Wind and Structures

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Mean wind loads on T-shaped angle transmission towers

  • Guohui Shen (College of Civil Engineering and Architecture, Zhejiang University) ;
  • Kanghui Han (College of Civil Engineering and Architecture, Zhejiang University) ;
  • Baoheng Li (College of Civil Engineering and Architecture, Zhejiang University) ;
  • Jianfeng Yao (College of Civil Engineering and Architecture, Zhejiang University)
  • Received : 2023.06.15
  • Accepted : 2024.03.04
  • Published : 2024.05.25
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Abstract

Compared with traditional transmission towers, T-shaped angle towers have long cross-arms and are specially used for ultrahigh-voltage direct-current (UHVDC) transmission. Nevertheless, the wind loads of T-shaped towers have not received much attention in previous studies. Consequently, a series of wind tunnel tests on the T-shaped towers featuring cross-arms of varying lengths were conducted using the high-frequency force balance (HFFB) technique. The test results reveal that the T-shaped tower's drag coefficients nearly remain constant at different testing velocities, demonstrating that Reynolds number effects are negligible in the test range of 1.26 × 104-2.30 × 104. The maximum values of the longitudinal base shear and torsion of the T-shaped tower are reached at 15° and 25° of wind incidence, respectively. In the yaw angle, the crosswind coefficients of the tower body are quite small, whereas those of the cross-arms are significant, and as a result, the assumption in some load codes (such as ASCE 74-2020, IEC 60826-2017 and EN 50341-1:2012) that the resultant force direction is the same as the wind direction may be inappropriate for the cross-arm situation. The fitting formulas for the wind load-distribution factors of the tower body and cross-arms are developed, respectively, which would greatly facilitate the determination of the wind loads on T-shaped angle towers.

Keywords

Acknowledgement

The authors would like to acknowledge the financial support of National Natural Science Foundation of China (52178511).

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