Modelling of 25 storey building with the specified properties using ETABS

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: Tx1Tx1= 4.4 second Ty1Ty1= 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

AIM: To know the modeling of a high rise building in ETABS software

Introduction: modeling the 25 storey building with etabs and use special property on etabs with applying load and check as per IS 1893(part1)-2016

Procedure:

step 1) just open etabs software

then click on new model and choose use buit-in setting with option

after that choose proper option from given and press ok

then click on custom grid spacing

and edit the setting by clicking on edit grid data

go to grid system data

edit by adding grid and define X ordinate distance and Y ordinate distance

and then press ok

step 2)

then go for custom storey data

so select custom storey option from given

edit the setting by adding 25 storey

and press ok

step 3)

now our basic model is ready

then define material

so just go on define option on ribbon

and choose material option from that

and click on add new material property

then click on Ok

then, also add fe415 steel proprty

so go to add new material

select steel otion and press ok

our material proprty is added successfully

step 4)

now go for section property

from define option

and select frame option from that

fill all detail and modify modifiers and rebar

same work for column

go to frame section select rectangle section

step 5) go for slab defination

click on add new property

fill all data and press ok

step 6) then go for load patterns

\

add wall load and type as super dead load

also modify earthquake load from modify option

then add and modify EQX and EQY lateral force

step 7) mass sources

put load value according to load

step 8) check for load case

go to define

and click on load case option from list

check all and press ok if all correct

step 9) load combination

go to load combination from define

step 10) modeling stage

draw column by clicking on draw column option

now set working plane as all storey, cause column for all stories

and column on grids like that

we can also use replicate option for draw column

step 11) now same do for Beams

go to frame draw

select beam property as 300X400mm

and draw on overall

step 12) slab

so go for storey one it is master storey

go to draw floor option

select working plane as similar storey

then choose slab property as S150

and draw the slab on floor

like that to all grids

step 13) assign frame load

go to select option and select all the beams

then go to assign and frame load assignment ( distrubuted loads )

same assign load on slab

same process done for slab and assign 3KN/m for all slab

then select slab again and assign diaphragm

select D1 and press ok

step 15) now analyse the model

go to run analyse and click on it

then save the file

Result: