Transmission Tower(Optimal Design)

Optimal Design of Power Transmission Towers Project Description Optimize design of a latticed power transmission tower and poles to withstand transient dynamic loads due to a severe earthquake. earthquake. Members of the structure should be selected s elected directly from the commercially available ones.

Analysis Model for Tower # of members: 316 (angle (angle sections modeled as 3D beam elements) # of joints: 111 (666 degrees of freedom) Loading: Static loads : normal conductor loads, wind loads, broken conductor loads  Dynamic load : El Centro earthquake record Analysis: Nonlinear transient dynamic analysis using ANSR program

z

1

1

y

y

E

x

z

1.125 244

x

2

3

2

1.125

H

1.36 78

A

79

A

1.10

71

1.05

14

D

I

1.05

259

80

81 (3.35, 18.44, 0.)

1.10 198

1.05 1.05

82

83

2.29

C

G 2.00

42

39 (1.04, 10.95, 1.04)

.

1.75 1.85

B F

135

. .

1.70

1.40

55 (1.48, 4.25, 1.48)

66

2.15

A

. 1.30

   0    8  .    0

2.10

3.52

Cross-Section A-A

I

151 63 (1.76, 0., 1.76)

I

1.30

a. Front View

b. Side View

FIG. 110 kV Tangent-Type Tower (not to scale, units are in m., number in the parenthesis are nodal coordinates, member numbers are in italics)

Design Variables Member sizes available available in a vendor catalog. catalog. Members are grouped grouped into 9 sections. Thus there are are 9 discrete design variables. variables.

Cost Function Minimize total cost of the structure; taken as proportional to mass of the structure.

Constraints Based on ANSI/ASCE Manual, Design of Latticed Steel Transmission Structures. Time dependent constraints constraints are imposed on combined axial axial compression and bending, combined axial tension and bending, and shear stress. In addition constraints constraints on slenderness slenderness ratio and member member sizes are imposed.

Results Several discrete variable optimization methods are developed and evaluated. Each optimization run took about two weeks on a medium medium level HP desktop workstation.