Energy Dissipation Technologies in Seismic Retrofitting: A Review

Abstract

In order to ensure the safety of existing buildings constructed many years ago in zones with high seismicity, it is very important to consider and apply retrofitting measures. The seismic retrofitting of buildings can be achieved by techniques such as increasing the stiffness and ductility of the building and reducing the seismic demand. Energy dissipative devices such as various types of dampers are among the most popular and widely studied devices for improving the performance of buildings exposed to earthquakes. This paper presents a systematic literature review of the seismic retrofitting of existing buildings using energy dissipating devices. More than 230 journal and conference articles were collected from three well-known scientific resources published from 2010 to 2024. The main classification of papers considered was based on energy-dissipating devices employed for retrofitting goals. According to this analysis, there is a vast number of energy dissipative devices and design methods studied by scholars, and energy dissipation based on friction, viscous, and hysteretic mechanisms are the most useful for dampers. On the other hand, only relatively few articles were found about seismic loss assessment and the economic aspects of buildings retrofitted with the proposed damping tools.

1. Introduction

Buildings are known as a crucial portion of today’s modern world, and it is very important to continuously monitor and upgrade their performance in order to ensure their safety and efficiency. In developed regions such as European and Northern American countries, a considerable number of buildings were built many decades ago, and they have started to age. For instance, in Canada, more than 50% of buildings were constructed before the 1990s, while 80% of buildings were constructed before the 1990s in Europe [1,2]. Building codes and standards are being updated every year due to new demands and lessons learned from past natural disasters. Obviously, buildings constructed several decades ago do not meet the provisions of recently published codes. Furthermore, past seismic events have demonstrated that older buildings are more susceptible to earthquakes, and it is essential that we upgrade measures to reduce the vulnerability of buildings and financial and human losses due to earthquakes. According to reports published after the seismic events in Peru, Italy in 2009, Haiti in 2010, New Zealand in 2010 and 2011, and Turkey in 2023, buildings are still vulnerable, and solutions are needed to address this issue [3,4,5,6].

There are two general strategies to address the mentioned issue: seismic retrofitting and demolition and reconstruction. Obviously, seismic retrofitting is preferred to demolition and reconstruction due to its lower cost and shorter time period, unless seismic retrofitting may not be feasible in the proposed building [7]. During the seismic retrofitting process, engineers may focus on the whole structural system or specific parts of the structure. Using the former strategy corresponds to local measures, while employing the latter corresponds to global measures. During the application of local measures, engineers aim to strengthen some specific parts of the buildings. For instance, in reinforced concrete (RC) buildings, the structural elements can be upgraded to fiber-reinforced polymer (FRP), textile-reinforced mortar (TRM), and high-strength mortars, leading to improvement in the stiffness, ductility, and strength of the RC members. Many researchers have studied different local retrofitting techniques that employ various approaches. It is noted that, sometimes, employing local retrofitting strategies solely may not be enough, and it is essential that we use global retrofitting strategies to upgrade the structures exposed to earthquakes [2,7,8,9,10,11,12,13,14].

Global retrofitting measures can be carried out by installing a new lateral force-resisting system working parallel with the primary lateral force-resisting system, base isolation, and energy-dissipating devices. Adding a new lateral force-resisting structural system has already been studied by many scholars, and several studies already present a literature review of this aspect. It is noted that adding a new structural system increases the global stiffness of the main building, and, therefore, it may impose additional lateral forces on the buildings. The additional forces may lead to some failure modes such as overturning, foundation failure, and the failure of the soil beneath the buildings [2]. Furthermore, increasing the stiffness of the main building may lead to higher acceleration in the building’s floors and a higher damage level in the non-structural members. Installing base isolation and energy-dissipating devices is another alternative, leading to a reduction in the seismic forces and response of the structure. Vast studies have been conducted to inspect the effectiveness of both techniques in the seismic upgrading of structures [2].

Installing base isolation and dampers in structures aims to reduce the seismic demands. Due to the high number of publications in both fields, the main focus of the current paper is to first present a discussion on the different types of dampers for the seismic upgrading and retrofitting of existing buildings. There are various damper devices introduced and used by scholars for the seismic protection of buildings. These dampers can work based on viscous, friction, hysteretic, and viscoelastic mechanisms or a mixture of the mentioned mechanisms. This paper also covers studies performed for upgrading buildings exposed to earthquakes using a tuned mass damper (TMD), and viscous, friction, viscoelastic, and hysteretic dampers. A TMD is another energy-dissipating tool that can be used for seismic retrofitting. The organization of this paper is as follows: Section 2 discusses the methodology and data collection for the literature review. In Section 3, the research conducted on each device is discussed in detail, while concluding remarks are presented in Section 4.

2. Methodology

In the current study, a three-step systematic literature review (SLR) procedure was employed. This method has been used in several previously published papers. The steps were performed as follows:

• The search stage, which required finding the articles published in the proposed scope and removing irrelevant papers by careful filtering;
• The inspection stage, which involved conducting a deep study of the selected papers in order to find the core ideas proposed by the authors and employing bibliometric tools;
• The discussion stage, in which the outputs of the previous stages were synthesized and final outputs were presented.

Herein, three well-known scientific sources, Scopus, Google Scholar, and Web of Science, were employed to search for and find published articles in the area of seismic upgrading of buildings using energy-dissipating tools. Considering the scope of the current study, two categories of keywords were selected. The first category referred to seismic retrofitting, while the second one referred to energy-dissipating devices. For instance, three keywords referring to the former category included seismic retrofitting, seismic upgrading, and seismic strengthening, while some keywords used for the latter category included tuned mass damper, friction damper, hysteretic damper, energy dissipating, and viscous damper. Since the scope of this paper is to present a discussion on energy-dissipating tools such as different types of dampers, it does not cover base isolation for retrofitting, unless it is used together with base isolation. After the search stage, more than 1500 articles were found, published from the year 2010 to 2024, and all the articles found were published in English. Proposed keywords were searched in the title, keywords, and abstract. After finding the journal pages, the articles that were outside of the proposed scope were removed (Figure 1).

After the filtering stage, the selected articles were analyzed using VOSviewer (version 1.6.19), a powerful bibliometric analysis tool that categorizes publications based on factors such as recency, citation networks, and keyword co-occurrence. This approach ensures a structured and systematic selection of high-quality, relevant academic sources for analysis. By mapping research trends, the findings highlight the contributions of key institutions, influential researchers, and leading countries in this field.

The articles were further analyzed using VOSviewer on the basis of their recency. This methodology ensures a thorough and structured approach to selecting high-quality, relevant academic articles for analysis. Additionally, a systematic review was conducted to provide a comprehensive synthesis of existing research. This involved a structured process of identifying, selecting, and critically evaluating relevant studies to ensure the inclusion of high-quality and credible sources. By integrating bibliometric and systematic review methods, this paper offers a well-rounded assessment of the current knowledge landscape, identifying research gaps and potential areas for future exploration.

The gathered data were assessed using the VOSviewer software platform that provides a powerful tool for preparing literature review articles. Figure 2a shows the co-authorship network among different countries that publish articles in the area of building retrofitting by employing energy dissipative devices, and, in Figure 2b, the percentage of studies conducted by each country is displayed. According to the VOSviewer outputs, there are five major clusters represented by five different colors. Note that the countries with less than six published articles were considered under “Other Countries” for clarity. These countries include New Zealand, Australia, Greece, Germany, Poland, Spain, Mexico, and Thailand. It can be observed that Italy is the leading country with the highest number of publications, followed by China, South Korea, Japan, the United States, and Iran.

Figure 3a depicts the network map of co-citation among the journals with published articles in the related field. Based on Figure 3, Engineering Structures, Earthquake Engineering and Structural Dynamics, and Bulletins of Earthquake Engineering are central to this network. Figure 3b shows the scientific journals with the highest number of publications in the related scope. As observed, Engineering Structures is the highest-ranking journal with the highest percentage of published articles, followed by Earthquake Engineering and Structural Dynamics, Journal of Building Engineering, and Structures.

Figure 4 illustrates the network map of the keywords used in the articles. The keyword “seismic retrofitting” is dominant in the shown map, followed by “seismic performance”, “seismic retrofitting”, and “energy dissipation”. A significant number of keywords used in these studies refer to the devices employed for reducing seismic response of structures. The most frequently used devices are friction dampers, viscous dampers, slit dampers, metallic dampers, viscoelastic dampers, TMDs, and shape memory alloys.

Figure 5 depicts the number of papers published in the field of buildings retrofitted by employing energy-dissipating devices. There are only a few papers published before 2016, while most were published from 2017. A sudden rise in the number of published papers can be seen in 2017. According to the bar graph shown in Figure 5, the number of papers in the related field has shown a growing trend from 2019 onwards. The maximum number of published papers was observed in the year 2024. This growing trend shows the importance of retrofitting buildings as they become older. Furthermore, increasing the use of dissipating devices for seismic retrofitting of buildings has demonstrated the beneficial effects of these devices used in seismic upgrading of buildings.

Table 1. Leading authors with the highest number of publications on upgrading structures using energy-dissipating devices.

Author Name	Number of Publication
Kim, Jinkoo	43
Javadian, Mohammad Mehdi	15
Terenzi, Gloria	15
Sorace, Stefano	13
Quaglini, Virginio	9
Bruschi, Eleonora	8
Ferraioli, Massimiliano	8
Naeem, Asad	7
Chun, Seungho	6
Nasab, Mohammad Seddiq Eskandari	6
Noureldin, Mohamad	6
Xu, Zhao-Dong	6
Zhang, Ruifu	6

ranks authors with the most publications. In ascending order, Javadian and Terenzi published 15 papers, respectively, while Kim, the leading author with the highest number of publications in the field, published 45 papers. In line with this, a list, ranking institutions based on the number of publications in this field, is presented in

Table 2. Leading institutions with the highest number of publications.

Institution	Number of Publication
Department of Civil and Architectural Engineering, Sungkyunkwan University	31
Department of civil and environmental engineering, University of Florence	11
Department of Disaster Mitigation for Structures, Tongji University	6
School of Civil Engineering, Xi’an University of Architecture and Technology	6
Polytechnic Department of Engineering and Architecture, University of Udine	5
Politecnico di Milano, Department of Architecture, Built Environment and Construction Engineering	4

. A huge proportion of the articles in this field has been published by authors from the Department of Civil and Architectural Engineering at Sungkyunkwan University.

3. Energy-Dissipating Devices Used for Seismic Retrofitting

In this section, the devices used for the seismic retrofitting of buildings are discussed. These devices include friction dampers, TMDs, viscous dampers, viscoelastic dampers, and hysteretic dampers. In each section, research on each device was classified and summarized in tables.

3.1. Friction Dampers

Friction dampers (FDs) are one of the most widely used devices for retrofitting structures. In recent years, research on the use of friction-dissipating devices for building upgrades has increased. FDs can effectively dissipate input kinetic energy and, as a result, reduce the response of buildings and residual drifts. Recent research has proposed new devices and demonstrated the effectiveness of these devices via numerical modeling and experimental studies. Researchers have focused on novel devices that apply the friction mechanism for energy dissipation. Javadian et al. [15] developed a dissipative tool based on the Coulomb mechanism made of both springs and dampers, validated through numerical modeling and experimental tests. Aprile et al. [11] presented a novel friction damper that works as a beam-to-column joint [lecture notes]. Wang et al. [12] studied a buckling-plate, self-centering friction damper (BPSCFD) with a low post-yielding stiffness for the seismic upgrading of bridges. Grossi et al. [16,17,18] presented a conceptual study of a novel friction damper used in buildings constructed with precast materials. Bruschi [19] inspected the performance of a novel friction damper that enables high force production in a relatively small space.

Other researchers have focused on the design procedure of friction dampers for the seismic upgrade of buildings. Gharagoz et al. [20] introduced a machine-learning-based method for the design of friction dampers considering different performance levels. Gharagoz et al. [21] proposed a new design method for spring-friction dampers employed for the seismic retrofitting of buildings. Some articles have been published describing the assessment of buildings retrofitted using friction dampers. Melatti et al. [22] proposed a new methodology for the assessment and refinement of friction-based dissipative devices. Kim et al. [23] studied the seismic loss assessment of a structure retrofitted with slit-friction hybrid dampers. Other studies have focused on the optimization and optimal placement of friction dampers in buildings.

FDs can be used together with other devices for seismic retrofitting goals. For instance, friction dampers can be used together with braces to improve the dissipation properties of buildings under seismic vibration. Shimose et al. [24] explored the retrofitting of buildings with friction dampers and braces by using the shaking table test. Most of the mentioned studies have also investigated the consistency of experimental and analytical results. Spring rotation dampers are another type of damper that work based on the friction mechanism. Javadian et al. [25] studied the seismic retrofitting of a building with a soft story using rotational friction dampers. In addition, Qu et al. [26] introduced a novel self-centering friction damper that is installed on steel frames, leading to less consumption of shape memory alloys (SMAs).

There are seven main topic areas that have been the focus of most of the literature in the field of retrofitting buildings using friction dampers (

Table 3. Classification of studies conducted since 2010 for retrofitting buildings using friction dampers.

General Goal	Related Papers
Presenting and developing new friction damping devices	Javidan et al. [2], Aprile et al. [11], Wang et al. [12], Qu et al. [26], Li et al. [27], Grossi et al. [16], Grossi et al. [17], Grossi et al. [18], Suk et al. [28], Bruschi et al. [19], Melatti et al. [22], Bruschi et al. [29], Javidan et al. [30], Aloisio et al. [31], Javidan et al. [25], Kim and Jinkoo [32], Wang et al. [33]
Developing design method	Gharagoz et al. [20], Gharagoz et al. [21], Rad et al. [34], Tirca et al. [35]
Case and feasibility study	Sirinipitakul et al. [36], Saingam et al. [37], Shin et al. [38], Javidan et al. [15], Titirla and Magdalini [39], Woo et al. [40], Ahmadi et al. [41], Ferraioli et al. [42], Noureldin et al. [43], Naeem & Kim [44], Saingam et al. [45], Jara et al. [46], Noureldin et al. [47], Eldin et al. [48], Li et al. [49], Beheshti et al. [50], Khader et al. [51], Tabeshpour and Ebrahimian [52], Kim et al. [53], Zahraei et al. [54], Narita et al. [55], Tafakori et al. [56]
Comparative study	Cavalieri et al. [57], Afshar & Zahari [58], Mottier et al. [59], Moon et al. [60]
Optimization and arrangement of dampers	Eldin et al. [61], Kim et al. [23]
Evaluating the performance of retrofitted buildings	Caprili et al. [62], Lee et al. [63]
Loss assessment study	Kim et al. [23]

). These include (a) loss assessment evaluations, (b) a performance assessment of retrofitted buildings, (c) damper optimization and arrangement order, (d) comparative assessments, (e) case studies and feasibility assessments, (f) design methodology development, and (g) the development of innovative friction damping devices. It is evident that research has focused on the latter three topic areas.

There are various mechanical designs that have been introduced and developed for FDs. Figure 6a shows the structure of the Sumitomo-type FD [64]. It consists of cut springs, an outer wedge, a friction pad, an inner wedge, and an outer cylinder, producing damping forces based on a friction mechanism. Additionally, the placement of the FD is selected in a way to connect the braces to the diaphragm of the upper floor.

3.2. Tuned Mass Dampers

TMDs are energy-dissipating devices employed in the seismic retrofitting of existing buildings. TMD devices are composed of springs and dampers connected to a mass that dissipates energy [65,66,67,68]. Figure 7 shows a TMD device installed on the top floor of an n-story building [69]. The dampers used in TMDs can be viscous, hysteretic, and friction, and the springs and dampers installed in TMDs can be linear or nonlinear. Sometimes, installing a TMD in a building may be a challenging task due to its relatively high mass and high friction force between the mass and building floor. Some researchers have suggested the use of base isolators instead of typical springs and dampers to produce the equivalent restoring damping and spring forces and also reduce friction [70]. Zhang and Pauletta [71] used the passive control of bilinear hysteretic structures by a tuned mass damper for narrow band seismic motions.

The effectiveness of typical passive TMDs can be reduced considerably if the frequency of the main building changes [66,68]. Therefore, some scholars have proposed TMDs with a relatively high mass ratio to improve the robustness of TMDs during retrofitting [72]. Employing nonlinear TMDs is a common practice to improve the performance of TMDs for retrofitting buildings. Johnson et al. [73] studied the effectiveness of nonlinear/inelastic rooftop tuned mass damper frames (NRTMDFs) used as a retrofit to reduce the seismic response.

Nakai et al. [74] demonstrated the effectiveness of TMDs in high-rise buildings through analytical studies and field observations. Kaneko [75] studied the effectiveness of TMDs for retrofitting high-rise buildings. In addition, Ji et al. [76] presented a design method and assessment framework for TMDs. Lee et al. [77] studied a design process for retrofitting low-rise buildings using TMDs. Zhao et al. [78] and Xiang et al. [79] presented a novel design procedure of non-traditional TMDs for base-isolated or high-rise buildings.

Negative stiffness and nonlinear energy sink devices are another dissipative tool that are very similar to TMDs in many aspects. Similar to TMDs, these devices are composed of springs, dampers, and vibrating mass. However, the force imposed by the dissipative system to the building is essentially a nonlinear force. Idels et al. [80] used a negative stiffness device and fluid viscous damper to retrofit the frame structure.

The key objectives described in several articles published in the TMD field have been outlined in

Table 4. Classification of studies conducted on retrofitting using TMD device.

General Goal	Related Papers
Case study	Mazzon et al. [70], Nawrotzki et al. [81], Marrazzo et al. [72], He et al. [82], Zheng et al. [83], Basili et al. [84], Faiella et al. [85], Nakai [74], Kaneko et al. [75], Idels et al. [80]
Design method	Ji et al. [76], Lee et al. [77], Xiang & Nishitani [79], Salvi et al. [86]
New dissipating device	Johnson et al. [73]
Comparative study	Lin et al. [87]
Feasibility study	Zhang et al. [88]

. It can be noted that case studies have mostly been analyzed and presented in the literature, and only a handful of articles have concentrated on innovative TMD development for retrofitting buildings.

3.3. Viscous Dampers

Viscous dampers are another family of dissipative devices which rely on fluid viscosity to reduce the response of structures. Viscous dampers are known as one of the popular devices for vibration reduction under both earthquake and wind excitations. Figure 8 shows a viscous damper that can dissipate energy via a viscous fluid inserted within the damper [89,90]. De Domenico et al. [91] studied the multi-level performance-based design optimization of steel frames with nonlinear viscous dampers. Lin et al. [87] expanded on externally connected viscous dampers for the seismic retrofitting of existing critical buildings like hospitals.

Rajeswaran [92] introduced an alternative method for the design of the seismic retrofitting of RC frame buildings using viscous dampers. Qi et al. [93] studied the smart retrofitting of irregular steel joints in Chinese buildings using viscous dampers. Sun et al. studied the seismic performance of the conventional damped outrigger (CDO) which was improved by incorporating negative stiffness (NS) in parallel with viscous dampers. Landi et al. [94] presented a comparative study on the different distributions of viscous damper properties in asymmetric-plan frames. Jara et al. [46] studied the seismic response and reliability index of RC weak story buildings on soft soils in Mexico City. Jung et al. [95] investigated the displacement amplification mechanism of steel wire rope-pulley damping systems with viscous dampers. Idels [80] investigated the performance-based seismic retrofitting of frame structures using negative stiffness devices and fluid viscous dampers via optimization. Logotheti et al. [96] expanded on the inter-story drift for retrofitting steel frames using viscous dampers. Shen et al. [97] presented a novel design method of viscous dampers by employing a elastic–plastic response reduction curve. Bañuelos-García et al. [98] proposed a novel design method of viscous dampers based on the displacement of the seismic design procedure. Jara et al. [99] studied the seismic retrofitting of existing first soft-story buildings after the Mexico City seismic event using viscous dampers. Similar to other damping devices, viscous dampers can be used together with other retrofitting measures such as braces. Salehi et al. [100] used viscous dampers with braces together for seismic retrofitting. Chalarca et al. [90] evaluated the annual seismic loss of braced steel frames retrofitted with viscous dampers. They used the FEMA P-58 methodology to estimate the expected loss. In the dynamic motion equation, the term representing the damping forces produced by the dampers was a linear equation.

Kazemi et al. [101] pointed out a study in which the demolition of buildings using dampers was investigated. Pollini and Nicolò [102,103] considered the fail-safe optimization of viscous dampers for seismic retrofitting. Jamshidiha et al. [104] presented an advanced scalar intensity measure for the collapse capacity prediction of steel moment-resisting frames using fluid viscous dampers. Chalarca et al. [90] studied the seismic performance evaluation of a spring viscous damper cable system. Pollini et al. [105] introduced a novel optimization-based minimum-cost seismic retrofitting of hysteretic frames with nonlinear fluid viscous dampers. Li et al. [106] reviewed the retrofitting of existing frame structures to increase their economy and sustainability in high-seismic-hazard regions. Jamshidiha et al. [107] presented a study on a new vector-valued intensity measure for predicting the collapse capacity of steel moment-resisting frames with viscous dampers. Viscous dampers can also be used for retrofitting specific buildings such as high-rise buildings. Wang and Mahin [108] studied the retrofitting of high-rise, steel moment-resisting frames with fluid viscous dampers. Del Gobbo et al. [109] reviewed the improvement of the seismic performance of an entire building using linear fluid viscous dampers. Landi [110] studied the effectiveness of different distributions of viscous damping coefficients for the seismic retrofit of regular and irregular RC frames.

Table 5. Summary of papers published on the use of viscous dampers for seismic retrofitting.

General Goal	Related Papers
Presenting and developing new viscous damping devices	Jung et al. [95], Salehi & Ghobadi [100], Kim and Shin [111]
Developing design method	Bahmani and Zahrai [112], Hu et al. [113], De Domenico & Hajirasouliha [114], Rajeswaran & Wijeyewickrema [92], Terenzi et al. [115], Shen et al. [97], Bañuelos-García et al. [98], Pollini [103], Bahmani et al. [116], Guo et al. [117], Wang et al. [118], Pollini et al. [105], Pollini et al. [119], Weng et al. [120], Benavent-Climent and Amadeo [121], Guo et al. [122], Zhou et al. [123]
Case and feasibility study	Sorace et al. [6], Saingam and Panumas [37], Patil et al. [124,125], Yıldız et al. [126], Sorace et al. [127], Lin et al. [128], Qi et al. [93], Jara et al. [46], Miani et al. [129], Logotheti et al. [96], Akbar et al. [130], Sonda et al. [131], Jara et al. [99], Pettinga and Didier [132], Naeem et al. [133], Terenzi et al. [134], Hazaveh et al. [135], Barbagallo et al. [136], Li et al. [137], Wang et al. [138], Naeem & Kim [139], Zhao et al. [140], Wang & Mahin [141], Terenzi et al. [142], Sorace et al. [143]
Comparative study	Bougteb et al. [144], Sorace & Terenzi [145],
Optimization and arrangement of dampers	Landi et al. [94], Landi et al. [110], Lavan & Amir [146]
Evaluating the performance of retrofitted buildings
Predictive and loss assessment study	Chalarca et al. [90], Kazemi et al. [147], Jamshidiha et al. [104], Jamshidihaand Yakhchalian [107], Del Gobbo et al. [109], Tubaldi et al. [148], Tubaldi et al. [149]

details the principal areas of concentration for most published literature. Similar to the research carried out on friction dampers and the main topic areas presented in Table 3, most of the viscous damper-related research has also focused on the development of innovative viscous dampers, design conception methods, and case studies and feasibility assessments.

3.4. Hysteretic Dampers

Hysteretic dampers are a family of dissipative devices used for the seismic retrofitting of buildings. The energy dissipative mechanism that was employed by hysteretic dampers is based on the plastic deformation of the materials that make up the hysteretic dampers. Installing hysteretic dampers in buildings is another option for retrofitting buildings. Figure 9 shows a hysteretic damper produced and tested by Pavia et al. [150], Geng et al. [151].

Some of the papers published on hysteretic dampers focused on the development and experimental testing of these dampers. Naeem et al. [152] studied the verification of self-centering, disc-slit hysteretic dampers for buildings.

Novel energy-dissipating devices with more advanced capabilities to reduce seismic loss are another field studied by scholars. Di Salvatore et al. [153] developed an innovative hysteretic device for the seismic retrofit of single-story RC precast buildings. Javidan et al. [154] studied a seismic energy dissipation device that comprises a bracing member and a steel hysteretic damper made of steel hexagonal plates. Bruschi et al. [155] assessed the cyclic behavior of a novel hysteretic friction damper for the seismic retrofit of reinforced concrete frame structures. Javidan et al. [156] introduced and evaluated a new hysteretic damper for the seismic retrofit of soft-first story structures and its seismic retrofit effect. Javidan et al. [157] evaluated the seismic performance of a steel column damper using cyclic loading tests of two one-story, one-bay RC frames before and after retrofit.

In some studies, the development of the design procedures for hysteretic dampers was the main focus. Terenzi and Gloria [158] proposed a new design method for the seismic retrofitting of frame structures, considering energy as the central parameter in their design strategy. Bruschi et al. [159] presented a simplified design procedure for the seismic upgrade of frame structures equipped with hysteretic dampers. Gandelli et al. [160] presented a novel adaptive hysteretic damper for the enhanced seismic protection of braced buildings. Javidan et al. [30] proposed a simplified ductility-based design procedure for the seismic retrofit of structures using hysteretic devices. Rahmat Rabi et al. [161] introduced an energy-based method to design hysteretic bracings for the seismic rehabilitation of low-to-medium-rise RC frames.

Elasto-plastic dissipative bracings are another category of hysteretic-dissipating tools used to enhance the performance of buildings exposed to seismic events. De Domenico et al. [162] presented a novel displacement-based design procedure for the seismic retrofit of existing buildings with self-centering dissipative braces. Several case studies on the application of hysteretic dampers have been presented in the literature. Bruschi et al. [163] studied the reliability of two arch-type buildings equipped with hysteretic dampers. Self-centering, disc-slit dampers can also be considered in the family of the hysteretic dampers. Naeem et al. [152] studied the seismic performance of RC building structures retrofitted with self-centering, disc-slit dampers and conventional steel-slit dampers.

Table 6. Summary of the published papers that focus on hysteretic damping for seismic retrofitting.

General Goal	Related Papers
Experimental verification	Naeem et al. [9]
Case study	Wang et al. [24], Hu et al. [164], Bruschi et al. [163], Di Cesare et al. [165], Ma et al. [166], Ferraioli et al. [167], Naeem et al. [152], Sorace et al. [168], Ahmadi et al. [41], Ferraioli et al. [169], Javidan et al. [170], Nuzzo et al. [171], Lee & Kim [172], Benavent-Climent et al. [173]
Introducing and developing new device	Terenzi and Gloria [174], Dereje et al. [175], Di Salvatore et al. [153], Javidan et al. [30], Bruschi et al. [176], Javidan et al. [177], Gandelli et al. [160], Javidan et al. [154], Nuzzo et al. [178], Mazza and Fabio [179], Benavent-Climent et al. [180], Guo & Christopoulos [181]
Presenting new design method	Bruschi et al. [19], Bruschi et al. [29], Javidan et al. [177], Rahmat Rabi et al. [161], Bruschi et al. [176], Pollini et al. [119], Li & Shu [182], Ferraioli & Lavinon [183]
Optimization and arrangement of dampers	Apostolakis & G. F. Dargush [184]

summarizes the main objectives presented in most of the articles on hysteretic dampers. Four overarching topic areas include (a) innovative design methods, (b) novel device proposals and development, (c) the assessment of case studies, and (d) a proof-of-concept experimental analysis. The latter three topic areas have been the main focus of most of the literature related to hysteretic dampers.

3.5. Viscoelastic Dampers

Viscoelastic dampers can provide both stiffness and viscosity, and their employment in retrofitting buildings has gained popularity. Installing and using viscoelastic dampers in buildings can offer multiple advantages. First, unlike conventional dampers that block bays, these dampers lie within their vertical installation scheme and provide open space in the bay and architectural flexibility [15]. Figure 10 shows the schematic shape of a viscoelastic damper composed of steel plates and viscoelastic materials [185,186,187]. These dampers can help buildings to exhibit better performance while being exposed to seismic events. Some scholars have focused on presenting case studies about viscoelastic dampers through numerical modeling and experimental testing. Javidan et al. [188] studied the seismic retrofit of low-rise buildings by employing rotational viscoelastic dampers. Dereje et al. [175] presented the experimental and analytical study of a seismic energy dissipation device made of butterfly-shaped steel plates and viscoelastic pads. Dong et al. [189] evaluated the seismic performance and material-level damage evolution of retrofitted RC-framed structures by high-performance AVED under different shear–span ratios. Nasab et al. [190] investigated the soil–structure interaction effects on the seismic retrofit of soft first-story buildings. Nasab et al. [191] studied the seismic retrofit system made of viscoelastic polymer composite materials and thin steel plates.

Hu et al. [192] proposed a new hybrid self-centering brace with NiTi-SMA U-shaped and frequency-dependent viscoelastic dampers for structural and nonstructural damage control. Dong et al. [193] introduced high damping acrylic polymer matrix VEDs (HDPVEDs), and their HDPVEDs could solve the significant problem of service performance under medium–high-temperature environments, as well as low-frequency vibration control under earthquake actions for civil engineering structures. Javidan et al. [194] presented a new seismic retrofit system composed of a steel frame with viscoelastic hinges, and its applicability and efficiency are evaluated in a theoretical framework. Dong et al. [195] discussed the design parameters and material-scale damage evolution of seismic-upgraded RC frames by viscoelastic haunch bracing dampers. Bashir Pour et al. [196] studied the seismic damage assessment of steel buildings, considering viscoelastic dampers in near-field earthquakes.

Hao et al. [197] presented a design method for additional VEDs to retrofit low- to mid-rise RC structures. Zhou et al. [198] studied a displacement-based seismic design method for building structures with nonlinear viscoelastic dampers. Nasab et al. [191] developed a kriging model to predict the mechanical properties of a viscoelastic damper based on experimental data. Parvin Darabad et al. [199] studied the distribution of seismic damage in steel building components equipped with viscoelastic dampers against far-field earthquakes. Nasab et al. [191] evaluated the seismic retrofit of a soft first-story building using viscoelastic dampers and considering inherent uncertainties.

Table 7. Summary of the published papers on viscoelastic dampers for seismic retrofitting of buildings.

General Goal	Related Paper
Presenting and developing new viscous damping devices	Dong et al. [193], Hu et al. [164], Dereje et al. [175], Dong et al. [189], Dong et al. [4], Javidan et al. [2], Nasab et al. [200], Nasab et al. [201], Nasab et al. [202], Zhang et al. [203], Wang et al. [33]
Developing design method	Hao et al. [197], Beheshti et al. [204], Zhou et al. [198], Dong et al. [195], Xie et al. [205], Castaldo et al. [206]
Case and feasibility study	Javidan et al. [188], Parvin Darabad et al. [199], Nasab et al. [200], Nasab et al. [190], Dong et al. [207], Xu et al. [208]
Comparative study
Optimization and arrangement of dampers
Evaluating the performance of retrofitted buildings
Predictive and Loss assessment study	Bashir Pour and Mohammad Javad [196]

describes the areas of concentration for most VED-related articles. It can be observed that not only has extensive research been carried out to expound on the ways to design these novel viscoelastic dampers, but the practical development and experimental verification of these new devices have also been investigated.

4. Brief Discussion on the Advantages and Disadvantages of Each Device

In this section, the advantages and disadvantages of each energy-dissipating device are briefly discussed. The discussion is presented from different perspectives.

Friction dampers are cost-effective tools, offering low installation cost. Modeling friction dampers is not a very complicated process, and there are standard procedures for predicting the behavior of these dampers. Compared to hysteretic dampers, friction dampers provide higher energy dissipation in each oscillation loop due to the rectangular hysteretic shape produced by friction dampers [209,210]. Their energy dissipation behavior is also not dependent on the number oscillation cycles [211]. They can sometimes increase the stiffness of buildings and may not be effective under weak seismic excitations and wind loads [212]. In addition, the performance of friction dampers under a high strain rate is another issue that must be considered during the design process [209]. The behavior of these dampers after long-term inactivity and their maintenance can also sometimes be a challenging issue [209].

Viscous dampers have been widely utilized in buildings as energy-dissipating devices, and the level of knowledge regarding their behavior and performance is relatively advanced [213]. These dampers provide force feedback that is dependent on the relative velocity, making them less sensitive to temperature gradients across different parts of a structure. The stiffness contributed by these devices to the main buildings is minimal and often negligible. Therefore, viscous dampers are considered suitable for structures subjected to low-intensity vibrations, such as those caused by wind or minor seismic events. Another advantage is that their performance is not significantly influenced by the vibration frequency, which is generally regarded as a favorable characteristic [213]. However, viscous dampers tend to be expensive, with high inspection and maintenance costs. Oil leakage is a commonly reported issue, which can impair their functionality and lead to unreliable performance [213]. Finally, previous studies have indicated that the optimal parameters for a viscous damper may be dependent on the excitation intensity, which makes their design process optimization challenging [214].

TMDs are another popular device for energy dissipation when buildings are exposed to ambient loads. TMD devices are usually installed in tall buildings, and they can effectively reduce vibrations due to wind and earthquake. Unlike other dampers that should be installed in multiple stories in order to achieve effective vibration control, TMDs can effectively reduce vibration if they are installed in a single story. The top floor is usually selected for the installation of TMDs, and the damper device connected to the TMD can be either viscous, friction, or hysteretic. The TMD system is capable of reducing the response of buildings even under weak vibrations. However, the mass of the TMD system is high, and the space occupied by the TMD components on the top floor is large. The large mass of the TMDs used in buildings may produce a high static friction force, making the relative motion between the TMDs and buildings too difficult. Furthermore, passive TMDs can display improper performance when they are mistuned. The mistuning of TMDs can usually occur under extreme seismic events and when the main buildings show an inelastic response [66,68]. TMD devices are effective only in a small range of excitation frequencies.

Hysteretic dampers are useful devices, and extensive studies on these dampers exist. The installation and production of these devices are not very expensive, and their application does not incur high maintenance costs. However, these dampers have a higher initial stiffness compared to other dampers, and they can provide a lower ductility [213]. Furthermore, due to the high stiffness, they cannot be effective when exposed to weak excitations. Finally, the force feedback of these dampers is dependent on their deflection, and, as a result, they do not provide a high temperature adaptively [213].

Viscoelastic dampers are energy-dissipating devices that can provide both stiffness and damping forces when used. They can control vibrations even under weak environmental dynamic loads. They may, however, exhibit frequency- and temperature-dependent behavior [215]. Compared to other passive vibration control devices, not a lot of studies on these dampers exist. Furthermore, the production of these dampers can sometimes be expensive, and aging issues may lead to an increase in their maintenance cost. Additionally, their design and modeling process is usually complicated due to the lack of well-established theories in the related field [215].

5. Future Developments and Research Gaps

The application of passive energy-dissipating devices in the retrofitting of buildings has been shown to decrease the seismic response of buildings, leading to safer structures under natural disasters. However, there are several shortcomings in the existing research, and further research is necessary in order to gain a deeper insight into the functioning of these tools, improve building safety, and potentially decrease economic loss. This section presents some of these limitations in the research that has been conducted and also highlights solutions that have been proposed and tested in literature.

Most research has been devoted to the numerical modeling and experimental testing of small-scale structures equipped with dampers. However, larger buildings and their dampers are more complex and show a more realistic picture of the behavior of these devices. There are cost implications related to the use of more large-scale samples; hence, numerical modeling and the evaluation of small-scale samples are usually preferred. Furthermore, a recently developed technique known as hybrid simulation offers a promising option to achieve more realistic results through less expensive testing. In summary, there is a lack of large-scale experimental tests under real seismic excitations, and this issue should be addressed in future research [216,217,218,219,220].

Secondly, the force exerted by each energy-dissipating device is typically expressed and modeled using simplified formulae with deterministic parameters. However, in real-world scenarios, factors such as temperature fluctuations can cause variations in the parameters of dampers. For example, during a seismic event, the properties of a viscous or viscoelastic damper may change due to the thermal energy and heat generated during oscillation, leading to different damper parameters in each cycle. Recent studies have begun to explore thermal effects on the performance of these dampers. Moreover, a probabilistic approach may offer a more accurate modeling framework by accounting for the variability of damper parameters in real-world conditions [221,222].

Third, the installation of energy-dissipating devices in buildings generally results in higher construction costs. However, these devices can significantly reduce the potential damage costs associated with earthquakes. It is crucial that we evaluate their cost-effectiveness by defining quantitative indices that account for both maintenance costs and the reduction in rehabilitation expenses for structures. Consequently, a comprehensive examination of the economic and financial aspects of energy-dissipating devices is an essential area for future research [223].

Fourth, each energy-dissipating device discussed in this paper may offer distinct advantages and drawbacks. Consequently, a notable area of interest among researchers is the use of these devices in combination to assess the performance of buildings when two or more different passive devices are installed. Additionally, base isolation, an energy-dissipating technique not covered in this paper, has gained attention in recent literature. Recent papers have explored the seismic performance of buildings that incorporate both base isolation and an additional energy-dissipating device. Therefore, the integration of two distinct passive energy-dissipating devices in buildings represents a promising strategy for future research [224,225,226,227].

Fifth, passive TMDs are widely used and effective for seismic retrofitting. However, their performance can be compromised under mistuning conditions. Thus, selecting appropriate parameters during the retrofitting process is crucial for ensuring optimal performance. Furthermore, the development of new TMD devices that perform better under mistuning conditions is an important area of research. Typical solutions to address this challenge include nonlinear TMDs, semi-active TMDs, adaptive passive TMDs, and active TMD systems [228,229,230].

Sixth, energy-dissipating devices are typically modeled, designed, and evaluated under unidirectional seismic events. However, in practice, building motion often involves torsional and bi-directional movements. Therefore, incorporating the torsional mode of vibration in the main building and considering bi-directional input motion are critical aspects that warrant further investigation [231,232].

Seventh, many of the damping devices previously discussed have been installed and modeled on specific types of structural systems, such as reinforced concrete moment-resisting frames and eccentrically braced steel frames. However, the installation of each damping device on different structural systems must be studied independently due to the unique properties of each system. Additionally, determining the optimal placement of each device—one that ensures greater safety, minimizes damage to the primary structure, and maximizes the performance of the energy-dissipating device—is another important issue that requires further investigation in future research [233].

Eighth, recent literature has introduced numerous new design procedures for various energy-dissipating devices. A prevailing trend in these papers is the adoption of performance-based design approaches for energy-dissipating tools. However, further studies are necessary in order to address key questions regarding the performance-based design of damper devices in future research [234].

Lastly, among the devices discussed in this paper, viscoelastic dampers are the least studied and lack standardized design manuals and procedures. Therefore, it is essential that we establish standardized procedures for the design of these devices. Additionally, further in-depth studies are required in order to deepen the existing scientific knowledge on these devices [215].

6. Conclusions

In this literature review, the studies that have investigated the employment of energy-dissipating devices for the seismic retrofitting of buildings were presented. The main focus of this paper was to present current innovations related to different types of dampers. Base isolation was not considered due to the large number of publicly available publications. The methodology employed involved first selecting a systematic procedure to collect related articles that have been published in this field of research. To attain this goal, scientific resources, that is, Web of Science, Google Scholar, and Scopus, were used. The keywords for the search were classified into two categories, corresponding to the concept of seismic retrofitting and dissipative devices. In the initial search, more than 1000 articles that were published from 2010 to 2024 were found. Following this, the title, keywords, and abstracts of the articles were carefully evaluated in order to filter the search results and eliminate articles that were beyond the scope of this study. The result from this filtering process generated more than 230 articles that were selected to be discussed in this paper. The VOSviewer tool was then employed to classify the articles based on the country of publication, publishing journal, and keywords in the articles. The leading countries with the highest publication journals and published articles were enumerated, and the most commonly used keywords were found in the areas targeted by this paper.

The articles investigated were categorized based on two main aspects. The first aspect was the device used for seismic retrofitting, while the second aspect focused on the main objectives of the articles. In terms of the type of device, the most commonly used dissipative devices for seismic retrofitting were friction dampers, TMDs, viscous dampers, hysteretic dampers, and viscoelastic dampers, and most articles have evaluated the use of these devices for seismic retrofitting. In terms of the main objectives of the articles, the areas of concentration include the presentation and development of new dissipative devices, the development of novel design methods, case and feasibility studies, comparative studies, the optimization and optimal arrangement of devices, the evaluation of the performance of retrofitted buildings, and the analysis of loss assessments of buildings. The findings from this literature review and analysis have shown that there are very few articles that investigate the loss assessment of buildings retrofitted by dissipating devices. Moreover, although there are so many publications in this field, only a few consider real buildings after a seismic event.