# How do I combine the effects of the wind load acting on a guyed mast, which consists of mean wind loading and a patch load, according to the standard EN 1993‑3‑1 B.4.3.2.5 (1)?

Chapter B.4.3 of the standard EN 1993‑3‑1 describes the equivalent static method to analyze the dynamic response to wind turbulence.

The patch loads describe the fluctuating wind components.

${\mathrm S}_{\mathrm{TM}}={\mathrm S}_{\mathrm m\;}\pm{\mathrm S}_{\mathrm p}$

[2] Due to the nonlinear structural behavior, the patch loads have to be analyzed together with the mean wind loading in the patch load patterns Si. In this case, it is always necessary to analyze the selected span with the increased patch load and the remaining span with the mean wind loading. In order to determine the pure fluctuation components of the increased patch load related to the mean wind loading, the mean wind load Sm shoud be subtracted from the patch load patterns Si. The, the structural response Sp results from the root sum of squares of the mentioned difference.

${\mathrm S}_{\mathrm p}=\sqrt{\sum_{\mathrm i=1}^{\mathrm N}\left({\mathrm S}_{\mathrm i}-{\mathrm S}_{\mathrm m}\right)^2}$

where
i is the number of the actual spans
N is the total number of load patterns required (actual spans i)