Project 2_Design & Analysis of a Hostel building at Guwahati, Assam
1
Aim - To model the structural plan according to the architectural plan of the hostel building
according to the given loads and design the pile foundation on the safe
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 2.4m and remaining all floors as 3.45m
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 M25
Again add new material
Material type as rebar , indian standard and grade as FE415,FE500
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 B400x500
Give depth as 400 and width as 500 as given
In the same process add new propert as coloumn and name it as C450x650
Give depth as 450 and width as 650
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 C450x650 and draw at the grid points
Then select quick draw beams and select B400x500
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 3.5
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
Which is approximately equal
Torsional deviations
Torsional mode time period is less than X and Y direction time period
X - 80%
Y - 81% (yes)
Fundamental natural periods are almsot equal not less than 10% (NO)
Interstorey drift
It should not exceed 0.004 times height of building
The valus is almost same as we see in the graph
Check concrete frame design
Check weather all members passed or not
Check the longitudinal reinforcement and shear reinforcement
Then calculate the no of bars and dia and spacing of the bar
Typical Beam Longitudinal reinforcement
Total of 2200mm2
Then 4 no of top and bottom main reinforcement
4x490 = 2000
Then add 1 no of 12mm extra on either sides
Shear reinforcement
1300mm2
Consider
1000/100 x 4.2 x 50
= 1333.33
8mm stirrups at 150mm spacing
Typical Coloumn reinforcement
4 no of 32mm and 4 no of 25 mm
Total of 5000mm2
Aim - To import the base of the model from etabs we designed to safe and design the pile foundation from the model
Procedure
First of all we have to export the model from etabs as safe f2k file and save
Then open the safe
Then import the lastly saved hostel file and open
Modelling in SAFE
The grids will aotomatically appear as per the model imported
Then define materials M25 and FE500
Define slab materials
Pile cap , M25, Type as mat , Thickness as 800 and OK
Coloumn as type is stiff and thickness 800 and OK
Piles as type mat and thickness 500
Draw rectangular slab and select grids and pile cap
From starting point drag to end point
Then give points for piles and coloumns
Draw points and give by adjusting the pile to pile distance
Then give X as 1.55 and click in forst point
In the same way give all points by giving offset distance in X and Y direction
Then draw piles select quick draw areasType as alsb and property as pile 5000
Shape as circular slab and dia as 0.5 and give piles whereever you wanted on the points we have given
In the same way give the coloumns but select rectanguler slab and give Xand Y as 600
Then place at the centre point
Then assign the springs at the centres of the piles
Select all the centre of the pile points and assign support data and point spring
Then select and modify as in the Z direction and give 588.65 as stiffness
And give compression only and OK
Select the point in the coloumn and give load dats
Point load for coloumns is already imported
Then cheeck all the loads and design preferences and change the rebar to FE 500
Then Run the analysis
Capacity of piles individually is less than 200 then OK
Settlement under service loads is under 0.7 its OK
Punching shear is less than 1 OK
Service load reactions is almost 200 its good OK
Renforcement detailing
Max bottom reinforcement is 3200mm2
31 x 12 mm dia of 100mm spacing (31 x 113)
Top reinforcement 2800mm2
28 x 12mm dia of 100mm spacing
