RISA Glulam Arch Design

[mcustructureman]

I'm designing a structure with glulam arches @ 4'-0" o/c along the longitudinal axis. I've created my model using the continuous arc template with 10 arc increments. After loading each arc with gravity load and running the analysis, the program is not treating the entire member as continuous. Instead it is splitting up each member between the arc nodes and the moment and shear output resembles a SSB. Any help?

*First time RISA user by the way

 

[JoshPlumSE]

Yes, RISA doesn't have a curved member. Instead, it is modeled as a series of straight member that approximate the curve. Why do the axial, shear and moment diagrams look a little discontinuous / disjointed? Well, each segment gets it's moment and shear diagram plotted based on the local axis of that segment. Right? These local axes don't quite line up and the shear (or axial force) in each segment has a slightly different meaning.

The shorter the segments, the more "continuous" the moment and shear diagrams will you plot them together on screen. Sometimes, I will created multiple copies of the same curved beam side by side with the same loading, but with a different number of members to approximate the curve.

I do this so that I can compare the results. Max moment, max shear. End reactions. Code checks, et cetera. Just to see how many members I should use when generating the curved beam.