This paper presents a seismic vulnerability analysis of historic brick masonry buildings in Vienna, Austria from the period of the Austro-Hungarian monarchy (1840–1918). The vulnerability study is ...based on comprehensive data from the devastating earthquake damage to the masonry buildings in Zagreb, Croatia on March 22, 2020, which are from the Austro-Hungarian monarchy and comparable to Viennese buildings from that period, as well as on comprehensive numerical structural analyses calibrated on in situ test series. The statistical analysis of the earthquake damage to the Zagreb masonry stock and the comprehensive numerical simulations, allowed profound conclusions about the proportional damage distribution over individual structural areas of the masonry buildings, considering construction-specific characteristics such as the building height, the structural regularity/irregularity or the construction type under the ground level. This study enhances the still limited knowledge about the vulnerability of the historic brick masonry buildings from the period of the Austro-Hungarian monarchy and allows extensive conclusions about the seismic vulnerability of these buildings.
A severe earthquake hit Zagreb on the March 22, 2020 (magnitude ML = 5.5, with an epicenter 7 km north of the city center). During the COVID-19 lockdown, the event occurred and caused significant ...damage to the built environment and enormous disruption in everyday life. Brief facts about the Zagreb earthquake, the typology of buildings in the city, and the data collection after the quake itself are described. The paper focuses on post-earthquake assessment, damage classification, and failure patterns of residential buildings in Zagreb's old historical town, where masonry structures prevail. The earthquake critically damaged buildings that are important architectural achievements and ruptured Zagreb's historically recognizable city center. Furthermore, the data collected in the rapid post-earthquake assessment were analyzed and discussed. Graphical representations of damages are detailed and accompanied by photographs. This earthquake exposed Croatian building stock's vulnerability that should be mitigated as efficiently as possible in the coming years.
This paper highlights the principal features of the M
w
5.4 Zagreb earthquake. Located within the city limits at a depth of 10 km, the earthquake generated a peak ground acceleration of more than ...0.2 g and a maximum spectral acceleration of about 0.6 g at 0.1 s in the historic downtown area. The situation was particularly challenging since the event occurred amid a partial Covid-19 lockdown at temperatures close to 0 °C, emphasizing the extensive and complex vulnerability of the local communities and individuals. 27 people were reported severely injured, one of which later died. The surprisingly high economic costs, needed to achieve a full reconstruction of damaged buildings and infrastructure in the affected area, are currently evaluated at more than 10B euros. Description of the organization of the emergency response in the first days and the observed damage to buildings is given with typical examples. The focus is on the performance of older masonry residential and cultural heritage buildings in the historic downtown, their inspection and evaluation of damage to structural and non-structural components. This information provides the basis for understanding of the negative impacts and clarifies the overall context identifying the enablers and barriers to the still ongoing recovery process. It also helps to increase the awareness of the seismic vulnerability of European cities with similar construction practices.
Risk governance is mostly viewed through the lens of disaster or emergency management departments, agencies, or organizations. Visible in times of crises, risk governance is rarely seen as part of ...everyday public or private functions such as planning, social welfare, investments, or fiscal responsibilities. This paper emphasizes the importance of disaster risk governance in disaster risk management activities on the example of the post-disaster recovery of Croatia after a series of strong seismic events in mainland Croatia. The analysis is made based on a thorough review of national documents of Croatia and other selected countries overlapped with the national journals reporting on the situation from the affected areas. In accordance with the authors’ opinion, the necessary elements of disaster risk governance are clearly stated through the four Sendai framework priorities, and this statement is supported by the facts from the case study. Without either the political will or the enabling surrounding the disaster, risk management is next to impossible. The Croatian case study emphasizes the importance of disaster risk governance, showcasing the adaptation process for the post-disaster recovery process to start.
This special issue of Buildings Journal brings together outstanding papers presented at the 1st Croatian Conference on Earthquake Engineering 1CroCEE, held at the Faculty of Civil Engineering, ...University of Zagreb, Croatia, 22–24 March 2021 ...
On December 29, 2020, nine months after the March
Mw
5.4 Zagreb earthquake and amidst the COVID-19 lockdown, a devastating
Mw
6.4 earthquake struck near the town of Petrinja, about 50 km SE from the ...country’s capital Zagreb. It was preceded by the
Mw
4.9 foreshock from the day before. The main shock claimed 7 fatalities and caused widespread damage. Historical centers of nearby cities with invaluable heritage buildings were significantly affected as were the many residential buildings, built mainly of unreinforced masonry. Damage was observed as far as 60 km from the epicenter. This paper summarizes the seismological aspects of the
Mw
6.4 Petrinja earthquake, the emergency response and the main impacts to people and buildings. The description and findings are based on the field observations and a series of post-earthquake activities led by the team of the Faculty of Civil Engineering, University of Zagreb. Typical damage to buildings and usability data are presented with examples based on 50,000 inspection results. By far the most affected were the unreinforced masonry buildings, followed by confined masonry, whereas reinforced concrete buildings were the least affected. The total direct and indirect losses are estimated to 4.8 billion EUR. The provided information represents a useful basis and impetus for improving emergency action and long-term disaster reduction plans in other regions with similar building exposure and seismotectonic settings.
The city of Zagreb, the national capital and economic hub of Croatia, is situated in a seismically active region and hosts a significant array of historical buildings, from the medieval to ...Austro-Hungarian periods. These buildings possess varying but generally high degrees of vulnerability to seismic loading. This was highlighted in the Zagreb earthquake of 22 March 2020, emphasizing the need for seismic retrofitting in order to preserve this architectural heritage. In this paper, the seismic capacity of one such unreinforced masonry building is considered through a number of analysis methods, including response spectrum, pushover, and out-of-plane wall failure analyses. Given the advantages and disadvantages of the individual methods, their applicability and value in a seismic analysis is considered. Ambient vibration measurements before and after the Zagreb 2020 earthquake, used for model calibration, are also presented. Conclusions are drawn from each individual analysis and later compared. In conclusion, no single analysis method considers all relevant failure modes, and a combination of nonlinear static or dynamic analysis and out-of-plane analysis is recommended. Due to the large volume of the material, it is published in two parts, with ground motion record selection, dynamic analysis, and a comparison of the results published in part two.
As part of the development of a European Seismic Risk Model 2020 (ESRM20), the spatial and temporal evolution of seismic design across Europe has been studied in order to better classify reinforced ...concrete buildings (which represent more than 30% of the approximately 145 million residential, commercial and industrial buildings in Europe) and map them to vulnerability models based on simulated seismic design. This paper summarises the model that has been developed to assign the years when different seismic design levels (low code, moderate code and high code) were introduced in a number of European countries and the associated lateral forces that were specified spatially within each country for the low and moderate codes for typical reinforced concrete mid-rise buildings. This process has led to an improved understanding of how design regulations evolved across Europe and how this has impacted the vulnerability of the European residential building stock. The model estimates that ~ 60% of the reinforced concrete buildings in Europe have been seismically designed, and of those buildings ~ 60% have been designed to low code, ~ 25% to moderate code and 15% to high code. This seismic design model aims at being a dynamic source of information that will be continuously updated with additional feedback from local experts and datasets. To this end, all of the data has been made openly available as shapefiles on a GitLab repository.
At the beginning of 2020, the area of Zagreb was hit by an earthquake of magnitude Mw5.4, where a significant number of buildings in the historic core of the city was damaged. Not long after that, at ...the end of the same year, a strong earthquake of magnitude Mw6.4 hit the area of Sisak-Moslavina County, which is about 50 km away from Zagreb. It was a significantly stronger earthquake that had enormous consequences for that region and much wider. Earthquakes struck during the Covid-19 pandemic and shocked the whole country. This multi-hazard scenario surprised everybody, as the country was not ready. Regardless, in the first hours after the earthquake, a system of damage assessment was established based on experts from the academic and professional community, which would later grow into Croatian Centre for Earthquake Engineering. From a technical point of view, this paper refers to the response of the system to the earthquakes, post-earthquake activities of Croatian Centre for Earthquake Engineering and with challenges and problems in organization of damage inspection of the buildings. The paper briefly describes the earthquake scenarios in Zagreb and Petrinja. The typical vulnerable buildings typology and damage are described, trying to find explanations and guidelines for the future earthquakes. The focus is on the unreinforced masonry buildings and out of plane failures which prevail in damage, especially in historical buildings of cultural heritage. Such significant damage to buildings of historical importance makes us think about the way of their future protection and restoration that will follow. Also, some positive experiences in construction practice are highlighted. At the end, a perspective is given for the further development and improvement of the post-earthquake response system, and the need for cooperation of several professions is highlighted in order to obtain a synchronized response to earthquakes. In addition, international cooperation in the organization of the system before and after the earthquake is of key importance.
Buildings of strategic importance should be able to resist seismic forces in accordance with potential earthquakes that may occur at the location and remain fully operational afterwards. However, ...many of them were constructed before the modern principles of seismic design were known (especially regarding detailing and ductility), and therefore may be considered substandard. The first step in mitigating the seismic risk of such structures is to assess their seismic performance and, in particular, to identify their structural deficiencies. This study presents a comprehensive methodology for the seismic performance assessment of individual buildings, applied to an existing reinforced concrete (RC) hospital. This building is of an irregular layout, constructed as a structural wall system, and it is located in the seismically active region of Croatia. It includes the assessment of seismic hazards on the location, ambient noise measurements, experimental determination of structural modal parameters, creation of a detailed numerical model calibrated with experimental data, and a seismic performance assessment using various analysis methods. As a result, the building collapse mechanisms were determined and critical structural elements identified, which is the basis for future actions directed to the reduction of its risk (e.g., applications of specific measures for a target retrofit, proposal of evacuation routes and safe places inside the building, etc.).
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