Iith Tower_file (1).docx

ANALYSIS & DESIGN OF 45M TALL TOWER AT INDIAN INSTITUTE OF TECHNOLOGY- HYDERABAD ENTRANCE

Dr Anil Agarwal Department of Civil Engineering Indian Institute of Technology, Hyderabad

IIT ENTRANCE TOWER. The tower has a wide-based rhombus configuration with the maximum dimension of 4.70 m at the base. The total height of the tower is 45 meters. The tower is divided into four panels, with varying dimensions. The panel is the component of the tower, which consists of legs, diagonals, horizontals and redundant. The maximum height of a panel is 14.5 m (Panels 4), and the minimum height is 10 m (Panels 1 to 3). The primary tower is composed of angle sections and back to back double angle of varying cross-sections. For secondary members, it’s square hollow sections(SHS). The tower configuration with the panel numbers is shown in Figure 1. When we consider the slenderness ratio at several locations in the tower, higher sections are provided even if their member utilization ratio is minimum. 𝑟𝑥 is critical for double angle back to back section. At all joints moments 2-2(minor) and 3-3(major) are released.

3D-VIEW Fig: 1-a

Moment released Fig: 1-b

45 meters

Panel 8: 40 meters

Panel 7: 35 meters

Panel 6: 30 meters

Panel 5: 25 meters

Panel 4: 20 meters

15 Panel meter 3: 15 meters

Panel 2: 10 meters

Panel 1: 5 meters

Ground level: 0 meter

Elevation from ground level Fig: 1-c

A

B

C 2D-VIEWS Fig: 1-d

D

3rd & 4th 10-20 mts

1St & 2nd Panel: 0-10 mts

PANEL WISE VIEWS Fig: 1-e

5th & 6th Panel: 20-30 mts 7th ,8th & end:

PANEL WISE VIEWS Fig: 1-e

Panel: 30-45 mts

Table 1 When we consider the slenderness ratio at several locations in the tower, higher sections are provided even if their member utilization ratio is minimum. 𝑟𝑥 is critical for double angle back to back section.

Panel

1&2

Section used

ISA 200X200X18 ISA 150X150X18

Member ID

97,98,99,102,103,104,109,110

Type of angle

BRACINGS OF THE TOWER Double angle 6

5524.7

1674

991

0.6

safe

6

Double angle

5524.7

821

607

0.74

safe

6

Double angle

5524.7

711

600

0.85

safe

6

Double angle

5524.7

400

310

0.78

safe

4

6

Double angle

10000

713

239

0.34

safe

5&6

ISA 200X200X18

131, 132, 133, 134, 129, 130, 135, 136, 143, 144, 137, 138, 141, 142, 139, 140

-

Single angle

5524.7

453

304

0.68

safe

7&5

ISA 200X200X18

88

Double angle

9942.6

713

118

0.17

safe

3&4

ISA 150X150X15 ISA 130X130X12 ISA 200X200X18

107,108,96,94,105,106,111,112

Back to Back spacing(mm)

Force in Length Design Member the of Strength utilization Remarks member section (kN) ratio (kN)

115, 116, 117, 118, 121, 122, 127, 128 113, 114, 123, 124, 119, 120, 125, 126

6

ISA 150X150X12 ISA 150X150X18 ISA 200X200X18 ISA 150X150X12 ISA 150X150X15 ISA 70X70X10

16

6

Double angle

7298.3

373

40

0.11

safe

4582

276

18

0.07

safe

328

70

0.22

safe

2

-

Single angle

1, 18, 159, 160, 157, 158, 155, 156, 45, 43, 30, 38, 28, 146, 153, 53

-

Single angle

50, 51 9, 70 52

6668 6 -

Double angle

7740

342

53

0.16

safe

Single angle

4700

223

38

0.18

safe

Single angle

2142

70

6.5

0.1

safe

Table 2 All the angles are the single angle for horizontal & diagonal members, and 𝑟𝑣𝑣 is critical for single angle section. When we consider slenderness ratio at several location in the tower, higher sections are provided even if their member utilization ratio is minimum.

Panel

Section used

Type of angle

Member ID

At Z from ground level (m)

Force in Design Member Force in Length the Design Strength utilizati the of Compre Strength Compre on ratio Tension sectio ssion Tension( ssion Compre member n member kN) (kN) ssion (kN) (kN)

Member utilization ratio Tension

Remarks

Braces

HORIZONTAL & DIAGONAL MEMBERS OF THE TOWER 1

2

3

4

ISA 130x130x12 ISA 150x150x12 ISA 200x200x18 ISA 150x150x12 ISA 130x130x12 ISA 150x150x12 ISA 150X150X18 ISA 150X150X12

single angle

5,12,11,8

5

4070

155

8.5

0.06

676

14

0.03

safe*

Horizontal

single angle

26

5

4700

180

0.5

0.01

785.46

0.5

0.01

safe*

Diagonal

single angle

72,29,10 1,60

10

4700

562

467

0.84

1562

521

0.34

safe*

Horizontal

single angle

161

10

4700

180

6

0.04

785.46

15

0.02

safe*

Diagonal

single angle

13,19,15, 14

15

4070

155

12

0.08

676

21

0.04

safe*

Horizontal

single angle

27

15

4700

180

0.5

0.01

785.46

0.5

0.01

safe*

Diagonal

single angle

17,7,3,54

20

4700

265

237

0.9

1153

276

0.24

safe*

Horizontal

167

20

4700

180

0.3

0.01

785

3

0.01

safe*

Diagonal

5

6

7

ISA 130x130x12 ISA 150x150x12 ISA 150X150X18 ISA 150X150X12 ISA 130x130x12 ISA 130x130x12

single angle

20,21,22 ,23

25

4070

155

11

0.08

676

12

0.02

safe*

Horizont al

single angle

31

25

4700

180

0.5

0.01

785

0.5

0.01

safe*

Diagonal

single angle

71,67,27 2,100

30

4700

265

81

0.31

1153

101

0.09

safe*

Horizontal

single angle

169

30

4700

180

9.5

0.06

785

14.5

0.02

safe*

Diagonal

single angle

44,35,32, 42

35

4400

155

35

0.23

676

33

0.05

safe*

Horizontal

single angle

37

35

4090

155

3

0.02

676

1.5

0.01

safe*

Diagonal