Modelling of 25 storey building with the specified properties using ETABS

Question:

Model a 25-storey building on ETABS with structural properties as specified below. Ground floor or plinth floor level can be taken at a height of 1.5 metres from the base. Each of the successive 25 storeys has a storey height of 3 meters.

Given data:

Structural Element Sizes:

• Beams: 300 × 400 mm
• Columns: 800 × 800 mm
• Slab: 150 mm thick

Material Properties:

• Grade of Concrete: M30
• Grade of Steel Reinforcement Bars: Fe 415

Loading details:

• Dead Load on beams from infill wall: 10 kN/m (Let us assume the same for roof floor in view of parapet)
• Live load on floor: 3 KN/m2 (Let us assume the same for roof floor)

1. a) Buildings are assumed to be pinned at the base
2. b) All columns in all storey are of the same size
3. c) All beams in all storeys are of the same size
4. d) Building is located on Soil type-II and in Zone-III. Assume other factors if required.

Aim:

To model a 25-storey building using ETABS software and verify the seismic code requirement from ETABS analysis.

Procedure:

• Open ETABS software.
• Click New model.
• Give model initialization setting as follow
• Click ok
• In the new model quick template dialog box , select custom grid spacing and click Edit grid data
• Give the following settings in grid system data dialog box.
• Click ok.
• Select custom story data under story dimension and click edit story data.
• Give the story data for first- three story as follow having story 1 as master story.
• Write click on the first column and select add story and click keep existing story heights.
• Give number of added story as 22.
• Click ok
• The following page opens
• Click Define--> Material properties
• Click Add new material for assigning concrete
• .
• Click Add new material for assigning Rebars
• Click ok
• Click Define--> Section properties--> Frame sections.
• Select Add new property in the dialog box.
• Select the concrete shape as rectangular and give the following settings for the Beam
• Beam property is added.
• Again, click Add new property for creating property for column.
• Column property is added.
• Click--> Section properties--> Slab section
• Select Add new property and give the following settings.
• Clickà Define--> Load pattern
• Define load patterns by its name
• Click Define--> Mass source
• Check load cases by click Define-->Load cases.
• Create load combinations, Define--> Load combinations
• Create Columns by Quick draw column.
• Select quick draw beams.
• Select the first horizontal and vertical beams and go to edit and select replicate.
• Select first floor in plan view
• Draw slab using quick slab by having similar stories in the status
• Select all the beams from select tab
• Assign frame loads as distributed from assign tab.
• Select the slabs
• Assign shell loads as uniform
• Select the slabs from select tab and assign as diaphragm from assign tab.
• Click run analysis in the panel after saving the file.

Result:

• Click Display -->Story response plot. Change the display type to Maximum storey drift and desired combo to see the plots.