Modelling of 25 storey building with the specified properties using ETABS
Challenge 6
- Open etabs and select new model and make the following settings.
- click the custom grid spacing and maintain the spacing as 4m in both x and y direction.
- click ok, a box appears, enter the stories up to 25 maintain height of 3m except for base to plinth
- which is 1.5m and 1st storey is entered as master story.
- now go to define and select material properties, and enter the following.
- M30 grade concrete and steel 415
- now go to section properties and enter the size of beam column and slab.
- now go to the load pattern, and enter the loads as shown.
- now select the quick draw column from the screen and place the columns at each grid.
- similarly place the beams and slabs.
- now assign the load to roof slab, select all the slabs and go to assign option.
- select the load as live and 1.5kn/m2.
- for other floors assign 3kn/m2.
- now assign the load to all the beams of 10kn/m2.
- now go to define option and select mass source and assign the mass source as shown.
- go to the load combination and select modify, a list of combination appears.
- go to the shells from assign and then select diaphragm, assign as D1.
- now go to the analyze and check model.
- since there are no errors, building looks like this after applying loads.
- go to the display and select shown tables and then modal mass participating ratios.
- table is obtained.
- from the table we can say that time period of mode of torsion is less than fundamental mode.
- first 3 modes contribute more than 65% in the mass participating ratios of each plan direction.