This paper aims to quantify the evolution of damage in masonry walls under induced seismicity. A damage index equation, which is a function of the evolution of shear slippage and opening of the mortar joints, as well as of the drift ratio of masonry walls, was proposed herein. Initially, a dataset of experimental tests from in-plane quasi-static and cyclic tests on masonry walls was considered. The experimentally obtained crack patterns were investigated and their correlation with damage propagation was studied. Using a software based on the Distinct Element Method, a numerical model was developed and validated against full-scale experimental tests obtained from the literature. Wall panels representing common typologies of house façades of unreinforced masonry buildings in Northern Europe i.e. near the Groningen gas field in the Netherlands, were numerically investigated. The accumulated damage within the seismic response of the masonry walls was investigated by means of representative harmonic load excitations and an incremental dynamic analysis based on induced seismicity records from Groningen region. The ability of this index to capture different damage situations is demonstrated. The proposed methodology could also be applied to quantify damage and accumulation in masonry during strong earthquakes and aftershocks too.
This paper aims to quantify the cumulative damage of unreinforced masonry (URM) subjected to induced seismicity. A numerical model based on discrete element method (DEM) has been develop and was able to represented masonry wall panels with and without openings; which are common typologies of domestic houses in the Groningen gas field in the Netherlands. Within DEM, masonry units were represented as a series of discrete blocks bonded together with zero-thickness interfaces, representing mortar, which can open and close according to the stresses applied on them. Initially, the numerical model has been validated against the experimental data reported in the literature. It was assumed that the bricks would exhibit linear stress-strain behaviour and that opening and slip along the mortar joints would be the predominant failure mechanism. Then, accumulated damage within the seismic response of the masonry walls investigated by means of harmonic load excitations representative of the acceleration time histories recorded during induced seismicity events that occurred in Groningen, the Netherlands.
In case of induced seismicity, expectations from a structural monitoring system are different than in the case of natural seismicity. In this paper, monitoring results of a historical building in Groningen (Netherlands) in case of induced seismicity has been presented. Results of the monitoring, particularities of the monitoring in case of induced earthquakes, as well as the usefulness and need of various monitoring systems for similar cases are discussed. Weak soil properties dominate the structural response in the region; thus, the ground water monitoring as well as the interaction of soil movements with the structural response has also been scrutinized. The proposed study could be effectively used to monitor historical structures subjected to induced seismicity and provide useful information to asset owners to classify the structural health condition of structures in their care.It was shown that the in-plane cracks at the building would normally not be expected in this structure during small induced earthquakes happening in Groningen. 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.
Post-earthquake structural damage shows that wall collapse is one of the most common failure mechanisms in unreinforced masonry buildings. It is expected to be a critical issue also in Groningen, located in the northern part of the Netherlands, where human-induced seismicity has become an uprising problem in recent years. The majority of the existing buildings in that area are composed of unreinforced masonry; they were not designed to withstand earthquakes since the area has never been affected by tectonic earthquakes. They are characterised by vulnerable structural elements such as slender walls, large openings and cavity walls. Hence, the assessment of unreinforced masonry buildings in the Groningen province has become of high relevance. The abovementioned issue motivates engineering companies in the region to research seismic assessments of the existing structures. One of the biggest challenges is to be able to monitor structures during events in order to provide a quick post-earthquake assessment hence to obtain progressive damage on structures. The research published in the literature shows that crack detection can be a very powerful tool as an assessment technique. In order to ensure an adequate measurement, state-of-art technologies can be used for crack detection, such as special sensors or deep learning techniques for pixel-level crack segmentation on masonry surfaces. In this project, a new experiment will be run on an in-plane test setup to systematically propagate cracks to be able to detect cracks by new crack detection tools, namely digital crack sensor and vision-based crack detection. The validated product of the experiment will be tested on the monument of Fraeylemaborg.
Induced seismicity problems in the Groningen area caused by gas extraction have been one of the major challenges for the engineering and construction companies in the region and the Netherlands, not only because earthquake phenomena are new to the Dutch engineering community but also because the problem is very much complicated due to its social extents. The companies working in the structural engineering field in the region in different disciplines were forced to adapt very quickly to the earthquake related problems. It was a real size and investment problem for the SMEs, several of which benefited from this rush, however, only under certain conditions can this new skill set be sustainable. The SafeGo project aims mostly to help to facilitate sustainable development and build confidence for the SMEs in the field of earthquake engineering, rather than producing new scientific knowledge for them. SMEs are positioned in the seismic strengthening process either for collection of data or for providing and applying strengthening solutions. The proposed project aims to answer the question on how the “data-collection SMEs” can translate their data into more valuable assets to be used in the earthquake problem because the collection and the use of field data are vital. Furthermore, the question is also how the “strengthening SMEs” can verify and demonstrate their systems on a seismic shake table, because strengthening requires proven methodologies. The project goal is to combine these two central questions into findings on how the experimental and field data can efficiently be translated into suitable procedures, products and computer simulations for seismic assessment and strengthening of buildings, allowing SMEs to provide novel, integrated and accurate solutions not only in the region but also in international markets.
Induced seismicity problems in the Groningen area caused by gas extraction have been one of the major challenges for the engineering and construction companies in the region and the Netherlands, not only because earthquake phenomena are new to the Dutch engineering community but also because the problem is very much complicated due to its social extents.The companies working in the structural engineering field in the region in different disciplines were forced to adapt very quickly to the earthquake related problems. It was a real size and investment problem for the SMEs, several of which benefited from this rush, however, only under certain conditions can this new skill set be sustainable. The SafeGo project aims mostly to help to facilitate sustainable development and build confidence for the SMEs in the field of earthquake engineering, rather than producing new scientific knowledge for them.SMEs are positioned in the seismic strengthening process either for collection of data or for providing and applying strengthening solutions. The proposed project aims to answer the question on how the “data-collection SMEs” can translate their data into more valuable assets to be used in the earthquake problem because the collection and the use of field data are vital. Furthermore, the question is also how the “strengthening SMEs” can verify and demonstrate their systems on a seismic shake table, because strengthening requires proven methodologies. The project goal is to combine these two central questions into findings on how the experimental and field data can efficiently be translated into suitable procedures, products and computer simulations for seismic assessment and strengthening of buildings, allowing SMEs to provide novel, integrated and accurate solutions not only in the region but also in international markets.
