Wind-Induced Response of a Transmission Tower-Line System in a Goaf Area at the Allowable Tower Inclination Limit

Abstract

This study investigates the wind-induced response of a transmission tower-line system with an initial inclination induced by differential foundation settlement. A two-tower, three-span finite element model is established for a 220 kV tangent tower in a goaf area of Ordos, China. The allowable inclination ratio of 0.5% is adopted to define the initial settlement state. Single-support, two-support, and three-support settlement modes are considered together with wind acting either along or opposite to the settlement-induced initial lateral displacement, resulting in six cases. At the 0.5% inclination limit, the required settlements are 0.0721, 0.0422, and 0.0706 m, respectively. Although the two-support case requires the smallest settlement, it produces the largest local axial stresses in the middle and lower crossarms. Under along-settlement wind, the mean tower-top displacement, middle-crossarm conductor attachment point (CAP) displacement, and axial-stress amplitude increase by 44.09–49.02%, 38.60–47.91%, and 86.23–174.76%, respectively, relative to the corresponding static settlement states. Under opposite-settlement wind, the peak tower-top displacement decreases by 42.8–44.5% relative to the along-settlement cases. Overall, two-support settlement combined with along-settlement wind produces the largest local stress response among the investigated cases.