Project 1_Comparative study of different storey buildings for Seismic forces

ANSWER:-

Aim:-

To compare,

1) Fundamental natural periods of buildings E & F as well as G & H. And the significant difference in the fundamental natural

periods.

2) Fundamental natural periods of buildings H, J and K. Have the buildings become more flexible or stiff due to change in mass.

3) Fundamental natural periods of Buildings A, B, F and H with change in building height.

4) Fundamental natural periods of Buildings B, C and D with change in column orientation.

Procedure:-

1)Fundamental natural periods of buildings E & F as well as G & H. And the significant difference in the fundamental natural periods.

Step:-1

Building E

First we have to open the etabs software and create the new model and add the 10 storey in the story data as shown below.

Next we put the story1 and Story6 as Master Story, as shown below.

Next we have to set the material properties and section properties.

We assign the columns to bottom 5 storeys with the size of (600X600)mm, and add columns to top 5 storeys with the size of

(400X400)mm.

Next we assign the beams to all the storeys with the size of (300X400)mm.

Next we assign the slabs with the thickness of 150mm from 1st storey to 10th storey, as shown below.

Next we have to assign all the loads such as live load, dead load, brickwall load and seismic loads etc,.

After assigning all the loads, we have to check the model and the model shows no error.

After checking the model, then click on the run analysis.

Finally the run analysis has been finished, then the deformed shape of the model will appears, as shown below.

Next we have to click on the Display option and then select the show table option.

After selecting the show table option, then we need to select the Modal Participating Mass Ratios from the Structure output.

Then after the Modal Participating Mass Ratios table will appear, as shown below.

Just we need to do sem process for all buildings.

Final Result:-

1) Fundamental natural periods of buildings E & F as well as G & H. And the significant difference in the fundamental natural periods.

The fundamental natural period of Building E is T=1.561 sec.

The fundamental natural period of Building F is T=1.557 sec.

The fundamental natural period of Building G is T=3.618 sec.

The fundamental natural period of Building H is T=4.412 sec.

In the Building E we use two different column sizes, one has been assigned to top 5 storeys and another one to the bottom 5 storey. But in building F there is only one column size we use for the entire building, thats why there is a significant difference in the fundamental natural periods.

Similarly we use three different column sizes for building G, and one column size for building H.

Hence there is a significant difference in the fundamental natural periods

2) Fundamental natural periods of buildings H, J and K. Have the buildings become more flexible or stiff due to change in mass.

The fundamental natural period of Building H is T=4.412 sec.

The fundamental natural period of Building J is T=4.617 sec.

The fundamental natural period of Building K is T=5.288 sec.

When the mass of the building is increases, then the natural period of the building also increases.

When the mass of the building J increased by 10% compared to Building H, the Building J is more flexible than the building H.

When the mass of the building K increased by 20% compared to Building H, the Building K is more flexible than the building J and building H.

Finally when the weight of the building increases, the buildings become more flexible.

3) Fundamental natural periods of Buildings A, B, F and H with change in building height.

The fundamental natural period of Building A is T=0.5 sec.

The fundamental natural period of Building B is T=1.036 sec.

The fundamental natural period of Building F is T=1.557 sec.

The fundamental natural period of Building H is T=4.412 sec.

When the height of the buildings increases, the natural periods of buildings also increases.

4) Fundamental natural periods of Buildings B, C and D with change in column orientation.

The fundamental natural period of Building B is T=0.972 sec.

The fundamental natural period of Building C is T=1.086 sec.

The fundamental natural period of Building D is T=1.067 sec.

Here the natural periods of buildings shall be increased due to the change in column orientation.