O. Kegyes-Brassai

55027439600

Publications - 21

Enhancing seismic assessment and risk management of buildings: A neural network-based rapid visual screening method development

O. Kegyes-Brassai Nurullah Bektaş

Publication Name: Engineering Structures

Publication Date: 2024-04-01

Volume: 304

Issue: Unknown

Page Range: Unknown

Description:

Some of the existing buildings are designed based on lower design standards or even without considering seismic design standards. Recent earthquakes have further highlighted the vulnerability of these buildings when subjected to severe seismic activity. Consequently, it has become imperative to conduct seismic vulnerability assessments of the existing building stock. Therefore, the assessment of the existing building stock is required through the utilization of Rapid Visual Screening (RVS) methods. However, the existing conventional RVS methods used in seismic building assessments have shown limited accuracy. Furthermore, because these methods were developed based on expert opinions and/or due to access limitations to detailed assessment-based generated data used for their development, further enhancing them is challenging. To address these limitations, a new RVS method, which leverages Neural Networks (NN) and building-specific parameters, for reinforced concrete, adobe mud, bamboo, brick, stone, and timber buildings has been proposed in this study. Unlike conventional methods that rely on site seismicity class, the developed data-driven approach incorporates building-specific parameters such as the fundamental structural period and building spectral acceleration. The developed RVS method is specifically tailored to analyze diverse types of buildings in regions with varying seismicity risks, all in preparation for an impending earthquake. In this study, the developed RVS method demonstrated a promising 68% test accuracy, effectively representing the building performance against earthquakes. These findings illustrate the potential of the developed NN based RVS method in assessing existing buildings, thereby mitigating potential loss of life and property during imminent earthquake and alleviating the associated economic burden. Furthermore, this study introduces a new RVS method that can pave the way for future advancements in the field of seismic vulnerability assessment of existing buildings.

Open Access: Yes

DOI: 10.1016/j.engstruct.2024.117606

Developing a machine learning-based rapid visual screening method for seismic assessment of existing buildings on a case study data from the 2015 Gorkha, Nepal earthquake

O. Kegyes-Brassai Nurullah Bektaş

Publication Name: Bulletin of Earthquake Engineering

Publication Date: 2025-09-01

Volume: 23

Issue: 12

Page Range: 4981-5019

Description:

Each existing building is required to be assessed before an impending severe earthquake utilizing Rapid Visual Screening (RVS) methods for its seismic safety since many buildings were constructed before seismic standards, without taking into account current regulations, and because they have a limited lifetime and safety based on how they were designed and maintained. Building damage brought on by earthquakes puts lives in danger and causes significant financial losses. Therefore, the fragility of each building needs to be determined and appropriate precautions need to be taken. RVS methods are used when assessing a large building stock since further in-depth vulnerability assessment methods are computationally expensive and costly to examine even one structure in a large building stock. RVS methods could be implemented in existing buildings in order to determine the damage potential that may occur during an impending earthquake and take necessary measures for decreasing the potential hazard. However, the reliability of conventional RVS methods is limited for accurately assessing large building stock. In this study, building inspection data acquired after the 2015 Gorkha, Nepal earthquake is used to train nine different machine learning algorithms (Decision Tree Classifier, Logistic Regression, Light Gradient Boosting Machine Classifier, eXtreme Gradient Boosting Classifier, Gradient Boosting Classifier, Random Forest Classifier, Support Vector Machines, K-Neighbors Classifier, and Cat Boost Classifier), which ultimately led to the development of a reliable RVS method. The post-earthquake building screening data was used to train, validate, and ultimately test the developed model. By incorporating advanced feature engineering techniques, highly sophisticated parameters were introduced into the developed RVS method. These parameters, including the distance to the earthquake source, fundamental structural period, and spectral acceleration, were integrated to enhance the assessment capabilities. This integration enabled the assessment of existing buildings in diverse seismically vulnerable areas. This study demonstrated a strong correlation between determining building damage states using the established RVS method and those observed after the earthquake. When comparing the developed method with the limited accuracy of conventional RVS methods reported in the literature, a test accuracy of 73% was achieved, surpassing conventional RVS methods by over 40% in accurately classifying building damage states. This emphasizes the importance of detailed data collection after an earthquake for the effective development of RVS methods.

Open Access: Yes

DOI: 10.1007/s10518-024-01924-x

Assessing Local Site-Specific Response Spectra Based on Site Data in Gyor

O. Kegyes-Brassai Benjamin Labar

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 422-430

Description:

It is essential to understand seismic ground motion in order to understand how dynamically a structure responds to earthquakes. Due to variations in seismic loading, strong ground vibrations can damage structures to varying degrees. The different essential traits of powerful ground motions help explain this ground diversity during moderate to large earthquakes. This study mainly focuses on the comparison between ground motion parameters such as the Peak Ground acceleration (PGA), and local site spectra considering the design response spectrum and site-specific response spectra of varying soil profiles in Gyor. Multichannel analysis of Surface Waves (MASW) data from eleven different places in Gyor were considered and analyzed using the 1-dimensional response analysis software, STRATA, and a detailed comparison was carried out between the different site locations in terms of PGA, and local site spectra. The result revealed the sites with the highest amplifications based on peak ground values of acceleration, velocity, and displacements. With 1-dimensional STRATA software, peak ground acceleration profiles, and response spectrum results are obtained and compared to Eurocode 8 standards.

Open Access: Yes

DOI: 10.3233/ATDE240575

Enhancing Seismic Performance: A Comprehensive Study on Masonry and Reinforced Concrete Structures Considering Soil Properties and Environmental Impact Assessment

O. Kegyes-Brassai Nurullah Bektaş Benjamin Labar

Publication Name: Advances in Civil Engineering

Publication Date: 2024-01-01

Volume: 2024

Issue: Unknown

Page Range: Unknown

Description:

Approximately 20,000 people are killed annually on average by building and infrastructure collapses and failures caused by seismic activities. In earlier times, seismic design codes and specifications set minimal requirements for life safety performance levels. Earthquakes can be thought of as recurring events in seismically active areas, with severity states ranging from serviceability to ultimate levels. Buildings designed in accordance with site-specific response spectra, which take into account soil properties based on ground motion amplification data, are better at withstanding such forces and serving their design purposes. This study aims to investigate the site response of reinforced and masonry buildings, considering the effect of soil properties based on the amplification of ground motion data, and to compare the life cycle assessment of the buildings under consideration based on the design and the site-specific response spectrum. In terms of soil properties and site-specific response spectra, STRATA is used to determine the site-specific response for the considered locations for a return period of 475 years for 100 realizations based on the randomization of site properties. For structural analysis, AxisVM software, which is a compatible finite element analysis, is used for building design and analysis, generating comparative results based on the design- and site-specific spectra. To determine and identify potential failures in the model, response spectra were applied to understand the difference in horizontal deflection in two different instances (for elastic design- and site-specific spectra). After building design and analysis is performed, a life cycle analysis in terms of environmental impact assesments using OpenLCA and IdematLightLCA is done. This is done to ascertain the additional expenses in terms of ecocosts and carbon footprints on some failed elements in the structure which are required to make the buildings more resilient when the site-specific response spectrum is applied and to compare the potential economic losses that may occur based on ecological costs. The study presents a comprehensive investigation into the seismic response of masonry and reinforced concrete buildings in Győr, Hungary, incorporating advanced geophysical techniques like multichannel surface wave (MASW) and structural analysis software, AxisVM. Additionally, tailored retrofitting strategies are explored to enhance structural resilience in seismic-prone regions. Significant ground amplifications in soil properties across different profiles are revealed, emphasizing the effectiveness of these strategies in reducing structural deflection and improving resilience. Highlights of the results are observed where the site-specific response spectra are higher than the EC8 design response spectrum. Furthermore, the research underscores the substantial environmental impact, considering both ecocosts and CO2 emissions associated with retrofitting measures, highlighting the importance of sustainable structural interventions in mitigating seismic risks.

Open Access: Yes

DOI: 10.1155/2024/4505901

Pushover Analysis in Seismic Engineering: A Detailed Chronology and Review of Techniques for Structural Assessment

O. Kegyes-Brassai Kevin Karanja Kuria

Publication Name: Applied Sciences Switzerland

Publication Date: 2024-01-01

Volume: 14

Issue: 1

Page Range: Unknown

Description:

This study analyzes the progression, utilization, and inherent challenges of traditional non-linear static procedures (NSPs) such as the capacity spectrum method, the displacement coefficient method, and the N2 method for evaluating seismic performance in structures. These methods, along with advanced versions such as multi-mode, modal, adaptive, and energy-based pushover analysis, help determine seismic demands, enriching our grasp on structural behaviors and guiding design choices. While these methods have improved accuracy by considering major vibration modes, they often fall short in addressing intricate aspects such as bidirectional responses, torsional effects, soil-structure interplay, and variations in displacement coefficients. Nevertheless, NSPs offer a more comprehensive and detailed analysis compared to rapid visual screening methods, providing a deeper understanding of potential vulnerabilities and more accurate predictions of structural performance. Their efficiency and reduced computational demands, compared to the comprehensive nonlinear response history analysis (NLRHA), make NSPs a favored tool for engineers aiming for swift seismic performance checks. Their accuracy and application become crucial when gauging seismic risks and potential damage across multiple structures. This paper underscores the ongoing refinements to these methods, reflecting the sustained attention they receive from both industry professionals and researchers.

Open Access: Yes

DOI: 10.3390/app14010151

Evaluating the Reliability of Hinge Definitions in Pushover Analyses: A Comparative Study of SAP2000, AxisVM

O. Kegyes-Brassai Kevin Karanja Kuria

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 291-297

Description:

This study evaluates the performance of SAP2000, and AxisVM in conducting pushover analyses, with a focus on the manual (user) definition of plastic hinges versus the automatic definitions provided by the software. Three structures, namely a single column subjected to a point load, a 2D reinforced concrete (RC) frame model, and a 3D RC model, are considered. It explores the performance of the three models in different conditions, including, application of the different software, the use of user defined (manual) hinges, and automatically generated hinges to assess their response to various analytical excitations. The need for engineers to focus on understanding the application of defining the hinge properties according to existing guidelines, including FEMA-356, ASCE 41-13/17, and Eurocodes, is highly emphasized, in addition to the existing methods as found in the literature. This is achieved by considering and comparing the capacity curves generated by the software. The results vary in some instances, especially when comparing results from user-defined and automatic hinges. It is also found that when used with precision, the results are almost similar, it is also important to use software that allows ultimate precision for better results.

Open Access: Yes

DOI: 10.3233/ATDE240558

EXAMINATION OF INDUSTRIAL BUILDING HEATING MODERNIZATION AND ITS IMPACT ON SUSTAINABILITY ISSUES USING A CASE STUDY

Péter Triesz O. Kegyes-Brassai Norbert Nagy

Publication Name: Iet Conference Proceedings

Publication Date: 2024-01-01

Volume: 2024

Issue: 8

Page Range: 125-129

Description:

The purpose of this article is to analyse the possibilities of energy modernization of an industrial property and to evaluate the results achieved by the modernization. We examine the reason for the establishment of the property, the change in its nature of use and environment, and the reason for the related structural and mechanical improvements. Step by step, we analyze and compare the investment requirements of each development, as well as the results that can be achieved with them in terms of environmental protection, economy and comfort.

Open Access: Yes

DOI: 10.1049/icp.2024.2693

Nonlinear Static Analysis for Seismic Evaluation of Existing RC Hospital Building

O. Kegyes-Brassai Kevin Karanja Kuria

Publication Name: Applied Sciences Switzerland

Publication Date: 2023-11-01

Volume: 13

Issue: 21

Page Range: Unknown

Description:

Nonlinear Static Analysis otherwise known as pushover analysis will be used in this study to evaluate the seismic performance of an existing reinforced concrete (RC) hospital structure. This method aids in determining the structure’s ability to withstand lateral loads and calculating its local and global deformation requirements. The study begins with a thorough analysis of the geometry, materials, and structural elements of the structure, followed by a review of pertinent building regulations and codes. A finite element model in three dimensions of the hospital building is created, encapsulating the main features of the structure’s behavior under seismic loading. The lateral force method of analysis and static pushover analysis is then carried out and compared, and the findings are used to pinpoint crucial weak places, potential failure mechanisms, and regions needing additional research or fortification. Recommendations are given to improve the seismic performance of the current RC hospital building based on the pushover analysis’s findings. These adjustments can be made to the structural system via retrofitting techniques or to non-structural elements. For engineers, architects, and legislators concerned with the seismic assessment and renovation of hospital buildings and other crucial infrastructure, the findings from this study are valuable.

Open Access: Yes

DOI: 10.3390/app132111626

Development in Machine Learning Based Rapid Visual Screening Method for Masonry Buildings

O. Kegyes-Brassai Nurullah Bektaş

Publication Name: Lecture Notes in Civil Engineering

Publication Date: 2023-01-01

Volume: 433 LNCE

Issue: Unknown

Page Range: 411-421

Description:

The susceptibility of existing buildings to earthquakes is required to be assessed since building stock consists of structures that were constructed before the development of seismic standards, whether by disregarding them or by taking into account lower seismic regulations. Damage to buildings due to earthquakes not only endanger people’s lives but also causes economic losses. Because examining a large number of buildings by employing detailed building assessment methods is computationally expensive, Rapid Visual Screening (RVS) techniques are capable of assessing large building stock. Previous studies demonstrate that accuracy of the conventional RVS methods to precisely determine buildings’ damage states is limited. Therefore, it is required to develop a new RVS method. Since machine learning is extremely competent in establishing a relationship between input parameters and the target variable, this study introduces a new machine learning-based highly accurate RVS method, that can be applied in different countries, for masonry buildings using post-earthquake building screening data of 273 masonry buildings collected after the 2019 Mugello, Italy earthquake. The developed method differs from conventional RVS methods in terms of considered parameters such as spectral acceleration, the fundamental natural frequency of buildings, and the distance to the earthquake source. By comparing calculated building damage states with identified damage states through post-earthquake inspection, the developed method’s potential efficiency has been demonstrated as 88.9% accurate.

Open Access: Yes

DOI: 10.1007/978-3-031-39117-0_42

Decision of Construction Technology from a Sustainability Aspect, Life Cycle Analysis Based on Transport and Construction

O. Kegyes-Brassai Boglárka Eisingerné Balassa László Buics

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 103

Issue: Unknown

Page Range: 355-360

Description:

In the case of the different types of construction processes, an important aspect from the sustainability point of view is the organization of construction, the total construction time and cost, and their influence on CO2 emissions. In this study, in the case of construction projects, we examine the impact of the decided technology on the environmental impact. We take into consideration the aspects of transport and construction organization. Using life cycle analysis methods, we present the comparison of alternatives and sustainable solutions. Discrete event simulation is used to determine the CO2 emission rate under different maintenance approaches. In the simulation model, a 2 x 2 lane I2 type bridge is simulated with altered traffic lines according to the different scenarios of maintenance. In the case of a half-track closure, the capacity of a 2 × 2 lane road is reduced by half, while the capacity of a 2 × 1 lane road due to alternating traffic directions is reduced by more than 50 %. The extent of the reduction depends on the length of the closed section, which greatly affects the emptying time. According to the results of the simulation, the CO2 emission might be lower in the case of narrowed traffic alteration than in the case of half-track closure, but the maintenance timeframe is also an important factor.

Open Access: Yes

DOI: 10.3303/CET23103060

Urban Vulnerability and Earthquake Risks Incorporating Sustainability

O. Kegyes-Brassai Kuria Kevin Karanja

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 607-612

Description:

Amidst the backdrop of rapid global urbanization, this research delves deep into the nexus of urban vulnerabilities, seismic challenges, and sustainable infrastructure. As cities sprawl, the need to adapt and refine traditional building techniques becomes evident, especially in the quest for seismic resilience and ecological sustainability. The study introduces the innovative 'Sustainable Seismic Design' framework. A core component of the research is the quantitative material evaluation. Materials, notably Engineered Timber and Concrete, are assessed on their seismic resistance—measuring their capacity to withstand seismic forces and dissipate energy during earthquakes. Concurrently, their environmental impact is evaluated, considering factors like energy consumption during production, emissions, and recyclability. Engineered Timber emerges with a commendable 50 % higher environmental score, underscoring its eco-friendly nature compared to Concrete. Further, the research illuminates the often-overlooked geotechnical elements, such as soil characteristics and groundwater dynamics, that can amplify seismic vulnerabilities. The advocacy for green geotechnical strategies is accentuated, with the post-seismic rebuilding endeavors in Christchurch, New Zealand, serving as a practical exemplar of the benefits of this integrative strategy. In essence, the study champions policy adaptations that seamlessly weave sustainability into seismic construction standards and geotechnical practices, setting the stage for urban habitats that are both resilient to earthquakes and champions of green initiatives.

Open Access: Yes

DOI: 10.3303/CET23107102

Development in Fuzzy Logic-Based Rapid Visual Screening Method for Seismic Vulnerability Assessment of Buildings

O. Kegyes-Brassai Nurullah Bektaş

Publication Name: Geosciences Switzerland

Publication Date: 2023-01-01

Volume: 13

Issue: 1

Page Range: Unknown

Description:

In order to prevent possible loss of life and property, existing building stocks need to be assessed before an impending earthquake. Beyond the examination of large building stocks, rapid evaluation methods are required because the evaluation of even one building utilizing detailed vulnerability assessment methods is computationally expensive. Rapid visual screening (RVS) methods are used to screen and classify existing buildings in large building stocks in earthquake-prone zones prior to or after a catastrophic earthquake. Buildings are assessed using RVS procedures that take into consideration the distinctive features (such as irregularity, construction year, construction quality, and soil type) of each building, which each need to be considered separately. Substantially, studies have been presented to enhance conventional RVS methods in terms of truly identifying building safety levels by using computer algorithms (such as machine learning, fuzzy logic, and neural networks). This study outlines the background research that was conducted in order to establish the parameters for the development of a fuzzy logic-based soft rapid visual screening (S-RVS) method as an alternative to conventional RVS methods. In this investigation, rules, membership functions, transformation values, and defuzzification procedures were established by examining the data of 40 unreinforced masonries (URM) buildings acquired as a consequence of the 2019 Albania earthquake in order to construct a fuzzy logic-based S-RVS method.

Open Access: Yes

DOI: 10.3390/geosciences13010006

Development of a Fuzzy Inference System Based Rapid Visual Screening Method for Seismic Assessment of Buildings Presented on a Case Study of URM Buildings

O. Kegyes-Brassai Ferenc Lilik Nurullah Bektaş

Publication Name: Sustainability Switzerland

Publication Date: 2022-12-01

Volume: 14

Issue: 23

Page Range: Unknown

Description:

Many conventional rapid visual screening (RVS) methods for the seismic assessment of existing structures have been designed over the past three decades, tailored to site-specific building features. The objective of implementing RVS is to identify the buildings most susceptible to earthquake-induced damage. RVS methods are utilized to classify buildings according to their risk level to prioritize the buildings at high seismic risk. The conventional RVS methods are employed to determine the damage after an earthquake or to make safety assessments in order to predict the damage that may occur in a building before an impending earthquake. Due to the subjectivity of the screener based on visual examination, previous research has shown that these conventional methods can lead to vagueness and uncertainty. Additionally, because RVS methods were found to be conservative and to be partially accurate, as well as the fact that some expert opinion based developed RVS techniques do not have the capability of further enhancement, it was recommended that RVS methods be developed. Therefore, this paper discusses a fuzzy logic based RVS method development to produce an accurate building features responsive examination method for unreinforced masonry (URM) structures, as well as a way of revising existing RVS methods. In this context, RVS parameters are used in a fuzzy-inference system hierarchical computational pattern to develop the RVS method. The fuzzy inference system based RVS method was developed considering post-earthquake building screening data of 40 URM structures located in Albania following the earthquake in 2019 as a case study. In addition, FEMA P-154, a conventional RVS method, was employed to screen considered buildings to comparatively demonstrate the efficiency of the developed RVS method in this study. The findings of the study revealed that the proposed method with an accuracy of 67.5% strongly outperformed the conventional RVS method by 42.5%.

Open Access: Yes

DOI: 10.3390/su142316318

Conventional RVS Methods for Seismic Risk Assessment for Estimating the Current Situation of Existing Buildings: A State-of-the-Art Review

O. Kegyes-Brassai Nurullah Bektaş

Publication Name: Sustainability Switzerland

Publication Date: 2022-03-01

Volume: 14

Issue: 5

Page Range: Unknown

Description:

Developments in the field of earthquake engineering over the past few decades have contributed to the development of new methods for evaluating the risk levels in buildings. These research methods are rapid visual screening (RVS), seismic risk indexes, and vulnerability assessments, which have been developed to assess the levels of damage in a building or its structural components. RVS methods have been proposed for the rapid pre-and/or post-earthquake screening of existing large building stock in earthquake-prone areas on the basis of sidewalk surveys. The site seismicity, the soil type, the building type, and the corresponding building characteristic features are to be separately examined, and the vulnerability level of each building can be identified by employing the RVS methods. This study describes, evaluates, and compares the findings of previous investigations that utilized conventional RVS methods within a framework. It also suggests the methods to be used for specific goals and proposes prospective enhancement strategies. Furthermore, the article discusses the time-consuming RVS methods (such as FEMA 154, which requires from 15 to 30 min, while NRCC requires one hour), and provides an overview of the application areas of the methods (pre-earthquake: FEMA 154, NRCC, NZEE, etc.; postearthquake: GNDT, EMS, etc.). This review of the traditional RVS methods offers a comprehensive guide and reference for field practitioners (e.g., engineers, architects), and recommends enhancement techniques (e.g., machine learning, fuzzy logic) for researchers to be used in future improvements.

Open Access: Yes

DOI: 10.3390/su14052583

Comparative Life Cycle Analyses of Regular and Irregular Maintenance of Bridges with Different Support Systems and Construction Technologies

O. Kegyes-Brassai Zoltán Major Attila Németh Boglárka Eisingerné Balassa

Publication Name: Chemical Engineering Transactions

Publication Date: 2022-01-01

Volume: 94

Issue: Unknown

Page Range: 571-576

Description:

The maintenance cost of bridges is huge in every country e. g. in the USA it is (approx.) 41.8 G$. This causes a 6.2 % GHG emission rise annually. Reducing and minimizing cost, GHG level and CO2 pollution is a key factor and a major goal for sustainability. This study presents a comparative life cycle assessment (LCA) of bridges with different support systems and construction technologies but with the same span and location. LCA considers regular and irregular bridge maintenance as well having a great influence on the need and timing for major maintenance or restoration in every 25 to 30 y. Regular maintenance means every 1 - 5 and 10 - y minor maintenance works take place. The analysis is based on primary data collected in Hungary examining fully constructed bridges. For the LCA, the cost of maintenance over a 100 y timespan is based on NIF regulations, the total rate of CO2 pollution and the EF (Ecological Footprint, Gha) level is used (Long et al., 2020;). In practice the maintenance of the bridges take place occasionally when the damage on the bridges are already visible and cannot be postponed based on the in - depth interviews with experts. It is assumed that the cost, EF and CO2 pollution of the regular maintenance over the examined timespan is less compared to results of the irregular life cycle model. Based on the case study presented, it can be concluded that the cost of LCA for regular bridge maintenance is 637,348.32 (k€) and for irregular bridge maintenance it is 994,415.12 (k€). The CO2 pollution for regular bridge maintenance is 12,948.24 (kt) and for irregular bridge maintenance is 13,876.86 (kt). The EF pollution for regular bridge maintenance is 3,237.06 (kGha) and for irregular bridge maintenance it is 3,469.22 (kGha). Considering the long - term sustainability aspects, it is recommended that the maintenance should be a regular and a controlled activity. It is vital to draw the attention of the decision makers, the legislators of the businesses, the maintenance operators, and the inspectors to these sustainability aspects.

Open Access: Yes

DOI: 10.3303/CET2294095

Vulnerability assessment of buildings based on rapid visual screening and pushover: Case study of Gyor, Hungary

O. Kegyes-Brassai

Publication Name: Wit Transactions on the Built Environment

Publication Date: 2019-01-01

Volume: 185

Issue: Unknown

Page Range: 63-PII-74

Description:

The process of carrying out an earthquake risk assessment of a town can provide important data for authorities and disaster management to better understand risks to many buildings rather than a single building. This is even more important in the case of moderate seismic areas where any mitigation measures to be taken should be justified by seismic risk determination. Moderate seismicity does not necessarily equate to moderate damage from earthquakes. Vulnerability to earthquakes even increases with extending urban areas. Seismicity in the Pannonian Basin is moderate compared to seismicity of surrounding areas, nonetheless, reports of major earthquakes in Hungary often refer to heavy building damage and liquefaction (e.g. 1763 Komarom earthquake). Gyor was chosen to be the examined area for seismic risk analysis because it is the most important city of northwest Hungary with a large number of monumental buildings and a complex geological and geographical settings. In order to make the best use of limited resources usually characteristic to moderate seismic zones, the presented method used existing soil data, rapid visual screening of buildings, a limited number of field tests and free, but sophisticated, software. This paper focuses on the results of vulnerability analysis of buildings; however, it considers the results of seismic hazard and local site effects based on response analysis with more than 6000 realizations. Vulnerability of the buildings with different structural types were evaluated based on a rapid visual screening of 5000 building. Vulnerability based on visual screening was compared to a pushover analysis of the typical constructions. As one would expect, since the hazards and vulnerabilities were not uniformly distributed in the city districts of Gyor, there were zones of higher and lower risk. These results can then serve as useful tools for decision makers and can be applied directly to risk management plans.

Open Access: Yes

DOI: 10.2495/ERES190051

Assessing the impact of positive pressure ventilation on the building fire - A case study

O. Kegyes-Brassai Geza Zolyomi Rajmund Kuti

Publication Name: International Journal of Geomate

Publication Date: 2018-01-01

Volume: 15

Issue: 48

Page Range: 16-21

Description:

Closed-space fires often occur in Hungary, so it is necessary to examine the effects of fires on building structures, taking into account Hungarian architectural features. Fires inside the buildings are characterized by intense heat development and smoke generation that can cause permanent damage to the building structures. Heat and smoke extraction during fire extinguishing is based usually on natural ventilation. Not only being a non-effective process also makes it more difficult to accomplish firefighting tasks. Experiments in this research have been conducted with mobile positive pressure ventilation (PPV) in order to increase the efficiency of the firefighting process and to reduce the adverse effects of fires. The tests have been carried out in unused buildings, providing real conditions. Practical application has been examined in order to reduce the harmful effects of closed-space fires and to provide guidance for professional use. This research based on observations and experiments contributes to enhancing fire safety.

Open Access: Yes

DOI: 10.21660/2018.48.18042

Vulnerability assessment of residential buildings in Jeddah: A methodological proposal

O. Kegyes-Brassai Ahmed Al-ghamadi Md Faiz Shah Anas Ahmed R. P. Ray

Publication Name: International Journal of Geomate

Publication Date: 2018-01-01

Volume: 14

Issue: 44

Page Range: 134-141

Description:

The City of Jeddah in Saudi Arabia is expanding rapidly, in terms of new buildings and increasing population. The rapid urbanization leads to higher risk from seismic events; even in areas of moderate seismicity such as this city. The present study addresses the rapid evaluation of a large number of buildings in Jeddah involving steps to determine hazard, assessing building stock, and computing vulnerability with a scoring method from FEMA 155. Two districts were selected for investigation based on a cluster analysis applied to population and building data from the local municipality. One selected district was a contemporary developed urbanized area, and the other was a more traditional area. Such selection offered the possibility to compare vulnerability of buildings built according to different seismic codes and to make assumptions about the rest of the city based on typical structures of districts. The basic structural score was determined considering the building structure and moderate seismicity of the region using score modifiers, e.g. vertical irregularity score modifier; soil score modifier assuming sabkahs. The results of the investigation reveal a different level of vulnerability and areas where intervention is needed. The method can be applied for further analysis of the city.

Open Access: Yes

DOI: 10.21660/2018.44.85087

Effects of local ground conditions on site response analysis results in Hungary

O. Kegyes-Brassai Zs Szilvágyi None Wolf R. P. Ray

Publication Name: Icsmge 2017 19th International Conference on Soil Mechanics and Geotechnical Engineering

Publication Date: 2017-01-01

Volume: 2017-September

Issue: Unknown

Page Range: 2003-2006

Description:

Ground conditions play an important role for both seismic hazard assessment and structural design for seismic actions. Generally, 1D site response analysis is the first step toward evaluating local conditions. Often the process is simplified by applying a single reference peak ground acceleration general response spectrum based on soil category. Seismic waves are amplified selectively by near-surface soil deposits that possess strain dependent stiffness and damping parameters that vary with each layer as well as with depth. In order to take these local ground conditions into account, field investigations were carried out for this study. Seismic CPT and MASW measurements were used for determining in situ small strain stiffness profiles at different locations in Hungary. Results of the investigations were used as input data for ground response analyses. Results are presented to show benefits of the detailed investigations as compared to simplified analysis methods based on estimated soil parameters and to EC-8 design spectra.

Open Access: Yes

DOI: DOI not available

Predictive equations for soil shear-wave velocities of Hungarian soils based on MASW and CPT measurements around Győr

P. Tildy O. Kegyes-Brassai R. P. Ray

Publication Name: Acta Geodaetica Et Geophysica

Publication Date: 2016-12-01

Volume: 51

Issue: 4

Page Range: 685-707

Description:

Determination of shear-wave (S-wave) velocity profiles is the first step in seismic hazard assessment of a town, because the dynamic parameters of local soil types are vital for seismic response analysis of a specific area in order to determine the local soil effect in a case of a seismic event for seismic risk analysis. S-wave velocity profiles have been determined for many areas within Győr. Extensive use of historical boring logs allowed for correlations and reasonable extrapolation of soil performance throughout the area. This has led to a pattern of soil layer distributions and delineates several different soil zones for Győr.

Open Access: Yes

DOI: 10.1007/s40328-015-0148-y

Applying earthquake risk analysis methods to a town in Hungary

O. Kegyes-Brassai R. P. Ray

Publication Name: 18th International Conference on Soil Mechanics and Geotechnical Engineering Challenges and Innovations in Geotechnics Icsmge 2013

Publication Date: 2013-01-01

Volume: 2

Issue: Unknown

Page Range: 1519-1522

Description:

Determining the earthquake risk of buildings in a town or settlement has lately become a more prominent issue. The process can provide important data for governments, authorities, disaster management and insurance companies to better understand risks to many buildings and engineering systems rather than a single building. This paper addresses the rapid evaluation of a large number of similar buildings in one area using a forecasting approach. Back-casting mainly considers the effect of previous earthquakes by listing and categorizing the damaged buildings and casualties. Forecasting offers a method to evaluate the possible damages in advance, however many uncertainties need to be taken into consideration. A fast and simple method should be developed to avoid the time and expertise required from research-based approaches. The steps involve determination of the hazard, assessing building stock, and computing vulnerability. The method for determination of vulnerability functions is a non-linear static analysis using a bilinear approximation of the capacity curve, assuming first mode force distribution and mode shape thus linear strength distribution. From the curve of the seismic demand and the shear capacity of the building, the vulnerability function of the building can be obtained. These vulnerability functions should be derived for typical layouts; offering a family of curves allowing the experts to decide the vulnerability category of a specific building on-site based on visual screening. With the given value of possible PGA (peak ground acceleration), expected damages can then be estimated.

Open Access: Yes

DOI: DOI not available