# State-of-the-Art Review of Structural Vibration Control: Overview and Research Gaps
## 1 Introduction  
### General  
Structural vibrations in civil engineering have a significant impact on the performance, safety, and serviceability of various infrastructures, including buildings, bridges, and towers. Seismic vibrations pose a significant threat to the safety and performance of civil structures, particularly in regions prone to earthquakes. Structural vibration control has recently emerged as an effective technology for earthquake mitigation. Over the years, extensive research has been conducted to develop effective approaches for mitigating seismic vibrations and minimizing the adverse effects of earthquakes on structures. Researchers have studied different passive, active, semi-active, and hybrid control methods for the seismic response control of structures. Comprehensive, state-of-the-art reviews on structural control in general [1, 2, 3, 4] and specific controls [5, 6, 7] are presented, providing an overview of the various control strategies and their applications. A list of all state-of-the-art review papers is presented in Table 1. [PERSON] et al. [8] presented an in-depth reviewcovering diverse control systems, sensors, and research requirements from 1990 to 1996. Notably, this study pioneers the Physical Design Problem (PDP) concept, subsequently becoming a fundamental principle in various research endeavors. The authors advocate for prioritizing specific topics, including energy-efficient strategies for control devices and algorithms, integrating intelligent sensors for distributed sensing and control in dispersed systems, and addressing concerns related to near-field strong earthquake ground motion that influences structural control applications. Their recommendations set the stage for subsequent research, shaping the trajectory of advancements in the field during the specified period. Regarding active structural control, recent influential papers by [PERSON] [4; 9; 10] offer a comprehensive overview of the various active structural control systems developed up to 1990. Additionally, [PERSON] [11] provides a thorough review of the active control of structures subject to earthquake excitations. This review discusses different types of active control and their theoretical foundations, highlights key findings from parametric studies on various control strategies, addresses the limitations and practical challenges of active control systems, briefly examines the more promising semi-active control methods, and concludes with an outline of several active control strategies implemented in practice. [PERSON] [12] provides a comprehensive review of active control, delving into the challenges posed by engineering informatics. The review emphasizes the imperative for multi-objective control strategies, highlighting their dual focus on ensuring the structure's safety and serviceability while enhancing the robustness of the control system. Reviews on semi-active control are also reported [13; 14]. Other notable review papers include state-of-the-art reviews on the base isolation of structures [15; 16; 17]. The development of active, hybrid, and semi-active control systems has reached the stage of full-scale applications in actual structures. Nevertheless, every structural control system and its applications encounter challenges and limitations across various aspects. The challenges in implementing control strategies have hindered their expected applications. To maximize effectiveness, the controller must be designed with consideration for the issues and should be robust, stable, reliable, and simple to design and implement. This paper presents a comprehensive examination of these challenges and limitations, providing insights into future research requirements and directions. Structural control constitutes a vast and interdisciplinary research domain within civil engineering systems, making it impractical to discuss or reference all relevant publications and applications comprehensively.