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Long-span infrastructures are usually taken over for public shelters, in which single-layer reticulated dome is a kind of popular structure. But there was less research for the damage assessment of single-layer reticulated domes subjected to mainshock-aftershock sequences. How to accurately assess the damage by mainshock and the stability redundancy for aftershock becomes an important problem. In order to explore the effects on the structural damage, this paper processes the dynamic time-history analyses for single-layer reticulated domes subjected to mainshock-aftershock sequences. The finite element model of Kiewitt8 single-layer spherical reticulated shell structure is established in ANSYS. Ten pairs of ground motion sequences in horizontal direction are generated with modulating amplitude to simulate the rare and extreme earthquakes. The results demonstrated that the structure even suffered from the extreme earthquake mainshock still has loading capacity and structural safety with the local plastic damage. But the effect on structural damage of aftershock ground motion with greater earthquake intensity cannot be ignored for single-layer reticulated domes. A structural damage assessment method is utilized with combining the damage factor by performing static stability analysis twice. It can effectively reflect the remaining loading capacity and structural safety factor for the practical seismic engineering applications.

Much effort has been made in investigating the seismic response and failure mechanism of rectangular subway stations, however, the influence of earth retaining systems has generally been ignored in previous studies. This paper presents a numerical study on the seismic performance of a rectangular subway station with/without earth retaining systems by taking fender piles as the example, and aims to illustrate how the existence of fender piles affects seismic responses on subway stations. The loading conditions of subway stations and their surrounding soils prior to earthquakes are discussed. Next, seismic responses of subway stations with or without fender piles were simulated. Afterward, earthquake-induced deformations of stations and surrounding soils, as well as the internal forces and damage modes of the structural components, were systematically studied. Consequently, the seismic performance of the stations was affected by the existence of fender piles. In addition, earthquake intensity is illustrated. The study showed that deformation modes of surrounding soils and damage modes of stations were different with regard to the existence of fender piles. Meanwhile, earthquake intensity influencing the seismic performance of stations with or without fender piles were found to be opposite.

It is well known that earthquake brings about gigantic direct and indirect economic losses, such as building and lifeline system damages, every year at the global scales. Thus, efficient and accurately estimate the economic loss after earthquake is one of the important factors for the post-earthquake reconstruction and the recovery activity of ordinary life. To estimate the earthquake-induced direct economic losses (DEL), a regression empirical method based on the earthquake-induced direct building damage economic losses (DBDEL) is proposed in this study. Firstly, a linear model between DBDEL of the entire earthquake impact areas and the DBDEL of areas with earthquake intensity greater than VII are acquired based six historical earthquakes occurred at the mainland China. Then, another linear model between the DEL and the entire DBDEL are obtained based on 16 historical earthquakes. The DBDEL and DEL of the historical earthquake records are acquired from field investment. To evaluate the accuracy of the proposed method, the DEL of 2013 Lushan M 7.0 earthquake estimated. Using the field invested and high-resolution remote sensing image estimated DBDEL at the intensity greater than VII areas, the corresponding DELs are estimated based on the proposed method, respectively, with the relative error of 3.2% and 57.0%. In addition, an empirical DEL method based on earthquake magnitude and intensity is also used to estimate the Lushan earthquake DEL, with the relative error of 90.0%. The result indicates that the proposed method can properly estimate DEL based on the field invested or remote sensed DBDEL.

In an earlier study of the Diexi ancient dammed lake along the Minjiang River in Southwest China, 10 disturbed layers with envelope and flame structures were found in more than 240 m of lacustrine sediments. In this paper, the soft-sediment disturbances caused by earthquakes in the Diexi ancient dammed lake were studied based on field investigations and laboratory core observations. A two- to three-degree-of-freedom spring-type earthquake simulation vibration table was used to carry out disturbance tests on lacustrine sediments under different dynamic conditions. The results support the following conclusions: (1) The disturbance layers in the lacustrine sediments were caused by strong earthquakes in the region. (2) The characteristics of the disturbance layers are related to the seismic parameters and the degree of sediment consolidation. (3) The greater the earthquake intensity is, the greater the disturbance amplitude is; moreover, the lower the consolidation degree is, the greater the disturbance amplitude. (4) The simulation tests verify that the disturbance layers in the sediments of the Diexi ancient dammed lake correspond to strong earthquakes in the region. These results are valuable for ongoing palaeoseismic research in the region.

The intensity of earthquakes increases from time to time both in number and in strength; recently, in Indonesia, damage to buildings by earthquake acceleration usually begins with damage to walls. Besides having a function as a barrier between spaces in construction, walls also have an essential role in increasing a building structure's rigidity. Mortar, which is usually used as a wall and plastering, has a role as a binder between the walls themselves' components so that quality mortar will help the walls be stronger. This research aims to produce the ideal mortar mixture with low price, high quality, and easy to obtain material. The proposed added composition was husk ash and Fosroc SP 337 additive, varied based on cement's weight. The yield of mortar with added ingredients will be compared with ordinary mortar without added ingredients. The specimens' manufacture used 20 samples of 5cm x 5cm x 5cm cubes with five variations of mortar composition, and mortar compressive strength testing was carried out at 7, 14, and 28 days of age. The maximum compressive strength obtained for mortar with the addition of 15% rice husk ash, 1% fosroc sp 337, and the combination of the two experienced an increase in the compressive strength value, the ratio of the average compressive strength of the mortar, the highest average compressive strength results in the mixture 1 PPC cement: 4 Sand with the addition of 15% rice husk ash: 1% fosroc sp 337 with an average compressive strength yield of 116.6 kg / cm² at the age of 7 days, 145.6 kg / cm² at the period of 14 days and 154.6 kg / cm² at the age of 28 days.

The infill walls are usually considered as nonstructural elements and, thus, are not taken into account in analytical models. However, numerous researches have shown that they can significantly affect the seismic response of the structures. The aim of the present study is to examine the role of masonry infill on the damage response of steel frame without and with various types of openings systems subjected to nonlinear static analysis and nonlinear time history analysis. For the purposes of the above investigation, a comprehensive assessment is conducted using twelve typical types of steel frame without masonry, with full masonry and with different heights and widths of openings. The results revealed that the influence of the successive earthquake phenomenon on the structural damage is larger for the infill buildings compared to the bare structures. Furthermore, when buildings with masonry infill are analyzed for seismic sequences, it is of great importance to account for the orientation of the seismic motion. The nonlinear static response indicated that the opening area has an influence on the maximal strength, the ductility and the initial rigidity of these frames. But the shape of the opening will not influence the global behavior. Then, the nonlinear time history analysis indicates that the global displacement is greatly decreased and even the behavior of the curve is affected by the earthquake intensity when opening is considered. Doi: 10.28991/cej-2021-03091653 Full Text: PDF

The seismic intensity scale is one of the oldest instruments for determining the extent of seismic vibrations. Being initially a descriptive characteristic of seismic impact, intensity has long required only more detailed, thorough consideration and recording of the consequences and manifestations of various primary and secondary effects in earthquakes in order to increase its accuracy. The indicators were changes in the natural environment, the reactions of humans and animals, and the results of the impacts of seismic events on various engineering structures. Obviously, the latter research objects listed in this series have the most variable characteristics over time. The emergence of new building structures and materials had to be reflected in the seismic intensity scales. This is encouraging changes in the scales used and the development of new scales. At the same time, there is the problem of the correlation of earthquake intensity estimates over different seismic intensity scales. The article considers the problem of quantitative assessment of differences in intensity determination according to the MCS, MM, MSK-64, and EMS-98 scales, as well as two new national Russian standards, GOST R 57546–2017 and GOST 34511−2018. Comparison is carried out separately according to the macroseismic and instrumental parts of scales. Macroseismic descriptions of individual points (gradations) is analyzed using indicator object, people, objects, buildings and structures, and natural phenomena. Each indicator is considered separately. For the MCS, MM, and MSK-64 scales, as well as GOST R 57546–2017 and GOST 34511−2018, their instrumental parts were compared. Based on these studies, it was concluded that the macroseismic parts of these scales coincide, with the exception of low estimates of the dimensions of fissures in soils on the MSK-64 scale. Average differences in the descriptions of damage to buildings and structures do not exceed 0.1 points. Significant differences exist in the instrumental parts of MM, MSK-64, and GOST R 57546–2017.

Analysis of a peak ground acceleration value and earthquake intensity in Banten Province has been carried out using historical earthquake data from 2008 to 2018. This research aims to describe a prone area of the earthquake. The specification of data was a magnitude > 5 SR and the depth 0-70 km. The Donovan method was used to analyze peak ground acceleration value and the earthquake’s intensity. According to the data obtained, 31 earthquake points with a maximum earthquake strength occurred on October 16, 2019, with a depth of 10 km and a magnitude of 6.48 SR. This earthquake was located in Ujung Kulon with coordinates -6.81 LS and 105.113 BT. Based on data analysis result was obtained a peak ground acceleration value and the intensity of earthquake maximum in The Pandeglang Regency with a peak ground acceleration value was 211.56 cm/s2, and intensity of scale VIII and a large risk level of three. While a peak ground acceleration minimum is located in the South Tangerang City was 62.82 cm/s2 with a scale of intensity VII and a moderate risk level.

The purpose of this study is to identify efficient earthquake intensity measures (IMs) for evaluating the seismic vulnerability of integral abutment bridges. A total of 90 ground motion records and 20 typical IMs were employed for the numerical analyses. A series of nonlinear time-history analyses was performed on the bridges to observe the lateral displacement of the bridge piers. Statistical parameters such as the coefficient of determination, standard deviation, and correlation coefficient were calculated to identify the strongly correlated IMs with the seismic performance of the bridges. The numerical results show that the efficient IMs are spectral acceleration, spectral velocity, spectral displacement at the fundamental period, acceleration spectrum intensity, effective peak acceleration, peak ground acceleration, and A95. Moreover, a set of fragility curves of the bridges was developed with respect to the efficient IMs.

Rail irregularity is the leading cause of enhancing train-track coupling vibration and, therefore, should be studied in detail for safety requirements. In this study, the differences between existing rail irregularities without being subjected to an earthquake between different countries were first studied. Results show that existing power spectrum density and time-domain displacement samples of rail irregularities in the American code are the largest, while the irregularities of the Germany railway are higher than those of China in a specific range of rail wavelengths. Afterward, the effects of earthquake intensity, soil site, and duration on the rail irregularity of a Chinese typical high-speed railway bridge were investigated. For this purpose, a finite element model was established and validated by the shaking table test of a 1/12-scaled high-speed railway bridge experimental specimen. The calculation results indicated that the influences of earthquakes on the rail alignment irregularity were evident.

Kabupaten Pandeglang terletak di wilayah pesisir pantai selatan Pulau Jawa yang berdekatan dengan zona subduksi megathrust. Zona ini berasal dari pertemuan Lempeng Indo-Australia yang menunjam di bawah Lempeng Eurasia. Sehingga dapat menyebabkan sering terjadinya gempa bumi akibat pergerakan lempeng yang menunjam di wilayah tersebut. Selain itu, Kabupaten Pandeglang juga berbatasan dengan Selat Sunda di bagian barat di mana wilayah tersebut terdapat Gunung Krakatau yang berpotensi menimbulkan gempa bumi akibat letusan gunung berapi. Untuk itu, perlu adanya analisis perhitungan intensitas gempa bumi di Kabupaten Pandeglang sebagai langkah awal dalam mitigasi bencana. Proses ini menggunakan data gempa bumi multi-event yaitu periode tahun 2010 – 2018 dengan menggunakan metode perhitungan intensitas gempa bumi yang dihitung berdasarkan nilai PGA (Peak Ground Acceleration). Intensitas yang terdapat di Kabupaten Pandeglang adalah V – VII MMI dengan persentase terbesar (91,463%) yaitu VI MMI dengan luas 2513,526 km2. Sedangkan persentase terkecil (0,301%) yaitu V MMI dengan luas 8,27 km2. Kecamatan di Kabupaten Pandeglang yang memiliki intensitas tertinggi terhadap gempa bumi adalah Kecamatan Angsana, Cibitung, Cimanggu, Pagelaran, Panimbang, Patia, Sindangresmi, Sobang, dan Sukaresmi.

SUMMARY Considering spatial correlation of multiple earthquake intensity measures (IMs) is of particular importance in loss assessment of spatially distributed assets. This subject has been investigated in previous studies under the assumption of isotropy. Considering the fact that the assumption of isotropy is not valid in general, the present study employs a non-separable covariance model based on latent dimensions method to investigate anisotropic properties of spatial correlations and cross-correlations of intra-event residuals of multiple earthquake IMs. This method leads to the generation of valid covariance matrix in order to model anisotropic spatially distributed multivariate random fields. Two sets of IMs are considered in this study; the first set consists of peak ground intensity values (acceleration, velocity, and displacement), and the second set consists of spectral accelerations at three different periods. Data of 10 earthquake events in California and Japan are utilized in this study to estimate parameters of marginal and cross-covariance models. Moreover, parameters of covariance model of regional site condition, which is considered as average shear wave velocity of top 30 m of soil profile (Vs30), are obtained in order to investigate the effect of local sited conditions on spatial correlations of IMs. It is shown that maximum range and anisotropy ratio of covariance models of intra-event residuals of IMs are correlated with those of Vs30 values. Also, it is observed that the anisotropy direction of residuals of IMs is consistent with anisotropy direction of Vs30 values. Finally, predictive models are proposed to obtain marginal and cross-covariance functions for different earthquake IMs considering anisotropy.

The purpose of this paper is to develop a ground acceleration map in Yogyakarta Special Province under the 2006 Yogyakarta earthquake and look for evidence of site effects that affect to the ground response and building damage. The earthquake was more than one and half decade away, but its ground acceleration map and soil-site effects are still unclear. An estimation of the peak ground acceleration map under the Yogyakarta earthquake was conducted but limited for upper bound value and not including the influence of the site effects (Widodo in Bull N Z Soc Earthq Eng 51(2):92–104, 2018). Middle value PGA map at YSP including the site effects has been successfully developed. The development of PGA map is based on the maximum ground acceleration at two control points, i.e., at YOGI and BJI stations (see Box 2 in Fig. 1) and the result of earthquake intensity Imm field surveying (Wijaya in Isoseismal, Kerentanan dan Rasio Kerusakan Bangunan Rumah Tinggal; Studi Kasus Gempa Bumi Yogyakarta 27 Mei 2006, 2009). Two ground motion prediction equations have been used to interpolate ground acceleration between two control points and produce an equation of the relationship between ground acceleration with earthquake intensity. The relationship between earthquake intensity Imm with distance L (Wijaya 2009) is then combined with the previous equation and lead to final equation. The ground acceleration in all point data in the field is computed by using the final equation. The contours of the PGA as obtained apparently do not form a circle but tend to follow the path of Opak river fault. Moreover, the maximum ground acceleration does not occur in the epicenter area but shifts about 14 km west of the epicenter. The maximum ground acceleration in Imogiri sub-district reaches 0.45 g, while in the epicenter is only around 0.17 g. Site effects phenomena have occurred in the field both based on the result of analysis and the result of horizontal–vertical spectral ratio (HVSR) tests in the field. HVSR results from field tests by using microtremor showed that in the epicenter was obtained that the site period T = 0.078 s (rocky site), sediment thickness H = 6.6 m and percentages of housing collapsed was only 14.5%. Meanwhile, in the Imogiri sub-district (about 14 km west of the epicenter) the value of site period T = 1.52 s (soft soil), sediment thickness H = 86.6 m and the percentage of collapsed building reached 77.6%. This means that irregularities have occurred in earthquake intensity, ground acceleration and building damage, which are the characteristic of the site effect occurrence (Montalva et al. in Earthq Spectra 32(3):1469–1488, 2016).

The relationship of the design peak ground accelerations, earthquake frequency, and seismological conditions of a construction site for a performance-based design has been analyzed. The limitations of using the linear dependence of the repeatability logarithm on the earthquake intensity are given. Recommendations on how the new seismic scale can be used to solve engineering problems in designing structures in seismic areas are given. It is shown that the instrumental part of the new scale is quite acceptable for development of performance-based design. At the same time, in areas with a possible shaking intensity of more than IX, peak ground accelerations lose their importance for assessing seismic resistance, and there is a need to ration the input energy characteristics.

Earthquake is a natural disaster type that affects the life of life deeply. Although it differs according to the geotechnical properties of the ground, in some cases it can cause serious loss of life and property due to earthquake intensity. The vibration waves that occur with sudden breaks in the earth’ s crust create an earthquake. The fact that the earthquake time and severity are not known in advance, the stratified and unknown structure of the ground makes the situation more complicated. For this reason, it is necessary to determine the earthquake properties correctly and take necessary measures in advance. Therefore, it is deemed appropriate to determine the dynamic behavior of the ground in case of an earthquake, by determining it with field and laboratory studies and making the necessary analyzes. For this purpose, many software programs have been developed. In the developed software programs, the required data can be entered into the system and the dynamic behavior of the ground can be analyzed seismically. In this light, for the study of Aksaray Dogantarla, Turkey Building Seismic Code [1] also suggested the equivalent dynamic behavior of the floor using linear analysis methods were investigated. Using the soundings and seismic studies in the region, the possible behavior of the ground at the time of the earthquake was interpreted.

In order to improve the structural safety and stability of the tunnels crossing stick-slip fault, an indoor model test on the effect of tunnel antibreaking measures under the influence of fault stick-slip movements was conducted. Using contact pressure, longitudinal strain, and safety factor, the antibreaking effect of tunnels was compared and analyzed under 5 kinds of operating conditions, mainly including no measures, structural strengthening, structural strengthening and reducing dislocation layer, structural strengthening and reducing dislocation joint, structural strengthening and reducing dislocation layer, and reducing dislocation joint. The results showed that the longitudinal strain and contact pressure of the tunnel changed markedly (from severe change to more uniform change) when the reducing dislocation measures were adopted in the test, reducing dislocation layer/joint or reducing dislocation layer and reducing dislocation joint. The effect of reducing the fault stick-slip dislocation on the tunnel structure is very limited by only taking structure strengthening measures. The effect of reducing the fault stick-slip dislocation on the tunnel structure is obvious by using the reducing dislocation method, and the minimum safety factor is increased by more than 8 times. The effect of resisting and reducing the fault stick-slip dislocation on the tunnel structure is remarkable by adopting the measures of the structural strengthening and reducing dislocation layer and reducing dislocation joint, and the minimum safety factor is increased by more than 25.45 times. The results can provide reference for the design of antibreaking for the stick-slip fault tunnel in high earthquake intensity and dangerous mountainous areas.

Seismic design practices and seismic response analyses of civil structures and nuclear power plants (NPPs) have conventionally used the peak ground acceleration (PGA) or spectral acceleration (Sa) as an intensity measure (IM) of an earthquake. However, there are many other earthquake IMs that were proposed by various researchers. The aim of this study is to investigate the correlation between seismic responses of NPP components and 23 earthquake IMs and identify the best IMs for correlating with damage of NPP structures. Particularly, low- and high-frequency ground motion records are separately accounted in correlation analyses. An advanced power reactor NPP in Korea, APR1400, is selected for numerical analyses where containment and auxiliary buildings are modeled using SAP2000. Floor displacements and accelerations are monitored for the non- and base-isolated NPP structures while shear deformations of the base isolator are additionally monitored for the base-isolated NPP. A series of Pearson's correlation coefficients are calculated to recognize the correlation between each of the 23 earthquake IMs and responses of NPP structures. The numerical results demonstrate that there is a significant difference in the correlation between earthquake IMs and seismic responses of non-isolated NPP structures considering low- and high-frequency ground motion groups. Meanwhile, a trivial discrepancy of the correlation is observed in the case of the base-isolated NPP subjected to the two groups of ground motions. Moreover, a selection of PGA or Sa for seismic response analyses of NPP structures in the high-frequency seismic regions may not be the best option. Additionally, a set of fragility curves are thereafter developed for the base-isolated NPP based on the shear deformation of lead rubber bearing (LRB) with respect to the strongly correlated IMs. The results reveal that the probability of damage to the structure is higher for low-frequency earthquakes compared with that of high-frequency ground motions. Keywords: Nuclear power plant, Earthquake intensity measure, High-frequency ground motion, Pearson's correlation coefficient, Seismic fragility curve

Ground motion intensity measures are of great importance for the seismic design of structures. A well-chosen intensity measure will reduce the detailed ground motion record selection effort for the nonlinear dynamic structural analyses. In this article, a spectral-acceleration-based combination-type earthquake intensity measure is presented. This intensity measure considers the higher modes effect and period elongation effect due to nonlinear deformation at the same time. The modal mass participation factors are determined to take weighting coefficients and the product of elastic first-mode period T1 and a constant C is expressed to represent the elongated period. Therefore, the proposed intensity measure is a combination of earthquake ground motion characteristics, elastic structural responses, higher modes participation, and the period elongation effect due to inelastic structural behaviors. Four three-dimensional models of reinforced concrete stack-like structures including a 240 m-high chimney, a 180 m-high chimney, a 120 m-high chimney, and a 42.3 m-high water tower are established and analyzed in ABAQUS to investigate the correlation between the intensity measure and the maximum curvatures under 44 far-field ground motions and 28 near-fault ground motions with a pulse-like effect. With the optimal vibration modes and the proper period elongation coefficient, the efficiency of the introduced intensity measure is compared with the other 15 intensity measures. The results indicate that the proposed intensity measure is believed to be a good choice for high-rise stack-like structures, especially under the near-fault ground motions with pulse-like effect.

Tunnels are generally constructed in urban areas and metro cities to fulfill the rising need of space and passage due to urbanization. These infrastructure may get damaged because of earthquakes occurring in that particular area where tunnels are constructed. While designing tunnels in seismic prone zones, it is ensured that tunnels must withstand under both seismic and static loading. Recently occurred large magnitude earthquakes caused significant damages of the tunnels including the 1995 Kobe earthquake in Japan, the 1999 Chi-Chi earthquake in Taiwan and the 2008 Wenchuan earthquake in China. During damage evaluation, tunnel damages are broadly categorized into five classes based on damage index including no damage, minor damage, moderate damage, major damage and collapse. This paper gathers the materials of tunnels affected by the 1995 Kobe earthquake in Japan and the 1999 Chi-Chi earthquake in Taiwan, and the grades of damage are calculated based on seismic performance. Earthquake intensity, distance from fault, rock classification, tunnel length and overburden depth are considered as the tunnel damage factors while doing analysis. Considering these parameters, the formula for seismic damage evaluation for tunnel is deducted using the least square method. Further, this formula is modified after taking into account additional factors like construction time, seismic fortification strength and portal stability.

In order to study the longitudinal seismic capacity of shield tunnels, this work applies the structural seismic vulnerability analysis, based on incremental dynamic analysis (IDA), to a shield tunnel and explores the ground motion intensity measure suitable for the shield tunnel in different site types. The failure probability of the structure at each earthquake intensity is calculated by combining the probabilistic seismic demand model with the limits on the engineering demand parameters to establish the seismic vulnerability curve of the structure. The results indicate that the peak ground velocity (PGV) is the ground motion intensity measure suitable for the longitudinal seismic performance of the shield tunnel. The site type has the most profound influence on the extent of the longitudinal damage to the shield tunnel, and site type IV is the most dangerous under an earthquake. Further, the tunnel has stronger seismic resistance in the elastoplastic stage. The low-grade bolts between the rings damage more severely than the high-grade bolts. A tunnel with either a great depth of burial or a large cross section is more dangerous than the one with either a small depth of burial or a small cross section. The risk of the axial tension-compression failure of the shield tunnel is higher than that of the horizontal transverse shear failure.

At present, the national earthquake intensity quick report and early warning project is in the full implementation stage. In Fujian, the earthquake early warning information can be provided to the public through mobile app and specific terminals. But there is also a lack of effective solutions to use the early warning information to reduce personal and property losses for the majority of family users. Earthquake emergency disposal is the key technology to use the earthquake early warning information to solve the problem in last 1km. The intelligent gateway receives the earthquake early warning information through the message middleware, and processes to evaluate the safety of earthquake gas, then judges whether to start the gas earthquake emergency disposal system. The intelligent gateway communicates with the server through WiFi. and communicates with gas earthquake emergency disposal system through ZigBee wireless communication technologies, and realizes the automatic shutdown of gas when destructive earthquake occurrence. The system can prevent the occurrence of gas accidents in destructive earthquakes, make full use of earthquake early warning information, realize the home application of earthquake early warning information, and reduce casualties and economic losses caused by earthquakes.

This paper investigates the relationship between 23 earthquake intensity measures (IMs) and seismic responses of skewed bridges and then identifies the best IMs of damage of the bridge. A total of 290 ground motion records classified into low- and high-frequency content groups are employed for numerical analyses. A series of nonlinear time-history analyses for the skewed bridges is performed to observe its seismic responses. Seismic responses of the bridges are measured in terms of the drift ratio and shear forces of bridge piers. A series of Pearson’s correlation coefficients are calculated to recognize the correlation between each of the 23 seismic IMs and seismic responses of the bridge. The numerical results show that in the case of low-frequency ground motions the best IMs correlated with the seismic response of bridges are Arias intensity (Ia), characteristic intensity (Ic), spectral acceleration (Sa(T1)), and spectral velocity at the fundamental period (Sv(T1)). For high-frequency motions, the well-correlated IMs with seismic damage of bridge are specific energy density (SED), Arias intensity (Ic), root-mean-square of velocity (Vrms), and characteristic intensity (Ic). Additionally, PGV/PGA ratio, mean period (Tm), and predominant period (Tp) show to be weakly correlated with seismic responses of bridges subjected to both low- and high-frequency motions.

Tabriz is located in the northwest of Iran. Two huge earthquakes with magnitudes of 7.4 and 7.3 occurred there in 1780 and 1721. These earthquakes caused considerable damage and casualties in Tabriz. Using the method of scenario building, we aim to investigate what would happen if such earthquakes occurred in 2021. This scenario building was carried out using deterministic and GIS-oriented techniques to find the levels of damage and casualties that would occur. This procedure included two steps. In the first step, a database of factors affecting the destructive power of earthquakes was prepared. In the next step, hierarchical analysis was used to weigh the data, and then the weighted data were combined with an earthquake intensity map. The obtained results were used to predict the earthquake intensity in Tabriz. According to our results, the earthquake with a magnitude of 7.3 that occurred in 1721 caused huge destruction in the north of Tabriz, as this earthquake occurred inside the site. However, this earthquake caused minimal damage to the south of the city owing to the geological situation of this area of Tabriz. The earthquake with a magnitude of 7.3 that occurred in 1780 caused less damage because of its distance from the site. In the third step of this analysis, the vulnerability of buildings and the population were examined. According to the estimates, District 4 would experience the highest damage rate in the earthquake of 1721, with 15,477 buildings destroyed, while this area would have a lower damage rate in the earthquake that occurred in 1780. The total casualties in Tabriz would number 152,092 and 505 people in the earthquakes of 1721 and 1780, respectively.

International audience; We examine the average causal impact of the 2010 earthquake in Haiti on economic growth and recovery by conducting a disaggregated empirical analysis at the subnational level. To achieve this, we opt for a fixed effects difference-in-differences model and impulse response functions by using the earthquake's intensity as the main exogenous variable and nighttime light data as a proxy for economic activity from 1992 to 2019. Results indicate a robust evidence that the earthquake caused a significant decrease in the country's economic growth in the short-term. We also reveal that such declines in growth persited ten years after the disaster. Overall, estimates provide new insights on the short and long-run economic growth effects of major natural disasters. Therefore, our analysis of the effects of earthquake intensity on the growth of night lights is an important contribution to disaster economics. In the concluding reflections, the findings, implications, and avenues for future research are discussed. (C) 2022 Elsevier Ltd. All rights reserved.

On 12th November 2017, an earthquake with a magnitude of 7.3 Richter scale in the town of Sarpol-e Zahab took place that caused lots of human casualties and devastation. After the incident, issues ...

Palancı, Mehmet (Arel Author), Seismic damage and its correlation with the earthquake intensity measures (IMs) are important for both record selection and probabilistic seismic risk assessment studies. A lot of studies considering the various structural properties were performed to investigate the correlations of mainly PGA and PGV under different strength reduction (R) and ductility factors (mu). In this study, correlation of many scalar IMs named as PGA, PGV, a(rms), v(rms), d(rms), I-a, CAV, ASI, SI are studied. Building represented by single degree of freedom (SDOF) models were classified according to lateral strength ratios (V-t/W), ratio of strength capacity at yield (V-t) to seismic weight (W), varying from 10% to 50%. Effects of post yield stiffness capacities, hysteretic behavior type and the soil properties on deformation demand of SDOF models are also taken into account. Post yield stiffness ratios of 0%, 5% and 10% considered and assigned to building models. Elastic-perfectly plastic and modified Clough hysteretic models were used in the non-linear dynamic analyses. Strong motion records obtained from firm and soft soil sites were classified according to V-s(30) and inelastic deformation demands obtained from both soil conditions are calculated and compared. Variation of correlation coefficients of different IMs indicates that SI is the best earthquake parameter especially along the period range of 0.5-2 s which can be thought to represent building type structures. Furthermore, it was observed that sensitivity of SI parameter to post yield stiffness, hysteretic behavior type and the soil properties is very limited with respect to considered IMs. Correlation coefficients obtained from SDOF models are compared to that of multi-story buildings and the compatibility of both SDOF and MDOF models are presented.

This study examines the impact of neglecting non-spectral parameters of ground motions (GMs), particularly GM duration, on the structural responses using a risk-based seismic assessment framework, which measures the annual rates of exceedance for a specified amplitude of structural response. This study gives a special attention to the role of the primary intensity measure (IM) that used to characterize the severity of GM (i.e., known as the conditioning IM) on the degree to which GM duration affects the risk-based structural responses. For this purpose, the responses of three steel moment resisting frame buildings are compared when subjected to different ensembles of GMs selected based on the generalized conditional intensity measure (GCIM). The GCIM framework can include different features of GMs in the GM selection process through constructing their conditional distributions given a specified conditioning IM. However, the conditional distributions of GM features change as the conditioning IM changes. The results demonstrate that for all considered conditioning IMs in this study, except spectrum intensity (SI), it is nearly impossible to select a set of as-recorded GMs with the unbiased distributions for all considered IMs, particularly over rare hazard levels. In addition, the results indicate that neglecting non-spectral IMs, when the conditioning IM is SI, could overestimate (up to 50% over rare earthquake intensity levels) the MIDR risk-based structural responses with respect to a reference structural response, which resulted from a set of GMs with the unbiased distributions for all considered IMs, for the considered buildings and site. Furthermore, the findings confirm that GM duration in terms of significant duration even in case of shallow events could be an important parameter to be incorporated in GM selection. For the present case study structures and considered site, the induced bias in structural responses due to neglecting GM duration could vary up to about 40% over the rare hazard levels depending on the applied conditioning IM.

Two types of filled karst caves, with water and with water-mud mixture, in front of the tunnel face are studied, to estimate the required thickness of supporting rock stratum in order to prevent water and mud inrush under earthquake action. Generalized models and computational techniques are developed for such conditions. The models consider the shear and bending failures of the supporting rock stratum against the pressure from filling materials in the caves. Combined with pseudo-static and dynamic theories, computational models are developed to estimate the minimum thickness of the rock stratum between the face and the cave. The factors governing the minimum thickness of the supporting rock stratum to resist water and mud inrush from the caves are analyzed. Finally, the theoretical models and computational methods are verified with case studies. The studies show that: (i) Under earthquake action, the required rock stratum thickness shows an accelerated increase trend with the increasing earthquake intensity; (ii) Failure of the supporting rock stratum under the pressure from the filling material in the cave is likely due to bending; (iii) The minimum thickness of the rock stratum increases with tunnel depth, tunnel height and karst water pressure, while it decreases with increasing shear strength indexes of the filling material and surrounding rock quality.

Continuous girder bridges for high-speed railway (HSR) are increasingly used to overcome undulating terrain and to provide a flat surface for high-speed travel. Only a few dynamic experiments have been applied to such bridges, none of them focusing on HSR continuous girder bridges. The aim of this paper is to use experimental results to investigate the earthquake response of bridges of this type constructed in China. To address this aim, a 1/12-scale typical Chinese HSR continuous girder bridge specimen was constructed and the experimental procedures were detailed. From the experimental results it was found that the first natural frequency of piers was obviously decreased after the specimen was subjected to the peak ground acceleration of 0.38 g earthquake excitation. The acceleration response observed at the top of piers increased with the increase of earthquake intensity, and the concrete at the bottom of piers was cracked when the peak ground acceleration exceeded 0.20 g. The results also showed that a fixed bearing installed on the HSR bridge was damaged under 0.32 g earthquake excitation, whereas no damage was found in a girder for all test scenarios (i.e., from 0.15 g to 0.38 g). In addition, compared to unidirectional earthquake excitation, the earthquake response increased under bidirectional earthquake excitation. The experimental procedures and findings can be used as benchmarks for practical applications or for further similar experiments.

The seismic response of an active ground fissure site was simulated by a shaking table test and a FLAC3D numerical simulation model. Coupled dynamic ground motions of earthquake and fissure activity were loaded on the model. The characteristics of the fissure site, that is, the movement of the hidden fissure, the uneven subsidence, the acceleration and the lateral and vertical soil pressures, were monitored and analyzed. The following observations were made from this study. The subsidence of the hanging wall was greater than that of the footwall. The stretch caused by the uneven subsidence led to the appearance of the hidden fissure and the gradual widening of the fissure. The peak acceleration in the hanging wall was larger than that of the footwall. The PGA increased with the height of the site. The magnification coefficient of the PGA had the largest value in the fissure, and the magnification coefficient of the PGA decreased with earthquake intensity. The increments of lateral and vertical soil pressure also increased with earthquake intensity. The vertical soil pressure at the location of the fissure was the largest. These dynamic characteristics are vital to the safety design of underground structures in a fissure site.

In 2002, through the national standardization agency, the Indonesian government issued SNI 03-1726-2002 on Earthquake Resilience Planning Standard for Building Structure to anticipate the effects of earthquake on building. However, after the standard has been issued there have been several other major earthquakes that rendered it necessary to revise the existing standards. Therefore, in 2012 the government issued SNI 03-1726-2012 on Procedures for Earthquake Resistance Planning for Building and Non Building Structures. When viewed from both these standards, it can be seen that Aceh province is one of the provinces with high earthquake intensity so it is necessary to do a research to observe the effect of changes of both standards to the ratio of column capacity and minimum reinforcement requirements for buildings constructed in Aceh province. Based on the results of the research, the average column capacity ratio against the load in SNI 03-1726-2012 has increased by 45.02% and the average minimum reinforcement requirement available is only 54.5%. The increase is due to an increase in primacy factor from 1.0 to 1.5, causing increased structural load. In addition, there was an increase in the combined burden in the form of 30% additional redundant factors as well as the addition of earthquake load due to an increase in rock bed acceleration factors in some regencies. Thus it can be concluded that the building under review has not fulfilled the requirements of SNI 03-1726-2012 and is recommended for planning by adding a shear wall to reduce the structural load.

This paper studies the seismic response of an active ground fissure site subjected to earthquake by the shaking table model test. The settlement was induced by the earthquake in the ground fissure site. The settlement increased with the earthquake peak acceleration. The differential settlement has a third-order polynomial relationship with the earthquake intensity. The process of the settlement has three periods, including the rapid deformation stage, the stable deformation stage, and the accelerated development stage. The greatest settlement is in the hanging wall close to the fissure. The secondary fissures and new cracks developed and appeared during the earthquake. The high frequency component of the wave was reduced from the bottom to the top of the site and the low frequency component was amplified. The Fourier amplitude gradual increases correspond to the earthquake acceleration. The results discovery the relationship of subsidence, widen of fissure and the earthquake. It is contribute to the metro design of the fissure area.

The Mw 6.9 Samos earthquake occurred on 30 October 2020 11:51 offshore of the Samos island, west of the Kusadasi bay in the Aegean Sea. The earthquake caused destruction in villages of Greece and Turkey. The earthquake intensity reached a maximum of VII in Izmir–Bayrakli. A tsunami followed the shock and hit many villages around Samos and the Kusadasi bay. The Sigacik village of Izmir-Turkey suffered heavily from the tsunami. A post-event field survey in Sigacik has been conducted on 31 October 2020, and measurements of flow depth, run-up and limits of inundation were collected. The tsunami inundated the entire coastal area in Sigacik for at least 200 m inland. The maximum inundation has been observed NE of Sigacik. Sea water reached a distance of 391 ± 2 m. The maximum run-up is measured as 5.3 ± 0.3 m north of Sigacik. This is the highest value for the Samos tsunami measured along the Greek and Turkish coastal areas. The high run-up value is attributed to the elongated geometry of the Sigacik bay, the shallow seafloor, the low and flat land morphology in Sigacik and to the existence of four > 70-m-long E–W trending channels. The tsunami left limited amount of clay to sand size sediments forming a layer of less than 2–3 cm in the depression areas in Sigacik. The limited amount of evidence remained from the tsunami of this Mw 6.9 earthquake in Sigacik (a location with significant inundation and the highest run-up value) signifies the difficulty of palaeo-tsunami surveys for the Aegean Sea region.

Earthquakes can cause landslides on many scales in mountainous areas and pose danger to the residential area at the bottom of mountains. In some areas where the earthquake intensity is not high enough to cause large soil movement, the shaking effect on the stability of slopes during the following rainfall is not significant. However, in certain areas, shaking-caused large cracks on the slope surface play an important role in the stability of slopes subject to the following rainfall. The effect of pre-shaking on the slope stability when the slope is subject to rainfall is still not fully studied. In this study, centrifuge model tests on slopes subject to earthquakes and rainfall were carried out and due to insufficient shaking intensities and soil suction in the unsaturated slope, cracks were not seen on the surfaces of the slopes after shaking and only small displacement was induced, which made it difficult to specify the influence of earthquakes on the stability of slope subject to the following rainfall. The soil displacement and mobilization patterns of two slopes in this study were similar and the negative contribution of shaking to the slopes were not thoroughly investigated. However, the intensity and duration were the main factors that affected the occurrence and mode of the slide caused by rainfall; a uniform rainfall distribution is also necessary to validate the triggering mechanism of slide in the model tests.

'Alpha and Omega' deals with the emotional temperature difference between the fear and anxiety of those who have experienced a disaster and the attitudes of those who do not. This is because the artist, who returned to Seoul after suffering an earthquake around 5 am on February 11, 2018, when the second largest earthquake in Pohang (intensity 4.6), experienced the atmosphere of Seoul unlike Pohang. The severity of the earthquake felt at the epicenter of Pohang is not shared in Seoul. The artist interprets the difference in reaction between the two cities as "the difference in the senses due to the imbalance between information and experience." To express the sensory gap between the two cities, seismic data of two cities, which are objective indicators of earthquakes, are used, and the images of the horizontal (Seoul) and vertical (Pohang) axes created at the intersection reflect the earthquake intensity data of each city for 10 years. do. The higher the intensity of the earthquake, the greater the change in the axis width or line. The sound is also connected with data, and it is divided into two channels: Channel 1- Left (Seoul) and Channel 2-Right (Pohang). The sound converted to MIDI changes in pitch and rhythm depending on the magnitude of the earthquake. As such, the difference between the amount and intensity of the disaster experience shown by the data is proposed in a form that can be perceived as image and sound. Rather than simply reproducing the overwhelming fear and pressure of a disaster image, data sonication can listen to the data and provide a new synesthesia experience. In a space where disaster data is replaced by light and sound, audiences can freely experience a new type of disaster.

Earthquake disasters can cause damage to various types of infrastructure of the electric-gas system, and in severe cases, power outages and gas outages. Taking into account the uneven distribution of earthquakes in space, this paper constructs an earthquake disaster model based on the three-level latent focal region division scheme and an electric-gas system component failure probability model based on earthquake intensity distribution. Then, a planning-oriented resilience assessment framework of electric-gas system under earthquake disaster is proposed. Finally, this paper uses the electric-gas system composed of the IEEE RTS79 grid and the modified 14-node gas grid to verify the proposed resilience assessment framework.

Predmet ovog diplomskog rada je dvojna stambena građevina koja se nalazi u Zagrebu, točni-je u Gornjem Bukovcu. Građevina je zadobila teška oštećenja uslijed djelovanja potresa koji se dogodio 22.ožujka 2020.godine. Epicentar prvog potresa nalazio se 7 km sjeverno od središta Za-greba, točnije u Markuševcu, odnosno cca. 4 km od naše predmetne zgrade. Ubrzo nakon prvog po intenzitetu najjačeg potresa uslijedila su još 2 slabije magnitude. Iako je treći potres bio slabije magnitude od prva dva, pretpostavlja se da prouzročio najviše štete na predmetnoj građevini, od-nosno štetu prouzročenu prvim potresom još dodatno pojačao i produbio. Razlog toga je što se njegov hipocentar nalazio puno pliće, točnije na dubini od 2 km, te je time prijenos energije na površinu bio jači. Položaj predmetne građevine je najviše pridonio devastirajućem efektu. Predme-tna zgrada nalazi se na samom rasjedu i na direktnom putu širenja potresnog vala. Obavljen je statički pregled etaže 1 i etaže 2 nakon potresa. Dijagnosticirana su oštećenja prema tipu i jačini, te svrstana u odgovarajuće razrede oštećenja. Na temelju toga su predložene mjere sanacije i okvirni troškovnik radova. The subject of this master thesis is a semidetached residential building located in Zagreb, more preciesely in Gornji Bukovac. The building was severely damaged due to the earthquake that occurred on March 22.2020. The epicentre of the first earthquake was located 7 km north of the center of Zagreb more precisely in Markuševac, or approx. 4 km from our subject building. Shortly after the first strongest earthquake, 2 more weaker magnitudes followed. Although the third earthquake was of weaker magnitude than the first two, it is assumed that the third earthqua-ke caused the most damaged to the building in question, the damage caused by the first earthqua-ke was further intensified and produced. The reason for this is that its hypocentre was much shal-lower, more precisely at a depth of 2 km, and thus the transfer of energy to the surface was stron-ger. The position of the building in question contributed the most to the devastating effect. The building in question is located on the fault and on the direct path of propagation of the earthquake wave. A static control of floor 1 and floor 2 after the earthquake was performed. Damage by type and se-verity was diagnosed, and classified into appropirate damage classes. Based on that remediation measures and an approximate cost estimate of works were suggested.

Seismic protection of hospital buildings is at most important as they belong to lifeline structures. Proper definition of seismic demand is essential for earthquake protection of structural components. Generation of floor response spectra assumes significant in design and analysis of structural contents which require high seismic demand. Limiting the floor acceleration/drift is found to be difficult in most of the times in traditional lateral load resisting system and is period-sensitive in addition to ductility [1]. But decoupling the floor from the building using suitable isolation schemes found to reduce the floor accelerations and displacements [2]. The paper presents an investigation into the seismic demand reduction for a chosen isolation scheme on a 10-storey hospital building which essentially lies in the descending portion of response spectrum [3]. The passive isolation scheme consists of spring and damper assembly connecting isolated floor to the building. Nonlinear time history analysis has been carried out on both the floor isolated and non-isolated building subjected to an earthquake intensity of 0.3 g. Dynamic characteristics of the building were evaluated, and apparent dynamic magnification factors were found out which are useful for generation of floor response spectra. Seismic peak floor acceleration (PFA) is one of the significant parameters influencing performance of the building contents. In addition to PFA, spectral acceleration and displacements were selected as engineering demand parameters. Based on the acceleration and drift demands, suitable floor isolation system is suggested. With the chosen floor isolation scheme, seismic demand has been found to decrease imparting higher efficiency to the system. Accurate recommendation related to displacements and floor acceleration provisions are necessary for the efficient seismic protection design of non-structural elements.

Large earthquakes are followed by a sequence of aftershocks. Therefore, a reasonable prediction of damage potential caused by mainshock (MS)&ndash, aftershock (AS) sequences is important in seismic risk assessment. This paper comprehensively examines the interdependence between earthquake intensity measures (IMs) and structural damage under MS&ndash, AS sequences to identify optimal IMs for predicting the MS&ndash, AS damage potential. To do this, four categories of IMs are considered to represent the characteristics of a specific MS&ndash, AS sequence, including mainshock IMs, aftershock IMs (i.e., IMMS and IMAS, respectively), and two newly proposed IMs through taking an entire MS&ndash, AS sequence as one nominal ground motion (i.e., IM1MS&ndash, AS), or determining the ratio of IMAS to IMMS (i.e., IM2MS&ndash, AS), respectively. The single-degree-of-freedom systems with varying hysteretic behaviors are subjected to 662 real MS&ndash, AS sequences to estimate structural damage in terms the Park&ndash, Ang damage index. The intensities in terms of IMMS, IMAS, and IM1MS&ndash, AS are correlated with the accumulative damage of structures (i.e., DI1MS&ndash, AS). Moreover, the ratio (i.e., DI2MS&ndash, AS) of the AS-induced damage increment to the MS-induced damage is related to IM2MS&ndash, AS. The results show that IM2MS&ndash, AS exhibits significantly better performance than IMMS, IMAS, and IM1MS&ndash, AS for predicting the MS&ndash, AS damage potential, due to its high interdependence with DI2MS&ndash, AS. Among the considered 22 classic IMs, Arias intensity, root-square velocity, and peak ground displacement are respectively the optimal acceleration-, velocity-, and displacement-related IMs to formulate IM2MS&ndash, AS. Finally, two empirical equations are proposed to predict the correlations between IM2MS&ndash, AS and DI2MS&ndash, AS in the entire structural period range.

In a seismically active region, a concrete dam may be subjected to one or more aftershocks within a relatively short period of time following the occurrence of the mainshock. When the as-recorded mainshock-aftershock sequences are selected as the seismic input to evaluate the seismic performance of dams, the horizontal seismic components are generally applied along the principal structural axes during a time history analysis. It is important to notice that changing the orientation of the seismic input with regard to the principal structural axes will cause a quite different dynamic response to reinforced concrete building structures. The aim of the present study is to examine the effects of earthquake direction on seismic performance of concrete gravity dams subjected to seismic sequences. For this purposes, two seismic incident directions are applied along horizontal axes to assess the maximum structural demands. Nonlinear dynamic analyses of the dam-reservoir-foundation system subjected to as-recorded mainshock-aftershock sequences are conducted to investigate the effects: 1) direction of single earthquake events; 2) direction of seismic sequences; 3) aftershock polarity; and 4) earthquake intensity. The results indicate that earthquake direction can significantly change the damage propagation processes of concrete gravity dams.

Previously interpreted archaeological and geological field data from the Argive Basin, Greece, have been used to hypothesized that the nearby Late Bronze Age Mycenaean citadels of Tiryns and Midea, which settled on bedrock, might record synchronized co-seismic structural damage due to earthquake ground-shaking at ca. 1190 BCE, the end of the Mycenaean palatial period. However, from a quantitative archaeoseismological perspective, this hypothesis has flaws: ( a ) it overlooks that several structures excavated in the undeformed Holocene sediments lack evidence of co- seismic structural damage and damage is only documented for sturdier structures within the citadels, ( b ) it leaves unexplained the moment magnitude of the ‘causative’ surface-rupturing earthquake, and ( c ) disregards the role of local site effects on surface ground-motion. The plausibility of the previously proposed earthquake hypothesis is tested by estimating the earthquake magnitude of the alleged ancient earthquake and its local site effects at and around the citadels, assuming that the earthquake truly occurred. A retrospective geotechnical site microzonation coupled with the calculation of seismic amplification factors, surface ground-motions, and earthquake intensity account for the local site effects assessment. The present numerical modeling results indicate that the citadels and contemporaneous adjacent structures of the peasants had a lower and higher seismic hazard, respectively. Seismic amplification factors, earthquake-induced ground shaking, and seismic intensity are indeed lower for Tiryns than for Midea. Therefore, these results refute the idea of seismically induced destruction of the citadels and challenge the plausibility of the earthquake hypothesis. The previously archaeologically documented destruction patterns unlikely represent physical evidence of co-seismic damage by the archaeologically proposed earthquake. Other explanations ought to be sought to elucidate the interpreted destruction pattern seen in these Mycenaean centers.

In order to study the antibreaking effect of the fiber reinforced concrete lining in the tunnel, this paper takes the a subway tunnel engineering project in F2-3 section of Jiujiawan fault as the research background and carries out the antibreaking model test of the fiber reinforced concrete lining in the active fault zone of high earthquake intensity. The results show that the antibreaking effect of the principle stress and the longitudinal strain of the fiber reinforced concrete lining are 30%∼40% and 80%∼90%, respectively, and the minimum value of the structural safety factor is increased by 4∼5 times. The antibreaking effect of hybrid fiber reinforced concrete lining is better than that of steel fiber reinforced concrete lining. The safety of steel polypropylene hybrid fiber reinforced concrete tunnel lining is the highest, and its minimum structural safety factor is 1.62. In the aspect of improving the antibreaking effect of the tunnel, the toughening effect of fiber reinforced concrete is stronger than that of reinforcing. The research results are of great significance to improve the antibreaking effect of tunnels in active fault areas with high earthquake intensity.

Traditional earthquake rescue methods have many problems, such as the impact of road damage on earthquake rescue, the rational allocation of disaster relief materials, and the active division of rescue areas. According to the characteristics of earthquake relief, a new earthquake rescue model is designed from three aspects: high-altitude rescue, road transport relief supplies, and street human resources rescue. In this paper, the hierarchical Voronoi diagram is applied to the earthquake rescue problem, the earthquake rescue model is constructed, and the area affected by the earthquake is reasonably divided. We discussed the earthquake intensity and the proportion of the population in the disaster area and the number of disaster relief materials and other parameters and conducted an in-depth analysis of the model to form a useful earthquake rescue model. Visual simulation results have been obtained by computer simulation. Compared with the traditional earthquake rescue plan, the model proposed in this paper is more effective and scientific in improving the material distribution, personnel rescue, and postdisaster reconstruction after the earthquake, and it also provides a new idea for the rescue of other natural disasters. It has practical social value and broad application prospects. Besides, the models and conclusions given in this paper have been recognized by the Seismological Bureau of Hainan Province and the Mathematics Research Center of Hainan Province.

Destructive megathrust earthquakes, such as the 2015 Mw 8.3 Illapel event, frequently affect Chile. In this study, we assess the damage of the 2015 Illapel Earthquake in the Coquimbo Region (North-Central Chile) using the MSK-64 macroseismic intensity scale, adapted to Chilean civil structures. We complement these observations with the analysis of strong motion records and geophysical data of 29 seismic stations, including average shear wave velocities in the upper 30 m, Vs30, and horizontal-to-vertical spectral ratios. The calculated MSK intensities indicate that the damage was lower than expected for such megathrust earthquake, which can be attributable to the high Vs30 and the low predominant vibration periods of the sites. Nevertheless, few sites have shown systematic high intensities during comparable earthquakes most likely due to local site effects. The intensities of the 2015 Illapel earthquake are lower than the reported for the 1997 Mw 7.1 Punitaqui intraplate intermediate-depth earthquake, despite the larger magnitude of the recent event.

In existing study of seismic vulnerability of concrete dams, the classification of seismic damage degrees was based on single index and the incremental step length in IDA analysis failed to consider the structural responses. In this study, a seismic vulnerability analysis method of concrete dams based on improved IDA method is proposed. To begin with, the comprehensive damage index of the dam is calculated using the efficiency coefficient method, considering the indexes of crest displacement, stress and damage area, and the variable weight model is adopted to consider the influence of index value on the index weight. In addition, the IDA method is improved by modulating incremental step length based on obtained comprehensive damage indexes and damage degree classification, so that the structural response process of a dam from elastic state to complete failure can be calculated and analyzed more comprehensively. Finally, taking one block section of a concrete dam as an example, the finite element model is established, and the seismic fragility curve is plotted utilizing the improved IDA method. The results prove that this method can be used to analyze the failure probability of concrete dams under different earthquake intensity, and can provide theoretical basis for the seismic safety design of concrete dams.

Due to a large number of high concrete face rockfill dams (CFRDs) being constructed, the seismic safety is crucially important and seismic performance assessment must be performed for such dams. Fragility analysis is a method of great vitality for seismic performance assessment; it can intuitively forecast the structural effects of different ground motion intensities and provide an effective path for structure safety assessment. However, this method is rarely applied in the field of high earth dam risk analysis. This paper introduces fragility analysis into the field of high CFRD safety assessment and establishes seismic performance assessment methods. PGA, Sa (T1, 5%), PGV and PGD are exploited as the earthquake intensity measure (IMs). Relative settlement ratio of dam crest, cumulative sliding displacement of dam slope stability and a new face-slab destroying index (based on DCR and COD) are regarded as the dam damage measures (DMs). The dividing standards of failure grades of high CFRDs are suggested based on each DM. Fragility function is estimated according to incremental dynamic analysis (IDA) and multiple stripes analysis (MSA) methods respectively from a large number of finite element calculations of a certain CFRD, and seismic fragility curves are determined for each DM. Finally, this study analyzes the failure probabilities of the dam under different earthquake intensities and can provide references and bases for the seismic performance design and safety risk assessment of high CFRDs.

In this study the seismic performances of axi-symmetric steel building structures with circular plan shape were evaluated based on the ATC-63 approach. For analysis models, thirty-three-story vertically convex, concave, and gourd-type axi-symmetric buildings were designed using diagrid structure system, and their seismic performances were compared with those of the cylinder type regular steel structure. Seismic fragility analyses were carried out using twenty-two pairs of earthquake records to obtain the probability of failure for a given earthquake intensity. The validity of the response modification factor used in the seismic design of the model structures was also investigated. Based on the analysis results it was concluded that the response modification factor of 3.0 used in the design of the model structures is acceptable for the ATC-63 methodology. It was also observed that the seismic safety margin for a specific level of earthquake decreases as the vertical irregularity of the structure increases.