*Article* **A Comparative Study of the Effects of Earthquakes in Different Countries on Target Displacement in Mid-Rise Regular RC Structures**

**Ercan I¸sık 1,\* , Marijana Hadzima-Nyarko 2,\* , Hüseyin Bilgin <sup>3</sup> , Naida Ademovi´c <sup>4</sup> , Aydın Büyüksaraç <sup>5</sup> , Ehsan Harirchian <sup>6</sup> , Borko Bulaji´c <sup>7</sup> , Hayri Baytan Özmen <sup>8</sup> and Seyed Ehsan Aghakouchaki Hosseini <sup>9</sup>**


**Abstract:** Data from past earthquakes is an important tool to reveal the impact of future earthquakes on engineering structures, especially in earthquake-prone regions. These data are important indicators for revealing the seismic loading effects that structures will be exposed to in future earthquakes. Five different earthquakes from six countries with high seismic risk were selected and were within the scope of this study. The measured peak ground acceleration (PGA) for each earthquake was compared with the suggested PGA for the respective region. Structural analyzes were performed for a reinforced-concrete (RC) building model with four different variables, including the number of storeys, local soil types, building importance class and concrete class. Target displacements specified in the Eurocode-8 were obtained for both the suggested and measured PGA values for each earthquake. The main goal of this study is to reveal whether the proposed and measured PGA values are adequately represented in different countries. We tried to reveal whether the seismic risk was taken into account at a sufficient level. In addition, target displacements have been obtained separately in order to demonstrate whether the measured and suggested PGA values for these countries are adequately represented in structural analysis and evaluations. It was concluded that both seismic risk and target displacements were adequately represented for some earthquakes, while not adequately represented for others. Comments were made about the existing building stock of the countries considering the obtained results.

**Keywords:** target displacement; earthquake; peak ground acceleration; reinforced-concrete; pushover

### **1. Introduction**

Significant loss of life and property after earthquakes increases the consequence of efforts to reduce the effects of earthquakes. The studies on structural and seismic risk analyzes are carried out on both pre-earthquake and post-earthquake in order to prevent and minimize earthquake damages [1–9]. Such studies have special importance in regions with high seismic risk [10]. Ground motion parameters are needed to determine and evaluate the effects of earthquakes in a particular region [11–13]. These parameters are important in terms of both revealing earthquake characteristics and analyzing the behavior of structures under the influence of earthquakes [14–16]. Fault geometry, seismic waves,

**Citation:** I¸sık, E.; Hadzima-Nyarko, M.; Bilgin, H.; Ademovi´c, N.; Büyüksaraç, A.; Harirchian, E.; Bulaji´c, B.; Özmen, H.B.; Aghakouchaki Hosseini, S.E. A Comparative Study of the Effects of Earthquakes in Different Countries on Target Displacement in Mid-Rise Regular RC Structures. *Appl. Sci.* **2022**, *12*, 12495. https://doi.org/ 10.3390/app122312495

Academic Editors: Andrea Chiozzi and Dario De Domenico

Received: 31 October 2022 Accepted: 30 November 2022 Published: 6 December 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. 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/).

and earthquake characteristics should be known while the determination of the ground motion parameters by considering local ground conditions. The amplitude parameter is one of the engineering aspects of ground motion parameters. The ground velocity, acceleration and displacement values are known as amplitude parameters [17,18]. Knowing that the earthquake ground motions measurements as a function of time or frequency constitutes an important database for engineering applications and scientific studies for earthquakeresistant structure design [19–21]. In this context, many different programs are used to predict earthquake threats. Openquake Engine [22], Earthquake Loss Estimation Routine (ELER) [23], HAZUS [24], Ez-Frisk [25], PSHRisk-Tool [26], FRISK [27], CRISIS2007 [28], SEISRISK III [29] and OpenSHA [30] are some of the software that are commonly used programs for predicting earthquake threat.

The obtained ground acceleration records from strong ground motion measurements can be used to both determine seismic risk and to monitor the performance of structures during earthquakes. Acceleration records can also be used for the design of earthquakeresistant structures and for the development of attenuation relationships. In addition, the expected damage estimation and intensity distribution in the settlements at different distances from the station can be determined by using attenuation relationships. Earthquake ground motions can be quite complex from this perspective. It is possible to define earthquake motion with three components of linear motion [31,32]. The Peak Ground Acceleration (PGA) is the most common measure used to determine the amplitude of strong ground motion. Any accelerometer used for acceleration records has two horizontal (EW and NS) components and one vertical component. The maximum horizontal ground acceleration is either the geometric mean of the maximum values of the component in both directions or the largest one of them regardless of direction [33–35]. Therefore, obtained PGA values from any earthquake are used to determine seismic and structural risks. Different types of analyzes can be used to decide the performance levels of structures in performance-based design [36–38].

Pushover analysis is a widely used nonlinear analysis technique to estimate the dynamic demands imposed on a structure under earthquake impact. The maximum roof displacements, known as target displacement, are one of the results obtained from this analysis [39–42]. The earthquake performances and damage estimation of the structures can be predicted using the target displacements [43–46]. It is then required to decide the structural performance by comparing the demand values to the deformation capacity for the expected performance levels [47]. Adequate demand displacement values will better reflect real values for the damage estimation of structures and building earthquake performance [48].

In this study, seismic risk and target displacements were compared, taking into account the measured and suggested PGA values for different earthquakes in different countries. Six countries with different seismicity were selected, including as Bosnia and Herzegovina, Albania, Croatia, Iran, Türkiye, and Serbia, and these were within the scope of this study. Two different country groups were selected in this study. In the first group, neighboring Bosnia and Herzegovina, Serbia, Croatia, and Albania were taken into account, while in the second group, neighboring Türkiye and Iran were taken into account. Bulgaria, Macedonia, and Greece are located between these two groups of countries. Earthquakes that occur in both groups of countries also affect other countries within the group. Therefore, seismic and structural parameters were obtained for two different country groups. For this purpose, five different earthquakes were selected for each country. The earthquakes whose data can be accessed were taken into account in the selection of these earthquakes. First, the measured and suggested PGA values were compared for selected earthquakes. Information is provided about the seismicity and the selected earthquakes for each country, respectively. Structural analyzes were made for a sample reinforced concrete (RC) structure to reveal the effect of PGA values. In order to make the structural results more understandable, the RC building has been taken into account with three different numbers of stories, including four, six, and eight-storeys. In order to reveal the effect of different structural

conditions, four different variables, namely: the number of storeys, local soil class, building importance class and concrete class were selected. Within the scope of this study, regular mid-rise RC building models were taken into account. In addition, the natural fundamental periods obtained with the empirical formulas used in the earthquake regulations for each country were compared with the period values obtained from the structural analysis. The target displacement values used to determine the performance level and damage estimation of the structures were obtained separately for each number of storeys and each earthquake. In addition, information is given about the building stocks of these countries at the point of the earthquake-structure relationship. The main purpose of this study is to reveal if the suggested PGA values for the building design in seismic design codes and earthquake hazard maps meet the measured PGA values. The novelty of the study is the detailed comparison of both seismic parameters and structural analysis results for six different countries. This study will contribute to the development of seismic hazard maps and seismic design codes for the selected countries. This study will make important contributions to this and similar studies in many different countries and earthquakes. of storeys, local soil class, building importance class and concrete class were selected. Within the scope of this study, regular mid-rise RC building models were taken into account. In addition, the natural fundamental periods obtained with the empirical formulas used in the earthquake regulations for each country were compared with the period values obtained from the structural analysis. The target displacement values used to determine the performance level and damage estimation of the structures were obtained separately for each number of storeys and each earthquake. In addition, information is given about the building stocks of these countries at the point of the earthquake-structure relationship. The main purpose of this study is to reveal if the suggested PGA values for the building design in seismic design codes and earthquake hazard maps meet the measured PGA values. The novelty of the study is the detailed comparison of both seismic parameters and structural analysis results for six different countries. This study will contribute to the development of seismic hazard maps and seismic design codes for the selected countries. This study will make important contributions to this and similar studies in many different countries and earthquakes.

these earthquakes. First, the measured and suggested PGA values were compared for selected earthquakes. Information is provided about the seismicity and the selected earthquakes for each country, respectively. Structural analyzes were made for a sample reinforced concrete (RC) structure to reveal the effect of PGA values. In order to make the structural results more understandable, the RC building has been taken into account with three different numbers of stories, including four, six, and eight-storeys. In order to reveal the effect of different structural conditions, four different variables, namely: the number

*Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 3 of 40

### **2. Seismicity of the Selected Countries 2. Seismicity of the Selected Countries**

Within the scope of this study, six different countries with different seismic characteristics, including Albania, Bosnia and Herzegovina, Croatia, Serbia, Türkiye, and Iran were selected. Comparisons were made by considering the suggested and measured peak acceleration values for the five different earthquakes in each country. In addition to the information about the selected earthquakes, brief information about the seismicity of these countries is given in this section. The locations of selected countries in the active tectonic map were shown in Figure 1. Within the scope of this study, six different countries with different seismic characteristics, including Albania, Bosnia and Herzegovina, Croatia, Serbia, Türkiye, and Iran were selected. Comparisons were made by considering the suggested and measured peak acceleration values for the five different earthquakes in each country. In addition to the information about the selected earthquakes, brief information about the seismicity of these countries is given in this section. The locations of selected countries in the active tectonic map were shown in Figure 1.

**Figure 1.** Location of selected countries in the active tectonic map (adopted from [49,50]). **Figure 1.** Location of selected countries in the active tectonic map (adopted from [49,50]).

### *2.1. Albania*

Albania is a country with moderate seismicity in the Western Balkans. Located on the Alpine-Mediterranean plate, this region has historically been affected by high-intensity earthquakes. Albanian seismic activity is characterized by intense seismic microactivity (3.0 > M > 1.0) by lots of small earthquakes (5.0 > M > 3.0), few mid-sized earthquakes (7.0 > M > 5.0) and very rarely by large earthquakes (M > 7.0). The most important tremors in the last century are given in Table 1.


**Table 1.** Major earthquakes in Albania [51].

Albania and its neighborhood are in a rather complicated seismotectonic region and are prone to earthquakes. A high frequency of earthquakes has been experienced, resulting in loss of life and property destruction in the region (Table 1). According to available records, this region sits in a high rate of seismicity, ranging from moderate to a high seismic risk level. It is characterized by noticeable micro-seismicity (a high number of small earthquakes), sparse mid-sized earthquakes, and very rare large earthquakes. Considering the recorded earthquakes from the accessible data, the earthquakes given in Table 1 were selected by the authors [51].

The first seismic zone intensity map of Albania dates back to 1952. Since then, it has been updated many times until 1979, which is at the moment that the map for seismic evaluation is enforced by the law. The KTP-1963 and KTP-1978 seismic guides were based on the pre-1979s map, which had lower seismic load requirements than the updated values due to a lack of information at the time. Few authors have studied this issue [52]. The largest earthquake in Albania occurred on June 1, 1905, in the North-Western part of Albania with a magnitude of Ms = 6.6. The duration of the tremor was 10–12 s and caused extensive damage to the built environment. In Shkodra alone, around 1500 residential buildings were completely destroyed and all other buildings were severely damaged. In addition, the walls of the historical Shkodra fortress were damaged and partially destroyed. The 15.04.1979 earthquake is one of the strongest earthquakes to occur in the Balkan Peninsula with a moment magnitude of 6.9. The epicenter of this tremor was the coastal area near Petrovac/Montenegro. Several tremors occurred about two weeks before the main shock, and aftershocks lasted for more than nine months. A strong aftershock of Ms = 6.3 occurred on May 24 [53]. This earthquake was one of the main reasons that led to amendments to the earthquake code and seismic zoning maps. Today's seismic zonation map is still based on regions of maximum intensity, not peak ground acceleration. Another strong earthquake occurred in Durrës on November 26, 2019, with a magnitude of M<sup>s</sup> = 6.4 [14]. The fact that the epicenter of the earthquake was so close to Albania's most populated and urban area increased the loss of life and injuries. In particular, the old masonry structures in the region were severely damaged and some of them were completely demolished. In this study, this earthquake and its losses will be examined and the results of all analyzes will be compared with the actual damage to the buildings.

The seismic source zones of Albania, characterized by active faults and tectonic regimes, are the essential primary inputs for the estimation of seismic hazards [53]. The following nine earthquake zones have been defined in and around Albania:


*Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 5 of 40

	-

The compiled Albania earthquake catalog comprises earthquakes of magnitude Ms > 4.5 that struck the territory between 39.0◦ N and 43.0◦ N and between 18.5◦ E and 21.5◦ E spanning a timeline 1958–2005 [53]. The best assessments of maximum magnitude are done by taking into account the biggest seismic activity identified and observed in similar tectonic locations. All this data input is processed by utilizing a probabilistic methodology and appropriate attenuation relationships to develop the Probabilistic Hazard Map of Albania. The compiled Albania earthquake catalog comprises earthquakes of magnitude Ms > 4.5 that struck the territory between 39.0°N and 43.0°N and between 18.5°E and 21.5°E spanning a timeline 58- 2005 [53]. The best assessments of maximum magnitude are done by taking into account the biggest seismic activity identified and observed in similar tectonic locations. All this data input is processed by utilizing a probabilistic methodology and appropriate attenuation relationships to develop the Probabilistic Hazard Map of Albania.

populated and urban area increased the loss of life and injuries. In particular, the old masonry structures in the region were severely damaged and some of them were completely demolished. In this study, this earthquake and its losses will be examined and the results

The seismic source zones of Albania, characterized by active faults and tectonic regimes, are the essential primary inputs for the estimation of seismic hazards [53]. The fol-

of all analyzes will be compared with the actual damage to the buildings.

lowing nine earthquake zones have been defined in and around Albania:

1. Zone of Lezha-Ulqin 2. Zone of Peri-Adriatic Lowland

The seismic zonation map of Albania is based on the intensity values [54], whereas new modern seismic guidelines like Eurocode 8 use probabilistic seismic hazard maps utilizing the peak ground acceleration values derived by probabilistic approaches with different return periods. In many modern codes, Damage Limitation (DL) is expected to be satisfied for an earthquake with peak ground acceleration for a return period of 95 years. Meanwhile, for an earthquake with PGA within the return period of 475 years, buildings should perform as per the limit state of Significant Damage (SD). Seismic hazard maps for maximum horizontal ground acceleration with recurrence periods of 95 and 475 years, respectively, are given for hard rock conditions (Figure 2). The seismic zonation map of Albania is based on the intensity values [54], whereas new modern seismic guidelines like Eurocode 8 use probabilistic seismic hazard maps utilizing the peak ground acceleration values derived by probabilistic approaches with different return periods. In many modern codes, Damage Limitation (DL) is expected to be satisfied for an earthquake with peak ground acceleration for a return period of 95 years. Meanwhile, for an earthquake with PGA within the return period of 475 years, buildings should perform as per the limit state of Significant Damage (SD). Seismic hazard maps for maximum horizontal ground acceleration with recurrence periods of 95 and 475 years, respectively, are given for hard rock conditions (Figure 2).

**Figure 2.** Horizontal peak ground acceleration values for a return period of 475 years (probabilistic seismic hazard map of Albania [55]. **Figure 2.** Horizontal peak ground acceleration values for a return period of 475 years (probabilistic seismic hazard map of Albania [55].

As shown in Figures 2 and 4, in many cities with dense masonry structures, such as Durrës, Shkodra, Elbasan, Tirane, and Vlora, the expected PGA for an earthquake with a recurrence period of 95 years is around 0.20 g, whereas this value is around 0.30–0.40 g with a recurrence period of 475 years. If these values are compared to the recordings of the 26 November 2019 shakings, in most of the regions these values are near the values of a 95 year return period. The data for the selected earthquakes in Albania is shown in Table 2.


**Table 2.** Data of selected earthquakes in Albania.

A comparison of the measured and suggested PGA values of the selected earthquakes for Albania are given in Table 3.

**Table 3.** Comparison of the measured and suggested PGA values of the selected earthquakes for Albania.


While the number of damaged buildings in the first two earthquakes considered for Albania was quite high, the loss of life was quite low. In addition, the highest loss of life/damaged buildings ratio for this country was obtained for the fifth earthquake, and this ratio was 0.14. The measured PGA values in these earthquakes that have occurred in these regions with high earthquake risk were considerably lower than the suggested PGA values for the first three earthquakes. However, the measured PGA values for the third and fourth earthquakes are considerably higher than the recommended PGA values. For this country, the seismic risk can be expressed adequately by considering the earthquake ground motion levels for different probabilities of exceedance.

### *2.2. Bosnia and Herzegovina*

Bosnia and Herzegovina is located in the central part of the Dinaridic Mountain System [56]. The location of Mediterranean is characterized by various types of faults that have been identified in this region. The Adriatic coast and the Dinarides are specific for reverse faults, while normal faults are mainly identified in the Apennine Peninsula. The fault plane solution for major earthquakes in Adria has been presented by Slejko et al. [57], while obtaining data from various sources; Gasparini et al. [58], Herak et al. [59], Louvari et al. [60], Sulstarova et al. [61], and Harvard [62].

As stated in the article in [63], quote: "It is evident that with the increase of population in seismically prone areas, urban areas are becoming more vulnerable to seismic risk. Record losses were registered in 2011 [64] after earthquakes that hit Japan and New Zealand, for developed countries with a high degree of earthquake disaster awareness and preparedness. In absolute terms, the costliest disasters happen in the most developed countries, however, with respect to their GDP, it was limited to a few percentage points [65]. The analysis showed that countries of middle income in the last two decades were at a higher risk in comparison to the countries with low and high GDP. From the available data [65], Bosnia and Herzegovina falls into lower-middle-income."

Taking into account the high density of the population, high level of vulnerability of buildings, and moderate to high in some locations PGA results in a high risk of earthquakes in Bosnia and Herzegovina. After the Zagreb 2020 earthquakes, the engineering community awakened regarding the potential risk and level of devastation to the existing building stock in Bosnia and Herzegovina. It should be mentioned that the last devastating earthquake that hit Zagreb was in 1880. Then, 140 years later, the Zagreb 2020 earthquake and Petrinja earthquake occurred and had a major effect on the building and clearly showed the high vulnerability of the existing stock. It is important to state that the Pokupsko- Petrinja Fault is oriented in the NW-SE direction within the Eurasian plate. This is the strongest earthquake that occurred since the 1880 Great Zagreb earthquake (magnitude of 6.3). The seismicity of this region (Croatia and the upper part of Bosnia and Herzegovina-Banja Luka region) is given in Figure 4. Looking at the map, it is believed that the Petrinja fault is the same as the Banja Luka fault, as indicated in Figure 3 and indicated as PKBL = Pokuplje-Kostajnica-Banja Luka right-lateral fault. *Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 8 of 40

**Figure 4.** The spatial distribution of earthquakes in Croatia (373 BC–2019, according to the Croatian Earthquake Catalogue (CEC), of which an updated version was first described in [67], with the Pokupsko-Petrinja epicentral area indicated (blue rectangle). Thick, black-dashed lines mark regional active faults: PKBL = Pokuplje-Kostajnica-Banja Luka right-lateral fault, SPGT = Sisak-Petrinja-Glina-Topusko left-lateral fault, and OVBL = Orljava-Vrbas-Banja Luka left-lateral fault. **Figure 3.** The spatial distribution of earthquakes in Croatia (373 BC–2019, according to the Croatian Earthquake Catalogue (CEC), of which an updated version was first described in [67], with the Pokupsko-Petrinja epicentral area indicated (blue rectangle). Thick, black-dashed lines mark regional active faults: PKBL = Pokuplje-Kostajnica-Banja Luka right-lateral fault, SPGT = Sisak-Petrinja-Glina-Topusko left-lateral fault, and OVBL = Orljava-Vrbas-Banja Luka left-lateral fault.

After the Petrinja earthquake, a quick field inspection revealed that fresh fault planes in the outcrops on the Hrastovička gora appeared mostly along the longitudinal NW–SEstriking Pokupsko–Kostajnica–Banja Luka Fault and showed clear dextral coseismic strike-slip displacements and a 20 km long section of the Pokupsko Fault was (re)activated. It is assumed by Markušić et al. [68] that the creeping sinistral Sisak–Petrinja– Glina–Topusko Fault is locking the dextral Pokupsko–Kostajnica–Banja Luka Fault and a similar complex fault mechanism is also proposed for the Banja Luka area. According to Markušić et al. [68], the dextral Pokupsko–Banja Luka Fault could be one of the main in-After the Petrinja earthquake, a quick field inspection revealed that fresh fault planes in the outcrops on the Hrastoviˇcka gora appeared mostly along the longitudinal NW–SEstriking Pokupsko–Kostajnica–Banja Luka Fault and showed clear dextral coseismic strikeslip displacements and a 20 km long section of the Pokupsko Fault was (re)activated. It is assumed by Markuši´c et al. [68] that the creeping sinistral Sisak–Petrinja–Glina–Topusko Fault is locking the dextral Pokupsko–Kostajnica–Banja Luka Fault and a similar complex fault mechanism is also proposed for the Banja Luka area. According to Markuši´c et al. [68], the dextral Pokupsko–Banja Luka Fault could be one of the main inherited active faults between the crustal segments of Adria.

Taking this all into account, it is of the utmost importance to take Bosnia and Herzegovina into account regarding the effects of earthquakes on target displacement in RC structures and other structures as well. Other than the Peak Ground Acceleration, it is

Papeš [72] gave the most comprehensive picture of the tectonic structure in Bosnia and Herzegovina. The longest fault is the Sarajevo Fault, which spreads in the direction of NW-SW, followed by the Banja Luka fault and Konjic Fault. Sarajevo fault with a low to moderate seismic activity level is under-passed by all the transversal deep faults, where the highest seismic motions are noted. Ademović et al. [73] presented that 64% of all earthquakes have a focal depth of up to 10 km and that this is one of the causes of the damaging impact on the structures. Bosnia and Herzegovina in the last 50 years was hit by more than a few medium-sized earthquakes of magnitude M<sup>w</sup> up to 6.1 [74]. The earthquake, which had the most devastating impact on the structures, was the 1969 Banja Luka earthquake. According to the MSK-64, the Banja Luka earthquake was marked as a VIII intensity scale [75]. The aftermath of this earthquake was 15 fatalities, 1117 injured people, and

The second-largest earthquake that should be mentioned is the 1962 Treskavica earthquake with a magnitude Mw= 5.9, and a focal depth of 15 km. As the epicenter of the

ulation during the assessment of the seismic risk. After the Petrinja earthquake, the seismic community in Bosnia and Herzegovina discussions started, and at the moment, there are initiatives for a revision of the interactive seismic map of Bosnia and Herzegovina.

over \$300 million in damage [74,76].

herited active faults between the crustal segments of Adria.

indicated as PKBL = Pokuplje-Kostajnica-Banja Luka right-lateral fault.

while obtaining data from various sources; Gasparini et al. [58], Herak et al. [59], Louvari

in seismically prone areas, urban areas are becoming more vulnerable to seismic risk. Record losses were registered in 2011 [64] after earthquakes that hit Japan and New Zealand, for developed countries with a high degree of earthquake disaster awareness and preparedness. In absolute terms, the costliest disasters happen in the most developed countries, however, with respect to their GDP, it was limited to a few percentage points [65]. The analysis showed that countries of middle income in the last two decades were at a higher risk in comparison to the countries with low and high GDP. From the available data [65],

As stated in the article in [63], quote: "It is evident that with the increase of population

Taking into account the high density of the population, high level of vulnerability of

buildings, and moderate to high in some locations PGA results in a high risk of earthquakes in Bosnia and Herzegovina. After the Zagreb 2020 earthquakes, the engineering community awakened regarding the potential risk and level of devastation to the existing building stock in Bosnia and Herzegovina. It should be mentioned that the last devastating earthquake that hit Zagreb was in 1880. Then, 140 years later, the Zagreb 2020 earthquake and Petrinja earthquake occurred and had a major effect on the building and clearly showed the high vulnerability of the existing stock. It is important to state that the Pokupsko- Petrinja Fault is oriented in the NW-SE direction within the Eurasian plate. This is the strongest earthquake that occurred since the 1880 Great Zagreb earthquake (magnitude of 6.3). The seismicity of this region (Croatia and the upper part of Bosnia and Herzegovina-Banja Luka region) is given in Figure 3. Looking at the map, it is believed that the Petrinja fault is the same as the Banja Luka fault, as indicated in Figure 4 and

et al. [60], Sulstarova et al. [61], and Harvard [62].

Bosnia and Herzegovina falls into lower-middle-income."

**Figure 3.** Map of earthquake epicenters in Croatia and part of Bosnia and Herzegovina in the period from BC to 2015 according to the Catalog of Earthquakes in Croatia and the neighboring areas [66– **Figure 4.** Map of earthquake epicenters in Croatia and part of Bosnia and Herzegovina in the period from BC to 2015 according to the Catalog of Earthquakes in Croatia and the neighboring areas [66–71].

71]. Taking this all into account, it is of the utmost importance to take Bosnia and Herzegovina into account regarding the effects of earthquakes on target displacement in RC structures and other structures as well. Other than the Peak Ground Acceleration, it is necessary to take into account the vulnerability of structures and the exposure of the population during the assessment of the seismic risk. After the Petrinja earthquake, the seismic community in Bosnia and Herzegovina discussions started, and at the moment, there are initiatives for a revision of the interactive seismic map of Bosnia and Herzegovina.

Papeš [72] gave the most comprehensive picture of the tectonic structure in Bosnia and Herzegovina. The longest fault is the Sarajevo Fault, which spreads in the direction of NW-SW, followed by the Banja Luka fault and Konjic Fault. Sarajevo fault with a low to moderate seismic activity level is under-passed by all the transversal deep faults, where the highest seismic motions are noted. Ademovi´c et al. [73] presented that 64% of all earthquakes have a focal depth of up to 10 km and that this is one of the causes of the damaging impact on the structures. Bosnia and Herzegovina in the last 50 years was hit by more than a few medium-sized earthquakes of magnitude M<sup>w</sup> up to 6.1 [74]. The earthquake, which had the most devastating impact on the structures, was the 1969 Banja Luka earthquake. According to the MSK-64, the Banja Luka earthquake was marked as a VIII intensity scale [75]. The aftermath of this earthquake was 15 fatalities, 1117 injured people, and over \$300 million in damage [74,76].

The second-largest earthquake that should be mentioned is the 1962 Treskavica earthquake with a magnitude Mw= 5.9, and a focal depth of 15 km. As the epicenter of the earthquake was in an abandoned area of Mount Treskavica, there were no major casualties, nor significant damage to the buildings due to the low level of population and construction in this region at that time [77]. Several structures have been damaged in Sarajevo by this earthquake activity (Building of the Executive Council, the Main Post Office, Faculty of Medicine) [73]. The damage caused by this earthquake in the financial means was equal to 396 million dinars [78]. Looking at the period from 306 to 2015, 66.9% of all earthquakes had a magnitude between 3.6–4.5, while 20.5% of the earthquakes had a magnitude in the

Imotski,

Petrinja, Croatia

Zagreb-

1

2

5

range of 4.6 to 6. This region was not often hit (4.2% of all earthquakes) by an earthquake of larger magnitudes, while only 8.5% of all earthquakes that hit this region had a magnitude between 3.1 to 3.5 [73]. 4 Montenegro Makarska 1979 6.9 208 0.04 High 0.276 Croatia Makarska <sup>1978</sup> 4.7 <sup>24</sup> 0.03 High 0.276

Puntijarka <sup>2020</sup> 6.4 <sup>60</sup> 0.04 High 0.279

*Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 10 of 40

3 Montenegro Dubrovnik 1979 6.9 105 0.08 High 0.305

Figure 5 shows epicentres of regional north-western Balkan earthquakes observed between 1900 and April 2021 with Mw ≥ 3.0 [79], as well as the boundaries of Croatia, Bosnia and Herzegovina, and Serbia. It also shows epicentres of the earthquakes from which PGA values have been recorded on rock, as well as the recording sites. In 2018, new seismic hazard maps were compiled for Bosnia and Herzegovina and incorporated into the National Annex to Eurocode 8 [80]. It should be noted that the reference PGA values in these maps are given for ground type A, i.e., for the rock sites. Recently, in all three countries (Croatia, Bosnia and Herzegovina, and Serbia), current official seismic hazard maps are part of the respective National Annexes to Eurocode 8 and the PGA values for rock sites (ground type A) are used to express the hazard. Hence, in Table 5, we have presented only the PGA values recorded on rock (i.e., sites with shear wave velocity in the top 30 m of the soil larger than or equal to 800 m/s). This has unfortunately posed a challenge, since for some devastating historical earthquakes there were very few accelerograph stations on rock sites, while for others we could not find any available data. **Table 6.** Comparison of the measured and suggested PGA values of the selected earthquakes for Türkiye. **No Earthquake Location Station Name Year Earthquake Magnitude Magnitude Type PGA(g) Seismic Risk Zone PGA(g) As Per TSDC-2007 As Per TBEC-2018** 1 Türkiye Van 2011 7.2 Mw 0.182 High 0.399 2 Türkiye Bingöl 2003 6.3 Ms 0.511 Very High 0.633 3 Türkiye Düzce 1999 7.2 Ms 0.823 Very High 0.588 4 Türkiye Erzincan 1992 6.8 Ms 0.485 Very High 0.432 5 Türkiye Kocaeli 1999 7.4 Ms 0.399 Very High 0.690

**Figure 5.** Epicentres of the north-western Balkan earthquakes observed between 1900 and 2021 [79], including the epicentres of the earthquakes that were recorded in Croatia, Bosnia and Herzegovina, and Serbia on rock (blue circles show locations of the corresponding recording stations). **Figure 5.** Epicentres of the north-western Balkan earthquakes observed between 1900 and 2021 [79], including the epicentres of the earthquakes that were recorded in Croatia, Bosnia and Herzegovina, and Serbia on rock (blue circles show locations of the corresponding recording stations).

During the analysis, we have chosen the countries of the Balkan as two years ago several earthquakes hit Croatia, which, even though not of "extreme" magnitude, had a major impact on the building stock and community as a whole. The data on the 1981 Banja Luka earthquake are shown in Table 7. During the analysis, we have chosen the countries of the Balkan as two years ago several earthquakes hit Croatia, which, even though not of "extreme" magnitude, had a major impact on the building stock and community as a whole. The data on the 1981 Banja Luka earthquake are shown in Table 4.

**Table 7.** Data of the selected earthquake in Bosnia and Herzegovina [82,83].


**Table 4.** Data of the selected earthquake in Bosnia and Herzegovina [81,82].

The comparison of the PGA values for selected earthquakes in Bosnia and Herzegovina is shown in Table 5. In Table 5, all PGA values were taken from the EQINFOS database [83]. All given PGA values were recorded at rock sites (corresponding to ground type A according to Eurocode 8).

**Table 5.** Comparison of the measured and suggested PGA values of selected earthquakes for Bosnia and Herzegovina [83].


For Bosnia and Herzegovina, the loss of life/damaged buildings ratio for the first earthquake, whose data can be accessed, was 0.09. The measured PGA values for the three earthquakes were considerably higher than the predicted PGA values, however, it should be noted that these values were recorded at very short epicentral distances—7.1, 7.4, and 6.5 km, respectively—while the hypocentral depth was only 10 km. Smaller measured PGA values are recorded at large distances of 215 and 177 km, respectively.

### *2.3. Croatia*

As part of the Mediterranean–Trans-Asian belt, the territory of the Republic of Croatia is located in a seismically active area. The territory of Croatia consists of several tectonic units: The Pannonian basin in the north, the eastern part of the Alps in the northwest, the Dinarides, the transition zone between the Dinarides and the Adriatic plate, and the Adriatic plate [84,85]. Structural-geological data on recently active faults, combined with data on seismic activity, form the basis for the interpretation of seismotectonic activity, seismic hazard, and risk in seismically active areas.

The majority of earthquakes in Croatia occur around the Adriatic coast due to the interaction (collision) of the Adriatic Platform and the Dinarides (see Figure 6). However, the north-east parts of Croatia are located in an intraplate low to moderate seismicity region of the Pannonian Basin [85]. Moho depths in Croatia range from 25 km beneath the Pannonian Basin to 45 km beneath the Dinarides [86,87]. Since 2011, current official seismic hazard maps (for a return period of 95 and 475 years) for Croatia are part of

**No Date Lat. Lon.**

the Croatian National Annex to Eurocode 8 [88]. Hazard maps for the return period of 475 years for Croatia are presented in Figure 6. In Table 6, data on selected earthquakes in Croatia are given. All given PGA values were recorded at rock sites (corresponding to ground type A according to Eurocode 8). The ratio of loss of life/damaged buildings was 0.01 for the first earthquake and 0.09 for the third earthquake. Here, the first earthquake is the 6.4 Mw earthquake that devastated the village of Petrinja on 29 December 2020, with the epicentre 40 km south of the capital of Croatia, Zagreb [89]. The focal depth of the earthquake was around 10 km. Another earthquake that should be mentioned here, and which caused damages in Bosnia and Herzegovina as well as in Croatia and even Albania, is the 1979 Montenegro earthquake, which was the strongest earthquake recorded in the area of the former Yugoslavia, with the epicentre offshore in the Adriatic Sea (see Figure 5). While this earthquake was felt up to 900 km from the epicentre, it had destructive consequences only in a 100 km coastal zone and a 25 km stretch from the shore to the mountains [90]. Montenegro suffered 101 and Albania 35 fatalities as a result of the earthquake [90]. This earthquake contributed to the last two PGA values in Table 5, and the third and fourth PGA values in Table 6. *Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 12 of 40

**Figure 6.** Seismic hazard maps for Croatia for a return period of 475 years (http://seizkarta.gfz.hr/karta.php, accessed 30 August 2022) [93]. **Figure 6.** Seismic hazard maps for Croatia for a return period of 475 years (http://seizkarta.gfz.hr/ karta.php, accessed 30 August 2022) [91].

**Damaged Buildings**

**Location Mb Ms Mw**

\* UNICEF Country Office for Croatia, Earthquake Situation Report #5, 3 February 2021 [94].

The comparison of measured and suggested PGA of the selected earthquakes for

Table 5 shows all the PGA values recorded on rock sites in Croatia that could be

found at the moment. The first PGA value corresponds to the 2020 Petrinja earthquake [85]. The second PGA value was taken from the ISESD database [81,83]. The last three PGA values were taken from the EQINFOS database [82]. It is interesting to see from Table 5 that, although there were no casualties in Croatia, the PGA values recorded from this earthquake on rock sites at distances of 105 and 218 km are very similar to those recorded in Croatia at much smaller distances, but during moderate size events. From what can be seen from Table 5, the presented PGA values are very, very low compared to the corresponding PGA values given in the Croatian hazard map. However, it should be noted that some of these values were recorded at relatively large epicentral distances. For example, the first value was recorded at a distance of 60 km, while the third and fourth PGA values were recorded at distances of 105 and 218 km, respectively (the hypocentral depth was 12 km). The second value was recorded at the epicentral distance of 12 km while the epicentral depth was 13 km. The fifth value was recorded at the epicentral distance of 24 km,

**Loss of Life/ Damaged Buildings**

**Magnitude Loss of** 

Croatia is given in Table 5.

while the epicentral depth was 10 km.

**Table 8.** Data of selected earthquakes in Croatia [79,82,83].

**Life**

1 29.12.2020 45.40 16.22 6.0 6.4 7 8300\* 0.01 Petrinja, Croatia

3 17.12.1978 43.38 17.29 4.5 3.7 4.7 - - - Imotski, Croatia


**Table 6.** Data of selected earthquakes in Croatia [79,82,83].

\* UNICEF Country Office for Croatia, Earthquake Situation Report #5, 3 February 2021 [92].

The comparison of measured and suggested PGA of the selected earthquakes for Croatia is given in Table 7.

**Table 7.** Comparison of the measured and suggested PGA values of the selected earthquakes for Croatia [82,83,93,94].


Table 7 shows all the PGA values recorded on rock sites in Croatia that could be found at the moment. The first PGA value corresponds to the 2020 Petrinja earthquake [94]. The second PGA value was taken from the ISESD database [81,83]. The last three PGA values were taken from the EQINFOS database [82]. It is interesting to see from Table 5 that, although there were no casualties in Croatia, the PGA values recorded from this earthquake on rock sites at distances of 105 and 218 km are very similar to those recorded in Croatia at much smaller distances, but during moderate size events. From what can be seen from Table 7, the presented PGA values are very, very low compared to the corresponding PGA values given in the Croatian hazard map. However, it should be noted that some of these values were recorded at relatively large epicentral distances. For example, the first value was recorded at a distance of 60 km, while the third and fourth PGA values were recorded at distances of 105 and 218 km, respectively (the hypocentral depth was 12 km). The second value was recorded at the epicentral distance of 12 km while the epicentral depth was 13 km. The fifth value was recorded at the epicentral distance of 24 km, while the epicentral depth was 10 km.

### *2.4. Serbia*

The major part of Serbia is located in intraplate low to moderate seismicity regions. To the north, Serbia comprises the Pannonian Basin's southern part, with a rare occurrence of larger earthquakes [95]. To the southwest, Serbia is surrounded by Dinaric Alps and borders the Mediterranean-Trans-Asian belt, known for its frequent occurrence of stronger earthquakes. To the northeast, Serbia is surrounded by the Carpathian Mountains, and to the southeast by the Balkan Mountains and Rhodopes. The range of the Moho depths is similar to that in Croatia (shallowest beneath the Pannonian Basin and deepest beneath the Dinarides) [86,87]. Normal faults are, however, more common in Serbia than thrusts and strike-slip faults, which do account for practically all occurrences in the External Dinarides.

A series of earthquakes struck central Serbia in the twentieth century, causing largely rural devastation, such as the 1922 M6.0 Lazarevac, 1927 M = 5.9 Rudnik, 1980 M = 5.8 Kopaonik, and 1998 M = 5.7 Mionica earthquakes. The most recent devastating earthquake in Serbia was the M = 5.5 Kraljevo Earthquake, which occurred on 3 November 2010, with an epicentral intensity of VII-VIII ◦MCS. Two individuals died, 180 people were injured, and numerous buildings were damaged [96].

Data of selected earthquakes that are available for Serbia [97] is given in Table 8 and the comparison of PGA's is given in Table 10. All given PGA values were recorded at rock sites (corresponding to ground type A according to Eurocode 8).


**Table 8.** Data of selected earthquakes in Serbia [97].

In 2018, new seismic hazard maps were compiled for Serbia and incorporated into the National Annex to Eurocode 8. Similar to Croatia and Bosnia and Herzegovina, for Serbia, it was also a challenge to find PGA records on rock sites, especially because Serbia did not experience an event with Mw larger than 5.9 in the past 100 years. The values presented in Table 9 are the only ones we could find for the rock sites, and which were recorded by the Seismological Survey of Serbia's (2021) [98] accelerograph network in Serbia.

**Table 9.** Comparison of the measured and suggested PGA values of the selected earthquakes for Serbia [98].


Data of selected earthquakes that are available for Serbia is given in Table 8 and the comparison of PGA's is given in Table 9. All given PGA values were recorded at rock sites (corresponding to ground type A according to Eurocode 8).

For Serbia, the ratio of loss of life to damaged buildings was 0.01 for the first earthquake. The recorded PGA values considered for Serbia are very, very low compared to the corresponding PGA values given in the Serbian official seismic hazard map. However, most

of these values shown here were also recorded at relatively large epicentral distances. The epicentral distances for the last four PGA values were 69, 83, 102, and 46 km, respectively, while for the first value the distance was 13 km (the hypocentral depth was 13 km for the first four records and 12 km for the last record). respectively, while for the first value the distance was 13 km (the hypocentral depth was 13 km for the first four records and 12 km for the last record). *2.5. Türkiye*

For Serbia, the ratio of loss of life to damaged buildings was 0.01 for the first earthquake. The recorded PGA values considered for Serbia are very, very low compared to the corresponding PGA values given in the Serbian official seismic hazard map. However, most of these values shown here were also recorded at relatively large epicentral distances. The epicentral distances for the last four PGA values were 69, 83, 102, and 46 km,

*Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 14 of 40

### *2.5. Türkiye* Türkiye is situated within the Alpine-Himalayan orogenic belt and is among the most

Türkiye is situated within the Alpine-Himalayan orogenic belt and is among the most seismically active areas in the world [99,100]. The distribution of seismicity is focused on high-strain regions, many of which are major strike-slip faults, such as the North Anatolian Fault Zone (NAFZ), the East Anatolian Fault Zone (EAFZ), and the Western Anatolian Graben Zones (WAGZ). The NAFZ is a 1200 km long strike-slip fault zone that connects the East Anatolian convergent zone to the Hellenic subduction zone [101–103]. The distribution of earthquakes that dominate the seismic pattern of the northern part of Türkiye is mostly parallel to the NAFZ [104–106]. The NAFZ is a continuous and narrow fault system that cuts the Anatolian Peninsula in an E-W direction from Karlıova in the east to the northern Aegean in the west. The NAFZ, which is the northern plate boundary of the Anatolian Plate with the N-S extensional regime of the Aegean region, spreads as a complex fault system in the eastern part of the Marmara region, in contrast to the simple structure of the NAFZ (Figure 7). seismically active areas in the world [99,100]. The distribution of seismicity is focused on high-strain regions, many of which are major strike-slip faults, such as the North Anatolian Fault Zone (NAFZ), the East Anatolian Fault Zone (EAFZ), and the Western Anatolian Graben Zones (WAGZ). The NAFZ is a 1200 km long strike-slip fault zone that connects the East Anatolian convergent zone to the Hellenic subduction zone [101–103]. The distribution of earthquakes that dominate the seismic pattern of the northern part of Türkiye is mostly parallel to the NAFZ [104–106]. The NAFZ is a continuous and narrow fault system that cuts the Anatolian Peninsula in an E-W direction from Karlıova in the east to the northern Aegean in the west. The NAFZ, which is the northern plate boundary of the Anatolian Plate with the N-S extensional regime of the Aegean region, spreads as a complex fault system in the eastern part of the Marmara region, in contrast to the simple structure of the NAFZ (Figure 7).

**Figure 7.** Main tectonics elements for Türkiye [107]. **Figure 7.** Main tectonics elements for Türkiye [107].

Distribution of the epicenters (M ≥ 3.0) and main fault zones in Türkiye was given in Figure 8. Distribution of the epicenters (M ≥ 3.0) and main fault zones in Türkiye was given in Figure 8. *Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 15 of 40

**Figure 8.** Distribution of epicenters (M ≥ 3.0) and main fault zones in Türkiye. 1 13.03.1992 39.72 39.63 6.1 6.8 653 8057 0.08 Erzincan **Figure 8.** Distribution of epicenters (M ≥ 3.0) and main fault zones in Türkiye.

The earthquakes taken into account for Türkiye are the 1992 Erzincan, 1999 Kocaeli, 1999 Düzce, 2003 Bingöl, and 2011 Van. The 1992 Erzincan earthquake occurred in the

The loss of life and property of a total of selected earthquakes and their locations are shown in Table 11. Data on these earthquakes were obtained from the databases of two main institutions that record instrumental earthquakes in Türkiye such as the Republic of Türkiye Prime Ministry Disaster and Emergency Management Presidency (DEMP) and the Kandilli Observatory Earthquake Research Institute of Bogaziçi University (KOERI)

> **Loss of Life/ Damaged Buildings**

shock occurred in Pülümür [108]. After this 6.8 magnitude earthquake, many engineering structures were damaged [109]. The 1999 Gölcük (Kocaeli) earthquake, which was felt in and around the Marmara region, caused different levels of structural damage in these settlements. This earthquake, which occurred on the northern branch of the North Anatolian Fault Zone (NAFZ), is associated with a 145 km long surface rupture extending from the southwest of Düzce in the east to the west of the Hersek delta in the west [110]. The 1999 Düzce earthquake, which took place three months after the 1999 Gölcük earthquake, was felt in many different settlements and caused huge structural damage [111]. The surface rupture of this earthquake, which occurred on the Düzce Fault, which is an extension of the North Anatolian Fault Zone in the Bolu Basin, was 40 km long and the maximum right lateral deviation was measured as 500 ± 5 cm [112]. The 2003 earthquake that occurred in Bingöl, one of Türkiye's provinces with high seismicity, occurred approximately 60 km southwest of the triple junction near Karlıova, where the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ) intersect [113]. The earthquakecausing fault is a right-lateral strike-slip fault and it is stated that the earthquake depth is in the range of 5–15 km [114]. The last earthquake considered in the study is the 2011 Van earthquake that happened in the Lake Van Basin. The epicentral depth of this earthquake, which was centered in Tabanlı village between Van and Erçiş, was measured as 5 km [115]. The large aftershock of 9.11. 2011 (M<sup>W</sup> = 5.7) was caused by additional damage, especially in the city center of Van, and more than 40 fatalities [116,117]. The settlements where the epicentres of these five different earthquakes, which are considered for Türkiye,

**Table 11.** Data of selected earthquakes in Türkiye [118,119].

**Life**

**Damaged Buildings**

**Location Mb Ms Mw**

**Magnitude Loss of** 

have high seismic risk.

and [118,119].

**No Date Lat. Lon.**

The earthquakes taken into account for Türkiye are the 1992 Erzincan, 1999 Kocaeli, 1999 Düzce, 2003 Bingöl, and 2011 Van. The 1992 Erzincan earthquake occurred in the eastern half of the Erzincan basin, and two days after this earthquake, the largest aftershock occurred in Pülümür [108]. After this 6.8 magnitude earthquake, many engineering structures were damaged [109]. The 1999 Gölcük (Kocaeli) earthquake, which was felt in and around the Marmara region, caused different levels of structural damage in these settlements. This earthquake, which occurred on the northern branch of the North Anatolian Fault Zone (NAFZ), is associated with a 145 km long surface rupture extending from the southwest of Düzce in the east to the west of the Hersek delta in the west [110]. The 1999 Düzce earthquake, which took place three months after the 1999 Gölcük earthquake, was felt in many different settlements and caused huge structural damage [111]. The surface rupture of this earthquake, which occurred on the Düzce Fault, which is an extension of the North Anatolian Fault Zone in the Bolu Basin, was 40 km long and the maximum right lateral deviation was measured as 500 ± 5 cm [112]. The 2003 earthquake that occurred in Bingöl, one of Türkiye's provinces with high seismicity, occurred approximately 60 km southwest of the triple junction near Karlıova, where the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ) intersect [113]. The earthquake-causing fault is a right-lateral strike-slip fault and it is stated that the earthquake depth is in the range of 5–15 km [114]. The last earthquake considered in the study is the 2011 Van earthquake that happened in the Lake Van Basin. The epicentral depth of this earthquake, which was centered in Tabanlı village between Van and Erçi¸s, was measured as 5 km [115]. The large aftershock of 9.11. 2011 (M<sup>W</sup> = 5.7) was caused by additional damage, especially in the city center of Van, and more than 40 fatalities [116,117]. The settlements where the epicentres of these five different earthquakes, which are considered for Türkiye, have high seismic risk.

The loss of life and property of a total of selected earthquakes and their locations are shown in Table 10. Data on these earthquakes were obtained from the databases of two main institutions that record instrumental earthquakes in Türkiye such as the Republic of Türkiye Prime Ministry Disaster and Emergency Management Presidency (DEMP) and the Kandilli Observatory Earthquake Research Institute of Bogaziçi University (KOERI) and [118,119].


**Table 10.** Data of selected earthquakes in Türkiye [118,119].

Among the selected earthquakes in this study, the greatest damage occurred in the 1999 Kocaeli (Gölcük) earthquake. The loss of life per building was obtained as 0.24 for this earthquake. The lowest loss of life per building occurred in the 1999 Düzce earthquake. These five different earthquakes caused a total of 19,716 deaths in a total of 139,923 damaged buildings. This data is sufficient to clearly demonstrate Türkiye's earthquake hazard. The loss of life per building for five earthquakes was calculated as 0.14. The measured and recommended PGA values for these earthquakes are given in Table 11. The standard design earthquake ground motion level was selected to determine the suggested PGA values. This level is opposed to probabilities of exceedance of 10% in 50 years, which has a 475-year repetition period.


**Table 11.** Comparison of the measured and suggested PGA values of the selected earthquakes for Türkiye.

Except for the third and fourth Düzce earthquakes, the recommended PGA values for the design earthquake were not exceeded for the other three earthquakes. For Türkiye, the recommended PGA values for the first, second and fifth earthquake locations are lower than the predicted PGA values, and the seismic risk for these locations has been adequately taken into account. All earthquake hazard maps used in Türkiye until 2018 were prepared on a regional basis. However, the earthquake hazard is specified specifically for the geographical location with the map currently used after this date. In addition, while there was only one earthquake ground motion level in the previous seismic design code, four different exceedance probabilities are taken into account with the updated code. With the earthquake hazard specific to the geographical location, the expected target displacements from the structures under the effect of the earthquake could be obtained more realistically. Considering the earthquake ground motion levels for different probabilities of exceedance, it is possible for the structures to provide the desired performance levels under the influence of larger earthquakes.

### *2.6. Iran*

The Iranian plateau is located on the Alpine–Himalayan seismic belt, which is considered to be one of the most seismic zones of the world [120,121] and the source of major and destructive earthquakes that occurred in this country throughout history. Some of the most catastrophic earthquakes recorded in the seismic history of Iran include 1960 Lar (Ms = 6.5), 1962 Buin-Zahra (Ms = 7.2), 1978 Tabas (Mw = 7.35), 1990 Manjil (Mw = 7.37), and 2003 Bam (Mw = 6.6) [122]. One of the first elaborate attempts at research on the tectonics and seismicity of Iran was conducted by Ambraseys and Melville (1982) [123]. Berberian (1994) [124] published the first earthquake catalogue of Iran. Updated earthquake catalogues and seismic zoning maps of Iran are regularly published by the seismic zoning sub-committee of the Iranian Seismic Code's permanent committee and are provided by the Iranian Strong Motion Network (ISMN) as the major source of seismology and earthquake engineering in Iran [125]. Figure 9 shows the epicenter of earthquakes that occurred in Iran in 2017 recorded by ISMN (ISMN, 2017) [126], while Figure 10 represents records of large earthquakes that occurred in Iran and adjacent countries from 1900 up to recent years [127]. This figure shows 17 earthquakes with M<sup>w</sup> > 7, 103 earthquakes with 6 < M<sup>w</sup> < 7, and more than 1700 earthquakes with M<sup>w</sup> > 5 that have occurred in the recorded seismic history of Iran [125]. It is also demonstrated from Figure 10 that the Zagros zone in the western and southwestern part of Iran is the most seismically active zone which also confirms the major seismic zone categorization proposed by Shoja-Taheri and Niazi (1981) [128]. Based on Figures 11 and 12, as well as the earthquake zonation map of Iran, most of the provinces with large populations are located within high or very high seismic zone areas. As mentioned in the study by Izadkhah and Amini [129], more than 70 percent of cities in Iran are in the vicinity or within the route of active faults, which poses a great risk of seismic hazards to such cities.

**No Date Lat. Lon.**

**No Date Lat. Lon.**

*Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 17 of 40

of seismic hazards to such cities.

of seismic hazards to such cities.

areas. As mentioned in the study by Izadkhah and Amini [129], more than 70 percent of cities in Iran are in the vicinity or within the route of active faults, which poses a great risk

areas. As mentioned in the study by Izadkhah and Amini [129], more than 70 percent of cities in Iran are in the vicinity or within the route of active faults, which poses a great risk

**Figure 9.** Epicentre of earthquakes occurred in Iran in 2017, recorded by ISMN [130]. **Figure 9.** Epicentre of earthquakes occurred in Iran in 2017, recorded by ISMN [126]. **Figure 9.** Epicentre of earthquakes occurred in Iran in 2017, recorded by ISMN [130].

**Figure 10.** Large earthquakes in Iran and adjacent countries (1900–2019) [130]. **Figure 10.** Large earthquakes in Iran and adjacent countries (1900–2019) [126].

**Table 12.** Data of the selected earthquakes in Iran [130–135].

1 2003/12/26 29.04 58.33 - - 6.6 35,000 85% - Bam, Iran

1 2003/12/26 29.04 58.33 - - 6.6 35,000 85% - Bam, Iran

**Figure 10.** Large earthquakes in Iran and adjacent countries (1900–2019) [130].

in Table 12. Major sources of these data include USGS, ISMN, IIEES, and IRIS.

**Loss of Life Damaged** 

Epicentre locations, loss of life and properties, and magnitudes for some of the most

**Buildings**

**Location Mb Ms Mw**

buildings -

buildings -

**Loss of Life/ Damaged Buildings**

**Loss of Life/ Damaged Buildings**

> Manjil-Rudbar, Iran

Manjil-Rudbar, Iran

destructive earthquakes that occurred in the seismic history of Iran have been presented

**Buildings**

**Location Mb Ms Mw**

Epicentre locations, loss of life and properties, and magnitudes for some of the most

destructive earthquakes that occurred in the seismic history of Iran have been presented

**Loss of Life Damaged** 

**Magnitude**

**Magnitude**

<sup>2</sup> 1990/06/20 36.96 49.41 6.4 7.7 - 40,000–50,000 Nearly all

<sup>2</sup> 1990/06/20 36.96 49.41 6.4 7.7 - 40,000–50,000 Nearly all

*Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 19 of 40

**Figure 11.** The blueprint of the sample RC building. **Figure 11.** The blueprint of the sample RC building. for four-storey, six-storey, and eight-storey in Figures 12 and 13, respectively.

**Figure 12.** 2D models of the sample RC building for different numbers of stories. **Figure 12.** 2D models of the sample RC building for different numbers of stories.

Epicentre locations, loss of life and properties, and magnitudes for some of the most destructive earthquakes that occurred in the seismic history of Iran have been presented in Table 12. Major sources of these data include USGS, ISMN, IIEES, and IRIS.


**Figure 12.** 2D models of the sample RC building for different numbers of stories. **Table 12.** Data of the selected earthquakes in Iran [130–135].

**Figure 13.** 3D models of the RC building for different numbers of stories. The structural properties of the RC building model are shown in Table 14. Table 13 shows magnitudes, PGA values, and Design Base Accelerations (A(g)) for the calculation of base shear for building structures recommended by the Iranian Code of Practice for Earthquake Resistant Design of Buildings, Standard 2800 [136] for some of the most destructive earthquakes and corresponding seismic zones of Iran.


**Table 13.** Measured magnitude, PGA values, seismic risk zones, and recommended design base acceleration of selected earthquakes for Iran [126,130–135].

The measured PGA values for the first two recorded earthquakes in the considered stations for Iran are considerably lower than the recommended PGA values, and it can be said that the seismic risk for these locations represents a sufficient level. However, the measured PGA values for the last three earthquakes exceeded the recommended PGA values considerably. This clearly reveals Iran's high potential for seismic risk, taking into account the high population of the selected cities.

### **3. RC Building Models for Numerical Analysis**

Earthquake-resistant rules aim to construct buildings that do not experience damage under an expected ground motion level. Structural analyses for a total of five earthquake locations from each country, whose PGA values can be reached. The Seismostruct software was used for numerical analysis [137]. Pushover analyses were used in these analyses for the sample RC building models with four-storey, six-storey, and eight-storey using obtained data. The story plan was taken in the same way in all analyzed buildings and is shown in Figure 11. **Figure 11.** The blueprint of the sample RC building. The storey height in all building models is considered as 3 m. The sample RC building was chosen symmetrically in the X and Y directions, and each of this span is 5 m in each

The infrmFBPH (force-based plastic hinge frame elements) were used for structural elements such as beams and columns while creating all building models. These elements model force-based extensional flexibility and limit plasticity to only a finite length. The ideal number of fibers in the section should be sufficient to model the stress-strain distribution in the section [138]. A total of 100 fiber elements are defined for the selected sections. This value is sufficient for such partitions. Plastic-hinge length (Lp/L) was selected as 16.67%. The boundary conditions of the column were set in accordance with the cantilever boundary conditions, which resulted in a fully fixed column footing and a free top end. The boundary condition of the footings was fixed on the ground. direction was considered. The applied loads and 2D and 3D building models are shown for four-storey, six-storey, and eight-storey in Figures 12 and 13, respectively.

The storey height in all building models is considered as 3 m. The sample RC building was chosen symmetrically in the X and Y directions, and each of this span is 5 m in each direction was considered. The applied loads and 2D and 3D building models are shown for four-storey, six-storey, and eight-storey in Figures 12 and 13, respectively. **Figure 12.** 2D models of the sample RC building for different numbers of stories.

The structural properties of the RC building model are shown in Table 14.

**Figure 13.** 3D models of the RC building for different numbers of stories. **Figure 13.** 3D models of the RC building for different numbers of stories.

The structural properties of the RC building model are shown in Table 14.



In performance-based earthquake engineering, it is critical to estimate target displacements for damage estimation when certain performance limits of structural members are reached. The limit states envisaged in Eurocode 8 (Part 3) [141,142] were taken into account for damage estimation in this study. The target displacements are presented in Figure 14 and the description of these states are shown in Table 15. *Appl. Sci.* **2022**, *12*, x FOR PEER REVIEW 21 of 40

Within the scope of this study, firstly, the natural fundamental periods for the sample

In this part, the period values obtained according to the eigenvalue analyses were compared with the empirical ones predicted for each country. The time required for the undamped system to complete one vibration cycle is called the natural vibration period of the system. The more rigid one of the same mass with a single degree of freedom system will have a shorter natural period and a higher natural frequency. Similarly, of two structures of the same stiffness, the heavier (greater mass) has a lower natural frequency and a longer natural period. This value can be obtained both with approximate formulas and as a result of numerical analysis [143–146]. The empirical relations and explanations stipulated in the corresponding design code for each country are given in Table 16. The comparison of these periods with the ones obtained from structural analyses is shown in Table 16. The empirical formulas used in Table 16 are directly taken from the seismic design

and base shear forces for all the structural models were obtained for each country, respec-

**Table 16.** Comparison of the natural fundamental periods for selected countries.

0.484 0.402

0.484 0.402

0.468 0.402

0.484 0.402

the total height of the building <sup>6</sup> 0.655 0.597

the total building height 6 0.655 0.597

6 0.674 0.597 H is the total building height

the total building height 6 0.655 0.597

**Structural Analyses** 

**Period (s) Description**

0.242 0.402 h—the height of the structure (in meters).

0.645 0.402 H<sup>N</sup> is the building's total height; C<sup>t</sup> is the

b—dimension of the building in parallel to the applied forces (in meters).

C<sup>t</sup> is 0.075 for RC frame structures and H is

C<sup>t</sup> is 0.075 for RC frame structures and H is

C<sup>t</sup> is 0.075 for RC frame structures and H is

correction coefficient. Ct = 0.1 for RC building frames that built only beams and columns

**Period (s)**

6 0.362 0.597 8 0.483 0.796

8 0.813 0.796

8 0.813 0.796

8 0.873 0.796

8 0.813 0.796

6 0.874 0.597 8 1.084 0.796

**Figure 14.** Target displacements on idealized curves/typical pushover. **Figure 14.** Target displacements on idealized curves/typical pushover.

*4.1. Comparison of Natural Fundamental Periods*

**4. Structural Analyses Results**

codes currently used by countries.

**Storey Empirical Formula Empirical** 

*T1 = (0.09.h)/b1/2*

*T* = *C*t·H3/4

*T* = *C*t·H3/4

T = 0.05H0.9

*T* = *C*t·H3/4

TPA = Ct. HN3/4

tively.

**Country Number of** 

4

4

4

4

4

4

Albania

Bosnia and Herzegovina

Croatia

Iran

Serbia

Türkiye


### **Table 15.** Suggested limit states in Eurocode 8 (Part 3) [141,142].

### **4. Structural Analyses Results**

Within the scope of this study, firstly, the natural fundamental periods for the sample building models were obtained from the eigenvalue analysis. The target displacements and base shear forces for all the structural models were obtained for each country, respectively.
