## 1 Introduction  
In recent decades, long-span suspension bridges have been built all over the world; several are located in regions near fault-crossing sites [1]. The main tower columns of a super-long-span suspension bridge are much higher than those of long-span suspension bridges; thus, seismic control devices and measures are of greater importance for the safety of the former. In the traditional seismic design of bridges, structural components of the bridge are allowed to enter a nonlinear state to dissipate energy when exposed to strong earthquakes [2]. For the bridge tower of long-span suspension bridges, the traditional design view often treats each main tower column as one independent section component [3, 4]. An independent tower column structure has good overall integrity and is simple to construct. Previous studies have shown that bridge structures are easily damaged because of extreme events such as strong earthquakes [5, 6, 7]. Dampers have been widely adopted in industries for several decades, including aerospace, the military and automobiles [8, 9]. The damping system is also an important structural protection system for important bridge structure, and it has been widely investigated and adopted in bridges in China since the 1990s [10, 11]. A damping system is an important structural protection system for bridge structures. Recent research indicates that most of the long-span suspension bridges around the world have installed damping systems as shock absorbers or energy dissipation systems. Many types of damper have been installed in bridges to improve the dynamic performance of the bridge when exposed to wind or earthquake excitation [12; 13; 14]. The towers in long-span bridges are generally slender with large height, and the location and distribution of energy dissipation devices for the towers are important factors to be considered [15]. The traditional seismic response control strategies for long-span bridges mainly focused on the damping connection [16] or damped outriggers between the tower column and bridge deck [17]. In order to reduce the structure self-weight and improve the mechanical performance of the super-long span cable-stayed bridge under earthquake and wind excitation, the CFRP cables and UHPC members were designed and analyzed [18; 19]. The large retrofit costs of bridges after the Chi-Chi earthquake in 1999 revealed the need for alternative bridge design strategies, including improved performance when exposed to a near-fault earthquake. In China, the longest bridge crossing an active fault is the Puqian Bridge in Hainan Province [3]. It has been observed that bridges located in near-fault areas are more vulnerable when exposed to earthquakes [19; 20]. Near-fault earthquakes possess distinct characteristics [21], including the high-velocity pulse effect, the hanging wall effect, the directivity effect and the fling-step effect [22; 23; 24; 25]. It is necessary to study the influence of near-fault ground motion characteristics on the seismic responses of bridges to reduce seismic damage [26]. Some methods have been proposed to study the seismic responses of long-span suspension bridge under near-fault earthquake, and the seismic response reduction measures are also widely proposed. The responses of long-span cable-stayed bridge under near-fault ground motions considering velocity pulse effect and non-uniform excitation were investigated systematically through shake-table test [27]. The transverse seismic responses of soil-cable-stayed-bridge system under near-fault ground motions were also investigated by both of experimental test and numerical simulation [28]. In terms of research methods, several methods have been proposed to study the seismic responses of long-span bridges exposed to strong earthquakes, including structural health monitoring [29], shaking-table tests [27; 30; 31], non-destructive on-site tests [32] and numerical simulation [33]. The finite element simulation method is often chosen as one of the preferred methods in the schematic design phase.