Project 1_Comparative study of different storey buildings for Seismic forces
Project 1_Comparative study of seismic forces of buildings with different floors
AIM: Comparative study of seismic forces of buildings with different floor
Factors influencing the dynamic characteristics of a building
Factors influencing the shape of oscillations
The shape mode associated with the natural period of the building is the deformed shape of the building under natural period shaking. So the building has as many mode shapes as there are natural periods.
There are an infinite number of natural periods for a building. But in mathematical building modeling, usually the building is discretized into several elements. The connections of these elements are called nodes. Each node is free to move in all three Cartesian directions and rotate about three Cartesian axes. Therefore, if the number of discretization nodes is N, then there would be 6N oscillation modes and associated 6N natural periods and oscillation shapes.
Procedure:
Building A
2 storey building
size of beam 400X400mm
Step 1:
1) Open ETABS 17 application
2) Click the File menu and choose to Create a New Model option from there.
3) After choosing a New model a dialogue box will appear which is known as Model Initialization.
4) Choose the Built-in settings option and select the display units and codes.
Step 2:
1) After the model initialization needs to select Grid and Story inputs from the New model quick templates dialogue box.
2) In this dialogue box choose custom grid spacing and custom story data which is used to provide the inputs whatever we want.
Step 3:
1) In the Grid system data dialogue box, set x grid data as 5 numbers at a distance of 4m
2) And also set Y grid data as 4 numbers at a distance of 4m.
3) Click OK
Step 4:
1) In a story data dialogue box, need to input all the relevant details about the story which we want to model.
2) Put 3m height for all the story except plinth
3) Make 1st story as Master story
4) Choose all other stories as similar to 1st story
5) Click OK.
Step 5:
1) On the top right corner click the drop-down arrow
2) Choose New window option
3) Now the screen splits into two.
4) Here, we can see the plan and elevation of each story simultaneously.
Step 6:
Applying Properties to Materials
1) Click Define tab
2) Choose Material properties
Step 8:
1) After clicking ok for Add New Material Property dialogue box it redirects into another dialogue box called Material property data.
2) In this data all the relevant data values are assigned default as per IS code which we set previously.
Step 9:
1) After applying the properties of Beams and columns we need to apply the property of Slab
2) Click Define menu and choose Section properties
3) Select Slab Sections
Step 10:
1) Click to select Add New Property
Step 11:
1) Rename the Property name
2) Select the material as M30
3) Choose modeling type as Membrane from the drop-down list
Step 12:
Drawing of Columns and Beams:
1) To drawing the columns and beams in Etabs just click the Quickdraw columns tool in the model tree
2) After clicking the tool, the property tab will appear on that tab all the relevant detail about the particular objects will show.
Step 13:
1) Draw the Columns in accordance with the grids
2) Click the Select object tool to discard the drawing.
Step 14:
Applying Loads:
1) Click Define tab
2) Choose Load Patterns.
Step 15:
1) Add new load as Brickwall, EQX with both positive and negative eccentricity as per IS 1893:2016
2) Similarly add EQY with positive and negative eccentricity
Step 16:
1) After providing the names and codes of load
2) Click Modify Lateral load option
3) Assume the zone as Zone IV
Step 17:
1) After providing the load inputs need to assign the shell loads of each story
2) Change tab as Similar story
3) Select the entire grids
4) Click the Assign tab and choose Shell loads
5) Select Uniform
Step 18:
1) Choose the load pattern name as already set in the previous step.
2) Input the load as 3kn/sq.m as given in the question
3) Click ok
Step 19:
1) Similarly we need to assign the live loads for all the beams
2) click the Select tab
3) choose object type and select Beam
Step 20:
1) Choose the load pattern name from the drop-down list
2) Set load as 10Kn/sq.m
3) Click Ok
Step 21:
1) To view the loads click the toggle option on top of the screen
2) And rotate the view where we can see the loads applied.
Step 22:
1) Before running the analysis we have to set one more step i.e. Mass Source
2) Go to the Define tab
3) Select the Mass Source option.
Step 23:
1) Tick mark the specified load patterns
2) Add the load patterns which we want to assign the model
3) Click Ok
Step 24:
1) one of the important steps for modeling is to set load combination
2) Click the Define tab
3) Select Load Combinations
Step 25:
1) Choose the load combination
2) Select Concrete frame design
3) Click Ok
Step 26:
1) Immediately ETABS will give you various load combinations as per the code which we are set previously
2) Click Ok
Step 27:
1) Final step of analysis is to set Diaphragm
2) Click the Assign tab
3) Choose shell and select Diaphragm.
4) Choose an all story option from the bottom of the screen
Step 28:
1) Click the check tab
2) And check the model is there any mistakes. if not go ahead the analysis.
Building B
5 storey building
size of beam 400X400mm
step 1) storey data
our building frame are created
step 2) now going for section add beam section according to given size and material
step3) slab section
step 4) load patterns
step 5) mass source
step 6) load cases
step 7) create load combination
step 10) now go for column, slab and beam modelling
step 11) assign loads
step 12) diaphragms property
step 13) run analysis
Building C
5 storey building
size of beam 550X300mm
step 1) storey data
our building frame are created
step 2) now going for section add beam section according to given size and material
step3) slab section
step 4) load patterns
step 5) mass source
step 6) load cases
step 7) create load combination
step 10) now go for column, slab and beam modelling
step 11) assign loads
step 12) diaphragms property
step 13) run analysis
Building D
5 storey building
size of beam 300X550mm
step 1) storey data
our building frame are created
step 2) now going for section add beam section according to given size and material
step3) slab section
step 4) load patterns
step 5) mass source
step 6) load cases
step 7) create load combination
step 10) now go for column, slab and beam modelling
step 11) assign loads
step 12) diaphragms property
step 13) run analysis
BUILDING E (G+ 10 )
Column sizes :
for top 5 storeys: C 400X400
Column sizes :
for bottom 5 storeys: C600X600
STEP 1) Add 5 more story in previous structure
STEP 2
Change the column size as 600x600
STEP 3
Select the column,beam and slab from floor 6 to 10
STEP 4
Assign loads
step 5
CHECK for diaphragms
STEP 6
RUN ANALYSIS
BUILDING G (G+25)
Columns for top 5 stories: C400X400
Columns for middle 10 stories: C600x600
Columns for bottom 10 stories: C800x800
STEP 1) Add 15 more story in previous structure
STEP 3
Select the column,beam and slab from floor 6 to 10
1) Columns for bottom 10 stories: C800x800
2)Columns for middle 10 stories: C600x600
3)Columns for top 5 stories: C400X400
STEP 4
Assign loads
step 5
CHECK for diaphragms
STEP 6
RUN ANALYSIS
