Evaluation of simulated ground motions for seismic assessment of a steel frame structure using multi-criteria selection and scaling approach based on evolutionary algorithms

Recently, simulated ground motion records have supplanted real records as a key alternative. Unlike real motions, simulations encompass various intensities, source-to-site distances, and site characteristics. However, determining whether they are appropriate for engineering applications takes time and effort. Another challenging topic is the proper selection and scaling of ground motion records to assess the seismic performance of structures. This study aims to investigate the difference between the real and simulated motions selected according to the code design spectra. Simulations are accomplished through the stochastic finite-fault method, considering the uncertainty of the rupture of the North Tabriz Fault Plane in northwestern Iran, one of the hazardous regions with a seismic gap. A real ground motion dataset with consistent seismological characteristics is compiled. The records are selected and scaled through a multicriteria approach using the evolutionary algorithm. In this approach, the mean spectrum and the (period-depended) dispersion fit best with the target spectrum and its dispersion. Variations in real and simulated record sets are assessed using several ground motion intensity metrics. This study also investigates the effectiveness of the simulated motions for seismic demand evaluation of a three-story steel moment frame.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 reference LA/P/0112/2020. Also, it was 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

Utilising artificial neural networks for assessing seismic demands of buckling restrained braces due to pulse-like motions

Buckling restrained brace frames (BRBFs) exhibit exceptional lateral stiffness, load-bearing capacity, and energy dissipation properties, rendering them a highly promising choice for regions susceptible to seismic activity. The precise and expeditious prediction of seismic demands on BRBFs is a crucial and challenging task. In this paper, the potential of artificial neural networks (ANNs) to predict the seismic demands of BRBFs is explored. The study presents the characteristics and modelling of prototype BRBFs with different numbers of stories and material properties, utilising the OpenSees software (Version 2.5.0) for numerical simulations. The seismic performance of the BRBFs is evaluated using 91 near-fault pulse-like ground motions, and the maximum inter-storey drift ratio (MIDR) and global drift ratio (GDR) are recorded as a measure of seismic demand. ANNs are then trained to predict the MIDR and GDR of the selected prototypes. The model’s performance is assessed by analysing the residuals and error metrics and then comparing the trend of the results with the real dataset. Feature selection is utilised to decrease the complexity of the problem, with spectral acceleration at the fundamental period (T) of the structure (Sa), peak ground acceleration (PGA), peak ground velocity (PGV), and T being the primary factors impacting seismic demand estimation. The findings demonstrate the effectiveness of the proposed ANN approach in accurately predicting the seismic demands of BRBFs.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 reference LA/P/0112/2020

Ataxia Oculomotor Apraxia Type 1 in the Siblings of a Family: A Novel Mutation

How to Cite This Article: Karimzadeh P, khayatzadeh kakhki S,Esmail Nejad Sh. S., Houshmand M,Ghofrani M. Ataxia oculomotor apraxia 1 in two siblings of a family:a novel mutation. Iran J Child Neurol.Winter 2017; 11(1):78-81.AbstractAlthough AOA1 (ataxia oculomotor apraxia1) is one of the most common causes of autosomal recessive cerebellar ataxias in Japanese population, it is reported from all over the world. The clinical manifestations are similar to ataxia telangiectasia in which non-neurological manifestations are absent and include almost 10% of autosomal recessive cerebellar ataxias. Dysarthria and gait disorder are the most two common and typical manifestations. Oculomotor apraxia is usually seen a few years after the manifestations start. APTX gene on 9p13.3 chromosome is expressed in the cells of all human body tissues and different mutations had been discovered. Here we report two siblings (a girl and a boy) of consanguineous parents visited at Mofid Pediatrics Hospital in 2015, with history of gait ataxia, titubation, tremor, and oculomotor apraxia around five yr old and after that. The brother showed symptoms of disease earlier and more severe than his sister did. After ruling out the common etiologies of progressive ataxia, we did genetic study for AOA1 that showed a homozygous frameshift mutation as c.418_418 del was found. This mutation was not reported before so this was a new mutation in APTX gene.References1. Jafar-Nejad P, Maririch SM, Zoghbi HM .The cerebellum and hereditary ataxias. In: Swaiman KF, Ashwal S, Ferriero DM, Schor NF. Swaiman’s Pediatric Neurology Principles, and Practice.15th ed. 2012.P.939-952.2. Pina-Garza JE. Ataxias. In:Pina-Garza JE. Fenichel Clinical pediatric neurology. 7th ed. 2013.P.215-231.3. Le Ber I, Moreira MC, Rivaud-Péchoux S, Chamayou C, Ochsner F, Kuntzer T, et al. Cerebellar ataxia with oculomotor apraxia type 1: clinical and genetic studies. Brain 2003; 126:2761-72.4. Coutinho P, Barbot C. Ataxia with Oculomotor Apraxia Type 1. 2002 Jun 11 [Updated 2015 Mar 19]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. Available from: https:// www.ncbi.nlm.nih.gov/books/NBK1456/5. Shahwan A, Byrd PJ, Taylor AM, Nestor T, Ryan S, King MD. Atypical presentation of ataxia-oculomotor apraxia type 1. Dev Med Child Neurol 2006 Jun; 48(6):529-32. 6. Shimazaki H, Takiyama Y, Sakoe K, Ikeguchi K, Niijima K, et al. Early-onset ataxia with ocular motor apraxia and hypoalbuminemia: the aprataxin gene mutations. Neurology 2002; 59(4):590-5.7. Yokoseki A, Ishihara T, Koyama A, Shiga A, Yamada M, Suzuki C,and et al. Genotype-phenotype correlations in early onset ataxia with ocular motor apraxia and hypoalbuminaemia. Brain 2011; 134:1387-99.8. Moreira MC, Barbot C, Tachi N, Kozuka N, Mendonça P, Barros J, Coutinho P, Sequeiros J, Koenig M. Homozygosity mapping of Portuguese and Japanese forms of ataxia-oculomotor apraxia to 9p13, and evidence for genetic heterogeneity. Am J Hum Genet 2001; 68(2):501-8

Seismic assessment of typological masonry buildings using simulated ground motion records: A case study for Azores, Portugal

Earthquakes are the major causes of damage and loss to the built environment, including cultural heritages, monumental buildings, and historical centres. Many regions with predominant active tectonic plates and high seismicity lack recorded ground motion datasets regarding large-magnitude events or near-field records. Among them, the Azores islands in Portugal are the regions with high seismicity. The traditional buildings from the Azores are mainly constituted of rubble stone masonry, which represents one of the weakest materials once subjected to seismic loads. The seismic performance of buildings has recently increased, given the public awareness related to damage prediction and risk mitigation during earthquakes. This study uses the stochastic finite-fault ground motion simulation approach to simulate region-specific scenario earthquakes in the Azores Plateau at bedrock. Simulations are accomplished by considering the stochastic behaviour of input-model parameters in terms of source and path attenuation effects. As a result, the dataset includes a wide range of moment magnitude and source-to-site distance due to the rupture of active faults in the Azores Plateau. Structural models are simulated using an equivalent frame model. Subsequently, analytical fragility curves are derived for these structures using the generated ground motion datasets. Results reveal that the studied structures are vulnerable to seismic actions.ERC -European Research Council(LA/P/0112/2020

Macro vs Micro Limit Analysis models for the seismic assessment of in-plane masonry walls made with quasi-periodic bond types

Masonry bond patterns can considerably affect the seismic performance of in-plane walls. Although several numerical and experimental works addressed this topic, few attempts tried to investigate such an issue using analytical formulations. This paper aims to compare macro and micro limit analysis models investigating masonry walls arranged with different bond types, namely Running, Flemish and English. A dataset involving 81 combinations is generated by varying geometrical (panel aspect ratio, block aspect ratio, bond type) and mechanical (friction coefficient) parameters. Finally, one-way and two-way factor interactions are used to evaluate how each parameter affects the horizontal load multiplier and assess matching among the two adopted formulations.This work was partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit ISISE under reference UIDB/04029/2020. 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 programme (Grant agreement No. 833123), as an Advanced Gran

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

Stochastic simulation of earthquake ground motions for the seismic assessment of monumental masonry structures: source-based vs site-based approaches

Earthquakes are among the most destructive natural disasters and have resulted in a massive number of fatalities and economic losses all over the world. Simulated ground motion records are valuable, particularly for regions lacking seismic stations or with a limited history of large-magnitude earthquakes. Notably, a significant percentage of monumental masonry buildings are located in regions with limited access to real records; hence, simulated records play a paramount role in their seismic protection. However, few studies have investigated the structural response of heritage buildings via response history analyses to assess the performance of simulated earthquakes against real ones. To accomplish this, this study simulates the recorded time-series of the 9th of July 1998 Faial earthquake in the Azores (Mw = 6.2) at four available stations, using two different simulation approaches, that is, a source-based stochastic finite-fault method and a site-based broadband stochastic method. First, two masonry facades with sidewalls characterized by different slenderness levels are adopted to conduct this research. Moreover, the proposed approach is also applied to an existing monumental structure, that is, São Francisco Church, located at Horta, which was affected by damage during the Faial earthquake. Results demonstrate that both simulation approaches provide similar results in terms of structural response prediction. The proposed framework also demonstrates that a small mismatch in terms of predicted damage patterns can result in a significant relative error in terms of displacement predictions.This work was partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit ISISE under refer ence UIDB/04029/2020, and under the Associate Laboratory Advanced Production and Intelligent Systems ARISE under reference 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 also partly financed by MPP2030-FCT PhD Grants under the R&D Unit Insti-tute for Sustainability and Innovation in Structural Engineering (ISISE), under reference PRT/BD/154348/2022. This work is partly financed by national funds through FCT—Foundation for Science and Technology, under grant agreement UI/BD/153379/2022 attributed to the 4th author. This study has been partly funded by Foundation of Science and Technology, under grant agreement PRT/BD/154348/2022

Seismological and Engineering Demand Misfits for Evaluating Simulated Ground Motion Records

Simulated ground motions have recently gained more attention in seismology and earthquake engineering. Since different characteristics of waveforms are expected to influence alternative structural response parameters, evaluation of simulations, for key components of seismological and engineering points of view is necessary. When seismological aspect is of concern, consideration of a representative set of ground motion parameters is imperative. Besides, to test the applicability of simulations in earthquake engineering, structural demand parameters should simultaneously cover a descriptive set. Herein, simulations are evaluated through comparison of seismological against engineering misfits, individually defined in terms of log-scale misfit and goodness-of-fit score. For numerical investigations, stochastically simulated records of three earthquakes are considered: The 1992 Erzincan-Turkey, 1999 Duzce-Turkey and 2009 L’Aquila-Italy events. For misfit evaluation, seismological parameters include amplitude, duration and frequency content, while engineering parameters contain spectral acceleration, velocity and seismic input energy. Overall, the same trend between both misfits is observed. All misfits for Erzincan and Duzce located on basins are larger than those corresponding to L’Aquila mostly placed on stiff sites. The engineering misfits, particularly in terms of input energy measures, are larger than seismological misfits. In summary, the proposed misfit evaluation methodology seems useful to evaluate simulations for engineering practice

Benzeştirilmiş kuvvetli yer hareketi kayıtlarının deprem mühendisliği uygulamalarında kullanımı.

With the recent advances in scientific computing, ground motion simulations have become more common. However, use of simulated motions for earthquake engineering purposes is still not well investigated. In this thesis, the efficiency of records simulated with the stochastic finite-fault technique in seismic demand estimation is studied in two different earthquake engineering applications. First, vulnerability assessment in a selected region, Erzincan (Turkey) is performed with simple single-degree-of-freedom structural models. For this purpose, seismic loss estimation for past and potential events is carried out considering both regional seismicity and local building information. Comparison of the estimated damage with the observed damage during the 1992 Erzincan earthquake reveals that, with well-defined local parameters, realistic ground motions can be simulated and used as input to SDOF models for seismic loss estimation. In the second part, nonlinear time history analyses of reinforced-concrete multi-degree-of-freedom models are performed to compare structural responses to simulated records with those to the corresponding real records. For this purpose, three case studies are considered: The 1992 Erzincan (Turkey) (Mw=6.6), the 1999 Düzce (Turkey) (Mw=7.1), and the 2009 L’Aquila (Italy) (Mw=6.3) earthquakes. Results show that for Erzincan with predominant basin effects, simulated motions fail to realistically predict real MDOF responses. However, results are promising for Düzce located on a shallow alluvial basin. For L’Aquila located mostly on stiff sites, results vary according to the simulation technique applied. In summary, when the simulated motions match the real records in terms of major seismological features, use of simulations in earthquake engineering seems feasible.Ph.D. - Doctoral Progra

SITE-SPECIFIC PROBABILISTIC SEISMIC HAZARD ASSESSMENT ANALYSES IN ZEYTINBURNU, ISTANBUL

The first step in estimation of seismic losses in urban areas is the assessment of regional seismic hazard. The source and local site parameters determine the accuracy of the hazard model. Using locally derived input parameters in site response modeling and hazard analyses, the earthquake potential of Zeytinburnu region in Istanbul is investigated in detail. In this study, two alternative source models including area and fault (line) sources are considered in the hazard computations. Analyses are initially performed using generic rock and soil conditions considering return periods of 475, 975 and 2475 years. Then, site-specific seismic hazard analyses are made using available local soil conditions. Probabilistic seismic hazard analyses with line sources and local soil models yield significantly different results than area sources and a generic soil model for all return periods. This observation points out the fact that detailed local source and site parameters should be employed in hazard analyses. In summary, numerical results obtained with locally derived input parameters indicate that Istanbul has significant potential for hazard in terms of both local earthquake occurrence and site amplifications