Loading, Analysis and Design Procedure in STAAD Pro
Week 8 Challenge
Q.1 Applying Load Exercise.
Aim: To apply the load for the structure modelled in previous exercise.
- Form a Load case as DL for Dead Load
- Apply Self weight
- Apply member load of 3 kN/m on the rafter
- Apply member load of 6 kN/m on the secondary beams
- Apply point load of 20 kN at node intersecting inclined member on the top chord.
- Form a Load case as LL for Live Load
- Apply member load of 4 kN/m on the rafter
- Apply member load of 7.5 kN/m on the secondary beams
- Form load combination 1.5DL+1.5LL
Procedure:
> Open the STAAD file.
> Go to Loading Tab, and click on Loading Tab and Add loading case.
> Select the Load Type as Dead and give the name as Dead Load and assign the Self Weight for different Strucutral Element under this load case.
> Selfweight has been assigned to all structural element.
> Now, similarly under the Dead Load Case add 3kN/m Member load on Rafter.
> Now, add 6 kN/m member load on Secondary beam
> Now, assign the Nodal load of 20 kN on point of intersection of Rafter and inclined chord.
> Dead Load has been assigned.
> Now, similarly we create case for Live Load and apply the load as shown in below figure.
> Final Loading Diagram after applying Dead Load and Live both will be as shown in figure.
> Now, we will define a load combination of 1.5DL +1.5LL as shown in figure.
> Click on Add and the load combination has been added in Load Case.
Result:
* All the given Dead Load and Live Load cases has been created succesfully.
2. Find Maximum Force and Minimum Force for member and present the STAAD result.
Aim: To run the analysis and find the following results on the member mentioned
- Run the analysis
- Find the Maximum Moment in the Secondary beam for 1.5DL+1.5LL case
- Find the Maximum Axial force on the inclined bracing and identify the member having the maximum force for 1.5DL+1.5LL case
- Identify Bottom chord of Truss having Maximum shear Force & Maximum moment for 1.5DL+1.5LL case and present the values.
Procedure:
> Loading has been done already, Now run the analysis. Go to Analysis Tab, click on the last load case and click on Define Commands. A window will pop up. select All and click on Add.
> Now Click on Run Analysis from the tab. After analysis, a window will pop up, click on View output file to view results.
> The Final Result of the analysis will be pop-up in a different window as shown below.
> Now, we will find the Maximum moment in the secondary beam for 1.5DL + 1.5LL case. Go to Post Processing Option on Left Side. Go to View and select Secondary beam to view.
> Select only Secondary Beams, Go to Result Tab, and select Mz to view the Bending Moment Diagram.
> Now go to annotate option to view the Maximum Bending Moment.
> Similarly find the maximum axial force on the inclined bracing for the 1.5DL+1.5LL Case.
* Maximum Axial force we got as 1051.851 kN on Beam Number 1904.
> Similarly find the Maximum Shear Force and Maximum Bending Moment for the bottom chord of the Roof Truss.
Result: Following results were obtained from the analysis:
- Maximum Moment in the Secondary beam for 1.5DL+1.5LL case = 62.801 kN-m.
- Maximum Axial force on the inclined bracing and identify the member having the maximum force for 1.5DL+1.5LL case = 1051.851 kN
- Maximum ShearForce and Maximum Bending Moment for the bottom chord of the Roof Truss as 13.735 kN & 18.616 kN-m.
3. View and Rectify the Warning, instabilities in the structure.
Aim: To identify the Warnings and fix the same and run the analysis for the given STAAD File.
Procedure:
> After running the analysis few warning messages were displayed as shown in the below figure.
> Reason for Error: A joint exists where the only structural components connected at that node are truss members, there is no rotational stiffness at that node along any of the global D.O.F
> Solution: Go to the Specification menu to create Master Node.
Result:
* Analysis has been done and 8 warning messages showing were resolved successfully and an analysis report with 0 warning messages has been obtained.
4. Design Parameter exercise.
Aim: To apply Design parameters for structure modeled for code IS 800:2007.
- Effective Length Lx, Ly, Lz for beams, Truss elements
- Effective length factors Ky, Kz for Columns
- Apply other design parameters for respective members
Procedure:
> Go to the analysis and design tab, select all the structural members and assign steel as the basic material. On the right-hand side, select the IS 800 code as shown in the below figure.
> Now, define the parameter for the like Ly, Lz for beams and trusses; Ky, Kz for columns
> Now, run the analysis again to see that there is no error
Result:
* The design parameter has been successfully applied to the modeled structure in STAAD PRO.