Structural Model & Project Settings
General project settings are found in thetab of Project Manager when nothing is selected. These settings appear under the heading "Project Settings".
- Start a New Project
- Project Settings: Project settings
- Project Units
- Structure Type: Degrees of freedom, connection types
- Element Connections
- Title & Billing, Notes
- Performance Settings
Start a New Project
As in previous versions of VisualAnalysis, you can still go through the usual steps to create a Project. The project is the document you save to disk. It contains all the information about your model and results. Create your project using themenu item and follow the instructions in the wizard.
Project Settings (Project Settings)
The following settings are visible in the Project Manager, Modify tab, when nothing is selected.
Structure types determine the displacement behavior of a model. Each structure type allows for different sets of 'global degrees of freedom' at each node. You may define or change the structure type, project information, and Project Settings in the, on the tab when nothing is selected in the Model View.
You may change the structure type at any time, but be aware that you may lose information. Sometimes it is useful in a 2D model to switch to a 3D model temporarily in order to take advantage of a rotation out of plane.
In a truss model, joints are assumed to be frictionless hinges that do not transmit any moment. In a frame or grid model, the joints are all rigid moment connections by default. Use member end releases to create a hinge in a frame model.
|Structure Type||Nodal Degrees of Freedom|
IES recommends using a Space Frame structure type for all your work as this is the most capable, most common, and therefore most reliable system. The only advantages to using other structure types are some "simplicity" with defining input values, however with simplicity comes restrictions. In truss structures, members cannot bend, even the top chord of a truss, so they are used primarily for academic problems. You may easily simulate "truss" behavior in a frame model using "simple" member connections to allow rotation.
North Axis: You can select one of the global coordinate directions (plus or minus) to be the North direction for your project. This setting is used in the automatic naming of model objects.
Static Analysis Method
You can select from three different types of static analysis for your project
- 1st Order: linear or iterated (for one-way elements)
- P-Delta: iterated 2nd order analysis
- AISC Direct Analysis: 2nd order analysis with notional loads and reduced stiffness
Auto. Mesh Count
If you have auto-meshed Areas, you can control (to some extent) how many plate elements are generated in your entire project. Increase this number for more or decrease it for fewer automatic plate elements. When you change it the areas are automatically re-meshed, in the background, it may take a minute or so for the results of your change to appear. You should use this feature to perform mesh-refinement for your plate analysis problems.
You can specify building code items that affect loads and load combinations and perhaps design checks. Occupancy Use affects both wind loads and seismic load combinations. Vertical Axis can affect a lot of things. For the most part these items are defined in IBC or ASCE 7.
Wind (IBC 2012 / ASCE 7-10)
These settings affect the generation of ASCE 7 wind loads in the project. There are also settings in each Service Load Case used for wind loads, and more settings in Area Loads: all three sets of data control the generation of wind loads for your project. The Help Pane shows basic definitions of items in the Project Manager if you hover your mouse over the item.
Basic Wind Speed is the 3-second gust defined in ASCE 26.5.
Seismic (IBC 2012 / ASCE 7-10)
These settings affect the generation of Building Code Combinations as well as which load combinations are used for design checks. You specify on a Design Group whether or not overstrength load combinations should be used. IBC seismic category is partly determined by Sds, but you can override it in the few situations where it is controlled by Sd1 (which VisualAnalysis does not need or use). Overstrength load combinations are not used when seismic category A is selected, they won't be used for 'other', non-IBC or ASCE7 building code combinations.
Type 5 Irregularity
Horizontal structural irregularity as defined in Table 12.3-1. ASCE-7 orthogonal combination procedure per section 12.5.3 will be required for type 5 irregularities. Many more autogenerated load cases will be created for the type 5 irregularity.
Design (Requires: Design Level)
Auto-Group: Design groups can be created automatically for you based on the shapes, materials, and orientations of members in the model, and the load combinations defined. The software will try to group like-elements into single groups. You may always delete design groups, remove members from groups, or create new groups manually. You can turn this option off to avoid generating any (or any more) design groups. Groups are generated automatically each time you switch to a Design View window, if this option is turned on and there exist members that are not grouped.
Auto-Stress Checks: For member shapes or materials that are not supported by built-in design types, you can perform generic stress-level and deflection checking in the Design View. This option will automatically group ungrouped members for these kinds of checks. If you turn off the Auto-Group option, you can get stress checks for all members, even if VA could do more complete and specific types of checks.
Auto-Connection Group: If you have VAConnect installed this option will automatically create connection design groups where possible.
Use Metric Rebar: Concrete design groups will use the appropriate category (USA or Metric) when designing members. There is a default for this option in the preference settings.
Export Results Type: When exporting connection-design forces to VAConnect or QuickFooting you can select whether VisualAnalysis should export service case or load combination results. These results from VisualAnalysis become loads in the design tool. Exporting of service case results is usually better for these tools, but if your project is nonlinear or contains more sophisticated results that need checking, you may export the results as "pre-factored" into these tools.
This setting has no effect on exports to VisualFoundation, which always (and only) uses the service-level reactions.
Miscellaneous: Title & Billing
Title is an optional descriptive name for your project. If left blank, the filename for your project becomes the title.
Billing Reference is an optional name or number used for your internal business purposes, this number will appear on reports.
Project Notes: Optionally enter a description, notes, thoughts, or information that you can include in a report and that is saved with the project to help you remember what you need to do, or why you modeled something, or anything you need to remember.
Nodal tolerance is used to control whether sketching, import, or copy & paste operations will generate a new node or use an existing node. The default is very small (1/16th of an inch), but you can make this value larger to prevent accidentally creating nodes very close to other nodes. This setting is used in the Model | Consolidate Close Nodes command.
Project units define how physical quantities are displayed throughout the software. You can quickly change unit styles using the Command Bar drop-down list, or you can use the Edit | Project Units menu command. Each unit style has a precision setting to control how many decimals are displayed (based on significant digits) and may have other options for certain units. Custom units allow you to specify each unit type. This information is stored on your machine for use with all VisualAnalysis projects. You may enter values in any acceptable unit, anytime, just type "2.54 cm" rather than "1 in", for example.
Structure type affects the default connections between elements. A truss structure type has simple (pin) connections by default. All members may freely rotate where they connect to other members. A truss model is an ideal truss in that members may not bend and therefore loads may NOT be applied to them except at the nodes. This behavior does not model most real world situations. In fact, most trusses have continuous chord members that do indeed bend between panel points.
In frame and grid structures the opposite is true. Joints are rigid (moment connections) by default and members bend and moments are carried across the joints.
Selecting a proper structure type can greatly increase your efficiency. Use the structure type with just the degrees of freedom you need to reduce the amount of input data and to simplify the results.
You can always use a structure type with more degrees of freedom than you really have. If you select a structure type that omits a displacement you need, the results will be incorrect. If all the members really do not bend and all the joints are ideal pins, use a truss structure. In most cases you will need to use a frame or the grid.
You can adjust how many places along members where VisualAnalysis calculates intermediate member results. This can have a significant impact on analysis and design performance; however there is a trade-off with result accuracy. These settings are found under.