*Editorial* **Special Issue on "Efficient Damping and Isolation Systems for Civil Structures"**

**Felix Weber**

Maurer Switzerland GmbH, Grossplatzstrasse 24, 8118 Pfaffhausen, Switzerland; f.weber@maurer.eu

Civil engineering structures may vibrate due to different sources of excitations such as earthquakes, wind, traffic, humans, etc. The resulting vibrations may not be acceptable from the perspective of vibration comfort or can even impair the structure's safety. Depending on the excitation mechanism, anti-vibration measures range from increasing the structural damping using local dampers, decoupling the structure from the disturbance using vibration isolators and compensating for the excitation forces using vibration compensators. These three basic anti-vibration approaches were mainly developed over the last two centuries and are described in-depth in, e.g., Den Hartog's famous book *Mechanical Vibrations*, first edited in 1934. Driven by the steadily increasing requirements of vibration reduction measures, engineers and researchers were, and still are, focused on further developing anti-vibration systems. New materials and computer technology have made it possible to consider not only passive systems but also anti-vibration systems with adaptive properties or properties controlled in real time. As a result, the variety and complexity of newly developed anti-vibration systems are very wide.

This Special Issue aimed to collect some of the recent advances in the field of efficient damping and isolation systems for civil engineering structures. A total of nine papers are published in this Special Issue. Casini and Vestroni [1] investigate the impact of hysteretic dampers on the total damping of civil structures that are modelled as multidegree-of-freedom systems. Due to the nonlinear dynamics of hysteretic dampers, the phenomenon of modal coupling is demonstrated and explained. Péntek et al. [2] analyse the efficiency of Tuned Sloshing Dampers (TSD) at reducing the acceleration of windexcited tall buildings and compared the results with those of the well-known Tuned Mass Damper (TMD). The paper by Weber et al. [3] on Tuned Mass Dampers with Inerters (TMDI) investigates the efficiency of these devices according to different TMDI topologies and with both analytically derived and numerically optimized TMDI parameters. Reiterer and Schellander [4] describe and analyse a new type of a Tuned Liquid Column Damper (TLCD), which only consists of one horizontal tube filled partially with water and partially with gas. This Featured Paper demonstrates that significant advances in the field of vibration compensation are possible. Majima et al. [5] present an innovative idea for how to use the vibrations of suspended ceilings to operate local dampers using the relative motion between the suspended ceilings and the main structure, thereby increasing the total damping of the building. Farajian et al. [6] describe an interesting approach to make liquid storage tanks safer against seismic excitation by including meta materials in the foundation. The paper by Weber et al. [7] on cable damping by transverse dampers shows that real-time controlled, semi-active transverse cable dampers can compensate for the efficiency losses of passive transverse cable dampers due to cable bending rigidity. Koo et al. [8] present an interesting case study on the challenging task of isolating vulnerable buildings, in this case, a nuclear power plant, from seismic excitation in all three principal directions. Gu et al. [9] describe an experimental study on High-Damping Rubber Bearings (HDRB) with low shape factors for various test conditions.

After approximately one year, the Special Issue on "Efficient Damping and Isolation Systems for Civil Structures" is now closed. Nevertheless, further research and develop-

**Citation:** Weber, F. Special Issue on "Efficient Damping and Isolation Systems for Civil Structures". *Appl. Sci.* **2023**, *13*, 965. https://doi.org/ 10.3390/app13020965

Received: 21 December 2022 Accepted: 31 December 2022 Published: 11 January 2023

**Copyright:** © 2023 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

ment are needed to make the built environment more resilient and safer against undesirable structural vibrations.

**Funding:** This research received no external funding.

**Acknowledgments:** Thanks go to all the authors, peer reviewers and staff of MDPI for their valuable contributions to this Special Issue.

**Conflicts of Interest:** The author declares no conflict of interest.

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