Cosmas Tzavelis

Professor of Civil Engineering

Robot Structural Analysis software instructions

Open RobotSA

Select a Project type using the large icons. Click on Building Design (for a 3-D building), Truss 2D Design (for 2-D Trusses), etc.

In the model area, click the House Cube (on the upper right) and then the Front view to show the ZX plane. Or Click the View menu and then Projection Zx

Define a Grid to draw your model by clicking the View menu, Grid, Grid Step Definition. While there, define your Grid step Dx and Dy and click Apply.

If you have a statically indeterminate structure, you need to define some x-sections . Click on Geometry, Properties, Sections and on the Section window click the top left white icon, which defines a New Section. In the New Section window, click on the Standard Tab (top left) or Parametric etc and define your new Section. Make sure you have the correct material in the Section Type at the bottom right (Steel, Timber, etc).

Click the Geometry menu and then Bars. Click the … next to Section, to change the x-Section. If you have set the grid correctly, you should now click on the grid points and define the Beginning and End point of each Bar.

Note the Green field on the Bars menu that defines the current point. If you make a mistake you can click the bar and Delete.

If you do not like the coordinates of a Node you can click on it and change them via the Object Inspector window (on the left of your screen. See Geometry and expand Coordinates.

Click the Geometry menu and then Supports to define your supports. If Roller does not exist, click on the top left of the Supports window (white page icon) to add a New Support Definition. (Fixed directions should be clicked for UZ only if you define a Roller)

Click on a Node to define the support

Click on the Loads menu to define Load types. Click Add to add the default Dead Load and then click on Nature, Live, Add, to define the Live Load Case. Close

Make sure that the correct Load Case is displayed on a small white field on the top of your screen.

Click the Loads menu again, and Load Definition. Make sure that the correct Case No is shown! If not Close the Load Definition window and select the correct Load Case from the small white field on the top of your screen. While in the correct Load Definition window, click Node and the Left most icon to see a Nodal Force window where you can define your X force and your Z force on the node (Z is UP positive!). Click Add and then click on the node where you want the load to be applied. For another Load click on the Load Definition and repeat the procedure. If you want to delete a Load use the X button on the Load Definition window. If you do not see any of the Loads you applied try clicking the yellow buttons on the bottom of you screen

To run the Analysis just click the Analysis menu and then Calculations. You may see nothing on the screen, but on the bottom of your screen you should see a Green dot with Result (FEM) available.

Click the Results menu, Diagrams for Bars, and Click on Fx Force, Apply, to see the Axial load diagram. Click Normalize if the diagram is too large and in the Diagrams window, scroll to the right and select Parameters (click labels or text and then Apply) in order to see values on your diagram.

You can also click on Stresses to see a table of Axial Stresses. These stresses should be less than the allowable for a correct design. You can try optimizing your design by assigning different x-sections to bars, until most stresses are close to allowable. A safe structure is when ALL stresses are less than the allowable.