2a. Input Data Menu:  Similar to screenshot 2; however, here the user can specify up to 100 rectangular footings over horizontal ground surface.

3. Foundation Profile:  Using mouse functions and/or numerical coordinates, the boundary between foundation layers is defined (up to 50 layers).  Tabs allow for convenient access to each layer. At this stage, the total unit weight and Poisson's ratio are input.  The importance of Poisson's ratio is in calculating elastic settlement and in non-vertical Boussinesq stresses due to surcharge; if these values are not required, the numerical value of the ratio is inconsequential.  Color of layers can be set using a function in the toolbar.

4. Embankment Geometry:  Using mouse functions and/or numerical coordinates, the boundary between embankment layers is defined (up to 20 layers).  Tabs allow for convenient access to each layer. As an example, the user can use the multilayer option for staged construction or for a 'composite' embankment made of lightweight fill (e.g., Geofoam, foamed concrete, shredded tires) with a protective cover of soil.  The embankment is not restricted to symmetrical geometry nor to horizontal layers.  Color of layers can be set using a function in the toolbar.

4a. Multiple Footings Layout:  Up to 100 rectangular footings, each having different B by L dimensions and contact pressure q, can be input.  The footing layout is shown to scale on the X-Y plane.

6. Consolidation Data:  Here the various parameters controlling the consolidation settlement and rate are input.  The user specifies which layer is consolidating; up to 50 layers may consolidate simultaneously, each at its own rate and boundary conditions.  The 'accuracy' of the numerical finite difference scheme may be selected.

7. PVD Data:  If Prefabricated Vertical Drains ('wick drains') are invoked, the user needs to input data such as installation pattern in which consolidating layers the PVD are installed, the horizontal coefficient of consolidation, and, in sub-dialogs, data related to the efficiency of the specific PVD.

8. PVD Drain Resistance:  The previous screen enables the user to access dialogs related to the efficiency of the specific PVD.  Here the user can either input very specific, but rarely available, data or specify an acceptable and conservative reduction for flow resistance in the drain.

9. Undrained Shear Strength Data:  Relating the undrained shear strength of a consolidating layer to its effective overburden pressure and its loading history, the user can specify two experimentally defined parameters (see Ladd 1991) to calculate the strength at any time after loading starts.  This data is also applicable to staged construction.  The undrained shear strength is calculated with depth and at various time increments.

10. Immediate Settlement:  If the immediate settlement is selected when running FoSSA, the user needs the two elastic parameters to be input: Young's modulus and Poisson's ratio.  Although Poisson's ratio was input with the foundation soil data, its value can be adjusted here again.

11. Water Table:  Water table can be input using a spreadsheet-like table or using mouse functions. The water table can be represented as phreatic surface and porewater pressure then will be calculated accordingly (in an approximate way).  Knowledge of porewater pressure, superimposed at any time by the excess pressure, enables the calculation of effective stresses.

11a. Porewater Pressure:  Instead of a phreatic surface (see screenshot 11), the user can input a distribution of porewater pressure that corresponds to a steady state flow (i.e., not consolidation related) signifying, for example, the effects of a confined aquifer.

12. Computational Accuracy:  The user can control the accuracy of the computational process.  Increase in numerical accuracy may require much longer computations. The user can conduct quick parametric study to realize whether the increase in accuracy is practically significant. 

13. Domain for Stress Calculations:  This dialog enables the user to define the nodes at which Boussinesq stresses are to be calculated.  It can be one point within the foundation, points along a horizontal section, points along a vertical section, or a grid (shown). 

14. Graphic Display of Vertical Stress Distribution:  Integrating Boussinesq basic equation for the nodal points defined in screenshot 13 yields the vertical stress increase shown in this screen. The user can print this screen, can display the other stress increment components (tensor) or view the numerical value in tables.  

16. Tabulated Display of Vertical Stresses:  Using a dropdown menu in the results, the user can review the stresses at all specified nodal points.  In the vertical direction, total and effective stresses including the overburden pressure and stresses due to surcharge are presented.  

16a. Tabulated Results:  All tabulated results can be sent to the printer or saved as a text file.  Also, tabulated results can be exported directly to Excel.  This functions are executed by a click of a button.

17. Display of Consolidation Settlement:  A convenient way to display the ultimate settlement of all consolidating layers is using an exaggerated scale.  This settlement can also be presented at the drawing scale.  Also, the numerical values can be viewed.  The user may select points along the foundation soil surface for which the ultimate settlement is calculated.   

18. Time-Rate Consolidation Setting:  Before running the time-rate consolidation analysis for all layers, the user can set an objective of either a specific time or a specific average degree of consolidation in all layers; the prevailing criterion would be the one that happens last.  Also, the stress increment causing consolidation can be utilized from Boussinesq analysis or input by the user; user's initial values can be obtained from piezometers reading and can serve in calibrating the consolidation parameters based on field data. 

19. Isochrones Display:  For the desired average degree of consolidation, FoSSA displays the distribution of excess porewater pressures within each consolidating layer at 10 equally time increments.  By placing the mouse on any desired line, the numerical values of the corresponding time, depth and excess porewater pressure are displayed.  Note that the red thick line represent the initial increase in water pressure and is equal to Boussinesq stress distribution through each layer (or, if so elected, specified by the user).  Also note the black bullets; it represents the maximum excess pore water pressure within the layer.  This screenshot is for a singly drained layer (top); FoSSA can show up to 50 layers consolidating simultaneously, each at its own rate.  Numerical results can be accessed through this dialog.

20. Time-Rate Consolidation - Tabulated Results:  The numerical details of the results presented graphically in screenshot 19 are tabulated.  The excess porewater distribution at various time increments can be seen through each consolidating layer.  Moreover, the average degree of consolidation at each time, as well as the consolidation settlement, is presented.   By a click of a button, the user can 'flip' between tables, each assembled for an independently consolidating layer. 

21. Calculated Undrained Shear Strength:  This graphical display shows the distribution of the undrained shear strength with a consolidating clay layer at the same increments of time that the isochrones were calculated with.  The numerical value of strength at a particular location and time can be obtained by placing the mouse over the desired curve.  Note that the thick red line shows the undrained shear strength at the beginning of consolidation. The black bullet shows the minimum strength at respective times.

22. Undrained Shear Strength - Tabulated Results:  The numerical details of the results presented graphically in screenshot 21 are tabulated.  The undrained shear strength distribution at various time increments is presented through each consolidating layer.  By a click of a button, the user can 'flip' between tables, each assembled for an independently consolidating layer. 

23. Setting of Computation for Staged Construction:  By a click of a button, a layer can be added to represent the next loading stage.  The added load due to the added layer is superimposed on the excess porewater pressure at the end of the previous stage to represent the initial conditions.  

24. Graphical Results in Staged Construction (Stage 1):  For the specified consolidation time, FoSSA displays the distribution of excess porewater pressures within each consolidating layer at 10 equally time increments.  By placing the mouse on any desired line, the numerical values of the corresponding depth and excess porewater pressure are displayed.  Note that the red thick line represent the initial increase in water pressure and is equal to initial excess porewater pressure distribution through each layer.  Also note the black bullets; it represents the maximum excess pore water pressure within the layer.  This screenshot is for a singly drained layer (top); FoSSA can show up to 50 layers consolidating simultaneously, each at its own rate.  Numerical results can be accessed through this dialog.

25. Graphical Results in Staged Construction (Stage 2):  This screenshot can be compared with screenshot 24; it represents the second stage of loading.  Note that the initial condition (the thick red line) is much different than that for the first stage (screenshot 24).  It is the excess porewater pressure at the end of the previous loading stage superimposed by the induced extra load due to the placement of the next layer. 

26. Tabulated Results for PVD's in Staged Construction:  For each loading stage and each consolidating layer where PVD's were installed, FoSSA calculates the average degree of consolidation due to vertical drainage, horizontal drainage, and the overall value.  The settlement of each respective layer is also presented.

27. Settlement History Notebook:  FoSSA enables the user to save the results of each run (up to 15 runs) and add remarks for identification.  Such record makes the 'bookkeeping' associated with a design iterative approach a bit easier. 

28. Printed Report:  Various results can be printed with a final report.  The user can select the desired tabulated results based on the menu shown in this screenshot.  Graphical results can be printed or saved as bitmap files in the dialogs displaying results. 

29. Help Documents:  Each screen has a specific help information.  The main Help (toolbar) includes the FHWA design manual for PVD's (accessible from FoSSA; the document is a PDF file).

30. Consolidation Parameters for Sublayers: The user can subdivide a single consolidating layer into maximum of 10 sublayers, each possessing different consolidation parameters. Time rate will follow this data and the free or not free draining outer boundaries specified by the user in the previous dialog (not shown).

31. Isochrones for Inhomogeneous Layer Comprised of 3 Homogeneous Sublayers:  FoSSA calculates that for the given problem, the average degree of consolidation of 90% for the layer, it takes 625 days.  The respective isochrones are plotted at time intervals of 62.5 days. Each shade of color indicates a sublayer (in this example, three sublayers).