IES VisualPlate User's Guide
Line Stiffeners
Line Stiffeners are created using the command to draw line stiffeners on top of an existing plate boundary in the model. Line stiffeners distribute applied loads to the plate boundary and add stiffness to the model. Material Properties are defined for the selected line stiffener(s) in the tab. Line stiffeners that adjoin one another, regardless of orientation, are modeled such that load transfer (shear and moment) occurs between the members (i.e. there are no end release options for line stiffeners).
The shape for a line stiffener member is defined on the tab when one or more stiffener is selected. There are four types of shapes available for use in VisualPlate: Database Shapes, Standard Parametric Shapes, Custom Shapes, and Analysis Blobs. Custom Shapes are created in IES ShapeBuilder and added them to the Custom Shape Database.
IES includes a large shape database of steel, wood, aluminum, cold-formed, and other shapes common in the USA and some other countries. The database is customizable using IES ShapeBuilder, but cannot be modified directly using VisualPlate. Selecting a database shape will typically also define material and therefore it is best to define the shape prior to defining the material. The shape database contains Virtual Joists and Virtual Joist Girders which are developed by the Steel Joist Institute. Their website has information on the basic concept and purpose. You may create models with these shapes as if they were steel beams (please understand their purpose and limitations before using them).
Parametric shapes are defined by dimensions such as width, depth, and thickness, which are input by the user. Parametric shapes are commonly used for defining concrete members (e.g. square, rectangle, round, etc.). VisualPlate offers the following types of parametric shapes: Angle, Channel, Circle, I-Shape, Pipe, Rectangle, Rectangular Tube, Spandrel, Tee, and Zee.
Custom Blobs are a quick way to defined the numerical properties of a shape that are needed to perform the analysis (the actual dimensions of the shape are not defined). Custom Blobs are only available in the project in which they were created (i.e. they are not added to the shape database). Use Custom Blobs with care as the shape properties are not checked other than to ensure they are positive.
The tab shows the types of shapes available in the Source drop-down list: Standard Parametric, Database Shape, <Add Custom 'Blob'...>, <ShapeBuilder>, followed by a list of shapes that are already used or have been recently used in the project. Use this list to quickly find a shape for a new line stiffeners.
Vertical forces and moments in two directions can be applied to line stiffeners. The self weight of the line stiffener can be included by checking the option for the selected stiffener in the tab. Line stiffener loads can be entered as distributed evenly along the member length or as the resultant total. Loads can be entered in the global coordinate system or in the line stiffener's local coordinate system (defined as parallel or perpendicular to the member).
In the finite element model, line stiffeners are modeled using member elements in the same plane as the plate elements used to model the boundary. The stiffness of the line stiffeners are adjusted based on the Vertical Offset setting (i.e. the parallel axis theorem is used to modify the stiffness).
The line stiffener results from the finite element analysis are displayed graphically in the Analysis Results view. The tab displays the numerical results that correspond to the colored graphics. The line stiffener's displacement, shear force, moment, and stresses can be viewed by changing the Result Type drop-down menu under the Line Stiffener Results category of the tab. With nothing selected, the results displayed in the tab are a summary for the selected result case, whereas if a single line stiffener is selected, the Project Manager shows the result range for the selected line stiffener. The various Result Cases that were included in the finite element analysis can be selected using the Result Case drop down from the tab. Furthermore, moment, shear, and displacement diagrams for line stiffener(s) for each result case can be viewed using the Member Graph tab.
Analysis Results can be viewed in text form using the Text Reports tab. Once on the Text Report tab, a list of available tables is shown on the tab and can be added to the text report by double-clicking an individual table or dragging and dropping a table into the report.