Truss analysis

[mekafime]

Hi,

I try to analyze a truss but I have two different results when I try to modelate a continuos chord and divided chord. How I can resolve this? please

 

[STpipe]

Without more details, it is difficult to say, especially in terms of how the results are different. My first guess would be that you released the moments at all the joints which would explain the difference in the results. Your top and bottom chords can transfer moments when your top and bottom chord are continuous.

 

[wannabeSE]

If the colors represent utilization (demand to capacity), I would look at the top chord out-of-plane unbraced length.

 

[JoshPlumSE]

I cannot speak to SAP with total confidence. But, if you had modeled it this way in RISA, the default unbraced length used for the top chord code checks would have been different. Basically the same thing that WannabeSE suggested.

 

[JasonMcKee71]

It is due to the buckling length calculations. The frame should be given straight and not divided so that buckling length is calculated properly.

Jason McKee
proud R&D Manager of
Cross Section Analysis & Design
Software for the structural design of cross sections
Moment Curvature Analysis
Interaction Diagrams
Reinforcement Design etc.