Selection and scaling validation of ground motions according to TBEC-2018 for the seismic assessment of masonry structures

This paper addresses the selection and scaling of earthquake time histories for analysing masonry structures' Out-Of-Plane (OOP) response according to the 2018 Turkish Building Earthquake Code (TBEC-2018) guidelines. Ground motion simulations are proposed for regions with limited seismic networks or lacking information regarding recorded accelerograms for large-magnitude events. Selection and scaling procedures are automatised according to the TBEC-2018 recommendations. The pre-selection is conducted according to specific seismological characteristics, and the optimal scaling factors of individual records are computed using a metaheuristic optimisation based on the Differential Evolution Method (DEM). Two sets of records (11 real and 11 simulated) are generated and used as input to conduct non-linear dynamic analyses. A U-shaped masonry prototype is adopted as a structural benchmark. The structural response is monitored with an emphasis on the OOP response.ERC -European Research Council(LA/P/0112/2020

ANN-based ground motion model for Turkey using stochastic simulation of earthquakes

Turkey is characterized by a high level of seismic activity attributed to its complex tectonic structure. The country has a dense network to record earthquake ground motions; however, to study previous earthquakes and to account for potential future ones, ground motion sim- ulations are required. Ground motion simulation techniques offer an alternative means of generating region-specific time-series data for locations with limited seismic networks or re- gions with seismic data gaps, facilitating the study of potential catastrophic earthquakes. In this research, a local ground motion model (GMM) for Turkey is developed using region- specific simulated records, thus constructing a homogeneous data set. The simulations employ the stochastic finite-fault approach and utilize validated input-model parameters in distinct re- gions, namely Afyon, Erzincan, Duzce, Istanbul and Van. To overcome the limitations of linear regression-based models, artificial neural network is used to establish the form of equations and coefficients. The predictive input parameters encompass fault mechanism (FM), focal depth (FD), moment magnitude (Mw), Joyner and Boore distance (RJB) and average shear wave velocity in the top 30 m (Vs30). The data set comprises 7359 records with Mw ranging between 5.0 and 7.5 and RJB ranging from 0 to 272 km. The results are presented in terms of spectral ordinates within the period range of 0.03–2.0 s, as well as peak ground acceleration and peak ground velocity. The quantification of the GMM uncertainty is achieved through the analysis of residuals, enabling insights into inter- and intra-event uncertainties. The simulation results and the effectiveness of the model are verified by comparing the predicted values of ground motion parameters with the observed values recorded during previous events in the region. The results demonstrate the efficacy of the proposed model in simulating physical phenomena.This work was partly financed by FCT/MCTES through National funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020, and under the Associate Laboratory Advanced Production and Intelligent Systems ARISE under refer ence LA/P/0112/2020. This study has been partly funded by the STAND4HERITAGE project that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 833123), as an advanced grant. This work is financed by national funds through FCT—Foundation for Science and Technology, under grant agreement 2020.08876.BD attributed to the second author. This work is financed by national funds through FCT—Foundation for Science and Technology, under grant agreement UI/BD/153379/2022 attributed to the third author. Shaghayegh Karimzadeh: Conceptualisation, Data curation, Formal analysis, Investigation, Methodology, Resources, Supervision, Validation, Visualisation, Writing—original draft, Writing—review & editing. Amirhossein Mohammadi: Formal analysis, Investigation, Methodology, Resources, Visualisation, Writing—original draft, Writing—review & editing. Sayed Mohammad Sajad Hussaini: Formal anal ysis, Investigation, Writing—original draft, Writing—review & editing. Daniel Caicedo: Formal analysis, Investigation, Writing— original draft, Writing—review & editing. Aysegul Askan: Data curation, Resources, Writing—review & editing. Paulo B. Lourenço: Funding acquisition, Resources, Supervision, Writing—review & editing

Traditional seismic hazard analyses underestimate hazard levels when compared to observations from the 2023 Kahramanmaras earthquakes

A sequence of two major earthquakes, Mw7.8 Pazarcik, and Mw7.5 Elbistan, struck Southeastern Turkey in February 2023. The large magnitudes of the earthquakes and the short time between the two events raised questions about whether this sequence was an extremely rare disaster. Here, based on prior knowledge, we perform seismic hazard assessment for the region to estimate exceedance probabilities of observed magnitudes and ground motions. We discuss that many regional studies indicated the seismic gap in the area but with lower magnitude estimations. Observed ground motions generally agree with empirical models for the Pazarcik event. However, some records with high amplitudes exceed the highest observed amplitudes in an extensive database of shallow crustal earthquakes. We observe a notable trend of residuals for the Elbistan earthquake, leading to underestimation at long periods. We discuss potential advances in science for better characterization of such major earthquakes in the future.ISSN:2662-443

Evaluation of seismic performance measures for MDOF RC structures subjected to simulated and real ground motions

Nonlinear time history analyses of structures require full time series of ground motion records. For regions with sparse seismic networks or potential large earthquakes, ground motion simulation has gained more attention in recent years. Simulated records are required to be generated using regional input dataset and then verified against existing recorded ground motions of past events. To use simulated ground motions in engineering applications, estimation of reliable seismic demand parameters is essential. In this study, the real and simulated records of the 2009 L’Aquila, Italy earthquake with (Mw=6.3) are investigated for their use in engineering practice. In the first step, misfits are evaluated for alternative seismological measures (peak values, duration and frequency as well as energy content of the time histories). Next, varying multi-degree-of-freedom reinforced concrete structures with different number of stories are selected. Numerical models of the structures are performed in the OpenSees platform. Seismic performance measures in terms of inter-story drift ratio for the selected structures are assessed through nonlinear time history analyses for both the real and simulated ground motions. Then, the misfits are estimated in terms of structural demand parameters. Results reveal a good fit between the seismological and engineering demand misfits for the selected ground motion simulation approaches

The sensitivity of global structural parameters for unreinforced masonry buildings subjected to simulated ground motions

This research performs a parametric study based on Equivalent Single Degree of Freedom (ESDOF) models for simplified seismic analysis of unreinforced masonry (URM) structures. This is a necessary action due to the fact that it is not affordable to model and analyze populations of masonry buildings by using detailed continuum-based models during regional seismic damage and loss estimation studies. Hence, this study focuses on the sensitivity of major structural parameters of a selected idealized hysteretic model for URM buildings. The numerical models are subjected to region-specific simulated ground motion time histories generated using validated seismological parameters. The variations in dynamic analysis results are evaluated using statistical tools for major structural and seismological parameters. The results reveal that the strength factor is the most influential structural parameter, whereas magnitude and distance have a significant impact on the response of idealized URM models as seismological parameters. Furthermore, the specific seismic performance exhibiting limited ductility capacity and the narrow margin of safety between the initial state of inelastic behavior and the ultimate (collapse) state for URM buildings is verified by the statistical approaches employed in this study.The last author is financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020 and under the Associate Laboratory Advanced Production and Intelligent Systems ARISE under reference LA/P/0112/2020

Broadband Ground Motion Simulation Within the City of Düzce (Turkey) and Building Response Simulation

In areas with significant seismic activity and insufficient seismic networks, simulated ground motions are required for both seismic hazard and engineering analyses. One important task is evaluating the efficiency of the simulated records in building response estimation. In this study, a hybrid ground motion simulation framework is presented to obtain broadband ground motion time histories of a past major earthquake in Düzce (Turkey). The hybrid ground motion simulation framework presented herein is a combination of a discrete-wavenumber finite element method for simulating low frequencies and a stochastic finite-fault method for the higher frequencies. The proposed technique is first validated by the simulation of the 12 November 1999 Düzce earthquake (Mw = 7.1), which occurred in the North Anatolian Fault Zone, Turkey. Peak simulated ground motions at selected nodes are then compared against ground motion prediction equations derived with global and local data sets. Next, the spatial distribution of simulated peak ground motion intensities are obtained in the region and compared with the observed damage distribution. Results demonstrate that the earthquake is simulated effectively despite the limitations in number of stations and velocity models. Finally, to evaluate the simulated records in building response estimation, nonlinear time history analyses of three reinforced-concrete multi-degree-of-freedom structures are performed with real and simulated records of the 1999 Düzce earthquake in the OpenSees platform. The results reveal that reasonable predictions can be made regarding the dynamic response of structures using the records simulated with the approach presented herein

Seismic Intensity Maps for the Eastern Part of the North Anatolian Fault Zone (Turkey) Based on Recorded and Simulated Ground-Motion Data

Seismic intensity maps are employed globally in the aftermaths of earthquakes for rapid response purposes. These maps involve correlations between intensity and peak ground-motion values. In this study, we focus on eastern sections of the North Anatolian fault zone (NAFZ). The eastern segments of the NAFZ are less investigated and have sparse seismic networks compared with western ones. In particular, we study Erzincan, which is a small city in eastern Turkey, located in the conjunction of three active faults: North Anatolian, North East Anatolian, and Ovacik faults. Erzincan city center is in a pull-apart basin underlain by soft sediments, which significantly amplify the ground motions. Combination of the tectonic and geological settings of the region have led to destructive earthquakes such as the 27 December 1939 (Ms = 8.0) and the 13 March 1992 (Mw = 6.6) events resulting in extensive losses. In this study, we initially perform ground-motion simulations for a set of scenario events as well as the 1992 Erzincan earthquake. We then use local relationships between Modified Mercalli Intensity (MMI) and Peak Ground Acceleration (PGA) as well as Peak Ground Velocity (PGV) to obtain the corresponding MMI values. We present our results in the form of synthetic intensity maps for the 1992 event and the scenario earthquakes

Genetic and phenotypic aspects of infection with Mycobacterium avium ssp. paratuberculosis in German Holstein cows

Mycobacterium avium ssp. paratuberculosis (MAP) is the causative agent for the global occurrence of paratuberculosis (Johne´s disease) in ruminants. Infection with MAP leads to chronic enteritis and is responsible for economic losses, especially for dairy farmers. Because of cost and time efficiency the majority if studies about MAP infection deal with ELISA test results for phenotyping. The present study demonstrates with a dataset of 9 367 fecal culture tested German Holstein cows that the MAP status of the animals, the farm and the lactation number, as well as the interaction between MAP status and farm significantly affect the milk parameters, especially milk yield in kilograms. Also the interaction between lactation number and MAP status is significantly associated with milk kg per day of life. Although, if only a part of the real losses could be considered, the presented results of MAP infection to production traits underline the economic importance to control and eradicate the disease. So far, there is no therapy or vaccination against MAP, but there are suggestions that susceptibility to MAP infection has a genetic component. To verify the hypothesis also for fecal culture tested animals, a large dataset of 11 285 fecal culture tested German Holstein cows were used to estimate heritability for MAP infection. With results between 0.157 and 0.228 it could be demonstrated that the fecal culture test method is more suitable for further studies than ELISA test results. Furthermore, the estimated heritabilities are comparable with other traits which are already included successfully in breeding programs. Because of the genetic background of the disease, numerous studies deal with the analysis of possible candidate genes and their association with MAP infection as well as with genome-wide association (GWA) studies to identify genetic region of interests with MAP infection. Amongst others the nucleotide-binding oligomerization domain containing 2 (NOD2, formerly CARD15) was described as a candidate gene for susceptibility with MAP infection in cattle. In the present study eleven SNPs in the NOD2 gene could be identified, and finally, four SNPs were included in a case-control study using 324 German Holstein cows tested for paratuberculosis using fecal culture and ELISA. Thereby the SNP (GenBank) AY518738S04:g.521G>A in exon 4 showed a significant association (P = 0.0056) between the fecal culture status of the animals and NOD2 allele variants. Furthermore a GWA study was performed with the Illumina Bovine SNP50BeadChip using a case-control assay of 305 cows tested for MAP by fecal culture with an additional four different commercial ELISA-tests. No so far reported association for MAP infection could be confirmed. However, new regions of interest and potential candidate genes could be found. These results lead to the conclussion, that different test methods for MAP infection result in diverse identified gene loci, and therefore in different candidate genes associated with MAP. Furthermore it seems to be once more, that paratuberculosis is not affected by just one gene. The results of the present study are reflecting the problem of the diagnostic of MAP infection. The different test methods and the different grouping of phenotyping leads to different results of the studies. Therefore, further improvement of diagnostic for MAP infection is essential to get a correct and consistent phenotype for further studies concerning MAP infection. Beside which, the phenotyping of the large number of tested animals, at best with whole pedigree information, is a limitation factor for genetic studies. Both improvement of phenotyping and the increasing number of animals are basic factors for further genetic studies of MAP infection.Mycobacterium avium ssp. paratuberculosis (MAP) ist die Ursache für die bei Wiederkäuern ubiquitär vorkommende Krankheit Paratuberkulose. Eine Infektion mit MAP führt bei den betroffenen Tieren zu einer chronischen Darmentzündung und hat damit eine entsprechende Leistungsminderung zur Folge. Mit MAP infizierte Tiere können daher die Ursache für geringere Leistungen in Milch produzierenden Betrieben und somit ursächlich für erhebliche ökonomische Verluste sein. Im Rahmen der vorliegenden Arbeit konnte auf Daten von 9.367 Deutsche Holstein-Kühen zurückgegriffen werden. Diese Kühe wurden im Gegensatz zu zahlreichen anderen Studien mittels Kotkulturen auf MAP-Infektionen getestet. Diese Methode ist zwar nicht so zeit- und kosteneffizient wie die weithin genutzten ELISA-Tests, liefert aber verlässlichere Ergebnisse. Die Analysen dieser Daten innerhalb der vorliegenden Arbeit zeigten, dass sowohl der MAP-Status, der Betrieb und die Laktationsnummer als auch die Interaktion zwischen dem MAP-Status und dem Betrieb einen signifikanten Effekt auf verschiedene Milchparameter (insbesondere die Milchmenge) haben. Darüber hinaus ist die Interaktion zwischen MAP-Status und Laktationsnummer signifikant mit dem Merkmal „Milchkilogramm pro Lebenstag“ assoziiert. Die nachgewiesenen Assoziationen des MAP-Status mit der Milchleistung von Deutsche Holstein-Kühen und die damit verbundenen wirtschaftlichen Einbußen unterstreichen die Notwendigkeit, Paratuberkulose zu kontrollieren und zu bekämpfen. Bisher gibt es keine erfolgreiche Therapie oder zugelassene Impfung gegen Paratuberkulose, jedoch wird eine genetische Komponente im Zusammenhang mit MAP vermutet, so dass längerfristig eine Zucht gegen Paratuberkulose möglich sein könnte. Um diese genetischen Einflüsse zu überprüfen, wurde innerhalb der vorliegenden Arbeit ein Datensatz von 11.285 mittels Kotkultur getesteten Tieren verwendet, um die Erblichkeit für MAP-Infektionen zu ermitteln. Mit Heritabilitäten zwischen 0,157 und 0,228, die im gleichen Bereich liegen wie Erblichkeiten anderer Merkmale, die bereits erfolgreich in Zuchtprogramme eingebunden sind, konnte gezeigt werden, dass die Kotkultur im Vergleich zu ELISA eine geeignetere Methode für zukünftige Studien ist. Aufgrund des genetischen Hintergrunds der Krankheit wurden bereits zahlreiche Kandidatengenanalysen und genomweite Assoziationsstudien (GWA) zur Identifizierung interessanter Genregionen im Zusammenhang mit MAP Infektionen durchgeführt. Darunter wurde das nucleotide-binding oligomerization domain containing 2 (NOD2, früher CARD15) als Kandidatengen im Zusammenhang mit Paratuberkulose bei Rindern beschrieben. In der vorliegenden Studie wurden elf SNPs im NOD2-Gen identifiziert, von denen letztendlich vier in eine Fall-Kontroll-Studie mit 324 Deutsche Holstein-Kühen verwendet wurden. Die Tiere wurden mittels Kotkultur und ELISA auf MAP getestet. Dabei zeigte der SNP (GenBank) AY518738S04:g.521G>A in Exon 4 des NOD2 eine signifikante Assoziation (P = 0,0056) zum Kotkulturstatus der Tiere. Des Weiteren wurde eine GWA-Studie mithilfe des Illumina Bovine SNP50 BeadChip durchgeführt. Hierfür wurde eine Fall-Kontroll-Studie mit 305 Kühen durchgeführt, welche zum einen mit Kotkultur und zum anderen mit vier kommerziellen ELISA-Tests auf MAP getestet wurden. Zwar konnte keine der bisher beschriebenen Assoziationen bestätigt werden, jedoch konnten weitere interessante Genregionen und potentielle Kandidatengene identifiziert werden. Zum einen konnte dadurch gezeigt werden, dass durch die unterschiedlichen Testmethoden für MAP verschiedene Genregionen identifiziert werden und damit unterschiedliche potentielle Kandidatengene für Paratuberkulose, und zum anderen, dass mehrere Genregionen beim Krankheitsgeschehen der Paratuberkulose beteiligt sind. Die Ergebnisse der vorliegenden Studie reflektieren die Problematik der Diagnose für MAP-Infektionen: Die unterschiedlichen Testmethoden und die sich daraus ergebende unterschiedliche Gruppierung des Phänotyps führen zu unterschiedlichen Ergebnissen innerhalb der Studien. Neben der Phänotypisierung großer Tierzahlen, möglichst mit vollständigen Pedigree-Informationen, sind daher Verbesserungen der Diagnostik für MAP vonnöten, um einheitliche und wiederholbare Ergebnisse zur Phänotypisierung für weitere Studien zu erhalten. Beides - sowohl die Verbesserung der Phänotypisierung wie auch eine erhöhte Anzahl untersuchter Tiere - ist eine Grundvoraussetzung für informative genetische Untersuchungen im Zusammenhang mit MAP-Infektionen

The site effects in Izmir Bay of October 30 2020, M7.0 Samos Earthquake

Due to the unique soil and morphological conditions prevailing in Izmir Bay basin, structural damage has been governed by site effects. Consistently, during October 30, 2020 M7.0 Samos Earthquake, which took place offshore of Samos Island, structural damage and life losses were observed to be concentrated in Bayrakli region of Izmir Bay, despite the fact that the fault rupture was at a distance of 65-75 km from the city of Izmir. Additionally, strong ground motions recorded in Izmir Bay showed unique site amplifications that were observed surprisingly at both rock and soil sites. Soil amplifications and duration elongations were mostly due to site effects governed by the response of very deep alluvial deposits of low plasticity. Similarly, due to very extensive faulting-induced fracturing and unusually stratified nature of rock sub-layers, unexpected long period amplifications were also observed at rock sites. These earthquake and site resonance effects were more pronounced in the period range of 0.5-1.5 s. When they were superposed with relatively coinciding natural period of 7-9 story residential buildings of Izmir City, it was concluded that the triple resonance effects among incoming rock ground motions, soil deposits, and the damaged buildings, amplified and prolonged the overall system response. Within the confines of this manuscript, the governing role of site effects leading to increased seismic demand was assessed, through a series of 1D equivalent linear, total stress-based site response assessments, the results of which clearly highlighted the variation of seismic demand in Izmir Bay.The earthquake reconnaissance studies were supported by Middle East Technical University. The authors would also like to thank the undergraduate students, who collaborated on field campaigns and data processing.Middle East Technical Universit