Groningen gas field is the largest on-land gas resource in the world and is beingexploited since 1963. There are damaging earthquakes, the largest of which was 3.6 magnitude. The recursive induced earthquakes are often blamed for triggering the structural damages in thousands of houses in the area. A damage claim procedure takes place after each significantly felt earthquake. The liability of the exploiting company is related to the damages and the engineering firms and experts are asked to correlate the claimed damages with a past earthquake. Structures in the region present high vulnerabilities to the lateral forces, soilproperties are quite unfavourable for seismic resistance, and structural damages are present even without earthquakes. This situation creates a dispute area where one can claim that most structures in the region were already damaged because of the fact that the soil is soft, the ground water table oscillates, and structures are vulnerable to external conditions anyhow and deteriorate in time, which can be the main cause of such structural damages. This ambiguity of damage vs earthquake correlation is one of the main sources of the public unrest in the area up until today. This study presents the perspective of people in the region in terms of liveability and the social acceptance of earthquakes in their lives. An attempt has been made to translate these social effects and expectations into structural performance metrics for ordinary houses in the region. A new seismic design and assessment approach, called Comfort Level Earthquake (CLE) has been proposed.
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This paper aims to analyze the behavior of experimentally tested unreinforced masonry walls subjected to in-plane loading. Monotonic load analyses are conducted using FEM and AEM modeling approaches. The models presented here are based on the assumption of both unit and mortar joints modeled as solid elements, which behave nonlinearly. Therefore, the damages occur along the mortar and brick in the analyses. The FEM analysis is carried out by using LS-DYNA, and the AEM analysis is carried out by using ELS (Extreme Loading for Structures). Experimental studies of a masonry wall in-plane loading conditions are used for verification against numerical models. Analysis of the tests performed on masonry shear walls by Raijmakers and Vermeltfoort [1] within the CUR [2] project is carried out. The presented analyses methods can be applied to other unit and mortar compositions. Computational results from this study provide a monotonic load-deformation curve, which then is compared to the envelope of the horizontal load-deformation curves that are experimentally obtained. The agreement of each method with the experimental results, in terms of strength, stiffness and ductility, as well as the predicted damage mechanisms, are discussed.
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''New technologies are advancing at an unprecedentedly accelerating pace over the years. The distance humanity has covered in 2200 years, from the Antikythera mechanism of ancient Greek world, the oldest known analogue computer, to the 4-bit first microprocessor in 1971, is not even comparable to the advancement of technology in the last 50 years. This dazzling journey of technological development has impacted all aspects of modern life, including industry.Earthquake engineering is one of the disciplines that has embraced new technologies. Earthquake engineers, accustomed to dealing with highly nonlinear and dynamic problems that require complex mathematical and often iterative approaches, are called nowadays to summon dexterity on advanced coding, and masteries on statistics and handling of large amount of data. Artificial Intelligence, Sensing Technologies of all sorts, and Big Data Analytics emerge as essential tools for reducing uncertainty, facilitating engineering process and enhancing knowledge. This Special Issue is a manifestation of the fact that the new technologies can be useful for the most challenging problems of earthquake engineering, opening new prospects in the field.''
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''Ever increasing population in seismically active urban areas, aging building stock, and expansion of urbanization to previously agricultural lands with soft soil deposits render the protection of human lives against earthquake disasters extremely more difficult by the time. Although much effort is put in further improving the current seismic design practices for new buildings, recent earthquakes show us, again and again, that life losses occur in older and much more vulnerable structures. Finding those substandard, collapse-vulnerable buildings before a destructive earthquake is like finding a needle in a haystack. It is clear that the problem in hand cannot be addressed with the existing, and mostly old-fashioned tools anymore.This manuscript focuses on how the emerging technologies, such as Artificial Intelligence, image processing, and data sciences in general, can be implemented as useful tools for conducting an urban scale seismic risk assessment while estimating the risk for every individual building. A review of the available technologies is given for the exposure component. Furthermore, a novel method of estimating the vulnerability of individual buildings, based on autoregressive machine learning algorithms, is presented. The manuscript discusses that the technological advancement is mature enough to radically alter how the earthquake risk is estimated.''
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''Heritage buildings are often subjected to loading conditions that they were not exposed to in their earlier life span. Induced earthquakes in non-seismic regions caused by energy exploitation activities, or strains in the ground that are caused by the climate changes, are new phenomena that alter the usual loading situations for historical buildings.In this paper, monitoring results of a historical building in Groningen (Netherlands) in case of induced seismicity as well as climate change effects has been presented. Long-term monitoring results, detected cracks and relevance of the monitoring data are discussed. In the special case of Groningen, weak and agricultural soil properties dominate the structural response in the region. The gas extraction activities caused a soil subsidence in the giant Groningen Gas Field, resulting decameters of settlement in the entire area, thus an increase of the ground water level in respect to the ground surface. This is the reason why the heritage structures in the region are more vulnerable to soil-water-foundation interactions caused by climate change as compared to the time these heritage structures were constructed. The ground water monitoring as well as the interaction of soil movements with the structural response become important. The study presented here suggests ways on how to effectively monitor historical structures subjected to induced seismicity as well as harsh climate effects at the same time.It was shown here that the newly developed cracks on the structure were detected in a very narrow time window, coinciding with extreme drought and a small induced earthquake at the same time. One explanation provided here is that the soil parameters, such as shrinking of water-sensitive soil layers, in combination with small earthquakes, may cause settlements. The soil effects may superimpose with the earthquake effects eventually causing small cracks and damage. The effects of the climate change on historical buildings is rather serious, and structures on similar soil conditions around the world would need detailed monitoring of not only the structure itself but also the soil-foundation and ground water conditions.''
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Two strong earthquakes hit Thessaly region on March 3rd, 2021 (Mw = 6.3) and on March 4th, 2021 (Mw = 6.1). The epicentres of the earthquakes were located at approximately 23 and 29 km respectively NW of Larissa, one of the most populous cities in Greece. Several aftershocks followed thereafter. Although no injuries were recorded, several structures suffered significant damage close to the epicentre, while some others collapsed. Approximately 300 residents of the village of Damasi were transferred to temporary settlements and tents. The event occurred during the COVID19 lockdown and created significant stress and disruption to residents. This paper focuses on the earthquake swarm itself as well as the damages observed in residential buildings, schools, and churches in the earthquake-stricken region. The earthquakes mainly impacted low-rise domestic masonry buildings, while the more modern reinforced concrete structures built following the recent seismic regulations were almost unaffected. The typology of buildings in the region, together with photographs demonstrating the extent of damage are presented herein. Despite the rather satisfactory performance of modern buildings in recent earthquakes in Greece, the preliminary investigations from the Thessaly Earthquakes showed that there is still a significant level of vulnerability in existing masonry building stock constructed using traditional methods and materials. This issue could re-emerge in future earthquakes striking other rural areas of Greece, something that needs to be addressed systematically in the future.
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''On February 6th, 2023, two severe earthquakes struck southeastern Türkiye near the Syrian border. The first earthquake, Mw7.8, occurred at 04:17 local time in the East Anatolian Fault Zone near the city of Gaziantep. The second earthquake, Mw7.5, occurred approximately 9 h later at 13:24 local time near Elbistan County, in Kahramanmaraş province. These seismic events ruptured multiple segments of the East Anatolian Fault Zone (EAFZ), with rupture lengths exceeding 300 km, and deformation exceeding 5 m on both sides of the faults. In this study, we aim to analyze characteristics of the strong ground motion induced by the mainshocks, focusing on ground motion intensity measures such as the peak ground acceleration (PGA), the peak ground velocity (PGV), and the pseudo-acceleration response spectra (PSA). The first earthquake produced extremely high PGA values in both horizontal (> 2 g) and vertical (> 1 g) components. At near field distances, large PGVs are measured (> 180 cm/s) with more than 30 impulsive motions which may indicate source-related effects. Large spectral demands are also recorded for both earthquakes, partially underestimated by Ground Motion Models (GMMs), especially in the near-field. Specifically, we compare the PSA for horizontal directions with the design spectra provided by both the new and previous Turkish building codes. We also present building and ground damage observations that provide insights into the observed ground motions in the heavily damaged areas.''
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''This research aims to address a post-earthquake urgent strengthening measure to enhance the residual seismic capacity of earthquake-damaged reinforced concrete wall structures with coupling beams. The study consists of a series of tests on half-scale prototype coupling beams with various detailing options, including confined with reduced confinement, partially confined, and unconfined bundles, under cyclic loading conditions. The methodology employed involved subjecting the specimens to displacement-controlled reversal tests, and carefully monitoring their response using strain gauges and potentiometers. The main results obtained reveal that GFRP wrapping significantly enhances the seismic performance of earthquake-damaged coupling beams, even in cases where specimens experienced strength loss and main reinforcement rupture. The strengthened beams exhibit commendable ductility, maintaining high levels of deformation capacity, and satisfying the requirements of relevant seismic design codes. The significance of the study lies in providing valuable insights into the behavior and performance of damaged coupling beams and assessing the effectiveness of GFRP wrapping as a rapid and practical post-earthquake strengthening technique. The findings can be particularly useful for developing urgent post-earthquake strengthening strategies for high-rise buildings with structural walls. The method may be particularly useful for mitigating potential further damage in aftershocks and eventual collapse. In conclusion, this study represents a significant advancement in understanding the post-earthquake behaviors of coupling beams and provides valuable guidance for practitioners in making informed decisions regarding post-earthquake strengthening projects. The findings contribute to the overall safety and resilience of structures in earthquake-prone regions.''
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