Project 1_Comparative study of different storey buildings for Seismic forces

A

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

Open a new model in etabs

Give units as metric SI

Steel as indian

Design code as IS 800 : 2002

Concrete design IS 456 : 2000

Then give grids and story data

Give spacing in X and Y direction for the grids

Then gove story data

From base to plinth give height as 1.5m and remaining all floors as 3m

Total of 2 stories

Give story 1 as master story

Then give remaining all as similar to 1st story

Give material properties

In the define tab go to material properties

Add new material India concrete and grade as M30

Again add new material

Material type as rebar , indian standard and grade as FE415

Give beams,coloumns and slab

In the define tab select sectional properties and framed sections for beam and coloumns

Add new propert and rectangular concrete

Give property name as B300x400

Give depth as 400 and width as 300 as given

In the same process add new propert as coloumn and name it as C400x400

Give depth as400 and width as 400

For slab

In the define tab select sectional properties and select salb sections

Add a new property

Then rename as S150 and give modelling type as membrane and give thickness as 150 and OK

Then start modelling

Go to any plan view and select all stories

Select quick draw coloumns and select C400x400 and draw at the grid points

Then select quick draw beams and select B300x400

Then draw beams at the grid lines

You can also replicate the beams and coloumns by giving offset and no of times

Add slab

First select similar stories

Go to any plan view and select quick draw floors and select S150

Select the space where slab to be laid

Then assign the loads

In the define tab select load patterns

Select dead load with multiple of 1

Add live load of multiple 0

Wall load as super dead load and multilpe 0

Eq in X directiion of seismic load and code of IS 1893 2016

Eq in Y directiion of seismic load and code of IS 1893 2016

Then select Eqx and modify and select zone as 2 and I factof as .16 same for Eqy

Then OK

Assign live loads

Select all the slabs

Then assign shell loads and uniform loads and as live and give value of 3KN/M

Then assign wall loads

Select all beams

Then assign and frame loads

Then UDl and give value as 10

Mass source

For earthquake load we have to assign mass source

Define and mass source

Select specefied load pattern and Ok

Now generate load combinations

Define tab and load combinations and select default design combinations

Then select concrete frame design and edit table and OK

Diaphragm

Select all the floors

In the assign tab and shell tool and select diaphragm

You can see the eccentricity of the structure which is useful in lateral loading

We can check the model cases in define

Then analyse the structure by clicking run analysis key

Go to tables in the left side

Analysis result and structural output and model oinfo

Vibration in X and Y direction

Model periods and dispaly tables

Model 1 - 4.01

Model 2 - 3.08

B

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the first model we already done modeled the same no of grids , beams , slabs

But the stories changed

We have to just change the stories

First open the old file

Then save as and rename as challenge B

In the edit tab there is edit grids and story toll and invoke it

Then add the stories extra 3

Then give similar stories to all stories

Check the loads if added or not

Then select only floors

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output and tables and check the seconds

C

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the first model we already done modeled the same no of grids , beams , slabs

But the coloumn sizes is to be changed

We have to just change the coloumn sizes

First open the old file

Then save as and rename as challenge c

Add the new famed material or coloumn

Add new coloumn as 500 x 300

First in the view options untick floors and beams

Then select all the coloumns

Then assign frame then sectional properties and modify and select C500X300

Then visible floor and beams

Check the loads if added or not

Then select only floors

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output and tables and check the seconds

D

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the first model we already done modeled the same no of grids , beams , slabs

But the coloumn sizes is to be changed

We have to just change the coloumn sizes

First open the old file

Then save as and rename as challenge c

Add the new famed material or coloumn

Add new coloumn as 300x500

First in the view options untick floors and beams

Then select all the coloumns

Then assign frame then sectional properties and modify and select C300x500

Then visible floor and beams

Check the loads if added or not

Then select only floors

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output and tables and check the seconds

E

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the first model we already done modeled the same no of grids , beams , slabs

Add 5 more stories in the add grids and stories tool and give similar to first story in all the beams

But the coloumn sizes is to be changed

Here coloumn size differ from floors also

And it has 10 stories

We have to just change the coloumn sizes

First open the old file

Then save as and rename as challenge E

Add the new famed material or coloumn

Add new coloumn as 400x400

And again Add new coloumn as 600x600

First in the view options untick floors and beams

In the view tab select building view limits

Give botto as base and top as 5th and ok

Then select all the coloumns

Then assign frame then sectional properties and modify and select C600x600

First in the view options untick floors and beams

In the view tab select building view limits

Give bottom as 5th and top as 10th and ok

Then visible floor and beams

Check the loads if added or not

Then select only floors

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output and tables and check the seconds

F

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the first model we already done modeled the same no of grids , beams , slabs

Add 5 more stories in the add grids and stories tool and give similar to first story in all the beams

But the coloumn sizes is to be changed

Here coloumn size differ from floors also

And it has 10 stories

We have to just change the coloumn sizes

First open the old file

Then save as and rename as challenge F

Add the new famed material or coloumn

And again Add new coloumn as 600x600

First in the view options untick floors and beams

Then select all the coloumns

Then assign frame then sectional properties and modify and select C600x600

First in the view options untick floors and beams

Then visible floor and beams

Check the loads if added or not

Then select only floors

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output and tables and time frequency

G

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the E model we already done modeled the same no of grids , beams , slabs

Add 15 more stories in the add grids and stories tool and give similar to first story in all the beams

But the coloumn sizes is to be changed

Here coloumn size differ from floors also

And it has 10 stories

We have to just change the coloumn sizes

First open the old file

Then save as and rename as challenge F

Add the new famed material or coloumn

Add new coloumn as 400x400

And again Add new coloumn as 600x600

And again Add new coloumn as C800x800

First in the view options untick floors and beams

In the view tab select building view limits

Give bottom as base and top as 10th and ok

Then select all the coloumns

Then assign frame then sectional properties and modify and select C800x800

First in the view options untick floors and beams

In the view tab select building view limits

Give bottom as 10th and top as 20th and

Then assign frame then sectional properties and modify and select C600x600

In the view tab select building view limits

Give bottom as 20th and top as 25th and

Then assign frame then sectional properties and modify and select C400x400

Then visible floor and beams

Check the loads if added or not

Then select only floors

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output

H

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the G model we already done modeled the same no of grids , beams , slabs

And it has 25 stories also

We have to just change the coloumn sizes

First open the old file

Then save as and rename as challenge H

We already have C800x800

Then unsee the floors and slabs

Then select all the coloumns

Then assign frame then sectional properties and modify and select C800x800

Then visible floor and beams

Check the loads if added or not

Then select only floors

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output

J

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the H model we already done modeled the same no of grids , beams , slabs

And it has 25 stories also

We have to just change the live loads

First open the old file

Then save as and rename as challenge J

Select only floors

Then assign

Sheel loads

Then uniform

Increase it to 10% which is 3.3

And replace with current load

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output

K

Aim - Model and analyse then find factors influencing natural time period according to given dimensions

Procedure

In the J model we already done modeled the same no of grids , beams , slabs

And it has 25 stories also

We have to just change the live loads

First open the old file

Then save as and rename as challenge K

Select only floors

Then assign

Sheel loads

Then uniform

Increase it to 20% to H which is 3.6

And replace with current load

Then diaphrgm in the shell and check

Then run analysis

Then in the analysis results and structural output

Our results are

Effect of stiffness on time period of building

E - 2.20s

F - 2.22s

G - 5.36s

H - 5.67s

Effect of mass on time period of

H - 5.67s

J - 5.66s

K - 5.7s

Effect of building on time period

A - 0.60s

B - 1.266s

C - 1.36s

D - 1.32s

F - 2.22s

H - 5.67

Displace of the coloumns in the building

B it is almose same (Eqx - 2.40 , Eqy - 2.4)

C is different Eqx - 2.25, Eqy - 2.40 because coloumn size is reduced in the X direction

When the inertia is zero in B building

We got the value of - 3.41s with zero moment of inertia

Regular we got of - 1.266s

H building

With zero axial area

With zero axial area we got the value of - 5.67s

While in the regular we got - 5.67s

In the B building

If the base are fixed then - 1.12s

In the pinned support we got - 1.266s