Hi,
I'm doing a calcullation of a grid of steelbars, subjected to a surface load on the middle of the grid. The bars are placed over and under eachother, so i want alt the connections between the bars to be pinned instead of being fixed, which is the case right now.
If you want longitudinal beams to be continuous (without releases/hinges) between supports and transversal beams to be continuous between supports and to model pinned connections between longitudinal and transversal beams then you can model it using compatible nodes.
In such case it will be necessary to divide beams at intersections.
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Hi Pawel,
Even i'm using the compatible nodes function, i think the bending moment diagram for the continious steel bars between the supports isn't correct. Am i doing it wrong?
Hello,
checking the model received outside of the forum I noticed that compatible nodes are not assigned to proper bars and moreover the definition of compatible nodes defined by you does not consider proper degrees of freedom.
I will contact you with more information.
Regards,
After defining compatible nodes correctly results seem as expected - continuous bending moments along beams, no torsion moments (eccentricity of members in the grillage neglected). See the screen capture below:
When defining compatible nodes using the "Manual" mode it is important to start without overlapped nodes and to observe the displayed hints: "Compatible nodes - select the first node" means that when I click such node another compatible node will be created in the same location.
Then the displayed hint changes to "Compatible nodes - select a bar or press <Esc> to terminate". It means that now bar(s) should be selected which will be reassigned from the original (first) node to the new compatible node.
Pressing Esc will terminate the definition of this pair of compatible nodes and Robot will be ready to define another one - the hint will change respectively.
In model like above it is rather tedious process - more than 200 pairs of compatible nodes (15-20 minutes) and easy to make a mistake.
The best way to identify mistakes is to see results - for instance torsion moment diagrams in the above model.
The best way to fix these mistakes is to select appropriate bars, open the table of bars filtered for such selection and correct node numbers in bar definitions.
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Regards,
