Structural Modelling using Etabs 2018
Aim
To create the architectural drawing G+7 residential building in zone 5 has been provided
Procedure
To run a modal response spectrum analysis and check the analysis results of the ETABS modal for inter-storey drift requirements
Pinned Support , Base + 9 Story (Ground to terrace ) + Mumty
Coloumn 450 * 600 mm , Beam 400*500 mm , Slab 150 mm thick , Shear wall 300 mm thick
Live load 2.5 kN/m^2 , Floor finish 1.5 kN/m^2 ,Wall load 5 kN/m , Water tank 20k litre over mumty equivalent to 200 kN
overall load
Conceptual design consideration before analysis
Re-entrant and cutout check & modification ( Compromise )
Vertical irregularity (Soft story)
Planner irregularities (Looks symmetrical)
2% shear wall area with respect to building area (8 m^2)
Stiffness modifier for coloumn , Beam & shear wall (0.35 for beam , 0.7 for vertical)
Key points to remember while modelling
No slab , No wall load in the Ground floor
Proper end releases in Beams as per engineer intent
No interior wall load in Terrace
Comparison of static and dynamic forces and revising the factor
To create the model in the ETABS for that we have to create the grid view
Open the ETABS software and then create the model by using
Use build-in-option
Display units - Metric si
Steel section database - Indin
Steel design code - IS 800-2007
Concrete design code - IS 456-2000 by selecting this options in the ETABS and then click ok
New modal quick templates property box is appears on the screen
Custom grid spacing -Edit grit Data and then enter the grid values
By using the table as the reference we have to enter the values in the X Ordinate and also to give the value in the Y Ordinate
After the creation of X and Y Ordinates we have to create the custom storey data
Specify Custo storey data
Checks after analysis
Modal mass participation for first 3 modes dominates at least 65% (Achieved for X-axis only)
Mode-1 and Mode-2 differs by 10% (Achieved)
Principal modes be greater than Torsional mode (Achieved)
Inter story drift ratio limited 0.004 (Achieved )
Axial stress in Coloumn and Shear wall (Achieved)
Base shear share between shear wall & Coloumns (Not dual system)