A personal computer processing system for simulation of earthquake seismogeny, occurrence and development is given in this paper. It can automatically process the discontinuous events such as earthquake occurrence dur...A personal computer processing system for simulation of earthquake seismogeny, occurrence and development is given in this paper. It can automatically process the discontinuous events such as earthquake occurrence during computation. The program can be paused when you want to display the computation results. After you analyze these graphical results the simulation process can be continued.展开更多
We use an efficient earthquake simulator that incorporates rate-state constitutive properties and uses boundary element method to discretize the fault surfaces, to generate the synthetic earthquakes in the fault syste...We use an efficient earthquake simulator that incorporates rate-state constitutive properties and uses boundary element method to discretize the fault surfaces, to generate the synthetic earthquakes in the fault system. Rate-and-state seismicity equation is subsequently employed to calculate the seismicity rate in a region of interest using the Coulomb stress transfer from the main shocks in the fault system. The Coulomb stress transfer is obtained by resolving the induced stresses due to the fault patch slips onto the optimal-oriented fault planes. The example results show that immediately after a main shock the aftershocks are concentrated in the vicinity of the rupture area due to positive stress transfers and then dis- perse away into the surrounding region toward the back- ground rate distribution. The number of aftershocks near the rupture region is found to decay with time as Omori aftershock decay law predicts. The example results dem- onstrate that the rate-and-state fault system earthquakesimulator and the seismicity equations based on the rate- state friction nucleation of earthquake are well posited to characterize the aftershock distribution in regional assess- ments of earthquake probabilities.展开更多
Introduction In recent years, all kinds of observation networks of seismology have been established, which have been continuously producing numerous digital information. In addition, there are many study results about...Introduction In recent years, all kinds of observation networks of seismology have been established, which have been continuously producing numerous digital information. In addition, there are many study results about 3D velocity structure model and tectonic model of crust (Huang and Zhao, 2006; Huang et al, 2003; Li and Mooney, 1998), which are valuable for studying the inner structure of the earth and earthquake preparation process. It is badly needed to combine the observed data, experimental study and theoretical analyses results by the way of numerical simulation and develop a database and a corresponding application platform to be used by numerical simulation, and is also a significant way to promote earthquake prediction.展开更多
According to the precursory data of the 1976 Tangshan earthquake( M =7.8), and combining with the research results of rock fracture, seismic source, tectonics, seismic precursors, dynamic condition and crust structu...According to the precursory data of the 1976 Tangshan earthquake( M =7.8), and combining with the research results of rock fracture, seismic source, tectonics, seismic precursors, dynamic condition and crust structure, the seismogenic process of Tangshan earthquake has been numerically simulated by using the model of water saturated porous medium with a rhombic hard inclusion. First, a system of seismogenic dynamics equations of solid liquid two phase medium has been set up under considering rock inelastic dilation, strain softening and pore water permeation. Then, the finite difference method to solve the equation system in incremental form has been presented. Finally, the seismogenic process of Tangshan earthquake and the temporal spatial characteristics of its precursors have been numerically simulated when the hard inclusion includes a soft fault belt. The numerically simulating result shows that the development of Tangshan earthquake mainly undergoes following processes: elastic accumulation, early inelastic cubic dilation, accelerative softening (failure and creep) of fault first time, inelastic dilation twice in Tianjin—Ninghe area, accelerative softening of fault twice and instability. Corresponding to the fault accelerative softening, elastic recovery and inelastic dilation twice in some parts of seismogenic medium. By comparing with the data of precursory observation, ones can find the preceding simulating result explains the varied characters of practical data better. Meanwhile, the numerical simulation further displays the temporal spatial change law and complex patterns of the field of Tangshan earthquake development as well. It makes a base study for the physical mechanism of change of the seismic precursory field.展开更多
Based on a simplified media model of Gonghe area, the precursor characteristics of Gonghe M 7.0 earthquake in 1990 are simulated in this paper by using the constitutive relationship of binary medium (solid and wate...Based on a simplified media model of Gonghe area, the precursor characteristics of Gonghe M 7.0 earthquake in 1990 are simulated in this paper by using the constitutive relationship of binary medium (solid and water). The results show that the simulated state distribution and extension variation of media are identical with the spatial and temporal distribution of reliable anomalies before Gonghe earthquake. The study also suggests that the development of the Gonghe earthquake has experienced a series of processes such as elastic deformation of large scale, early nonelastic dilatation, strain softening and elastic recovery in the neighbour region of Xining, nonelasscale, early nonelastic dilatation, strain softening and elastic recovery in the neighbour region of nonelastic dilatation of high dense block near seismic source and earthquake occurrence. Therefore, it can be concluded that this earthquake development is neither a simple process for fissures developing and linking up with one another, nor a process of nonelastic volume expanion and water flowing into medium around seismic source, conrary, it is a complicated medium saate changing process, and the style of such changing depends on geological structure environment of seismic source and its neighbour region. It is considered that different earthquakes are accompanied by different geological conditions, the spatial and temporal behavior of their precusors are certainly different.展开更多
Recently published results of field and laboratory experiments on the seismic/acoustic response to injection of direct current (DC) pulses into the Earth crust or stressed rock samples raised a question on a possibi...Recently published results of field and laboratory experiments on the seismic/acoustic response to injection of direct current (DC) pulses into the Earth crust or stressed rock samples raised a question on a possibility of electrical earthquake triggering. A physical mechanism of the considered phenomenon is not clear yet in view of the very low current density (10-7-10-s A/m^2) generated by the pulsed power systems at the epicenter depth (5-10 km) of local earthquakes occurred just after the current injection. The paper describes results of laboratory "earthquake" triggering by DC pulses under conditions of a spring-block model simulated the seismogenic fault. It is experimentally shown that the electric triggering of the laboratory "earthquake" (sharp slip of a movable block of the spring-block system) is possible only within a range of subcritical state of the system, when the shear stress between the movable and fixed blocks obtains 0.98-0.99 of its critical value. The threshold of electric triggering action is about 20 A/m^2 that is 7-8 orders of magnitude higher than estimated electric current density for Bishkek test site (Northern Tien Shan, Kirghizia) where the seismic response to the man-made electric action was observed. In this connection, the electric triggering phenomena may be explained by contraction of electric current in the narrow conductive areas of the faults and the corresponding increase in current density or by involving the secondary triggering mechanisms like electromagnetic stimulation of conductive fluid migration into the fault area resulted in decrease in the fault strength properties.展开更多
Earthquake simulator tests of a 1/6-scale nine-story reinforced concrete frame-wall model are described in the paper. The test results and associated numerical simulation are summarized and discussed. Based on the tes...Earthquake simulator tests of a 1/6-scale nine-story reinforced concrete frame-wall model are described in the paper. The test results and associated numerical simulation are summarized and discussed. Based on the test data, a relationship between maximum inter-story drift and damage state is established. Equations of variation of structural characteristics (natural frequency and equivalent stiffness) with overall drifts are derived by data fitting, which can be used to estimate structural damage state if structural characteristics can be measured. A comparison of the analytical and experimental results show that both the commonly used equivalent beam and fiber element models can simulate the nonlinear seismic response of structures very well. Finally, conclusions associated with seismic design and damage evaluation of RC structures are presented.展开更多
Following a quasi-dynamic scheme proposed by Minear and Toksoz (1970), thermal structures of subduction zonesfor different models by finite element method (FEM) were calculated. Density distribution and p-wave anomaly...Following a quasi-dynamic scheme proposed by Minear and Toksoz (1970), thermal structures of subduction zonesfor different models by finite element method (FEM) were calculated. Density distribution and p-wave anomaly ofsubduction zones were calculated at the same time. Comparing with seismological evidences and results of laboratories. it is proposed that earthquakes occurred below 400 km depth are probably controlled by anti-crackmechanism.展开更多
For a disaster whose scale includes an urban area, it is difficult to be studied with physical experiments. Numerical simulation is found a very efficient tool for such problem. This paper aims at developing an integr...For a disaster whose scale includes an urban area, it is difficult to be studied with physical experiments. Numerical simulation is found a very efficient tool for such problem. This paper aims at developing an integrated urban earthquake simulation system (UESS) that uses GIS as the model source, CAD as the model generating tools, FEA as damage prediction, and virtual reality (VR) as the post-process platform. An automatic procedure was developed to buildup the 3D structural model of buildings in an urban area, as well as to simulate their earthquake performances, from the digital map of GIS. And the simulation results were presented in an integrated interface with a GIS view-port for position finding, a CAD view-port for 3D structural damage identification, and a VR view-port for 3D dynamic structural vibration display. An urban example with more than 7000 buildings was select to demonstrate the feasibility of proposed system.展开更多
A new combined steel lead damper (NCSLD) was presented. Construction and working mechanism of NCSLD were introduced,pseudo-static tests of the small size dampers which would be used in the subsequent shaking table tes...A new combined steel lead damper (NCSLD) was presented. Construction and working mechanism of NCSLD were introduced,pseudo-static tests of the small size dampers which would be used in the subsequent shaking table tests were carried out for the study of mechanical properties of NCSLD using electro-hydraulic servo press-shear machine. Processing technology of the damper was improved. Shaking table tests under two-dimensional excitation on structural aseismic control of a one-story structure model were carried out using the small size NCSLD; parameters of the structure and shaking table were also introduced. Results indicate that process improvement is beneficial to the implementation of working mechanism of the damper,NCSLD has full hysteresis loop which takes on bilinearity,NCSLD has obvious energy dissipation effect and it can control structural seismic response effectively.展开更多
Based on the assumption that concrete is macroscopic homogeneous,the cracking evolution process and damage mode of high arch dams are studied in consideration of the heterogeneity of concrete in mesos-cale.The bilinea...Based on the assumption that concrete is macroscopic homogeneous,the cracking evolution process and damage mode of high arch dams are studied in consideration of the heterogeneity of concrete in mesos-cale.The bilinear damage evolution model and the damage evolution model expressed in power function with descending section are adopted to combine with the Mohr-Coulomb criterion with tension cut-off to investigate the crack development and fracture mode of high arch dams under the action of an earthquake.The analysis result of a high arch dam in China under design shows that cracks that take place in concrete are caused by excessive tensile stress.The cracks initiate at the middle of the dam top and distribute at the upper half of the dam while the rest of the parts remain intact.This conclusion agrees with the model test result.展开更多
This study achieved the construction of earthquake disaster scenarios based on physics-based methods-from fault dynamic rupture to seismic wave propagation-and then population and economic loss estimations.The physics...This study achieved the construction of earthquake disaster scenarios based on physics-based methods-from fault dynamic rupture to seismic wave propagation-and then population and economic loss estimations.The physics-based dynamic rupture and strong ground motion simulations can fully consider the three-dimensional complexity of physical parameters such as fault geometry,stress field,rock properties,and terrain.Quantitative analysis of multiple seismic disaster scenarios along the Qujiang Fault in western Yunnan Province in southwestern China based on different nucleation locations was achieved.The results indicate that the northwestern segment of the Qujiang Fault is expected to experience significantly higher levels of damage compared to the southeastern segment.Additionally,there are significant variations in human losses,even though the economic losses are similar across different scenarios.Dali Bai Autonomous Prefecture,Chuxiong Yi Autonomous Prefecture,Yuxi City,Honghe Hani and Yi Autonomous Prefecture,and Wenshan Zhuang and Miao Autonomous Prefecture were identified as at medium to high seismic risks,with Yuxi and Honghe being particularly vulnerable.Implementing targeted earthquake prevention measures in Yuxi and Honghe will significantly mitigate the potential risks posed by the Qujiang Fault.Notably,although the fault is within Yuxi,Honghe is likely to suffer the most severe damage.These findings emphasize the importance of considering rupture directivity and its influence on ground motion distribution when assessing seismic risk.展开更多
In this article, the fragility of reinforced concrete and steel structures in Bucharest, a city of high seismic hazard, designed using the recent building codes in Romania, is assessed. A total of 24 reinforced concre...In this article, the fragility of reinforced concrete and steel structures in Bucharest, a city of high seismic hazard, designed using the recent building codes in Romania, is assessed. A total of 24 reinforced concrete and steel structures with heights varying from five stories to 13 stories were analyzed. Their seismic fragility was evaluated using two procedures from the literature. In the first procedure(SPO2 FRAG), the fragility was derived based on the pushover curves using the SPO2 IDA algorithm, while in the second procedure(FRACAS), the fragility was derived from nonlinear time-history analyses. The analyzed structures were designed for three levels of peak ground accelerations, corresponding to mean return periods of 100,225, and 475 years. Subsequently, the damage assessment of the analyzed structures was performed using ground motions generated from a Monte-Carlo simulated earthquake catalogue for the Vrancea intermediate-depth seismic source. The damage degrees that were estimated using the SPO2 FRAG approach are higher than those estimated using the FRACAS approach. The life-cycle analysis of the structures shows that a further increase of the design peak ground acceleration for Bucharest is feasible from an economic point of view using the SPO2 FRAG results.However, based on the FRACAS results, the opposite conclusion can be drawn. Finally, generic lognormal fragility functions are proposed as a function of building height and structural system.展开更多
文摘A personal computer processing system for simulation of earthquake seismogeny, occurrence and development is given in this paper. It can automatically process the discontinuous events such as earthquake occurrence during computation. The program can be paused when you want to display the computation results. After you analyze these graphical results the simulation process can be continued.
基金supported by the NSF Frontiers in Earth-System Dynamics(EAR-1135455)the Extreme Science and Engineering Discovery Environment(XSEDE),which is supported by National Natural Science Foundation grant No.OCI-1053575the Blue Waters sustained-petascale computing project,which is supported by the National Natural Science Foundation(award No.OCI 07-25070)and the state of Illinois
文摘We use an efficient earthquake simulator that incorporates rate-state constitutive properties and uses boundary element method to discretize the fault surfaces, to generate the synthetic earthquakes in the fault system. Rate-and-state seismicity equation is subsequently employed to calculate the seismicity rate in a region of interest using the Coulomb stress transfer from the main shocks in the fault system. The Coulomb stress transfer is obtained by resolving the induced stresses due to the fault patch slips onto the optimal-oriented fault planes. The example results show that immediately after a main shock the aftershocks are concentrated in the vicinity of the rupture area due to positive stress transfers and then dis- perse away into the surrounding region toward the back- ground rate distribution. The number of aftershocks near the rupture region is found to decay with time as Omori aftershock decay law predicts. The example results dem- onstrate that the rate-and-state fault system earthquakesimulator and the seismicity equations based on the rate- state friction nucleation of earthquake are well posited to characterize the aftershock distribution in regional assess- ments of earthquake probabilities.
基金Specific fund from the Ministry of Science and Technology (2002DEB30092)
文摘Introduction In recent years, all kinds of observation networks of seismology have been established, which have been continuously producing numerous digital information. In addition, there are many study results about 3D velocity structure model and tectonic model of crust (Huang and Zhao, 2006; Huang et al, 2003; Li and Mooney, 1998), which are valuable for studying the inner structure of the earth and earthquake preparation process. It is badly needed to combine the observed data, experimental study and theoretical analyses results by the way of numerical simulation and develop a database and a corresponding application platform to be used by numerical simulation, and is also a significant way to promote earthquake prediction.
文摘According to the precursory data of the 1976 Tangshan earthquake( M =7.8), and combining with the research results of rock fracture, seismic source, tectonics, seismic precursors, dynamic condition and crust structure, the seismogenic process of Tangshan earthquake has been numerically simulated by using the model of water saturated porous medium with a rhombic hard inclusion. First, a system of seismogenic dynamics equations of solid liquid two phase medium has been set up under considering rock inelastic dilation, strain softening and pore water permeation. Then, the finite difference method to solve the equation system in incremental form has been presented. Finally, the seismogenic process of Tangshan earthquake and the temporal spatial characteristics of its precursors have been numerically simulated when the hard inclusion includes a soft fault belt. The numerically simulating result shows that the development of Tangshan earthquake mainly undergoes following processes: elastic accumulation, early inelastic cubic dilation, accelerative softening (failure and creep) of fault first time, inelastic dilation twice in Tianjin—Ninghe area, accelerative softening of fault twice and instability. Corresponding to the fault accelerative softening, elastic recovery and inelastic dilation twice in some parts of seismogenic medium. By comparing with the data of precursory observation, ones can find the preceding simulating result explains the varied characters of practical data better. Meanwhile, the numerical simulation further displays the temporal spatial change law and complex patterns of the field of Tangshan earthquake development as well. It makes a base study for the physical mechanism of change of the seismic precursory field.
文摘Based on a simplified media model of Gonghe area, the precursor characteristics of Gonghe M 7.0 earthquake in 1990 are simulated in this paper by using the constitutive relationship of binary medium (solid and water). The results show that the simulated state distribution and extension variation of media are identical with the spatial and temporal distribution of reliable anomalies before Gonghe earthquake. The study also suggests that the development of the Gonghe earthquake has experienced a series of processes such as elastic deformation of large scale, early nonelastic dilatation, strain softening and elastic recovery in the neighbour region of Xining, nonelasscale, early nonelastic dilatation, strain softening and elastic recovery in the neighbour region of nonelastic dilatation of high dense block near seismic source and earthquake occurrence. Therefore, it can be concluded that this earthquake development is neither a simple process for fissures developing and linking up with one another, nor a process of nonelastic volume expanion and water flowing into medium around seismic source, conrary, it is a complicated medium saate changing process, and the style of such changing depends on geological structure environment of seismic source and its neighbour region. It is considered that different earthquakes are accompanied by different geological conditions, the spatial and temporal behavior of their precusors are certainly different.
基金funded by Russian Foundation for Basic Research according to research project No.15-55-53104National Natural Science Foundation of China according to International cooperation project No.41511130032
文摘Recently published results of field and laboratory experiments on the seismic/acoustic response to injection of direct current (DC) pulses into the Earth crust or stressed rock samples raised a question on a possibility of electrical earthquake triggering. A physical mechanism of the considered phenomenon is not clear yet in view of the very low current density (10-7-10-s A/m^2) generated by the pulsed power systems at the epicenter depth (5-10 km) of local earthquakes occurred just after the current injection. The paper describes results of laboratory "earthquake" triggering by DC pulses under conditions of a spring-block model simulated the seismogenic fault. It is experimentally shown that the electric triggering of the laboratory "earthquake" (sharp slip of a movable block of the spring-block system) is possible only within a range of subcritical state of the system, when the shear stress between the movable and fixed blocks obtains 0.98-0.99 of its critical value. The threshold of electric triggering action is about 20 A/m^2 that is 7-8 orders of magnitude higher than estimated electric current density for Bishkek test site (Northern Tien Shan, Kirghizia) where the seismic response to the man-made electric action was observed. In this connection, the electric triggering phenomena may be explained by contraction of electric current in the narrow conductive areas of the faults and the corresponding increase in current density or by involving the secondary triggering mechanisms like electromagnetic stimulation of conductive fluid migration into the fault area resulted in decrease in the fault strength properties.
基金Basic Research Fund of Institute of Engineering Mechanics, China Earthquake Administration for Special Project Under Grant No.2007A02Joint Earthquake Science Foundation of China Under Grant No.95-07-443
文摘Earthquake simulator tests of a 1/6-scale nine-story reinforced concrete frame-wall model are described in the paper. The test results and associated numerical simulation are summarized and discussed. Based on the test data, a relationship between maximum inter-story drift and damage state is established. Equations of variation of structural characteristics (natural frequency and equivalent stiffness) with overall drifts are derived by data fitting, which can be used to estimate structural damage state if structural characteristics can be measured. A comparison of the analytical and experimental results show that both the commonly used equivalent beam and fiber element models can simulate the nonlinear seismic response of structures very well. Finally, conclusions associated with seismic design and damage evaluation of RC structures are presented.
文摘Following a quasi-dynamic scheme proposed by Minear and Toksoz (1970), thermal structures of subduction zonesfor different models by finite element method (FEM) were calculated. Density distribution and p-wave anomaly ofsubduction zones were calculated at the same time. Comparing with seismological evidences and results of laboratories. it is proposed that earthquakes occurred below 400 km depth are probably controlled by anti-crackmechanism.
基金the National Key Project of Scientific and Technical Supporting Programs by Ministry of Science & Technology of China(No. 2006BAK01A02-09)
文摘For a disaster whose scale includes an urban area, it is difficult to be studied with physical experiments. Numerical simulation is found a very efficient tool for such problem. This paper aims at developing an integrated urban earthquake simulation system (UESS) that uses GIS as the model source, CAD as the model generating tools, FEA as damage prediction, and virtual reality (VR) as the post-process platform. An automatic procedure was developed to buildup the 3D structural model of buildings in an urban area, as well as to simulate their earthquake performances, from the digital map of GIS. And the simulation results were presented in an integrated interface with a GIS view-port for position finding, a CAD view-port for 3D structural damage identification, and a VR view-port for 3D dynamic structural vibration display. An urban example with more than 7000 buildings was select to demonstrate the feasibility of proposed system.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50508012)Science &Technology Plan Project of Guangdong Province(Grant No. 20055190030)+1 种基金Key Basic Research Project of Science and Technology Ministry (Grant No. 2004CCA03300)Science &Technology Project of Guangzhou Education Bureau(Grant No.08C05)
文摘A new combined steel lead damper (NCSLD) was presented. Construction and working mechanism of NCSLD were introduced,pseudo-static tests of the small size dampers which would be used in the subsequent shaking table tests were carried out for the study of mechanical properties of NCSLD using electro-hydraulic servo press-shear machine. Processing technology of the damper was improved. Shaking table tests under two-dimensional excitation on structural aseismic control of a one-story structure model were carried out using the small size NCSLD; parameters of the structure and shaking table were also introduced. Results indicate that process improvement is beneficial to the implementation of working mechanism of the damper,NCSLD has full hysteresis loop which takes on bilinearity,NCSLD has obvious energy dissipation effect and it can control structural seismic response effectively.
文摘Based on the assumption that concrete is macroscopic homogeneous,the cracking evolution process and damage mode of high arch dams are studied in consideration of the heterogeneity of concrete in mesos-cale.The bilinear damage evolution model and the damage evolution model expressed in power function with descending section are adopted to combine with the Mohr-Coulomb criterion with tension cut-off to investigate the crack development and fracture mode of high arch dams under the action of an earthquake.The analysis result of a high arch dam in China under design shows that cracks that take place in concrete are caused by excessive tensile stress.The cracks initiate at the middle of the dam top and distribute at the upper half of the dam while the rest of the parts remain intact.This conclusion agrees with the model test result.
基金supported by the Guangdong Provincial Key Laboratory of Geophysical High-Resolution Imaging Technology (2022B1212010002)Key Special Project for Introduced Talents Team of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2019ZD0203)the Shenzhen Science and Technology Program (KQTD20170810111725321)
文摘This study achieved the construction of earthquake disaster scenarios based on physics-based methods-from fault dynamic rupture to seismic wave propagation-and then population and economic loss estimations.The physics-based dynamic rupture and strong ground motion simulations can fully consider the three-dimensional complexity of physical parameters such as fault geometry,stress field,rock properties,and terrain.Quantitative analysis of multiple seismic disaster scenarios along the Qujiang Fault in western Yunnan Province in southwestern China based on different nucleation locations was achieved.The results indicate that the northwestern segment of the Qujiang Fault is expected to experience significantly higher levels of damage compared to the southeastern segment.Additionally,there are significant variations in human losses,even though the economic losses are similar across different scenarios.Dali Bai Autonomous Prefecture,Chuxiong Yi Autonomous Prefecture,Yuxi City,Honghe Hani and Yi Autonomous Prefecture,and Wenshan Zhuang and Miao Autonomous Prefecture were identified as at medium to high seismic risks,with Yuxi and Honghe being particularly vulnerable.Implementing targeted earthquake prevention measures in Yuxi and Honghe will significantly mitigate the potential risks posed by the Qujiang Fault.Notably,although the fault is within Yuxi,Honghe is likely to suffer the most severe damage.These findings emphasize the importance of considering rupture directivity and its influence on ground motion distribution when assessing seismic risk.
文摘In this article, the fragility of reinforced concrete and steel structures in Bucharest, a city of high seismic hazard, designed using the recent building codes in Romania, is assessed. A total of 24 reinforced concrete and steel structures with heights varying from five stories to 13 stories were analyzed. Their seismic fragility was evaluated using two procedures from the literature. In the first procedure(SPO2 FRAG), the fragility was derived based on the pushover curves using the SPO2 IDA algorithm, while in the second procedure(FRACAS), the fragility was derived from nonlinear time-history analyses. The analyzed structures were designed for three levels of peak ground accelerations, corresponding to mean return periods of 100,225, and 475 years. Subsequently, the damage assessment of the analyzed structures was performed using ground motions generated from a Monte-Carlo simulated earthquake catalogue for the Vrancea intermediate-depth seismic source. The damage degrees that were estimated using the SPO2 FRAG approach are higher than those estimated using the FRACAS approach. The life-cycle analysis of the structures shows that a further increase of the design peak ground acceleration for Bucharest is feasible from an economic point of view using the SPO2 FRAG results.However, based on the FRACAS results, the opposite conclusion can be drawn. Finally, generic lognormal fragility functions are proposed as a function of building height and structural system.