and passive limit pressures
FoS of propped walls by the Strength Factor method - Wedge calculation was not actually implemented.  
Errors in Active and Passive limit pressures for Normally Consolidated soil by the Wedge calculation. Errors were significant but not drastic.
Advice: All calculations involving the Strength Factor method or NC soil should be repeated.
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Retaining Wall Analysis Program  -  WALLAP Version 5.04     
Revision A25.B35.R33                              17th January 2007

New feature
Wedge stability analysis for calculating active and passive limit pressures
Version 5.04 marks the introduction of a major new facility for calculating Active (and/or Passive) Limit Pressures in a more rigorous way than the conventional use of earth pressure coefficients, Ka and Kac. (or Kp, Kpc).

This option is appropriate for certain cases where the usual assumptions of earth pressure theory are not strictly applicable, such as:

	Sloping backfill with cohesion (for which the usual earth pressure coefficients are not applicable)
	A berm or uneven ground on the active (or passive) side
	Intense surcharges over a limited width
	Ramp surcharges
	Weak soil layers at depth
	Non hydrostatic water pressures

The maximum number of characters in a Soil description has been increased to 20 characters.
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Retaining Wall Analysis Program  -  WALLAP Version 5.03     
Revision A24.B34.R33                              2nd January 2007

New feature
WALLAP can now deal with the situation where the wall is tending to fail from right to left. If you get the message 

  Wall tending to fail from right to left

You will also see a message 
 
   Note: To obtain a Factor of Safety for the case of wall failing from    
         right to left you should reverse the data (Ctrl+K) and re-analyse.

Where the direction of failure alternates during the construction sequence you will have to do separate analyses to obtain factors of safety for all stages.
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Retaining Wall Analysis Program  -  WALLAP Version 5.03     
Revision A23.B34.R33                           13th December 2006

New feature
Iteration limits increased
200   iterations per stage for Subgrade Reaction analysis
2000 iterations per stage for 2D FE analysis

Bug fix
Improved menu for help on earth pressure coefficients
Analysis options menu - formatting error corrected
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Retaining Wall Analysis Program  -  WALLAP Version 5.03    
Revision A22.B33.R33                                   30th June 2006

New feature
Pile section data displayed as a prompt with EI value of wall.

Bug fix
1)  Program would hang when calculating FoS by the Strength Factor method in certain cases with a berm when the Factor of Safety was large.
2)  Pasted text in data input could have non-standard characters
3)  Improved copying of graphics to Windows clipboard
4)  If, after analysing the data it was modified or saved under a new name,  the program stated that it could not find the results file or that the results did not match the data. On pressing "OK" the program then returned an error. "I/O error No. 103 The semaphore can not be set again at USER12". Once this error has been received further analysis OF ANY DATA FILE yielded unreliable results. In order to clear this problem it was necessary to shut WALLAP down and restart. The bug has been fixed - no error message is displayed and subsequent analyses produce correct results.
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Retaining Wall Analysis Program  -  WALLAP Version 5.03     
Revision A21.B32.R31                               6th October 2005

New feature
Licensee and serial number included in About box

Bug fix
Rate of change of cohesion w.r.t. depth could be given a value even for cohesionless soil !
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Retaining Wall Analysis Program  -  WALLAP Version 5.03     
Revision A20.B32.R29                                  10th April 2005

Bug fix
The program would hang when using a monitor with a resolution greater than 1024 x 768  pixels.
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Retaining Wall Analysis Program  -  WALLAP Version 5.03     
Revision A19.B32.R29                                20th March 2005

Bug fix
Relaxation of the wall when changing EI was not implemented if the EI change was not the last stage.
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Retaining Wall Analysis Program  -  WALLAP Version 5.03     
Revision A19.B31.R28                             7th February 2005

Bug fix
Improved calculation of passive resistance of berms when there is a strong layer overlying a weak layer. 
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Retaining Wall Analysis Program  -  WALLAP Version 5.03     
Revision A19.B30.R26                                       August 2004

New feature
Factor soil strength option 
It is now possible to factor all strength parameters by a common factor. 
Type Ctrl E within the Soil Types menu or select the option under Edit in the Main Menu

Bug fixes
1) Factor all moduli (Ctrl F) was not working from the Main Menu

2) Pwp point elev check for stage 0 - bug corrected 

3) EI change - initialisation message caused error 
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Retaining Wall Analysis Program  -  WALLAP Version 5.03     
Revision A17.B30.R26                                           July 2004

New features  
1) The "Change EI of wall" construction stage now includes an additional option to control the treatment of displacements in conjunction with the change of wall stiffness. The options are:
		a) Allow the wall to relax with new modulus value
		b) Reset wall displacements to zero at this stage
		c) No adjustments to wall  displacements

    Full details are given in the online help.

2) Wall of variable cross-section
    It is now possible to model a wall composed of different materials at various elevations. This is done through the "Change EI of wall" construction stage

3) Relaxation of wall under long term conditions
    It is now possible to model the extra displacements and stresses resulting from the long term reduction of the modulus of a concrete wall.  This is done through the "Change EI of wall" construction stage.

4) Where the wall stiffness varies with depth, the table of displacements and bending moments includes the value of wall stiffness at each elevation. 
 
Bug fixes
1) Wall/Soil interface
The  Wall / Soil  interface parameter was not behaving properly. Editing this parameter had the effect of setting it for the left side of the wall only .  The  rough/smooth setting for the right side of the wall remained set to smooth regardless of the value shown in the data listing.  This was not clear to the user as the data listing showed only one value which apparently referred to both sides of the wall.  

The parameter is only relevant to the 2D FE analaysis.  The effect of the bug was generally to overestimate displacements and bending moments slightly because a smooth wall offers less resistance to displacements than a rough one.

2) Text data
An  '@'  character in a title or soil name used to cause formatting errors
The units of wall stiffness did not always inlcude the final string  '/m run'
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Retaining Wall Analysis Program  -  WALLAP Version 5.02     
Revision A16.B29.R24  January 2004

New features
Cohesion can vary with depth in drained soil.

Undrained soil in Single Pile analysis - an error message is displayed  but the soil type is not changed automatically any more.

The mouse cursor moves with change of focus from data to graphics.
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Retaining Wall Analysis Program  -  WALLAP Version 5.02     September 2003

This was revision A14.B28.R21 dated 16.09.03  which superseded revision A13.B28.R20 of 31.08.03
There was a minor bug in revision A13.B28.R20 related to Stage Selection while viewing results. The results of calculations were not affected.

New features
The "Factor all moduli" feature is now implemented

It is now possibe to apply a moment load at a node where a rotational restraint is already acting. The effect of the rotational restraint is suspended during the stage in which the moment is applied but operates again as usual in all subsequent stages.
   
Output of results to an Excel spreadsheet is supported

Bug fixes
The calculation of passive resistance of berms was underestimated for very small berms

In the help facility for calculating Ka, Kp,  negative values of wall friction (delta/phi) and backfill slope angle (beta) were ignored.

The wrong bending moment scale was shown on summary plots when "Common Scale" was used and the maximum bending moment was on left hand side.

For single pile analyses there was bogus printout of Factors of Safety, both for individual  stages and in the summary. There is in fact no FoS calculation for the single pile analysis!

The data display did not always match the stage number when editing construction stage data.

Greek characaters are now shown properly in the edit menus.

The message  "Wall failing from right to left" had been changed to  "Wall moving from right to left".

There is now room for 9 digits in the strut modulus box.
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Release notes for WALLAP version 5.01 - 2002

WALLAP version 5.01 is the first windows version of WALLAP.

WALLAP Version 5 has been designed to provide a high degree of compatibility with its predecessor, version 4.10 at many levels:-

•	Version 4 data files (both Standard and Large versions) can be read and processed by Version 5.

•	The definition and usage of all engineering parameters is preserved in version 5.

•	The methods of calculation are identical apart from:-

Revised criterion for maximum water filled tension crack depth
Revised arching active pressure calculation

•	The formatting of printed data and results is preserved virtually unchanged.

To summarise, you  should be able to read and process your version 4 data files and obtain virtually identical output using WALLAP version 5.

Old bug fixes and modifications

Version 4.10  A20.B21.R24 (13.09.01)

•	The maximum POSSIBLE depth of water filled tension crack is now calculated assuming that water pressure in the crack provides support to the active soil block. The maximum POSSIBLE depth of tension crack is now given by the expression:
		
2.Cu/gamma'

where gamma' is the submerged density of the soil. In previous versions of WALLAP (up to and including 4.10) the maximum POSSIBLE depth of tension crack had been calculated according to the expression:

2.Cu/gamma

The maximum ACTUAL depth of tension cracks permitted in analyses can still be limited by use of the "maximum water filled tension crack depth" parameter.

•	The calculation of arching active has been modified to achieve more rapid convergence in difficult cases. Values of bending moments and strut forces differ only slightly from those obtained previously.

•	Bug fix. The combination of the following options:-

Finite element analysis
Arching active option
FoS by Strength Factor method

was causing errors in the tabulated values of active pressures and nett pressures. The erroneous values were Coulomb active pressures where arching active values should have been shown. The values of bending moments, shear forces and strut forces were not affected.

•	Bug fix. The combination of the following options:-

Finite element analysis
Arching active option
Water filled tension cracks

was causing arching active pressures to be calculated in water filled tension cracks! Values of active pressures and therefore of bending moments may have been slightly underestimated. The effects are unlikely to have had critical design implications.