Release History

LimitState:SLAB 2.1e

Number: 2.1e

Build: 24265

Release date: February 2020

Update

• Academic licenses are now accessed from new server address in advance of shutdown of legacy server in Q3 2020 [ref:5407]

LimitState:SLAB 2.1d

Number: 2.1d

Build: 23785

Release date: September 2019

Bug Fixes

• Fixed a bug that prevented v2.1.c files from being opened in previous releases. Version 2.1.d files are backwards compatible throughout all v2.x releases [ref:5341]
• Fixed a bug that caused the License Dialog to be incorrectly titled DXF Import [ref:5350]
• Fixed a bug that meant that a project could not be saved following completion of a Wizard if the licensing was changed to "Academic" from some other license type [ref:5351]

LimitState:SLAB 2.1c

Number: 2.1c

Build: 23657

Release date: August 2019

Enhancements

• Set the styling of construction lines created on import of a DXF geometry to match that of lines created manually (i.e. grey, dotted lines) [ref 5305]

Critical Bugfix 

• Fixed a critical bug which caused the moment of resistance to be calculated incorrectly in the rare circumstance of an orthotopically reinforced slab with orthogonally inclined reinforcement and moments of resistance specified at angles of exactly 45, 135, 225 or 315 degrees [ref 3508]

Bugfixes

• Fixed the ability to print a report directly from the report dialog [ref 5306]
• Fixed a bug that caused DXF files to import incorrectly (or sometimes crash the software) [ref 5254]

LimitState:SLAB 2.1b

Number: 2.1b

Build: 23016

Release date: March 2019

Enhancements

• Added option in the installer to use software rendering. Reinstall with this option selected if graphical or startup issues are experienced. These occasionally occur due to graphics driver compatibility problems. [ref 5210]
• Improved formatting of diagrams in help files. [ref 5321]

Minor changes

• Added forward compatibility with previous 2.x versions. [ref 5229]

LimitState:SLAB 2.1a

Number: 2.1a

Build: 22568

Release date: December 2018

Enhancements

• Very high resolution (e.g. 4K) screens are now supported on Windows. The size of text on such screens is optimized for readability [ref 5115]
• Changed structural definition drag cursor to make it easier to drop on boundaries [ref 4944]

Bug Fixes

• Fixed localization error that broke calculator when using commas instead of decimal points [ref 4983]
• Fixed error that meant a load type changed in the property editor wasn't changed in the load manager [ref 5069]
• Fixed a bug that caused occasional failures due to numerical tolerance issues in geometrical calculations [ref 5133]

LimitState:SLAB 2.0b

Number: 2.0b

Build: 20281

Release date: April 2016

New Functionality

• Added a number of new support types and behaviours. The software now allows the user to choose from the following options [ref 4691] [ref 4766]:

External Boundaries

 - Free
 - Symmetry
 - Fixed
 - Simple
 - Partially fixed

Internal Boundaries

 - None
 - Knife-edge  

Lift-Off

 - For boundaries with Simple or Knife-Edge support types, the option to allow lift-off of the slab has also been added. This allows the potential for uplift of the slab to be modelled where appropriate.

• Added new functionality to allow the problem to be re-scaled during the solution phase, thereby increasing solver reliability and robustness  [ref 3943]
• Added a new 'Rigid' structural definition type [ref 4772]

Enhancements

• Modifications to the way in which self-weight is treated [ref 4762]:
  • Problems generated using a wizard now consider self-weight loading by default.
  • A diagnostic warning is issued for problems containing slab definitions with non-zero self-weight properties, but no load cases with self-weight loading.
  • A diagnostic 'information' message is issued for problems with self-weight loading and containing only the default 'Unit MP Weightless' definition.    
  • A diagnostic warning is issued for problems containing load cases with self-weight loading, but not utilizing slab definitions with non-zero self-weight (other than that mentioned above).
  • Updated example files to prevent warning above warning messages being displayed [ref 4786]
• Added a new diagnostic message that warns the user if a disproportionately small number of nodes (<20% of the overall total) exist within solids [ref 4831]
• Enhanced "DXF Import" dialog to add information relating to the units used and the bounding limits of the file being imported. Where the file is unitless, dimensions will be assumed to be the same as those set in the software (e.g. metres or feet). Additionally, warn the user if the geometry appears to be too large, too small or positioned a long distance from the origin [ref 4767]
• Improved the way in which DXF files are handled [ref 4839]:
  • Prevent zero thickness solids from being created (where two boundaries lie on top of each other in a DXF).
  • Added a check that attempts to identify isolated islands in DXF files and alert the user so that they are able to fix the issue.
  • Fixed a bug when removing DXF entities from unwanted layers, which could cause the software to crash.
• No longer do filter stage by default at the end of an analysis, reducing solution time and improving solver reliability. In the filter stage nodes were added at yield-line crossover points, and one or more analyses were subsequently performed, in some cases leading to a very slightly improved solution (thus some existing files may report a very slightly higher adequacy factor and/or a marginally different failure pattern as a result of this change) [ref 4830]
• Allow creation of new vertices at intersection between boundaries and construction lines [ref 4860]
• Updated 'Irregular office block floor' example file to have more accurate geometry and material properties [ref 4744]
• Upgrade Mosek solver and add Win 10 support [ref 4688] [ref 4881]
• Updated Product Description [ref 4879]

GUI Updates

• Resize structural definitions explorer to use larger grid [ref 4693]
• Rename 'Slab Definition' to 'Structural Definition' throughout [ref 4689]
• Upgrade to Qt 5.4.2, which brings improvements to GUI appearace including improved rendering and a cleaner interface [ref 4688]
• Change help icon and about dialog [ref 4783]
• Improve locale settings e.g. so that commas and/or points are treated as decimal places according to the settings of the host machine [ref 4814]

Bugfixes

• Fixed a bug that could prevent new solids from being created within concave sections of an existing solid [ref 4856]
• Fixed a bug that prevented solids within another solid (i.e. 'islands') from being split by a user-defined boundary [ref 4859]
• Fixed a bug that could cause a crash by allowing the side length of a wizard generated geometry to be zero. A minimum length of 0.01 units is now enforced [ref 4858]
• Fixed a bug that could cause a crash when trying to merge two boundaries that initially shared a single vertex [ref 4862]
• Fixed a bug that caused images to be exported at a different size to that specified in the software preferences [ref 4863]
• Default slab definition thickness modified to become a more realistic value (0.25m) [ref 4791]
• Fixed a numerical issue involving geometry points with x coordinates very close (but not equal to) zero that caused the solver to show "Error: 01007: Out of bounds x-coordinate..." [ref 4761]
• Fixed a bug that could cause 'floating solids' to appear when deforming some complex failure mechanisms [ref 4600]
• Fixed a number of Imperial unit issues (primarily where they were displayed as the Metric equivalents) [ref 4598][ref 4679]
• Fixed a bug that could cause a crash when switching between loads and geometry tab in the 'new slab wizard' [ref 4634]
• Fixed a bug that allowed both radio buttons to be disabled in the post-solve animation settings [ref 4622]
• Fixed a bug that prevented user defined camera position from being used [ref 4773]
• Fix snap settings to account for user preferences [ref 4860]
• Fixed 'ln' function in the calculator [ref 4723]
• Fixed a bug that prevented files from being saved when creating new ones. Also changed default behaviour to request new file name from user when saving for the first time [ref 4724]
• Fixed a bug that could cause file corruption when pressing Cancel in the Project Details dialog (ultimately causing the software to crash) [ref 4872]
• Fixed a bug that could cause a crash if a Wizard was cancelled after specifying loads [ref 4875]
• Allow partial safety factor on material to be exported and imported along with other values in the CSV file [ref 4870]

LimitState:SLAB 1.0d 

Number: 1.0d

Build: 18482

Release date: March 2015

Enhancements

• Upgrade the installation software and check for x86 (32bit) operating systems when attempting to run the 64bit installer [ref 4572]

Bug Fixes

• Warn the user (and offer to fix) when a solid object is loaded twice by a pressure load with exactly the same specifications (Load, Action Type, Adequacy and Position) [ref 4586]
• Add a new diagnostic check for duplicated self-weight or pressure loads [ref 4588] 
• Improved the logic when merging solid zones or boundaries with different properties. Previousy the allocation of nodal spacing, slab definition and pressure loading was done on an ad-hoc basis. The software now assigns the new zone the properties from one of the merged objects and alerts the user as to which has been used [ref 4582] [ref 4586]
• Fix load case spin box so that it does not display "0 of 0" when the load case manager is shown then cancelled [ref 4584]

Note that from version 1.0d communications with the update server have been set to allow automatic updating to newer releases (for those not behind a restrictive firewall).

LimitState:SLAB 1.0c

Number: 1.0c

Build: 18406

Release date: March 2015

Enhancements

• Enhance solid selection when applying pressure loads [ref 4558]
• Synchronize tabs on viewer and load case manager during the editing of load cases [ref 4563]
• Prevent flickering in the viewer window during a solve [ref 4561]
• Fix internal boundary colors when using slab with hole wizard [ref 4569]
• Enhancements and corrections to manual [ref 4545] [ref 4536] [ref 4546] [ref 4547] [ref 4548]
• Add context help to Load Case Manager dialog [ref 4552]
• Prevent the grid from being shown with thicker lines when opening a file [ref 4463]
• Use consistent terminology for plastic moments of resistance in the report [ref 4554]

Bug Fixes

• Prevent exception when clicking on the pressure load icon [ref 4557]
• Change analysis icon in the New Project wizard [ref 4562]
• Remove Torsional Rotation and Shear Displacement 'Yield-line' properties from Property Editor (as they are not currently calculated) [ref 4568]
• Set the SLAB subfolder in 'Documents' to be 'LimitState SLAB files', not 'slab files' [ref 4556]
• Remove Property Editor references to multiple-definition Boundaries, as these are not achievable in the software [ref 4567]

LimitState:SLAB 1.0b

Number: 1.0b

Build: 18360

Release date: February 2015

New Functionality

• Allow skew angle for reinforcement [ref 4266] [ref 4527]
• Enable imperial units [ref 4362]
• Add new wizard to model a rectangular slab with hole [ref 4454]

Enhancements

• Enhance rendering quality and performance [ref 4316]
• Improve the quality of the GIF and AVI animations [ref 4452]
• Enhance released example files [ref 4419]
• Make default grid spacing 1m with 10 subdivisions [ref 4459]

GUI

• Move Loads toolbar to the top [ref 4470]
• Reduce the size and spacing of boundary hatching to aid user understanding of boundary fixity [ref 4483]
• Hide loads before solve [ref 4422]
• Make it easier to select objects in the viewer [ref 4381]
• Removed 'Support Type' information from the 'Vertices' and 'Solids' explorer windows.  (The ability to apply supports to these features is not currently available.) [ref 4479] [ref 4529]
• When the Rotate toolbar button is selected, ensure that the overlay (circle with draggable handles) is always visible and not obscured by the model [ref 4482]
• Enhance loads visualization to make it easier to use [ref 4486]
• Reduce default slab definitions explorer width [ref 4469]
• Apply spot light correctly on all generated frames in the animation [ref 4492]
• Fix line load color [ref 4411]
• Change default slab definition color [ref 4533]

Solver

• Fix numerical issue with problems using skewed columns [ref 4480]
• Upgrade Mosek solver to 7.1 [ref 4498]
• Changed material partial factors to be divisors [ref 4512]
• Ensure that the load case name is displayed in the output window during a solve [ref 4415]
• Fix numerical issue when a load is applied on a support [ref 4466]
• Remove incorrect partial factor sets [ref 4495]

Documentation and Report

• Major changes to manual and other documents [ref 4505]
• Added reference in manual and report output to journal paper detailing the theory behind yield-line analysis using DLO [ref 4387]
• Modify the symbols used for the material definitions in the property editor and the report [ref 4467]
• Ensure that the 'Details...' hyperlink in the Units tab takes you to the appropriate manual entry [ref 4418]
• Enhance slab definitions in the report [ref 4376]
• Reword report summary [ref 4535]

Usability

• Group pressure loads of the same type in the Load Cases Manager [ref 4340]
• Show pressure loads as a red triangle in the top right corner of the solid (with no offset) [ref 4382]
• Remove unneeded attributes from property editor [ref 4523]
• Rename load magnitude attributes in property editor [ref 4532]
• Fix construction line usability issue [ref 4471]
• Add unit MP Concrete slab definition [ref 4487]
• Prevent snapping of point and line loads to the grid when SNAP is disabled [ref 4488]
• Add diagnostic message for solids with no slab definition [ref 4534]
• Update product description [ref 4386]

Bug Fixes

• Fix trial license [ref 4379]
• Fix academic license [ref 4394]
• Fix descriptions in property editor [ref 4468]
• Fix issue where the deformations used to illustrate the failure mechanism are calculated incorrectly in certain circumstances [ref 4474]
• Prevent page breaks inside tables in the RTF report. Make RTF the default output format [ref 4406]
• Ensure that the 'locked' attribute for the slab definitions is saved to file [ref 4460]
• Prevent crash when unlock is pressed whilst diagrams are being shown [ref 4461]
• Ensure that the slab Load Case Manager dialog displays the correct title [ref 4462]
• Update the status of the toggle buttons in the 'Show' toolbar after opening a file [ref 4369]
• Show the right selection type status on the main form  [ref 4370]
• Show the correct title on the Edit Slab Definitions Dialog [ref 4524]
• Fix a bug when a dxf file is imported, and allow negative offset for loads in the Load Case Manager [ref 4501]
• Disallow adding multiple slab definitions to the same solid [ref 4528] [ref 4541]
• Avoid having multiple slab definitions when drawing solids using the viewer, and create new solids on the viewer with no default slab definition [ref 4432]
• Fix undo/redo when loads are added/edited [ref 4420]
• Prevent crash when using the Load Case Manager in a new project that was created without using one of the wizards [ref 4476]
• Fix boundary external/internal status in newly created files [ref 4424]
• Fix a bug when deleting first load case [ref 4538]
• Fix spotlight when changing preferences [ref 4543]
• Avoid hiding solids in multiple load case projects when one load case is deformed [ref 4410]

LimitState:SLAB 1.0a - Beta version

Number: 1.0a

Build: 17914

Release date: December 2014

LimitState:SLAB is a software program designed to rapidly evaluate the load carrying capacity of existing and proposed concrete slab structures using the yield line analysis method.

Features

POWER

Rapidly determine the capacity of concrete buildings and bridge decks without the need to pre-guess the failure mechanism.

ECONOMY

Uses plastic limit analysis methods, which promotes more efficient solutions than alternative techniques based on elastic material properties.

FLEXIBILITY

Define any concrete slab geometry by drawing on screen, using a built-in wizard or by importing the layout from CAD.

EASE OF USE

An intuitive GUI means learning to use the software is a straightforward process.

CLARITY

Presents a clearly defined failure mecha nism and numerical factor on the applied loading. Animations are used to enhance user understanding of the collapse mechanism.