Modelling of 25 storey building with the specified properties using ETABS

Challenge 6 – ETABS modelling of a 25 storey building

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 metres.

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 

• 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)

a) Buildings are assumed to be pinned at the base

b) All columns in all storey are of the same size

c) All beams in all storeys are of the same size

d) Building is located on Soil type-II and in Zone-III. Assume other factors if required.

 

Carry out the following exercises:

• Check if the translational fundamental natural period of vibration in both the x and y direction is approximately: $T_{x1}$= 4.4 second $T_{y1}$= 4.2 second

This check will help confirm if modelling is done correctly. Some deviations from the above values is possible (± 2%). But any major deviation will suggest an error in modelling. 

• Check if the following provision in Table 5 of IS 1893 (part 1) – 2016, on torsional irregularity satisfied:

The natural period corresponding to the torsional mode of oscillation must be less than the two fundamental translational modes of oscillation along each principal plan directions.

• Check if the two provisions of clause 7 in Table 6 (shown below) of IS 1893 (part 1) – 2016, regarding vertical irregularity is satisfied

 

• Check if provision on inter-storey drift limitations in clause 7.11.1.1 satisfied. Please note that this check is for Serviceability Limit State and hence is for situation when stucture is subjected to unfactored seismic base shear

 

 

STEP 1  :  TO OPEN THE ETABS

 

Doble click on ETABS 2018 icon 

Go file in manubar 

Click on new model 

Go to model initialization window

Select use built in settings with

Then select display units as metric SI

Steel section data base as Indian

Steel design code as IS 800 : 2007

Concrete design code as IS 456 : 2000

Finaly click on ok 

 

 

 

 

STEP 2  :  EDIT THE GRID DATA AND STORY DATA AS PER YOUR PLAN 

 

Go to new model quick template 

Go to grid dimensions (plan)

Select the uniform grid spacing 

Give the no of grid lines in X direction - 5

No of grid lines in Y direction - 4

Spacing of grid in X direction - 4m

Spacing of grid in Y direction  - 4m

 

Go to storey dimensions 

Then select / click on custom storey data 

Go to edit storey data 

Edit the storey as your required 

Change the storey name as your required 

Change the height of storey also as your required 

Change the similar to as plinth and storey 1 is none and remain floors as similar to storey 1

To add the remain floors

Mouse right click 

Select add storey 

Click on keep existing storey height 

Give the storey height as 3m or based on your required 

no of added storey as based on your plan

click on ok 

then change the storey name as your required 

Click on ok 

Finally click on ok 

 

 

 

STEP 3  :  TO DEFINE THE MATERIAL PROPERTIES 

 

CONCRETE MATERIAL AS M 30

Go to define in manubar 

Then select material properties 

Then open define material window

Go to add new material 

Then select region as Indian 

Material type as Concrete 

Standard as India

Grade as M 30 or as your required 

click on ok

Check the data 

Click on ok

 

REBAR MATERIAL AS HYSD 415

Go to define in manubar 

Then select material properties 

Then open define material window

Go to add new material 

Then select region as Indian 

Material type as Rebar

Standard as India

Grade as HYSD 415 or as your required 

click on ok

Check the data 

Click on ok

 

 

STEP 4  :  TO DEFINE THE SECTION PROPERTIES AS FRAME SECTIONS

 

COLUMN SIZE 800 X 800

 

Go to define in manubar 

Then go to section properties 

Then select the frame sections

Then open the frame section window

Go to add new properties 

Then select the Concrete rectangular shape 

Then give the property name as column 800 X 800

Material as M 30 

Depth as 800 mm

Width as 800 mm

Then go to properties modify  / show modifiers 

Then change the moment of inertia about 2 axis - 0.7

moment of inertia about 3 axis - 0.7

NOTE : MOMENT OF INERTIA ABOUT THE AXIS IS 70% AS PER IS 1893 : 2016 (PART 1) CLAUSE NO 6.4.3.1

Then click on ok 

Then go to Reinforcement 

Then click on modify / show rebar

Design type as P - M2 - M3 Design (column)

Then go to rebar material 

To change longitudinal bar as HYSD 415

Confinement bar as HYSD 415

Then go to Confinement bar size and area as 8mm

Finally click on ok 

Click on ok 

 

BEAM SIZE 300 X 400

 

Go to define in manubar 

Then go to section properties 

Then select the frame sections

Then open the frame section window

Go to add new properties 

Then select the Concrete rectangular shape 

Then give the property name as beam 300 X 400

Material as M 30 

Depth as 400 mm

Width as 300 mm

Then go to properties modify  / show modifiers 

Then change the moment of inertia about 2 axis - 0.35

moment of inertia about 3 axis - 0.35

NOTE : MOMENT OF INERTIA ABOUT THE AXIS IS 35% AS PER IS 1893 : 2016 (PART 1) CLAUSE NO 6.4.3.1

Then click on ok 

Then go to Reinforcement 

Then click on modify / show rebar

Design type as M3 Design (beam)

Then go to rebar material 

To change longitudinal bar as HYSD 415

Confinement bar as HYSD 415

Finally click on ok 

Click on ok 

 

 

STEP 5  :  TO ASSIGN THE SECTION PROPERTIES AS FRAME SECTIONS

 

TO ASSIGN THE COLUMNS

Go to draw in manubar 

Then go to draw beam / column / brace objects 

Then select quick draw column

Then go properties of objects 

Select the property as column 800 X 800

Then go to storeys options 

Then select the all storey 

Then assign or place the column on grid lines as your required 

Then click on Esc

 

 

TO ASSIGN THE BEAMS

 

Go to draw in manubar 

Then go to draw beam / column / brace objects 

Then select quick draw beam / column

Then go properties of objects 

Select the property as beam 300 X 400

Then go to storeys options 

Then select the all storey 

Then assign or place the beams on grid lines as your required 

Then click on Esc

 

 

 

STEP 6  :  TO DEFINE THE SECTION PROPERTIES AS A SLAB SECTIONS

 

SLAB THICKNESS 150mm

 

Go to define in manubar 

Then go to section properties 

Then select the slab section 

Then go to slab properties window 

Click on add new properties 

Then open slab properties data window 

Then give properties name as slab 150

Slab material as M 30

Modeling type as membrane

Thickness as 150mm

Click on ok 

Finally click on ok 

 

 

 

 

STEP 7  :  TO ASSIGN THE SECTION PROPERTIES AS SLAB SECTIONS

 

Go to draw in manubar 

Then go to draw floor / Wall objects 

Then select quick draw floor / Wall

Go to properties of objects window 

Select properties as slab 150

Then go storey options in down

Selecstorey as similar storey 

Then assign or place the slab as your required plan

 

 

STEP 8  :  TO ASSIGN SUPPORTS CONDITIONS 

 

Go to view in manubar 

Select the set plan view 

Go to select plan view window 

select base plan

Click on ok

 

Select the all column base points 

Then go to assign in manubar 

Go to joint

Select restraint 

Go to joint assignments restraint window 

select required pined support 

click on apply

click on ok 

 

 

STEP 9  :  TO CHECK THE RENDER VIEW 

Select the 3d view window 

Go to view in manubar 

Select show rendered view

Check the 3d view

 

STEP 10  :  TO DEFINE LOAD PATTERNS 

 

Go to define in manubar 

Go to select load patterns 

In default dead load and live load

Then add required Wall load and seismic load

WALL LOAD

Then give load as wall load

Type as super dead

Click on add new load

 

SEISMIC LOAD

Then give load as EQ X

Type as seismic

Auto lateral load as IS 1893 : 2016

Click on add new load

 

Then give load as EQ  +X

Type as seismic

Auto lateral load as IS 1893 : 2016

Click on add new load

 

Then give load as EQ  -X

Type as seismic

Auto lateral load as IS 1893 : 2016

Click on add new load

 

Then give load as EQ Y

Type as seismic

Auto lateral load as IS 1893 : 2016

Click on add new load

 

Then give load as EQ +Y

Type as seismic

Auto lateral load as IS 1893 : 2016

Click on add new load

 

Then give load as EQ -Y

Type as seismic

Auto lateral load as IS 1893 : 2016

Click on add new load

 

Then select EQ X load

Then click on modify lateral load 

Then go to IS 1893 : 2016 seismic Loading window

Then select X dir only

Then deselect remain options 

Then go to seismic zone factor Z

Select percode as 0.16 (zone III)

Site type as II

Important factor as 1.5

Response reduction as 5

Then go to time period

select user define T as 0.5 sec

Click on ok

 

 

Then select EQ +X load

Then click on modify lateral load 

Then go to IS 1893 : 2016 seismic Loading window

Then select X dir + eecertricty only

Then deselect remain options 

Then go to seismic zone factor Z

Select percode as 0.16 (zone III)

Site type as II

Important factor as 1.5

Response reduction as 5

Then go to time period

select user define T as 0.5 sec

Click on ok

 

Then select EQ -X load

Then click on modify lateral load 

Then go to IS 1893 : 2016 seismic Loading window

Then select X dir - eecertricty only

Then deselect remain options 

Then go to seismic zone factor Z

Select percode as 0.16 (zone III)

Site type as II

Important factor as 1.5

Response reduction as 5

Then go to time period

select user define T as 0.5 sec

Click on ok

 

 

Then select EQ Y load

Then click on modify lateral load 

Then go to IS 1893 : 2016 seismic Loading window

Then select Y dir only

Then deselect remain options 

Then go to seismic zone factor Z

Select percode as 0.16 (zone III)

Site type as II

Important factor as 1.5

Response reduction as 5

Then go to time period

select user define T as 0.5 sec

Click on ok

 

Then select EQ +Y load

Then click on modify lateral load 

Then go to IS 1893 : 2016 seismic Loading window

Then select Y dir + eecertricty only

Then deselect remain options 

Then go to seismic zone factor Z

Select percode as 0.16 (zone III)

Site type as II

Important factor as 1.5

Response reduction as 5

Then go to time period

select user define T as 0.5 sec

Click on ok

 

Then select EQ -Y load

Then click on modify lateral load 

Then go to IS 1893 : 2016 seismic Loading window

Then select Y dir - eecertricty only

Then deselect remain options 

Then go to seismic zone factor Z

Select percode as 0.16 (zone III)

Site type as II

Important factor as 1.5

Response reduction as 5

Then go to time period

select user define T as 0.5 sec

Click on ok

 

 

 

 

STEP  11  :  TO ASSIGN THE LOAD PATTERNS 

 

TO ASSIGN THE DEAD LOAD AS SLEFWEIGHT 

 

Go to select in manubar 

Then go to select options 

Then select the object type 

Select the beam

Click on select 

Click on close

 

Go to assign in manubar

Then go to frame load

Then click on distributed

Then go to frame load assignments distributed window 

Then select load pattern name as dead

Go to uniform load

Then give load as 1.5 KN/m

Click on apply 

Click on ok

 

 

 

TO ASSIGN THE WALL LOAD

 

Go to select in manubar 

Then go to select options 

Then select / click on objects type 

Select the beam 

Click on select 

Click on close

 

 

Go to assign in manubar 

Then go to frame load

Then click on distributed 

Then go to frame load assignments distributed window 

load patterns name as wall load 

Go to uniform load

Then give load as 10 KN/m

Click on apply 

Click on ok

 

TO ASSIGN THE DEAD LOAD ON SLAB / FLOOR 

 

Go to select in manubar 

Then go to select options 

Then select / click on objects type 

Select the floor 

Click on select 

Click on close 

 

Floor load as 3.75 KN/m^2 ( dead load )

 

Go to assign in manubar 

Then go to shall load 

Select uniform 

Then go shall load assignments uniform window 

Then select load patterns as dead load

Then go to uniform load 

Then load as 3.75 KN/m^2 ( dead load )

Click on apply 

Click on ok

 

TO ASSIGN THE LIVE LOAD ON SLAB / FLOOR 

 

Go to select in manubar 

Then go to select options 

Then select / click on objects type 

Then select the floor 

Click on select 

Click on close 

 

FLOOR LOAD AS 3 KN/m^2 ( Live load )

 

Go to assign in manubar 

Then go to shall load 

Select the uniform 

Then go to shall load assignments uniform window 

Then select load patterns as live

Then go to uniform load

Then give load as 3 KN/m^2 ( Live load )

Click on apply 

Click on ok

 

 

STEP  12  :  TO DEFINE AND ASSIGN MASS SOURCES

 

Go to define in manubar 

Then select mass source

Then go to mass source window 

Then click on modify / show mass source 

Go to mass source data window 

Then give the mass source name mass source 

Then go to mass source 

Uncheck the elements selfmass and additional mass

Select the specified load patterns 

Then go to mass multipliers for load patterns 

 

Then select load patterns as dead load and multipler as 1

Click on add

Then select load patterns as wall load and multipler as 1

Click on add

Then select load patterns as live load and multipler as 0.25

Click on ok

Finally click on ok 

 

 

 

STEP  13  :  TO DEFINE AND ASSIGN THE MODEL CASES

 

Go to define in manubar bar

Select modal cases

Go to model cases window 

Click on modify / show case

Go to loads applied 

Then click on add 

Load Type as acceleration 

Load name as UX 

Then click on add 

Load Type as acceleration 

Load name as UZ 

Then click on add 

Load Type as acceleration 

Load name as UY

Then go to other parameters 

Then maximum number of modes as 25

Minimum number of modes as 1

Then click on ok

Finally click on ok 

 

 

STEP  14  :  TO DEFINE AND ASSIGN THE LOAD COMBINATIONS 

 

Go to define in manubar 

Then select load combinations 

Then go to load combinations window 

Then click on add default design combinations 

Go to add default design combinations window 

Select the Concrete frame design 

Click on ok 

finally click on ok 

 

 

STEP  15  :  TO ASSIGN THE DIAPHRAGMS AS FLOORS

 

Go to select in manubar 

Then go to select options 

Then select objects type 

Then go to select by objects type window 

Select floors

Click on select 

Click on close 

 

 

Then go to assign in manubar 

Then go to shall 

Then click on diaphragms

Then go to shall assignments diaphragm window 

select D1

Click on apply 

Click on ok

 

 

STEP  16  :  TO ANALYZE THE MODEL 

 

TO CHECK MODEL 

 

Go to analyze in manubar 

Then click on check model

Then go to check model window 

Select the select / deselect all

Click on ok

Then no warning's arise Then the model is ready

 

TO RUN ANALYSIS MODEL 

 

Go to analyze in manubar 

Then click on run analysis / press F5 function key

Our model as been analysised

 

STEP  17  :  TO CHECK THE SUPPORT RECTIONS 

 

Go to display in manubar 

Then go to force / stress diagrams

Then select support / spring rection

Then go to reaction window 

Then select the required load

Then select the required display results for these components 

Then click on apply 

Click on ok

 

STEP  18  :  TO CHECK THE DEFLECTION 

 

Go to display in manubar 

Then go to deformed shape / F6 function key 

Go to deformed shape window 

Select required load / combo / mode options

Then click on apply 

Then click on ok 

 

 

STEP  19  :  TO CHECK THE TABLES

 

Go to display in manubar 

Click on show table 

Go to choose table for display window 

Go to structure output 

Click on + symbol 

Then select the required information 

Then check the data 

 

 

 

 

STEP  20  :  TO CHECK THE STORY RESONSE PLOTS

 

Go to display in manubar 

Click on storey response plots

Go to storey response plots  window 

Go to display type 

Select the required plot 

 

RESULT  :

FROM THE TABLE THE TIME PERIODS , T X1 = 7.079 AND T Y1 = 6.825

THE 25 STORY BULIDING AS SUSFFULY ANALYZIED

THE TIME PERIOD SEPARATION OF LEAST 10% IS NOT ACHIEVED