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It is now possible to enter externally applied moments at specific locations along beams and members, for all the Sizer load types. This feature is allows you to model situations where a member with a rotationally fixed connection is connected to the member being designed, and imparts a moment to the member. It also allows you to model the case where a column supports a beam at midspan, resulting in an eccentric axial load that imparts a moment.
Applied moments can be added to both beams and columns, but not in Concept mode.
User Input
In both Beam Column Load view, the selection Applied Moment is added to the end of the Distribution drop list, as shown below for beam loads view.
The activation of the various input fields is similar to that for point loads, with the magnitude showing the kN-m, lbs-ft, or kip-ft.
Load Input drawing
Moments are shown by a small semi-circular arc with an arrow on the end. Positive moments are clockwise, negative moments are counter clockwise. Each moment is dimensioned similar to point loads.
The moments are not scaled as to magnitude; all moment symbols in a drawing have the same size.
In Beam load view, the applied moment is always drawn on top of the member, regardless of whether the applied moment is negative or positive.
In Column load view, a negative applied moment is to the right of the member, and a positive moment is to the left of the member, similar to point loads.
Output Reports
The Loads table that appears in all of the output reports has been modified as to show the Moment type and the force-distance magnitudes.
Loads Analysis
The program includes the effect of the applied moment in the analysis of members, combining the moments appropriately with other loads in the load combination. The effects of applied moments are evident in the analysis diagrams.
Design
The program currently determines the design moment, that is point of maximum moment, by using taking the moment wherever the shear crosses the axis, on the assumption that moment is a continuous function and that it is maximised where it’s first derivative, that is, shear, is zero.
This is no longer the case if there are jumps in the moment due to applied moment, so the program now inspects the locations of applied moments, as well as where the shear crosses the axis, to determine the point of maximum moment.