Beam Sections
The Beam Sections command is used to access beam data in the library currently loaded and is accessible from the Libraries menu, or selecting its respective icon. The sections listed upon opening this box correspond to the currently loaded section library file (default.cs1) selected under Libraries | Setup. To load a different file, you must use the Libraries | Setup option.
On the left side of the Beam Sections screen is a list of predefined section types. These sections are standard sections, and although you cannot add a new type, you can add, modify, or copy an item in the list. To add, modify, or copy an item, highlight the section ID from the list on the Beam Sections Library and click Add for the Section Detail to display. Enter the data for ID, Description, and Dimensions.
There are three options available under Section Properties:
The first option, User Input, allows you to input your own values for all dimensions and for the center of gravity (Cg), area, Moment of Inertia about the x-axis (Ixx), volume to surface area (vol./area), and the Moment of Inertia about the y-axis (Iyy). The second option, Dimensions calculates the section properties based on the section dimensions entered above. (Note that the fields under Section Properties will appear grayed out.) The third option, Drawing, allows you to draw your own beam section, as explained in the next section. In this case, the program computes the section properties based on your drawing. To access the drawing option, click Edit.
Regardless of what option is selected for computing section properties, the user must enter some specific dimensions. These dimensions are used for various engineering calculations by the program. To better understand this feature, we recommend experimenting using all three options offered. You will quickly observe the differences between each option.
The Volume/Surface Area ratio is used in the computation of restraining moments, and is computed as the ratio of the cross-sectional area of the member divided by the perimeter of the beam. If the refined method of analysis is selected for computing the distribution factors, you should enter values for the moment of inertia about the y-axis, Iyy. To have the program compute this value for you, you can set the Section Properties to be computed based on Dimensions or based on Drawing.