Current Articles

2022, Volume 44,  Issue 5

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2022, 44(5)
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2022, 44(5): 733-733.
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Discussion
Some thoughts on earthquake resistance and disaster prevention
Zhang Minzheng
2022, 44(5): 733-742. doi: 10.11939/jass.20220088
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This paper attempts to discuss several issues in China’s earthquake engineering researches and disaster reduction undertakings based on a philosophical and scientific points of view. The paper points out that the seismic intensity by macroscopic investigation does not have the exact connotation and extension of scientific concepts, it is impossible to verify the results risk analysis, the adoption of seismic fortification standards fundamentally depends on the development level of social economy and technology, the research of fault avoidance has not yet reached the stage of engineering application, the exact results of numerical simulation of structural seismic response cannot be pursued. Finally, some of suggestions and prospects for seismic engineering researches are proposed.
Review
Risk-targeted seismic zoning maps
Pan Hua, Zhang Meng
2022, 44(5): 743-751. doi: 10.11939/jass.20220161
Abstract:
To ensure the consistency of building collapse risk within the country, a risk-targeted seismic zoning map is proposed. The risk integral method calculates the target risk by the convolution of the seismic hazard curve and the structural vulnerability curve. Currently, the use of risk-targeted seismic zoning maps has been widely used in practice in the United States, and related studies have been conducted in France, Romania, Canada, Indonesia, Europe and China. This article introduces the basic principles of using the risk integral method to determine the risk-targeted ground motion parameters and reviews the recent progress of research and application of this technique in China and abroad. In addition, we discuss the future development of risk-targeted seismic zoning maps and some of the problems may face.
Review on the commonly-used ground motion parameters attenuation relationships for shallow crustal earthquakes in Chinese mainland
Xiao Liang, Yu Yanxiang
2022, 44(5): 752-764. doi: 10.11939/jass.20220142
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This paper illustrates the key points of ground motion parameters, earthquake parameters, base models and regression methods, which are always involved in applying attenuation relationships of ground motion parameters. These parameters and models could satisfy the demands for earthquake engineering application in Chinese mainland. Taking North China as an example, this paper reviews the major features of several commonly-used attenuation relationships for shallow crustal earthquakes in recent decades, and their differences are compared and analyzed. Finally, the authors summarize the limitations of current researches on attenuation relationships in Chinese mainland, and propose the research prospect for future study.
Review on issues of near-fault velocity pulse-like ground motions
Zhao Xiaofen, Wen Zengping
2022, 44(5): 765-782. doi: 10.11939/jass.20220141
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The study of near-fault velocity pulse-like ground motions is of great value to revealits damage mechanism, seismic fortification, and seismic design in the near-fault region. In this paper, the formation mechanisms of the pulse are summarized. The idea of distinguishing the pulses caused by the forward directivity effects and fling effects is discussed. Secondly, the identification methods of near-fault velocity pulses are systematically introduced and their advantages and disadvantages are reviewed. In addition, based on the characteristics of the pulse, the influence of the forward directivity effect on the pulse characteristics and the amplification effects of pulses on response spectra are discussed. Finally, the ground motion input and influence of pulses on structures are summarized. And the key questions of the pulse ground motion input are discussed. In the future, the research work of velocity pulse ground motion should be fully integrated with the actual engineering needs, and the standardization of theoretical results and engineering practice should be promoted.
Review on research of ground motion site adjustment coefficient
Yan Jingru, Zhang Yushan, Kan Wenliang
2022, 44(5): 783-796. doi: 10.11939/jass.20220086
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This paper reviews and summarizes the main research results on the adjustment coefficients of ground motion field at home and abroad over the past 20 years, focusing on the effective means of considering the influence of filed conditions on ground motion parameters through strong ground motion observation and numerical theory methods. It summarizes the applicability along with the pros and cons of various methods, conducts a comparative analysis of the main results at home and abroad by combining relevant codes and provisions, and concludes that the coefficients of soft soil field in China are smaller than the international level. What’s more, the reasons for this difference are further analyzed. Finally, based on the current development trend of international seismic zoning work and the new technical requirements of the relevant codes in various industries, it puts forward prospects for the research work of the new generation of zoning maps.
Advances in ground motion attenuation relationship of Chinese mainland
Liu Ping, Xu Zhengwei, Luo Qifeng
2022, 44(5): 797-809. doi: 10.11939/jass.20220117
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Ground motion attenuation relationship is one of the primary methods for site ground motion estimation. In this paper, firstly, the development of the ground motion attenuation relationship equations is briefly described. Then it analyzes the importance of the conversion method proposed by Mr. Hu Yuxian, reviews the development process of the attenuation relationship in the Chinese mainland, and focuses on research progress of horizontal ground motion, vertical ground motion, and other ground motion parameters. Finally, the limitations existing in the study of attenuation relationships are discussed, and suggestions for developing the strong ground motion database and the attenuation relationship in regions with poor ground motion records are put forward.
Research Paper
An efficient seismic response spectrum method under multi-support excitations
Wang Junjie, Guo Jin
2022, 44(5): 810-823. doi: 10.11939/jass.20220093
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The seismic response spectrum analysis of structures is time-consuming under multi-support excitations. The seismic spectral response of structures can be expressed based on several correlation coefficients and the time consumption can be greatly reduced if the coefficients are expressed in closed-form. In this paper, approximate expressions of spatial coherence functions are suggested. Then integrals for the coefficients are carried out analytically and their closed-form expressions are obtained. The closed-form expressions are developed from Clough-Penzien’s auto-power spectral density and Hu’s APSD. The numerical results show that the approximate closed-form expressions of correlation coefficients are of enough engineering accuracy and high efficiency for response spectrum method under multi-support excitations.
Characteristics of pulses in near-fault ground motion based on Hilbert-Huang transform
Wang Dongsheng, Chen Xiaoyu, Zhang Rui, Guo Wei
2022, 44(5): 824-844. doi: 10.11939/jass.20220090
Abstract:
Large-amplitude and long-period pulses are observed in velocity time histories of near-fault ground-motion records. The pulses in these records can pose severe ductility or strength demands to the near-fault structures and can subject them to higher collapse risks. Further research on the characteristics of pulses in near-fault ground motion is beneficial to deepen the understanding of the response of structures close to faults, and provide theoretical basis for the aseismic design. At present, methods related to strong motion processing and identification of near-fault pulses mainly focus on the single pulse in a record, so the multi-pulse characteristics of near-fault ground motions are less involved. Hence, a set of methods based on Hilbert-Huang transform (HHT) are proposed here to investigate the multi-pulse characteristics. Firstly, the raw near-fault record is corrected by the proposed HSA method, and then the ideal pulse signal can be extracted by the HHT method from the corrected record. According to the extracted pulse signal, the statistical relationships between pulse parameters and earthquake parameters are investigated. Finally, an effective strong motion duration is defined based on the pulse duration, which is verified by the nonlinear time history analysis of multi-storey buildings. The developed methods are particularly suitable for multi-pulse records. Stable peak ground displacement (PGD) and physically baseline offset time history can be obtained by the HSA method. Each velocity pulse in a record can be located in the time domain exactly and automatically by the HHT method. The proposed definition of strong motion duration for near-fault records can well characterize the intensity of multi-pulse records.
Estimation of average displacement of fault surface co-seismic dislocations
Wang Long, Liu Aiwen, Li Xiangxiu, Fan Xiaoqing, Zhang Libao, Wang Yu
2022, 44(5): 845-852. doi: 10.11939/jass.20220122
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According to the concept of pipeline performance design, the current seismic code for oil and gas pipelines stipulates that the displacement of fortified faults in important sections and general sections are the predicted maximum displacement and average displacement, respectively. However, at present, the fault displacement estimation method generally gives only the maximum displacement of the fault in the next 100 years, but not the average displacement. Therefore, based on the investigation results of co-seismic dislocation distribution of seismogenic faults on the surface at home and abroad, the distribution characteristics of co-seismic dislocations along the surface fracture trend of the fault are summarized and analyzed in this paper. And then the ratio of the average co-seismic dislocation of the fault to the maximum co-seismic dislocation of the fault is summarized by the statistical comparison and analysis of the average displacement obtained by different calculation methods in the actual earthquake cases. Anyway, based on a large number of data of seismic fault displacement at home and abroad, considering a certain safety factor, this paper suggests that 2/3 of the maximum displacement of the predicted fault should be used as the fortification displacement of the oil and gas pipeline in general sections.
Ground motion prediction of MW≥7.5 on Xiadian fault
Zhou Hong, Wang Wenjing
2022, 44(5): 853-867. doi: 10.11939/jass.20220089
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The prediction of ground motion fields for potential earthquakes is important for urban planning and regional seismic hazard assessment. In this paper, the prediction of MW≥7.5 ground motion is carried out for the Xiadian fault. Firstly, the earthquake source is set based on the full rupture patterns to cover the unknown information of the Xiadian fault as much as possible. Then the ground motion field in the study area is simulated due to the MW≥7.5 earthquake on the Xiadian fault. Furthermore, the spatial distribution of ground motion at each site is filtered based on the quantile method, and the distribution characteristics of peak ground acceleration and peak ground velocity for the inclusion of uncertain sources are discussed. The results show that an MW7.9 earthquake on the Xiadian fault will produce the strong ground motion in Tongzhou district and Beijing center zone. After that, the spatial distribution of the ground motion due to the MW7.5 earthquake from the simulated source is discussed. The results illustrate that the simulated ground motion from the two types of sources can corroborate each other for the same magnitude. Our study provides a method for the earthquake hazard predictions due to the potential sources with some unknowns.
A new exploration of the risk assessment method of earthquake disasters in urban agglomerations:Taking the Guangdong-Hong Kong-Macao Greater Bay Area as an example
Jiang Hui, Guo Endong, Lin Xuchuan, Liu Zhi, Lu Banghua, Liu Aiwen, Zhang Yi
2022, 44(5): 868-880. doi: 10.11939/jass.20220096
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Based on the preliminary research results of earthquake disaster risk assessment in the Guangdong-Hong Kong-Macao Greater Bay Area, the earthquake environment, distribution of disaster-bearing bodies and site characteristics of urban agglomerations in the bay area are analyzed, and two scenario earthquake principles for determining the earthquake input are proposed, namely, setting earthquakes in potential source areas principle and maximum risk setting seismic principle, which can make risk assessment of earthquake disasters in urban agglomerations more accurate. On the basis of previous studies, the expression of earthquake disaster risk considering the influence of site conditions is proposed. The disaster risk assessment method of buildings and lifeline engineering suitable for 3D simulation of seismic input within non-uniform excitation is explored, and the idea of considering the influence of site in the disaster risk assessment of buildings and lifeline engineering is proposed. Some valuable suggestions are put forward to objectively evaluate the earthquake disaster and loss risk of urban agglomeration.
Extraction of seismic damage information of buildings from three-dimensional images of oblique photography based on multi-scale segmentation and deep learning
Shuai Xianghua, Jing Shuaijun, Zheng Xiangxiang, Liu Qin
2022, 44(5): 881-890. doi: 10.11939/jass.20220105
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The method of combining multi-scale segmentation and deep learning is used to extract the seismic damage information of buildings from three-dimensional images of oblique photography after an earthquake. In this way, the comprehensive damage information of the roof and wall of the building is obtained. Taking the 2017 MS7.0 Jiuzhaigou earthquake as an example, firstly, based on the three-dimensional image of the roof and wall of the building, the multi-scale segmentation of samples are divided into three categories: intact building surface, damaged building surface, other ground objects and background. Secondly, 211 sample set with 100×100 pixel are selected to train the neural convolutional network model. The trained model is used to extract the seismic damage information of buildings in Qianguqing scenic spot and Zhangzha primary school. Finally, the accuracy of the extracted results is compared with the visual interpretation results. The results show that the extraction accuracy of damaged building surface is 65.5% and 71.1% respectively, the overall classification accuracy is 82.1% and 84.1% respectively, and the Kappa coefficient is 68.7% and 64.9% respectively. The result indicates that this method has certain advantages in seismic damage extraction of buildings from three-dimensional images of oblique photography.
Effect of pulse characteristics of near-fault ground motions on the response of equipment-structure coupled isolation system
Han Miao, Jiang Jinwei, Du Hongkai, Zhao Minghe
2022, 44(5): 891-902. doi: 10.11939/jass.20220129
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Based on the model of equipment-structure coupled isolation system, 50 near-fault pulse-like seismic waves were selected and the effect of period ratio TP/T (the ratio of the pulse period to the basic period of the structure) and pulse energy on the structural response was analyzed using TP/T=1 as the dividing line; and the relationships between the displacement ratio of isolation layer and the period ratio and pulse energy were fitted while the zero-crossing times is not less than 5. The analyses show that the influence of pulse characteristics on the structure is mainly related to the period ratio TP/T and the pulse energy, while the influence of the zero-crossing times of the acceleration curve corresponding to the velocity pulse needs to be considered. Furthermore, the equipment response is directly related to the top floor acceleration, but there is no significant direct correlation with the pulse characteristics of near-fault ground motions.
A shake table test for the rotation response of rigid bodies under seismic excitation
Zhao Shiwei, Luo Qifeng, Pan Kang, Zhai Yongmei, Lu Wensheng, Zhao Bin, Cao Wenqing
2022, 44(5): 903-910. doi: 10.11939/jass.20220092
Abstract:
In 2008 Wenchuan earthquake, an interesting torsion phenomenon attracts our attention: Most of the stone statues, which were placed upon the banisters of one zigzag bridge in Taibai Park, Jiangyou City, Sichuan Province, rotated an angle from their original location with little translation displacements. To simulate and further study this phenomenon, a group of stone statue models with different asymmetric characteristics were made, and then they were arranged in different location and direction on the shake table to do shake tests. The results show that: ① The torsional phenomena of the statue models appeared when input 3D accelerations from the shake table, and the acceleration amplitudes are 1.5 times of the original seismic records. Also, the phenomena were similar to those in the Taibai Park in Wenchuan earthquake. However, when the input accelerations were only in two horizontal directions, the torsional phenomena would not appear even when the amplitude was large enough. ② The torsional phenomena of the stone statue models showed different modes with different model asymmetric characteristics and different acceleration input angles. ③ The most significant factor that causes the torsional phenomena is the vertical seismic input. The statue rotation did not occur without it. So for this case, vertical ground motion is crucial and cannot be ignored.
Study on structural dynamic response under near fault ground motion with different time-frequency characteristics
Han Miao, Zhao Minghe, Du Hongkai, Jiang Jinwei
2022, 44(5): 911-919. doi: 10.11939/jass.20220135
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The dynamic response of the anti-seismic structure and the seismic isolation structure Coupled equipment under the action of seismic waves with different time-frequency characteristics is studied, and the wavelet analysis of the test data of the five-layer steel frame shaking table model is carried out. The results show that: the dynamic response of the main structure is directly related to the time-frequency characteristics of seismic waves; due to the filtering effect of the main structure and seismic isolation bearings, the dynamic response of the equipment is significantly affected by the time-frequency characteristics of seismic waves, but there is no direct correlation; isolation can reduce the amplification coefficient of the equipment by moving the frequency of the device away from the frequency of the main structure; the variation trend of the acceleration of the main structure after coupling the equipment depends on the seismic wave energy distribution with different time-frequency characteristics.