Project 1
Aim: To analyse portal frame structure and compare results
Introduction:
Portal beam having length of 4m and cross section of 300mm x 600mm (depth) and portal columns have height of 3m and cross section 300mm x 300mm.
1. The portal beam has two Bearing locations 1m from either end. The load from each bearing is 75 kN.
2. Provide 3 support conditions with 50 kN
3. Change the cross section of column to 300 x 400 mm such that 300mm width of column aligns with 300mm width of Portal beam.
4. Now change the orientation of column such that 400mm size aligns with 300mm width of Portal beam.
Procedure:
Creation of staad model
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Result
2. Now change both the supports to fixed and compare the reactions and displacements with that of previous sub question.
Result:
After comparing
A fixed beam makes the structure stiffer due to which there is increase in horizontal reaction.
3. Now provide 3 support conditions with 50 kN such that total load on the frame is same as that of Point 1. The bearings are 1m apart and 1st bearing is 1m from the end. Compare the reactions with that of sub question 2 and comment on the results.
There is slight increase in horizontal reaction and moment due to increase in no. of loads.
4. Change the cross section of column to 300 x 400 mm such that 300mm width of column aligns with 300mm width of Portal beam. Rest all conditions remain same as that of sub question 2. Compare the portal beam and columns bending moment with that of sub question 2.
Results:
There is significant increase in horizontal reaction and moment for increase in size of pier in long./X direction as stiffness had increased.
5. Now change the orientation of column such that 400mm size aligns with 300mm width of Portal beam. Compare the beam and column results with that of Sub question 4. Comment on the results.
Results:
It is evident that reactions have reduced after changing alignment of pier in transverse/Z direction.
Square pier had less reaction compared to rectangle as it gets equally distributed in all direction as stiffness is same. Rectangular pier will be helpful for long spans where stiffness in transverse directions will be required.