Line Loads
Line loads are defined in kN/m and positioned using Load Points. The relevant Load Group and Load Number are selected from the load group options, while the load direction is defined using the Load Direction setting.
Application of Line Loads
Line loads may be applied in the global directions, or normal to the line itself within the plane of the FE surface by using the M (In Plane Normal to Line) option. The W (Y Global Full Length) option allows a vertical load to be applied even where the FE surface itself is vertical.
The position, shape and extent of the line load are controlled by the selected Load Points. The first Load Point entered defines the start of the line load, and the last Load Point defines the end. Where the load intensity varies, the order in which the Load Points are entered determines how the load is applied along the line.
Load Points may be entered:
manually, by typing the required Load Point numbers into the input field, separated by commas; or
graphically, by selecting the Load Points field and using the pick points
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option. This opens a small Pick Points window, allowing the required Load Points to be selected with the mouse. Each selected Load Point number is listed in the window. Once complete, confirm the selection using the .png)
option.
Line loads may be used to define either open or closed boundaries, and line loads may also cross over one another.
It is also possible to assign multiple coincident line loads between the same Load Points. For example, separate Dead and Live line loads may be applied along the same line by defining them as separate line load entries.
An example line load has been set up in the following screen capture.
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Varying Line Loads
The load intensity may be constant or may vary linearly along the line. A varying load is defined by entering start and finish values, separated by commas.
Defining Moments with FE Line Loads
Line loads can be used to define a moment acting over a line, where the rotation is about the line axis. This is achieved using the R(Moment about line axis) load direction.
The R load is 'about' the axis of the line the load is drawn on. Think of it as something you might use to create a cantilever moment on a slab edge. Because it's about the axis of the line, the direction the line is drawn in influences the direction of the moment. The moment will be counter clockwise as you look down the line from the start end.
