Project 1_Comparative study of different storey buildings for Seismic forces

Aim: To Compare fundamental natural periods of buildings H, J and K. using ETABS

Procedure:

Building H:

Step 1:

•  Click the Define tab and click section properties
• Select Add new property and choose Rectangular
• Add the new column dimension of 800 x 800
• Click OK

Step 2:

• Click the Select tab and select the columns
• Click assign tab and choose frame assignment as 800 x 800 dimension column
• Click OK

Step 3:

• After assigning loads of each frame run the analysis
• Click Display and choose the show table option
• Select Modal participating ratio from Structural output
• Click OK

Building J:

Step 1:

• Click the Edit tab and choose edit story
• Add 25 story and make 1st story as Master and all other as similar to 1st story
• Click OK

Step 2:

• Click the Select tab and select the columns
• Click assign tab and choose frame assignment as 800 x 800 dimension column
• Click OK

Step 3:

• Click the select tab and assign the column dimensions as 800 x 800
• Click the Select tab and choose floors
• Click assign tab and choose shell loads then uniform load
• Make live load and load pattern name and input 30kn/sq.m for load value
• Click Ok

Step 4:

• Click the Select tab and choose beams
• Click assign tab and choose frame loads then distribute
• Make brick wall load as input 10kn/sq.m for load value
• Click OK

Step 5:

• After assigning loads of each frame run the analysis
• Click Display and choose the show table option
• Select Modal participating ratio from Structural output
• Click OK

Building K:

Step 1:

• Click the select tab and assign the column dimensions as 800 x 800\
• Click the Select tab and choose floors
• Click assign tab and choose shell loads then uniform load
• Make live load and load pattern name and input 60kn/sq.m for load value
• Click OK

Step 2:

• After assigning loads of each frame run the analysis
• Click Display and choose the show table option
• Select Modal participating ratio from Structural output
• Click OK

Conclusion:

• For building H,J, K are the same 25 story but the load increases gradually like 10% and 20%, because of this the building becomes more Flexi due to an increase in weight.
• Time period of H is 3.0, j is 3.411 and k is 4.036.

Comparison 2:

Building A:

Step 1:

• Click the Edit tab and choose edit story
• Add 2 story and make 1st story as Master and all other as similar to 1st story
• Click OK

Step 2:

• Click the Select tab and select the columns
• Click assign tab and choose frame assignment as 400 x 400 dimension column
• Click OK

Step 3:

• After assigning loads of each frame run the analysis
• Click Display and choose the show table option
• Select Modal participating ratio from Structural output
• Click OK

Building B:

Step 1:

• Click the Edit tab and choose edit story
• Add 5 story and make 1st story as Master and all other as similar to 1st story
• Click OK

Step 2:

• Click the Select tab and select the columns
• Click assign tab and choose frame assignment as 400 x 400 dimension column
• Click OK

Step 3:

• Click the select tab and assign the column dimensions as 400 x 400
• Click the Select tab and choose floors
• Click assign tab and choose shell loads then uniform load
• Make live load and load pattern name and input 3 kn/sq.m for load value and brickwall load as 10 kn/sq.m
• Click OK

Step 4:

• After assigning loads of each frame run the analysis
• Click Display and choose the show table option
• Select Modal participating ratio from Structural output
• Click OK

Building F:

Step 1:

• Click the Select tab and select the columns
• Click assign tab and choose frame assignment as 600 x 600 dimension column
• Click OK

Step 2:

• After assigning the loads of each frame run the analysis
• Click Display and choose show table option
• Select Modal participating ratio from Structural output
• Click OK

Conclusion:

Due to the changing of building height the fundamental natural period varies gradually i.e.. for A is 89% at 0.39, for B is 83% at 0.911, for F is 75% at 0.48 and finally for H is 78% is 3.811.

Comparison 3:

Building C:

Step 1:

• Click the Select tab and select the columns
• Click assign tab and choose frame assignment as 550 x 300 dimension column
• Click OK

Step 2:

• Select the column object
• Click the Assign tab and choose frame sections then local axes
• Select rotation angle and enter the degree of 180
• Click OK

Step 3:

• After assigning loads of each frame run the analysis
• Click Display and choose show table option
• Select Modal participating ratio from Structural output
• Click OK

Buiding D:

Step 1:

• Click the Select tab and select the columns
• Click assign tab and choose frame assignment as 300 x 550 dimension column
• Click OK

 

Step 2:

• Select the column object
• Click the Assign tab and choose frame sections then local axes
• Select rotation angle and enter the degree of 90
• Click OK

Step 3:

• After assigning loads of each frame run the analysis
• Click Display and choose the show table option
• Select Modal participating ratio from Structural output
• Click OK

Conclusion:

Due to changing of orientation the fundamental of the natural period varies each building i.e.. for C is 0.91 and for D is 1.04 then for B is 0.941

Comparison 4:

Building E:

Step 1:

• Click the Edit tab and choose edit story
• Add 10 story and make 1st story as Master and all other as similar to 1st story\
• Click OK

Step 2:

• After assigning loads of each frame run the analysis
• Click Display and choose the show table option
• Select Modal participating ratio from Structural output
• Click OK

Building G:

Step 1:

• Click the Edit tab and choose edit story
• Add 25 story and make 1st story, 11th story and 21st story as Master and all other as similar to 1st, 11th, 21st  story
• Click OK

Step 2:

• Click the Select tab and select the columns of the 11th story ( make sure story selection must be in similar story mode)
• Click assign tab and choose frame assignment as 600 x 600 dimension column
• Click OK

Step 3:

• Click the Select tab and select the columns of 21st story ( make sure story selection must be in similar story mode)
• Click assign tab and choose frame assignment as 400 x 400 dimension column
• Click OK

Step 4:

• Click Select tab and select the columns
• Click assign tab and choose frame assignment as 400 x 400 dimension column
• Click OK

Step 5:

• After assigning loads of each frame run the analysis
• Click Display and choose the show table option
• Select Modal participating ratio from Structural output
• Click OK

Conclusion: When comparing these building there is significant difference due to different column sizes. The fundamental period of building E is 0.36 and for F is 0.48. similarly for building G is 3.85 and for building H is 3.01