Modelling of 25 storey building with the specified properties using ETABS

QUESTION .1:

Model a 25 storey building on ETABS 2018 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
• Live load on floor : 3 kN/m2

Buildings are assumed to be pinned at the base
All columns in all storey are of the same size
All beams in all storeys are of the same size

Carry out the following exercises:

• Check if the translational fundamental natural period of vibration in both the x and y direction is approximately the following:

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

ANSWER:

AIM:

To model a 25 storey building on ETABS 2018 with structural properties as specified above specifications.

PROCEDURE:

• Structural Element Sizes.
• Material Properties.
• Loading cases.
• Assign.
• Analysis.
• Result.

STEP1: Open ETABs software file. Go to the new model, set the model Initialization.

and press ok button.

STEP2:

Then, we can see the New Model Quick Template dialogue box.

In that box set the Grid dimensions and story dimensions.

Then you can see the model in window plan and 3D view tabs are open.

STEP3:

Go to the Define tab, and click Material properties

Define material dialogue box are appears and set the add material properties.

Add the REbar HYSD 500, HYSD 415.

STEP4:

Then, again click the Define tab, go to Section properties, and click Frame sections.

Now, you can see the Frame properties, Add the new property.

set the column properties.

Next set the beam.

STEP5:

Again, go and click section properties and click the slab Sections.

STEP6:

Draw the beam and column to the plan.

Then set the floor slab to all Stories.

STEP7:

Click the Define tab, to go to the load paterns and set the loads.

Now, set the all loads.

Then set the Diaphragm.

And also se the Mass Sourse Data.

and click 0ok.

STEP8:

Add Load Combination,

Set the default the combination it has the set automatically calculated the loads.

STEP9:

Now, ASSIGN the loads, Frames, Beams, Columns, Slabs everything.

live loads

dead loads:

DIAPHARGM:

step 10:

Analysis:

RESULT: