Challenge

Modelling of 25 storey building with the specified properties using ETABS

Challenge 6)

Aim: Model a 25 storey building on ETABS with structural properties as specified.

Opening and steup a new file:

Open the ETABS software, in the file menu there is an option for new model click on it.
A new window is display on the screen named 'Model Initializaton', click on the third option 'use built in display with' and select all the required perimeters.
When click on ok another display appears on screen named 'New Model Quick Template'.
Give all the grid Dimension and Story Dimensions and press ok.

After entering all the Grid spacing and story data, as per given details the home page of the etabs is visible as shown below.
There are automatically two views generated one is plan view and another one is the 3d view of the drawing.

Defining Materials:

Now to define material properties, Go to the define tab and click on the Material properties option.
A new display appears on the screen.
Click on the add new material option.
Now select the material type as Concrete and grade as M30.
Click on Ok. Another window displays showing material Property Data, click ok again.
Again select other material type as Rebar and grade as HYSD 415.

Defining Section Properties:

Now to define section properties, Go to the define tab and click on the Section properties option and then click on frame sections.
A new window appears on the screen named Frame Section Property Data.
Name the property as C800X800 for column.
Select material as M30 and Give the dimension for depth and widht as 800.
To provide reinforcement, Click on modify/show Rebar.
A new tab appears named Frame Section Property Reeinforcement Data.
Similiarly for the beam follow the same steps as for the column.
Name the beam as B300X400 and give the depth as 400 and width as 300.

Similiarly go for the slab sections, Go to define tab click on the section properties and then click on slab section.
A tab is opened named slab properties, click on add new property option.
A new tab is opened named slab properties data.
Enter the Property name as Slab150, Slab material as M30 and modelling type as Membrane.
In the property data section, select the type as slab and thickness as 150 mm. Click oK.

Defining Load Patterns:

Now to define load pattern, Go to the define tab and click on the Load pattern option.
A tab is displayed on the screen, where dead and live load are already present.
Add another load as wall and enter type as Super dead and click on Add New Load.
Similiarly add earthquake load in x and y direction and also add the positve and negative eccentricity of both the x and y.
And add the Auto Lateral Load as IS 1893:2016. And click Ok.

Defining Mass Source:

Now to define Mass Source, Go to the define tab and click on the Mass Source option.
A new popup displays on the screen click on modify/show mass source.
A new diplay appears on the screen, named mass source data.
Add the mass multipliers for load patterns 100% for dead and wall load and 25% for live load.
Click on oK twice.

Defining Load Combination:

Now to define load combination, Go to the define tab and click on the Load combination option.
Click on Add Default and Design combos.
Select the concrete frame design option, and click oK twice.

Modelling of columns:

Go for quick draw columns option, In the properties of object select the C800X800.
Select the all stories option as the column is created on all the stories of the building.
Click on each of the grid to create the column of the grids.

Modelling of beams:

Go for quick draw beams option, In the properties of object select the B300X400.
Select the all stories option as the beam is created on all the stories of the building.
Click on each of the grid to create the beams between the grids.

Modelling of slabs:

Go for quick draw floors option, In the properties of object select the S150.
Select the Similiar stories option as the slab is not created on base and plinth of the building.
Click on each of the grid to create the slabs between the grids.

Now select all the beams, Go to the select tab then click on select the object and select the object type as beam.
Go to the Assign tab, select the frame loads and click on the distributed opton.
A tab is opened named as the frame load assignment- Distributed.
Select the Load pattern name as Wall and give the load as 10kn/m. Click on apply and then click on close.

Similiarly select all the slabs, and apply the loads.
And again select the slab for diaphragms.
Go to assign tab, then go to the shell option and click on the diaphgram option.
A new tab is displayed on the screen ,Click on D1 then click on apply and press ok.

Exercise:

Fundamental Translational Natural Period:
- X-direction 4.385 that is similiar to 4.4
- Y-direction 4.193 which is similiar to 4.2
Yes, Torsional mode time period is lesser than X and Y direction time period.
Yes, the first threee mode together contributes more than 65% in mass participation.
No, Fundamental lateral period in two principal plane direction are away from each other by 10%.
Yes, the storey drift not exceed 0.004 times the story height.

Ship work like this
in your own course.