# Performance of Strengthened Accelerated Oscillator Damper for Vibration Control of Bridges
## 1 Introduction  
In the past, there have been significant advancements in the fields of transportation engineering safety and civil engineering safety [1; 2; 3; 4]. There is significant concern about the seismic safety of structures built in earthquake-prone regions [5; 6]. To mitigate the negative impacts of seismic activities on human life and productivity, numerous technologies concerning vibration control have been extensively developed. Vibration control techniques play a significant role in reducing displacement and force response when subjected to seismic [7], ice [8], wind [9], and other types of loads. Recent trends in civil engineering have led to a proliferation of studies focusing on the damping effects of spring-mass-damper systems [10; 11; 12; 13; 14; 15; 16]. The approach of [17], namely the tuned mass damper (TMD), first proposed by [PERSON], may offer a viable solution. [PERSON] et al. conducted a study on the TMD system [18; 19] and used a combination of vertical plates and TMDs to effectivelycontrol the vibration of the Trans Tokyo Bay Crossing Bridge [20]. After conducting research on the use of tuned mass dampers (TMDs) in a five-story reinforced concrete building, [PERSON] et al. concluded that the middle-rise structure with TMDs would not need repair intervention after the earthquake [21]. There has been keen interest among researchers in TMD-based derivative devices, with the multiple tuned mass dampers (MTMD) emerging as a prominent example. Significant advancements have been achieved in studying the impact of structural frequency change on MTMD, as seen in the studies conducted by academics [22; 23; 24; 25]. There is very extensive literature on the topic of the Inerter, which is a mechanical device with two terminals [26; 27; 28; 29; 30; 31; 32; 33]. This device serves the functions of inertia amplification and damping enhancement by transforming the linear motion of its moving terminal into the rotational motion of a flywheel, thereby generating significant inertia [34; 35]. According to [PERSON] et al. 's research [36], the tuned mass damper with In-erter (TMDI) can dissipate structural kinetic energy more efficiently during seismic events. The optimally designed Tuned Inerter Damper (TID) developed by [PERSON] et al. effectively suppresses structural displacement responses across a wide range of natural periods [37]. Furthermore, [PERSON] et al. introduced the dual-layer multiple tuned mass damper (DMTMD), which offers improved damping efficiency. However, one drawback of the DMTMD is that its secondary mass experiences an excessively long stroke [38]. An important constraint on all the work discussed in this area is the excessively long stroke of the secondary mass present in both TMDs and TMD-derived devices. This limitation substantially restricts their practical application in engineering, particularly in terms of displacement and force along the longitudinal direction of the bridge. The approaches of [39] may offer a viable solution to tackle this issue. This innovative device comprises a transmission mechanism (specifically, a rack-and-pinion system), a spring-connected secondary mass, and a damping component. The transmission device amplifies the relative displacement between the damper and the primary structure, thereby augmenting its energy absorption and vibration mitigation efficacy while simplifying the technical complexities. Nonetheless, there are two things that need to be improved in AOD. Improvement needed 1: Installing the secondary structure of AOD in actual bridge applications, which consists of secondary mass, secondary damping, and secondary spring, is challenging. Additionally, the amplification coefficient of the secondary damping and secondary spring can be increased. Improvement needed 2: As a generalized single-degree-of-freedom (SDOF) system, the AOD exhibits a remarkable sensitivity to the equivalent natural frequency of the system, especially in the near-resonance region [40].