Articles de revista
http://hdl.handle.net/2117/478
2019-12-15T19:41:03ZSeismic evaluation method for existing reinforced concrete buildings in North of Morocco
http://hdl.handle.net/2117/168106
Seismic evaluation method for existing reinforced concrete buildings in North of Morocco
Cherif, Seif-eddin; Chourak, Mimoun; Abed, Mohammed; Pujades Beneit, Lluís
The purpose of this study is to seismically evaluate reinforced concrete buildings in the northern region of Morocco. In the past, the area have suffered from numerous earthquakes, lately the 2004 earthquake near the city of Al Hoceima (Mw of 6.4 causing more than 600 fatalities) and the region is constantly subject to seismic threats. A total number of 2746 residential buildings from the cities of Al Hoceima and Imzouren have been investigated for the purposes of this study. The proposed method adapts the Japanese Seismic Index Method making it more time-efficient and tuned to the context of the Moroccan construction. The method is based on a visual inspection of buildings and an in-depth insight of how constructions are designed and built in the region. The results show that Imzouren is more exposed to damage than the city of Al Hoceima is, mainly due to the soil nature. The method also shows that as the building’s height increases, it becomes more vulnerable. Furthermore, constructions that comply with the seismic regulations have a significant capacity to withstand damage without collapsing unlike other non-engineered buildings that have an almost non-existent ductility and can collapse soon during intense earthquakes.
The final publication is available at Springer via http://dx.doi.org/10.1007/s10518-019-00643-y
2019-09-10T12:26:20ZCherif, Seif-eddinChourak, MimounAbed, MohammedPujades Beneit, LluísThe purpose of this study is to seismically evaluate reinforced concrete buildings in the northern region of Morocco. In the past, the area have suffered from numerous earthquakes, lately the 2004 earthquake near the city of Al Hoceima (Mw of 6.4 causing more than 600 fatalities) and the region is constantly subject to seismic threats. A total number of 2746 residential buildings from the cities of Al Hoceima and Imzouren have been investigated for the purposes of this study. The proposed method adapts the Japanese Seismic Index Method making it more time-efficient and tuned to the context of the Moroccan construction. The method is based on a visual inspection of buildings and an in-depth insight of how constructions are designed and built in the region. The results show that Imzouren is more exposed to damage than the city of Al Hoceima is, mainly due to the soil nature. The method also shows that as the building’s height increases, it becomes more vulnerable. Furthermore, constructions that comply with the seismic regulations have a significant capacity to withstand damage without collapsing unlike other non-engineered buildings that have an almost non-existent ductility and can collapse soon during intense earthquakes.Sensitivity analysis of seismic parameters in the Probabilistic Seismic Hazard Assessment (PSHA) for Barcelona applying the new R-CRISIS
http://hdl.handle.net/2117/167747
Sensitivity analysis of seismic parameters in the Probabilistic Seismic Hazard Assessment (PSHA) for Barcelona applying the new R-CRISIS
Aguilar Meléndez, Armando; Ordaz Schroeder, Mario Gustavo; Puente, Josep de la; Pujades Beneit, Lluís; Barbat Barbat, Horia Alejandro; Rodriguez Lozoya, H.E.; Monterrubio Velasco, Marisol; Escalante Martínez, Jesús E.; Campos Ríos, Amelia
One of the most common ways to represent results of the probabilistic seismic hazard assessments (PSHA) are maps of seismic hazard, which usually show values of Peak Ground Acceleration (PGA) in a region for a return period. A common return period is of 475 years. These types of maps are frequently incorporated in seismic codes, which include the minimum requirements to design new buildings. On the other hand, a sensitivity analysis usually gives us additional information about a procedure or result. For instance, a sensitivity analysis about a PSHA can give us information about what variables considered to compute the seismic hazard have a significant influence on the results of seismic hazard. In the present study, we performed a sensitivity analysis related to the PSHA for Barcelona. This analysis was oriented to identify the influence in the results of seismic hazard of the following variables: a) the relationship magnitude-macroseismic intensity chosen to convert values of macroseismic intensity to magnitudes; b) the beta parameter that was used to define part of the seismicity of a seismic source and; c) the ground motion prediction equation (GMPE) which was used to determine intensities values to different distances from the epicenter of earthquakes. For this purpose, we applied the code R-CRISIS, which is the updated version of CRISIS2015. Therefore, the present study had as an additional objective to test the functionality of the new R-CRISIS from the point of view of users. According to the results of the sensitivity analysis of the PSHA of Barcelona both the GMPE and the relationship magnitude-macroseismic intensity are the two variables that have the greater influence on the results of seismic hazard of the present study. For instance, in some results of seismic hazard for the city of Barcelona the values of PGA (for the same return period) differ between them until 82% depending on if we considered the means values of the PGA values of the GMPE or the mean values plus one standard deviation of the PGA values of the GMPE. Finally, according to our experience in the use of the new R-CRISIS in the present study, we can confirm that it is both a powerful and user-friendly software. R-CRISIS has valuable features, for instance, it allows to consider diverse types of criteria to define the type of seismic source. For example, R-CRISIS allows defining different types of geometries of the seismic sources, and different criteria to define the seismicity of each seismic source. An important feature of R-CRISIS is the fact that it includes a database with numerous GMPE ready to be used to compute seismic hazard. Additionally, R-CRISIS has valuables graphical tools which are very helpful during the following two stages: the assigning data and the analysis of results.
2019-08-27T15:16:03ZAguilar Meléndez, ArmandoOrdaz Schroeder, Mario GustavoPuente, Josep de laPujades Beneit, LluísBarbat Barbat, Horia AlejandroRodriguez Lozoya, H.E.Monterrubio Velasco, MarisolEscalante Martínez, Jesús E.Campos Ríos, AmeliaOne of the most common ways to represent results of the probabilistic seismic hazard assessments (PSHA) are maps of seismic hazard, which usually show values of Peak Ground Acceleration (PGA) in a region for a return period. A common return period is of 475 years. These types of maps are frequently incorporated in seismic codes, which include the minimum requirements to design new buildings. On the other hand, a sensitivity analysis usually gives us additional information about a procedure or result. For instance, a sensitivity analysis about a PSHA can give us information about what variables considered to compute the seismic hazard have a significant influence on the results of seismic hazard. In the present study, we performed a sensitivity analysis related to the PSHA for Barcelona. This analysis was oriented to identify the influence in the results of seismic hazard of the following variables: a) the relationship magnitude-macroseismic intensity chosen to convert values of macroseismic intensity to magnitudes; b) the beta parameter that was used to define part of the seismicity of a seismic source and; c) the ground motion prediction equation (GMPE) which was used to determine intensities values to different distances from the epicenter of earthquakes. For this purpose, we applied the code R-CRISIS, which is the updated version of CRISIS2015. Therefore, the present study had as an additional objective to test the functionality of the new R-CRISIS from the point of view of users. According to the results of the sensitivity analysis of the PSHA of Barcelona both the GMPE and the relationship magnitude-macroseismic intensity are the two variables that have the greater influence on the results of seismic hazard of the present study. For instance, in some results of seismic hazard for the city of Barcelona the values of PGA (for the same return period) differ between them until 82% depending on if we considered the means values of the PGA values of the GMPE or the mean values plus one standard deviation of the PGA values of the GMPE. Finally, according to our experience in the use of the new R-CRISIS in the present study, we can confirm that it is both a powerful and user-friendly software. R-CRISIS has valuable features, for instance, it allows to consider diverse types of criteria to define the type of seismic source. For example, R-CRISIS allows defining different types of geometries of the seismic sources, and different criteria to define the seismicity of each seismic source. An important feature of R-CRISIS is the fact that it includes a database with numerous GMPE ready to be used to compute seismic hazard. Additionally, R-CRISIS has valuables graphical tools which are very helpful during the following two stages: the assigning data and the analysis of results.Seismic site classification from the horizontal-to-vertical response spectral ratios: use of the Spanish strong-motion database
http://hdl.handle.net/2117/167058
Seismic site classification from the horizontal-to-vertical response spectral ratios: use of the Spanish strong-motion database
Pinzón, Luis A.; Pujades Beneit, Lluís; Macau, Albert; Carreño, Emilio; Alcalde Camino, Juan Manuel
Normally, the average of the horizontal-to-vertical (H/V) ratios of the 5% damped response spectra of ground motions is used to classify the site of strong-motion stations. In these cases, only the three-orthogonal as-recorded acceleration components are used in the analysis, and all the vector compositions that can generate a different response for each period oscillator are excluded. In this study, the Spanish strong-motion database was used to classify the sites of accelerometric stations based on the predominant periods through the average horizontal-to-vertical spectral ratios (HVSR) of recorded ground motions. Moreover, the directionality effects using the vector composition of the horizontal components of ground motions were also considered in the estimations of H/V ratios. This consideration is a relevant novelty compared to the traditional H/V ratios methods. Only earthquakes with magnitudes above 3.5 and hypocentral distances below 200 km were selected, which resulted in 692 ground-motion records, corresponding to 86 stations, from events in the period between 1993 and 2017. After the analysis, a predominant-period site classification was assigned to each station. On the whole, the obtained mean and standard deviation values of the spectral ratios are comparable to those shown by other researchers. Therefore, the advantages of the proposed procedure, which takes the directionality effects into account, can be summarized as follows: (a) The obtained information is richer and gives enables more sophisticated and realistic analyses on the basis of percentiles and (b) it is easier to detect anomalous stations, sites, and/or accelerograms. Moreover, the method eliminates the effect of directionality as a contributor to epistemic uncertainty.
2019-07-30T06:31:13ZPinzón, Luis A.Pujades Beneit, LluísMacau, AlbertCarreño, EmilioAlcalde Camino, Juan ManuelNormally, the average of the horizontal-to-vertical (H/V) ratios of the 5% damped response spectra of ground motions is used to classify the site of strong-motion stations. In these cases, only the three-orthogonal as-recorded acceleration components are used in the analysis, and all the vector compositions that can generate a different response for each period oscillator are excluded. In this study, the Spanish strong-motion database was used to classify the sites of accelerometric stations based on the predominant periods through the average horizontal-to-vertical spectral ratios (HVSR) of recorded ground motions. Moreover, the directionality effects using the vector composition of the horizontal components of ground motions were also considered in the estimations of H/V ratios. This consideration is a relevant novelty compared to the traditional H/V ratios methods. Only earthquakes with magnitudes above 3.5 and hypocentral distances below 200 km were selected, which resulted in 692 ground-motion records, corresponding to 86 stations, from events in the period between 1993 and 2017. After the analysis, a predominant-period site classification was assigned to each station. On the whole, the obtained mean and standard deviation values of the spectral ratios are comparable to those shown by other researchers. Therefore, the advantages of the proposed procedure, which takes the directionality effects into account, can be summarized as follows: (a) The obtained information is richer and gives enables more sophisticated and realistic analyses on the basis of percentiles and (b) it is easier to detect anomalous stations, sites, and/or accelerograms. Moreover, the method eliminates the effect of directionality as a contributor to epistemic uncertainty.Evaluation of Mallorca Cathedral seismic behavior using different analysis techniques
http://hdl.handle.net/2117/134630
Evaluation of Mallorca Cathedral seismic behavior using different analysis techniques
Elyamani, Ahmed; Roca Fabregat, Pedro; Caselles Magallón, Josep Oriol; Clapes Boixader, Jaime
The paper discusses the seismic assessment of Mallorca cathedral in Spain. This cathedral is an audacious Gothic structure built on the island of Mallorca during 14th-16th centuries, characterized by its large dimensions and slender structural members. For that purpose, different analysis methods were used. A 3D Finite Element (FE) model of the cathedral was created and then updated based on in-situ dynamic identification tests. Nonlinear static (pushover) analysis was firstly carried out applying the seismic loads in the longitudinal and transversal directions of the cathedral considering both positive and negative signs. The pushover results were compared with the results of the kinematic limit analysis as a way to cross check the seismic safety assessment. Although for such a large historical structure, the nonlinear time-history (dynamic) analysis requires a very high computer effort, an attempt to perform this type of advanced analysis was carried out.
2019-06-18T06:53:06ZElyamani, AhmedRoca Fabregat, PedroCaselles Magallón, Josep OriolClapes Boixader, JaimeThe paper discusses the seismic assessment of Mallorca cathedral in Spain. This cathedral is an audacious Gothic structure built on the island of Mallorca during 14th-16th centuries, characterized by its large dimensions and slender structural members. For that purpose, different analysis methods were used. A 3D Finite Element (FE) model of the cathedral was created and then updated based on in-situ dynamic identification tests. Nonlinear static (pushover) analysis was firstly carried out applying the seismic loads in the longitudinal and transversal directions of the cathedral considering both positive and negative signs. The pushover results were compared with the results of the kinematic limit analysis as a way to cross check the seismic safety assessment. Although for such a large historical structure, the nonlinear time-history (dynamic) analysis requires a very high computer effort, an attempt to perform this type of advanced analysis was carried out.Dynamic investigation of a large historical cathedral
http://hdl.handle.net/2117/133809
Dynamic investigation of a large historical cathedral
Elyamani, Ahmed; Caselles Magallón, Josep Oriol; Roca Fabregat, Pedro; Clapes Boixader, Jaime
The presented research aimed at studying the dynamic behavior of Mallorca cathedral (Mallorca Island, Spain) under ambient sources of vibration and seismic events. The cathedral is one of the greatest built masonry structures worldwide. It is characterized for its audacious dimensions and slender structural members. Because of it, the study of its dynamic behavior is a clear concern. The cathedral dynamic properties were firstly identified using ambient vibration testing. Afterwards, a dynamic monitoring system was implemented to continuously measure, record, and wirelessly transfer the acceleration records without having to set up an activating threshold. This monitoring type was implemented because of the low seismic intensity of Mallorca Island with a basic ground acceleration of only 0.04 g according to the Spanish seismic standard. The continuous monitoring allowed for capturing some seismic events and some drops in the natural frequencies were noticed because of a breathing crack effect. Using both ambient vibration testing and continuous monitoring system, global modes could be more accurately identified than more local ones. The identification of the global modes was more attainable than in the case of more local ones. The temperature was a more influential environmental parameter than humidity and wind for all of the identified modes except for one more directly depended on wind.
This is the peer reviewed version of the following article: [Elyamani, A., Caselles, O., Roca, P., and Clapes, J. ( 2017) Dynamic investigation of a large historical cathedral, Struct. Control Health Monit., 24: e1885. doi: 10.1002/stc.1885. ], which has been published in final form at https://onlinelibrary.wiley.com/doi/abs/10.1002/stc.1885. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
2019-05-31T17:53:57ZElyamani, AhmedCaselles Magallón, Josep OriolRoca Fabregat, PedroClapes Boixader, JaimeThe presented research aimed at studying the dynamic behavior of Mallorca cathedral (Mallorca Island, Spain) under ambient sources of vibration and seismic events. The cathedral is one of the greatest built masonry structures worldwide. It is characterized for its audacious dimensions and slender structural members. Because of it, the study of its dynamic behavior is a clear concern. The cathedral dynamic properties were firstly identified using ambient vibration testing. Afterwards, a dynamic monitoring system was implemented to continuously measure, record, and wirelessly transfer the acceleration records without having to set up an activating threshold. This monitoring type was implemented because of the low seismic intensity of Mallorca Island with a basic ground acceleration of only 0.04 g according to the Spanish seismic standard. The continuous monitoring allowed for capturing some seismic events and some drops in the natural frequencies were noticed because of a breathing crack effect. Using both ambient vibration testing and continuous monitoring system, global modes could be more accurately identified than more local ones. The identification of the global modes was more attainable than in the case of more local ones. The temperature was a more influential environmental parameter than humidity and wind for all of the identified modes except for one more directly depended on wind.An alternative approach to consider the effect of seismic directionality
http://hdl.handle.net/2117/132535
An alternative approach to consider the effect of seismic directionality
Díaz Carrasco, Sergio; Pinzón, Luis A.; Pujades Beneit, Lluís; Vargas Alzate, Yeudy Felipe
Recent researches have proven the importance of considering the seismic directionality effect. The performance of buildings subjected to earthquakes depends on its orientation respect to the seismic actions applied. This type of calculation is computed using the nonlinear dynamic analysis (NLDA) and rotating the acceleration horizontal components onto all non-redundant angles, which entails a high computational cost. This paper presents an alternative approach to consider the directionality effect. The method is based on the nonlinear static analysis (NLSA) and on the energy balance between the capacity curves and the response spectra of the rotated seismic actions. This approach was applied to a 4-story steel frame building 3D-model with ground motions records from Mexico City. A high variability in the building performance is observed due to the incidence angle of the seismic action; the proposed method would allow considering this variation in the structural analysis, in an easy way, demanding less calculation time and providing results compatible with those obtained through the NLDA.
2019-05-02T13:09:25ZDíaz Carrasco, SergioPinzón, Luis A.Pujades Beneit, LluísVargas Alzate, Yeudy FelipeRecent researches have proven the importance of considering the seismic directionality effect. The performance of buildings subjected to earthquakes depends on its orientation respect to the seismic actions applied. This type of calculation is computed using the nonlinear dynamic analysis (NLDA) and rotating the acceleration horizontal components onto all non-redundant angles, which entails a high computational cost. This paper presents an alternative approach to consider the directionality effect. The method is based on the nonlinear static analysis (NLSA) and on the energy balance between the capacity curves and the response spectra of the rotated seismic actions. This approach was applied to a 4-story steel frame building 3D-model with ground motions records from Mexico City. A high variability in the building performance is observed due to the incidence angle of the seismic action; the proposed method would allow considering this variation in the structural analysis, in an easy way, demanding less calculation time and providing results compatible with those obtained through the NLDA.A probabilistic approach for seismic risk assessment based on vulnerability functions: application to Barcelona
http://hdl.handle.net/2117/130231
A probabilistic approach for seismic risk assessment based on vulnerability functions: application to Barcelona
Aguilar Meléndez, Armando; Pujades Beneit, Lluís; Barbat Barbat, Horia Alejandro; Ordaz Schroeder, Mario Gustavo; Puente, Josep de la; Lantada Zarzosa, Maria de Las Nieves; Rodriguez Lozoya, H.E.
Risk assessment and management is an important step towards resilient and sustainable cities. Among many other perils, both natural and manmade, seismic risk is a major threat for resilience and sustainability. In recent decades, several methods for seismic risk assessment have been proposed, including the well-known Vulnerability Index Method (VIM). In this study, a probabilistic version of the VIM, which we call the Vulnerability Index Method-Probabilistic (VIM_P), is proposed. The VIM_P requires essential information on the seismic hazard and on the vulnerability of the building stock. Seismic hazard is determined using the exceedance rates of macroseismic intensities, as defined in the European Macroseismic Scale (EMS). Seismic vulnerability is defined by means of vulnerability probability density functions (pdf) that describe the probability distribution of the corresponding vulnerability index. Beta-like functions are used for these pdfs. VIM_P quantifies seismic vulnerability by means of three vulnerability curves, Lower, Best and Upper, according to the quantity and quality of available information, thus allowing three estimates of seismic vulnerability and risk. Then, seismic risk is computed via the convolution of seismic hazard and seismic vulnerability, considering semi-empirical damage functions. Seismic risk is given through the exceedance frequencies of the damage grades. To highlight the capabilities of the VIM_P, the seismic risk of about 70,000 residential buildings in Barcelona was assessed. According to the results, the exceedance frequency of the collapse damage state for more than the 50% of the buildings in the Eixample district would be greater than 1 × 10-5. This confirms the relatively high seismic risk in the city, mainly due to the high vulnerability of the built environment. Specific software, USERISK20015, has been developed for routine applications of VIM_P. It is hoped that VIM_P and this new tool for seismic risk assessment will be useful to stakeholders and civil protection authorities for risk management and prioritizing actions that can help to create more resilient, sustainable cities.
The final publication is available at Springer via http://dx.doi.org/10.1007/s10518-018-0516-4
2019-03-12T11:47:33ZAguilar Meléndez, ArmandoPujades Beneit, LluísBarbat Barbat, Horia AlejandroOrdaz Schroeder, Mario GustavoPuente, Josep de laLantada Zarzosa, Maria de Las NievesRodriguez Lozoya, H.E.Risk assessment and management is an important step towards resilient and sustainable cities. Among many other perils, both natural and manmade, seismic risk is a major threat for resilience and sustainability. In recent decades, several methods for seismic risk assessment have been proposed, including the well-known Vulnerability Index Method (VIM). In this study, a probabilistic version of the VIM, which we call the Vulnerability Index Method-Probabilistic (VIM_P), is proposed. The VIM_P requires essential information on the seismic hazard and on the vulnerability of the building stock. Seismic hazard is determined using the exceedance rates of macroseismic intensities, as defined in the European Macroseismic Scale (EMS). Seismic vulnerability is defined by means of vulnerability probability density functions (pdf) that describe the probability distribution of the corresponding vulnerability index. Beta-like functions are used for these pdfs. VIM_P quantifies seismic vulnerability by means of three vulnerability curves, Lower, Best and Upper, according to the quantity and quality of available information, thus allowing three estimates of seismic vulnerability and risk. Then, seismic risk is computed via the convolution of seismic hazard and seismic vulnerability, considering semi-empirical damage functions. Seismic risk is given through the exceedance frequencies of the damage grades. To highlight the capabilities of the VIM_P, the seismic risk of about 70,000 residential buildings in Barcelona was assessed. According to the results, the exceedance frequency of the collapse damage state for more than the 50% of the buildings in the Eixample district would be greater than 1 × 10-5. This confirms the relatively high seismic risk in the city, mainly due to the high vulnerability of the built environment. Specific software, USERISK20015, has been developed for routine applications of VIM_P. It is hoped that VIM_P and this new tool for seismic risk assessment will be useful to stakeholders and civil protection authorities for risk management and prioritizing actions that can help to create more resilient, sustainable cities.An efficient methodology to estimate probabilistic seismic damage curves
http://hdl.handle.net/2117/129671
An efficient methodology to estimate probabilistic seismic damage curves
Vargas Alzate, Yeudy Felipe; Pujades Beneit, Lluís; Barbat Barbat, Horia Alejandro; Hurtado Gómez, Jorge Eduardo
The incremental dynamic analysis (IDA) is a powerful methodology that can be easily extended for calculating probabilistic seismic damage curves. These curves are metadata to assess the seismic risk of structures. Although this methodology requires a relevant computational effort, it should be the reference to correctly estimate the seismic risk of structures. Nevertheless, it would be of high practical interest to have a simpler methodology, based for instance on the pushover analysis (PA), to obtain similar results to those based on IDA. In this article, PA is used to obtain probabilistic seismic damage curves from the stiffness degradation and the energy of the nonlinear part of the capacity curve. A fully probabilistic methodology is tackled by means of Monte Carlo simulations with the purpose of establishing that the results based on the simplified proposed approach are compatible with those obtained with the IDA. Comparisons between the results of both approaches are included for a low- to midrise reinforced concrete building. The proposed methodology significantly reduces the computational effort when calculating probabilistic seismic damage curves.
2019-02-25T23:33:10ZVargas Alzate, Yeudy FelipePujades Beneit, LluísBarbat Barbat, Horia AlejandroHurtado Gómez, Jorge EduardoThe incremental dynamic analysis (IDA) is a powerful methodology that can be easily extended for calculating probabilistic seismic damage curves. These curves are metadata to assess the seismic risk of structures. Although this methodology requires a relevant computational effort, it should be the reference to correctly estimate the seismic risk of structures. Nevertheless, it would be of high practical interest to have a simpler methodology, based for instance on the pushover analysis (PA), to obtain similar results to those based on IDA. In this article, PA is used to obtain probabilistic seismic damage curves from the stiffness degradation and the energy of the nonlinear part of the capacity curve. A fully probabilistic methodology is tackled by means of Monte Carlo simulations with the purpose of establishing that the results based on the simplified proposed approach are compatible with those obtained with the IDA. Comparisons between the results of both approaches are included for a low- to midrise reinforced concrete building. The proposed methodology significantly reduces the computational effort when calculating probabilistic seismic damage curves.Do directionality effects influence expected damage? A case study of the 2017 central Mexico earthquake
http://hdl.handle.net/2117/124754
Do directionality effects influence expected damage? A case study of the 2017 central Mexico earthquake
Pinzón, Luis A.; Pujades Beneit, Lluís; Díaz, Sergio Alberto; Alva, Rodrigo Esteban
We analyze the case of a building that collapsed in a multifamily complex of Tlalpan borough in Mexico City during the 19 September 2017 Central Mexico earthquake. Despite having similar materials and similar structural and geometric properties, this was the only building that collapsed in the complex. A structural analysis of the building and a study of the soils’ predominant periods indicated that resonance effects, if any, would not be significant. However, phenomena related to the anomalous performance of buildings in dense urban areas such as geological soil, soil–structure interaction, and soil–city interaction effects were also investigated. A detailed analysis of the directionality of seismic actions recorded at nearby accelerometric stations and of the azimuths of sound and damaged buildings indicates that directionality effects were responsible for the collapse of the building.
Subsequently, a set of 58, two-component acceleration records of the earthquake was used to perform a thorough directionality analysis. The results were then compared with the foreseen uniform hazard response spectra and the design spectra in the city. Seismic actions in the city due to this earthquake were stronger than those corresponding to the uniform hazard response spectra. In addition, although design spectra have been significantly improved in the new 2017 Mexican seismic regulations, they were exceeded in 11 of 58 analyzed spectra. In 4 of these 11 cases, the design spectra were exceeded due to directionality effects. These results confirm the necessity of considering directionality effects in damage assessments, strong-motion prediction equations, and design regulations.
2018-11-20T13:20:40ZPinzón, Luis A.Pujades Beneit, LluísDíaz, Sergio AlbertoAlva, Rodrigo EstebanWe analyze the case of a building that collapsed in a multifamily complex of Tlalpan borough in Mexico City during the 19 September 2017 Central Mexico earthquake. Despite having similar materials and similar structural and geometric properties, this was the only building that collapsed in the complex. A structural analysis of the building and a study of the soils’ predominant periods indicated that resonance effects, if any, would not be significant. However, phenomena related to the anomalous performance of buildings in dense urban areas such as geological soil, soil–structure interaction, and soil–city interaction effects were also investigated. A detailed analysis of the directionality of seismic actions recorded at nearby accelerometric stations and of the azimuths of sound and damaged buildings indicates that directionality effects were responsible for the collapse of the building.
Subsequently, a set of 58, two-component acceleration records of the earthquake was used to perform a thorough directionality analysis. The results were then compared with the foreseen uniform hazard response spectra and the design spectra in the city. Seismic actions in the city due to this earthquake were stronger than those corresponding to the uniform hazard response spectra. In addition, although design spectra have been significantly improved in the new 2017 Mexican seismic regulations, they were exceeded in 11 of 58 analyzed spectra. In 4 of these 11 cases, the design spectra were exceeded due to directionality effects. These results confirm the necessity of considering directionality effects in damage assessments, strong-motion prediction equations, and design regulations.Directionality models from ground motions of Italy
http://hdl.handle.net/2117/124748
Directionality models from ground motions of Italy
Pinzón, Luis A.; Pujades Beneit, Lluís; Hidalgo Leiva, D.A.; Díaz, Sergio Alberto
Directionality effects on the expected strong ground motion in Italy are investigated. After a brief description of the directionality effect and the intensity measures involved, a wide Italian database of strong ground motion records is used, with a total of 949 horizontal accelerograms (two components). The analysis is performed for 5% damped response spectra in the 0.01-4 s period range. Rotation-independent intensity measures, resulting from combining maximum values of the as-recorded accelerograms, are investigated. The study has also been performed using maximum values of the time histories resulting from the previous combination of as-recorded time histories. Ratios between these rotation-independent intensity measures and those formerly used in ground motion predictive equations have been computed and modelled by means of a simple theoretical model. Thus, the results are useful for updating former strong ground motion predictive equations in a simple and straightforward way.
2018-11-20T13:01:52ZPinzón, Luis A.Pujades Beneit, LluísHidalgo Leiva, D.A.Díaz, Sergio AlbertoDirectionality effects on the expected strong ground motion in Italy are investigated. After a brief description of the directionality effect and the intensity measures involved, a wide Italian database of strong ground motion records is used, with a total of 949 horizontal accelerograms (two components). The analysis is performed for 5% damped response spectra in the 0.01-4 s period range. Rotation-independent intensity measures, resulting from combining maximum values of the as-recorded accelerograms, are investigated. The study has also been performed using maximum values of the time histories resulting from the previous combination of as-recorded time histories. Ratios between these rotation-independent intensity measures and those formerly used in ground motion predictive equations have been computed and modelled by means of a simple theoretical model. Thus, the results are useful for updating former strong ground motion predictive equations in a simple and straightforward way.