BS 7733:1994

Committees responsible
National foreword
Section 1. General
1.1 Scope
1.2 Definitions
1.3 Symbols and abbreviations
1.4 Design basis
1.5 System design
1.6 Assessment of line reliability
1.7 Security requirements
1.8 Safety requirements
Section 2. Design criteria
2.1 General
2.2 Design criteria
2.3 Design criteria for towers
2.4 Design criteria for foundations
2.5 Design criteria for conductors and earth wires
2.6 Design criteria for insulators and hardware
Section 3. Loadings
3.1 General
3.2 Climatic loads, wind
3.3 Climatic loads, ice without wind
3.4 Climatic loads, combined wind and ice loadings
3.5 Loads for construction and maintenance
3.6 Loads for failure containment
Section 4. Strength of components and limit states
4.1 General
4.2 Components of transmission line systems
4.3 Limit states of line components
4.4 Strength data of line components
Section 5. Technical justifications
5.1 Scope
5.2 Relation between load and strength
5.3 Effect of span dispersion on reliability
5.4 Strength coordination of line components
5.5 Number of components subjected to maximum load
      intensity
Annexes
A. The effect of span dispersion on load-strength
      relationship: calculation of span use factor
B. The Beta distribution function
C. Statistical distribution of maximum yearly wind
      velocity and ice load
D. Characteristic strength of components
E. Determination of the meteorological reference
      wind velocity
F. Gradient wind speeds
G. Temperature measurements and their interpretation
H. Types of icing
J. Atmospheric icing process and terrain influences
K. Guidelines for the implementation of an ice
      observation programme
Tables
1. Typical strength coordination
2. Reliability corresponding to various assumptions
      of load and strength
3. Relationship between reliability levels and return
      periods of design loads
4. Reliability levels of transmission lines
5. Design conditions
6. Range of spatial coverage of maximum load
      intensity
      (given in number of towers)
7. Number of towers subjected to maximum load
      intensity
8. Strength factor phi N related to the number N of
      components subjected to the critical load
      intensity
9. Values of phi S
10. Definition of ground roughness
11. Values of high wind velocity
12. Values of KR for different ground roughness
13. Statistical parameters of ice loads
14. Values of ice load coefficient Kog
15. Return period of combined events
16. Combined wind and ice loading conditions
17. Values of KoL and KoH
18. Values of factors KiH and KiL
19. Drag coefficients of ice-covered conductors
20. Damage and failure limits of supports
21. Damage and failure limits of foundations
22. Damage and failure limits of conductors and ground
      wires
23. Damage and failure limits of interface components
24. Strength parameters of supports
25. Strength parameters of foundations (in uplift)
26. Strength parameters of interface components
27. Strength parameters of conductors and ground wires
28. Values of ratio of average strengths (RAS) and
      phiS
      required to insure that component R2 will fail
      after R1 with a 90 % probability
29. Strength coefficient phiN related to N components
      in series subjected to the critical load
A.1 Statistical parameters of wind span variation
A.2 Statistical parameters of weight span variation
A.3 Values of gamma u as a function of U and N for
      vR = 10 %
A.4 Values of gamma u for different strength
      dispersions
C.1 Values of the constants C1 and C2
C.2 Probability of exceeding an event having a return
      period T
C.3 Ratios of x/x for an extreme type 1
D.1 Values of Kc
D.2 Value of quality factor phi Q for lattice towers
E.1 Values of factor Kj
H.1 Physical properties of ice
H.2 Meteorological parameters controlling ice
      accretion
Figures
1. Relations between load and strength
2. Methodology for the design of transmission lines
3. Ground roughness A
4. Ground roughness B
5. Ground roughness C
6. Ground roughness D
7. Determination of the apparent length of 2 Lm of
      the two adjacent spans on the considered support
8. Gust factor of insulators and towers: Gi, Gt
9. Definition of the solidity ratio
10. Overall normal drag coefficients for rectangular
      towers composed of flat-sided members CxT
11. Overall normal drag coefficients for rectangular
      towers composed of circular section members CxT
12. Value of CxTc drag coefficient of cylindrical
      elements having a large diameter, as a function
      of Reynolds number Re
13. Factor related to the influence of the number of
      years of observation of ice
14. Factor related to the influence of conductor
      diameter
15. Variation of Kh with the height of conductors
      above the ground
16. Untitled
17. Untitled
18. Cases of combined ice-wind loadings given as an
      indication
19. Factor related to the influence of the number of
      years with observation of wind combined with ice
20. Definition of cylindrical ice shape
21. Application of longitudinal loads
22. Untitled
23. Untitled
24. Diagram of transmission line system
25. Diagram of a transmission line diagram
26. Values of Pf = (1 - Ps) for various distributions
      of Q and R for T = 50 years
27. Values of Pf = (1 - Ps) for various distributions
      of Q and R for T = 150 years
28. Values of Pf = (1 - Ps) for various distributions
      of Q and R for T = 500 years
B.1 Different forms of the Beta distribution
E.1 Relationship between meteorological wind
      velocities at a height of 10 m
K.1 Untitled