This topic provides a general guide to creating a model and some insights into the relationship among the various commands and features available in SAFE. The topics are hyperlinked to explanations about the feature or command; those explanations usually include instructions about how to use the command.
Review the Tip of the Day.
Click the File menu > New Model command to begin a model. The New Model command provides a quick and easy way to start a model for various standard designs (e.g., Base Mat, Flat Slab and so forth). Post-tensioning to balance a percentage of dead load may be included in Flat Slab template models. This command also will establish the grid system for your model. See Edit menu > Grid Data for more information about how to modify the grid system, as necessary. Models initiated using templates subsequently can be modified to meet your specific needs.
During this initial step, care should be taken:
to select the appropriate code (e.g., ACI 318-08, AS 3600-2001, and so on)
to review the Design Preferences (these are the parameters upon which calculations will be based unless they are overwritten [Beam Design Overwrites, Punching Check Overwrites, Slab Design Overwrites])
to establish the Units that will be used to store the model file; although different units can be used when inputting the various parameters to define the model, it is important to select an appropriate unit set before starting the model to reduce the possibility of round-off error (i.e., setting US units here and then using metric units for data entry is not a good idea)
With the initial model displayed on the screen, set the desired views. See the Options menu > Windows command and select the number of views you would like to use. Views may be 2D or 3D. Plan views are best used to display slab and beam objects that typically lay in the “model datum plane,” while 3D views are useful to display objects such as columns/braces and walls/ramps that extend out from the model datum plane. Any views created may be saved using the Display menu > Save Named Display command for easy recall. A single Plan View is the default. To the left of the Plan View is the Model Explorer window, which uses a hierarchical tree layout organized into three tabs (Model, Display and Detailing) to allow easy access to the forms used to define the model, such as property and load definitions, as well as all of the analysis, design and detailing results.
Define the materials and properties to be assigned to the various objects in the model. Materials typically are defined first because they are then used in the property definitions. The types of properties that can be defined include Slab Properties, Beam Properties, Tendon Properties, Column Properties, Wall Properties, Soil Subgrade Properties, Point Spring Properties, and Line Spring Properties. In addition, SAFE allows you to define Groups of objects. Grouping objects allows you to assign properties or perform operations on several objects simultaneously.
Draw objects to define the geometry for your model. Property assignments may be made simultaneously while drawing objects using the property forms. SAFE uses two approaches to drawing objects in the model.
The "quick draw" commands use a single click on a grid segment (Draw menu > Quick Draw Beams/Lines command for beams and other line objects), in an area bounded by four grids (Draw Menu > Quick Draw Slabs/Areas command for slabs and other area objects), or on a supported point (Draw menu > Quick Draw Areas Around Points command for drop panels) to draw the object.
The "point-to-point draw" commands use sequential drawing of objects by clicking on previously defined joints or points in space (Draw menu > Draw Slabs/Areas, Draw menu > Draw Rectangular Slabs/Areas, Draw menu > Draw Beams/Lines, Draw menu > Draw Columns, Draw menu > Draw Points, Draw menu > Draw Walls, Draw menu > Draw Design Strips, Draw menu > Draw Tendons). Note that in building a model in SAFE, it is not necessary to pre-define Point objects or joints. Joints are automatically added to the ends or corners of objects. The point object can be used as a joint.
If property assignments were not made while drawing the objects, select the objects and assign the defined properties to the various objects in the model. Assignments can be made to points (Point Restraints, Point Springs), lines in the model datum plane (Properties End Releases;Insertion Point; Line Springs), lines not in the model datum plane ( Properties; End Releases; Local Axis ), areas in the model datum plane (Properties; Edge Releases; Line Releases; Soil Properties), and areas not in the model datum plane (Properties; Normal Offset see Wall/Ramp Data in the Contents, Assign menu). If multiple objects are "stacked" on top of each other, hold down the Shift key and click on the location to display a Selection List that can be used to select a specific object.
Define loads for your model. Loads are defined as Load Patterns (e.g., Dead, Live, Quake, Snow, Wind, Pattern Live). In most cases, the program will generate load cases automatically, which define how the load patterns should be applied, when the load pattern is defined, although additional load cases can be specified. Results may be combined using Load Combinations. SAFE can generate default design combinations for selected design codes.
Select and assign loads to various objects in the model. Assignments can be made to points (Point Loads, Point Displacements), lines in the model datum plane (Point Loads on Lines, Distributed Loads on Lines) and areas in the model datum plane (Surface Loads). Add post-tensioning to the model by selecting design strips and adding tendons to strips or by adding tendons to beams.
Right click on a point (Point Object Information form), line in the model datum plane (Beam-Type Line Object Information form), line not in the model datum plane (Column-Type Line Object Information form), area in the model datum plane (Slab-Type Area Object Information form) or area object not in the model datum plane (Wall-Type Area Object Information form) to review, and if necessary modify, the assignments made to the object on an object-by-object basis. Alternatively, access property and object data by double clicking on the appropriate item in the Model Explorer window. Selecting an object (Area Objects, Line Objects, Tendon Objects, Design Strip Objects, Point Objects) with a single click in the Model Explorer will cause the object to be highlighted in the view displays.
Set the mesh options, design preferences, and run the analysis and design. If desired, view the model as a deformed shape and review loads on screen. The load case or mode can be changed instantaneously with the arrow buttons that appear at the bottom of the screen. After the analysis has been completed, SAFE provides options to display the various forces and stresses on screen, including Reaction Forces, Beam Forces/Stresses, Slab Forces/Stresses, and Strip Forces. Analysis results also may be viewed in tabular format.
With the design complete, SAFE provides options to display slab and beam reinforcing information as well as punching shear ratios. A right click on a displayed item will generate a detailed report for the item. Design results also may be viewed in tabular format.
Commands on the Run menu and Detailing menu can be used to generate preliminary design schematics (not intended for construction). When Detailing is run, the program automatically generates component views, beam and slab rebar schedules, and BOQs based on detailing preferences, slab/mat reinforcing preferences, and beam reinforcing preferences, including rebar curtailment rules. Those view objects are placed automatically on drawing sheets that are based on the drawing sheet setup and drawing format properties. The slab/mat sections and beam sections can be edited as well as editing slab/mat reinforcement and beam reinforcement. By default, the program may combine area objects to form a single slab object for detailing. Similarly, drop panels and beams may be detailed as a single mat object, while footing objects may be detailed separately. However, an option exits that can be used to specify groups of particular objects before detailing is run, giving you greater control over how detailing is performed. When Detailing is run, drawing sheets with title blocks, general notes and the like are generated in accordance with all of the preceding preferences and parameters. These drawing sheets can be further modified by adding or deleting views and editing individual views. After the drawing sheets are complete, the drawing sheets or individual views can be printed or exported in .DXF or .DWG formats. Many commands that can be activated using the Detailing tab of the Model Explorer are available for working with the views and drawings before generating output.
SAFE can include the effects of banded or distributed post-tensioning in the analysis and design.
In SAFE, it is only necessary to define large slab objects. No finite element mesh definition is required. All finite element meshing of the slab model is automatic. Every time the geometry or loading is changed, the mesh is instantaneously updated. In addition, SAFE gives you control over the averaging of the stress contours, allowing you to evaluate the adequacy of the refinement of the finite element mesh.
The SAFE model generation features allow on-screen linear and radial replication and mirroring of selected portions of the model.
Check the Extrude View check box in the Options area of the Set Display Options form to produce scaled perspective extrusions of the slab geometry.
All model, analysis and design information from SAFE is now available to the user in a standard database format - "Your SAFE is now open!'"