Structural Modelling using Etabs 2018
The architectural drawings for a G+7 residential building in zone 5 has been provided. The floor plan is the same for all 7 floor levels. Possible column positions have also been provided. Conceptualize a framing plan layout and then model the building in Etabs. The following architectural drawings have been provided:
- Typical floor plan – The location and thickness of the brick walls and the use of the
space (for estimating live load) can be obtained from this plan - A building section through the staircase and lift core is provided
- Parking layout in the ground floor – the column/shear wall arrangement must not
obstruct entry/exit of vehicles.
The following loadings are to be taken into account: - Brickwall made of AAC blocks
- Finishes – floor tiles of 75 mm thickness
- Live loads as per IS 875 part 2
- Water tank of 20 KL above the staircase at Mumty level
- Lift Machine room at mumty level above lift core
The structural model must comply with provisions of IS 1893 and IS 13920.
Run a modal response spectrum analysis and check analysis results of the etabs model for inter-storey drift requirements, vertical & planar irregularities, minimum shear wall requirements,maximum axial load ratio for column and shear walls, effective moment of inertia for beams
and columns etc.
Please note that the column positions shown in the architectural typical floor plan are only to provide an initial starting point for modelling. Participants will have to change its size, introduce shear walls, and add new vertical elements after running the analysis. You will have to run the analysis multiple times until a structural model is obtained that meets structural code requirements without compromising architectural functions. Also, there is no one ‘correct’ structural system for this challenge. There can be multiple possible solutions for this problem.
- Now, we can run the analysis.
- Once, the analysis is over, go to display --> show tables -->analysis result --> structure output --> modal information --> modal mass participating ratio.
Now, in display choose base reactions. Go to display --> show tables -->analysis result --> structure output --> base reactions.
- Now, we need to check the interstory drift. For this display --> story reponse plot -->maximum stry drift
- Here, for both RSx and RSy the max story drift is within 0.004 as given in IS1893-2016
Result:
- The structural modal of the G+7 building has been developed that complies with IS1896 and IS13920.
- After framing the layout, analysis has been carried out.
- Necessary checks have been carried out and also verified the values with the code.