# Fragility Analysis of Transmission Towers Subjected to Downburst Winds
###### Abstract
(2020) introduced the calculation method of wind and rain loads, conducted a fragility analysis of transmission towers, and proposed the critical collapse surface [12]. [PERSON] et al. (2020) conducted a fragility analysis of the transmission tower-line system to assess the anti-collapse performance and explored the effect of the length of side spans and wind attack angles [13]. [PERSON] et al. (2021) presented a component-based fragility modeling framework for transmission towers and demonstrated that it can effectively evaluate the transmission tower fragility curve [14]. [PERSON] et al. (2021) proposed a quasi-static approach to assess the fragility of a transmission tower under wind loads [15]. [PERSON] et al. (2023) presented a novel moment-matching technique for handling such uncertainties and estimating the structural fragility of a transmission tower system [16]. Although these efforts have been made, fewer studies have been conducted on the systematic analysis of the wind-induced fragility of transmission towers under the downburst considering wind speed and direction. Currently, the collapse accidents of transmission towers under the downburst have attracted extensive attention from scholars at home and abroad. There are few studies on the fragility analysis of a transmission tower under a downburst. [PERSON] et al. (2001) illustrated the model for the wind velocity time history of microburst events and the loading on the transmission tower [17]. [PERSON] et al. (2003) investigated the characteristics of downbursts through the experiment and performed a finite element analysis of different transmission towers [18]. [PERSON] et al. (2004) presented a deterministic-stochastic hybrid model of the downburst and conducted the wind-induced response of the slender structure in the time domain [19]. [PERSON] et al. (2006) used a stochastic model of the downburst to  
Figure 1: Collapses of transmission towers under downburst winds. explore the quasi-static loading conditions and compared these loads to the ABL loads [20]. [PERSON] et al. (2007) evaluated the effect of various downburst parameters on the performance of transmission towers and compared the structural behavior under the downburst with the result of the ABL load [21]. [PERSON] et al. (2012) studied the progressive failure of two transmission line systems under downburst wind loading [22]. [PERSON] et al. (2016) aimed to assess the capacity curve of a tower within the tower-line system under a downburst [23]. [PERSON] et al. (2018) proposed a method of multi-scale failure analysis of transmission towers under downburst wind loading [24]. [PERSON] et al. (2022) investigated the progressive collapse mechanisms of a transmission tower-line system under downburst wind loading by fully coupled dynamic simulations [25]. [PERSON] et al. (2016) assessed the capacity curve of a transmission tower under modeled downburst wind loading and compared it with that obtained for an ABL wind loading profile [26]. [PERSON] et al. (2018) conducted an extensive parametric study on a number of transmission line systems to evaluate their critical response to downburst loads [27]. [PERSON] et al. (2018) reported the first aeroelastic test for a multi-span transmission line under a simulated downburst [28]. [PERSON] et al. (2019) explored the dynamic effect of downburst loading on these longitudinal forces and examined the validity of using quasi-static analysis [29]. [PERSON] et al. (2022) revealed the wind-induced vibration response characteristics of a transmission tower-line system under a downburst [30]. [PERSON] et al. (2022) conducted a dynamic stability analysis of the transmission tower-line system under a downburst [31]. Scholars at home and abroad have conducted a lot of research on the wind-induced response of transmission towers under the effects of downbursts. The research on the fragility analysis of transmission towers under the downburst is very limited.