Pub Date : 2016-07-01DOI: 10.4018/IJGEE.2016070101
A. Rostami, H. Alielahi, A. Moghadam, M. Hosseini
Development of civil engineering science has introduced tunneling as an important option in reducing the traffic volume of urban environments. Digging tunnels, in every depth, causes changes in the surface ground structure; tunneling in urban areas, especially when has passed through the residential areas has its own particular importance; therefore, having knowledge about tunnels’ behavior and effects of diggings is necessary, and in order to prevent unpredictable damages to the structures is one of the requirements of designing. The performance and behavior of underground structures have been studied by many researchers, but the effects of tunneling on earthquake records and its effects on structures above the ground has taken less attention. This study will try to check earthquake record changes and their impact on steel structures located on top part of the tunnels, and has done this issue with digging some circular tunnels. The results indicate that, tunneling alters the earthquake records and also has affections on structural responses. KEywoRDS Acceleration, Earthquake Record, Structural Response, Tunnel
{"title":"Steel Buildings' Seismic and Interaction Behavior, Under Different Shapes of Tunnel Drilling","authors":"A. Rostami, H. Alielahi, A. Moghadam, M. Hosseini","doi":"10.4018/IJGEE.2016070101","DOIUrl":"https://doi.org/10.4018/IJGEE.2016070101","url":null,"abstract":"Development of civil engineering science has introduced tunneling as an important option in reducing the traffic volume of urban environments. Digging tunnels, in every depth, causes changes in the surface ground structure; tunneling in urban areas, especially when has passed through the residential areas has its own particular importance; therefore, having knowledge about tunnels’ behavior and effects of diggings is necessary, and in order to prevent unpredictable damages to the structures is one of the requirements of designing. The performance and behavior of underground structures have been studied by many researchers, but the effects of tunneling on earthquake records and its effects on structures above the ground has taken less attention. This study will try to check earthquake record changes and their impact on steel structures located on top part of the tunnels, and has done this issue with digging some circular tunnels. The results indicate that, tunneling alters the earthquake records and also has affections on structural responses. KEywoRDS Acceleration, Earthquake Record, Structural Response, Tunnel","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77090981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.4018/IJGEE.2016070102
P. Emani, Ritesh Kumar, Phanikanth Vedula
Structures resting on deep foundations like pile groups are subjected to entirely different kind of vibrations than those resting on shallow foundations, due to the inherent variations in the ground motions experienced at various levels of the foundation. The present work tries to generate response spectrum for single-pile supported structures using inelastic dynamic soil-pile interaction analysis. In the numerical model, the soil nonlinearity includes both separation at soil-pile interface and the plasticity of the near-field soil. The radiation boundary condition is also incorporated in the form of a series of far-field dampers which absorb the out-going waves. Inelastic response spectra for the structure, represented by a SDOF system, is generated after applying the synthetic time histories compatible with design (input) response spectra (as per IS 1893:2002-part I) at the base of pile to investigate the effects of ground response analysis including kinematics and inertial interaction between soilpile system. It is found that a structure supported by pile foundations should be designed for larger seismic forces/ accelerations than those obtained from the design spectrum given in IS 1893:2002-Part I. The verification of the developed MATLAB program is reported towards the end, using results from commercial Finite Element software ABAQUS. KEywoRdS Ground Response Analysis, Inelastic Response Spectrum, Inertial Interaction, Kinematics Interaction, Seismic Soil Pile Structure Interaction, Synthetic Time History
基于深层基础的结构，如桩群，与基于浅基础的结构相比，受到的振动类型完全不同，这是由于在地基的不同层次上所经历的地面运动的固有变化。本工作试图利用非弹性动力土-桩相互作用分析来生成单桩支撑结构的响应谱。在数值模型中，土的非线性既包括桩土界面的分离，也包括近场土的塑性。辐射边界条件也以吸收出波的一系列远场阻尼器的形式纳入。应用与设计(输入)响应谱相匹配的合成时程(参照is 1893:2002-part I)在桩基础上研究地基响应分析的影响，包括桩土系统之间的运动学和惯性相互作用，生成结构的非弹性响应谱，以SDOF系统表示。研究发现，与is1893:2002- part i中给出的设计谱相比，桩基础支撑的结构应设计为更大的地震力/加速度。最后，使用商业有限元软件ABAQUS的结果，报告了所开发的MATLAB程序的验证。关键词:地面反应分析，非弹性反应谱，惯性相互作用，运动学相互作用，地震土桩结构相互作用，合成时程
{"title":"Inelastic Response Spectrum for Seismic Soil Pile Structure Interaction","authors":"P. Emani, Ritesh Kumar, Phanikanth Vedula","doi":"10.4018/IJGEE.2016070102","DOIUrl":"https://doi.org/10.4018/IJGEE.2016070102","url":null,"abstract":"Structures resting on deep foundations like pile groups are subjected to entirely different kind of vibrations than those resting on shallow foundations, due to the inherent variations in the ground motions experienced at various levels of the foundation. The present work tries to generate response spectrum for single-pile supported structures using inelastic dynamic soil-pile interaction analysis. In the numerical model, the soil nonlinearity includes both separation at soil-pile interface and the plasticity of the near-field soil. The radiation boundary condition is also incorporated in the form of a series of far-field dampers which absorb the out-going waves. Inelastic response spectra for the structure, represented by a SDOF system, is generated after applying the synthetic time histories compatible with design (input) response spectra (as per IS 1893:2002-part I) at the base of pile to investigate the effects of ground response analysis including kinematics and inertial interaction between soilpile system. It is found that a structure supported by pile foundations should be designed for larger seismic forces/ accelerations than those obtained from the design spectrum given in IS 1893:2002-Part I. The verification of the developed MATLAB program is reported towards the end, using results from commercial Finite Element software ABAQUS. KEywoRdS Ground Response Analysis, Inelastic Response Spectrum, Inertial Interaction, Kinematics Interaction, Seismic Soil Pile Structure Interaction, Synthetic Time History","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78765893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.4018/IJGEE.2016070103
N. James
Due to the lack of proper preparedness in the country against natural disasters, even an earthquake of moderate magnitude can cause extensive damage. This necessitates seismic zonation. Seismic zonation is a process in which a large region is demarcated into small zones based on the levels of earthquake hazards. Seismic zonation is generally carried out at micro-level, meso-level and macro-level. Presently, there are only a few guidelines available regarding the use of a particular level of zonation for a given study area. The present study checks the suitability of various levels of seismic zonation for different regions and reviews the feasibility of various methodologies for site characterization and site effect estimation. Further the seismic zonation was carried out both at the micro (for the Kalpakkam) and macro-level (for Karnataka state) using the appropriate methodologies. Based on this, recommendations have been made regarding the suitability of various methodologies as well as the grid size to be adopted for different level of zonation based on actual studies. KEywoRdS Macro-Level, Micro-Level, Peninsular India, Seismic Hazard, Seismic Zonation, Site Effects
{"title":"Seismic Zonations at Micro and Macro-Level for Regions in the Peninsular India","authors":"N. James","doi":"10.4018/IJGEE.2016070103","DOIUrl":"https://doi.org/10.4018/IJGEE.2016070103","url":null,"abstract":"Due to the lack of proper preparedness in the country against natural disasters, even an earthquake of moderate magnitude can cause extensive damage. This necessitates seismic zonation. Seismic zonation is a process in which a large region is demarcated into small zones based on the levels of earthquake hazards. Seismic zonation is generally carried out at micro-level, meso-level and macro-level. Presently, there are only a few guidelines available regarding the use of a particular level of zonation for a given study area. The present study checks the suitability of various levels of seismic zonation for different regions and reviews the feasibility of various methodologies for site characterization and site effect estimation. Further the seismic zonation was carried out both at the micro (for the Kalpakkam) and macro-level (for Karnataka state) using the appropriate methodologies. Based on this, recommendations have been made regarding the suitability of various methodologies as well as the grid size to be adopted for different level of zonation based on actual studies. KEywoRdS Macro-Level, Micro-Level, Peninsular India, Seismic Hazard, Seismic Zonation, Site Effects","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82492796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-01DOI: 10.4018/IJGEE.2016010101
Kanu Kumar Das, N. Sharma
Developing countries have still shortage of housing due to natural disasters. Houses get destroyed wholly or partly and it causes the increase of lack of housing stock of a country. In disaster management cycle, rehabilitation or reconstruction is an important issue to protect, reduce or mitigate the effect of disasters. For sustainable urban development, disaster consideration is as important as it helps to maintain the development growth rate and tries to make sure that the settlements are in a stable way. The paper describes the natural disasters and issues related to proper disaster housing for sustainable urban development on the basis of literature.
{"title":"Post Disaster Housing Management for Sustainable Urban Development: A Review","authors":"Kanu Kumar Das, N. Sharma","doi":"10.4018/IJGEE.2016010101","DOIUrl":"https://doi.org/10.4018/IJGEE.2016010101","url":null,"abstract":"Developing countries have still shortage of housing due to natural disasters. Houses get destroyed wholly or partly and it causes the increase of lack of housing stock of a country. In disaster management cycle, rehabilitation or reconstruction is an important issue to protect, reduce or mitigate the effect of disasters. For sustainable urban development, disaster consideration is as important as it helps to maintain the development growth rate and tries to make sure that the settlements are in a stable way. The paper describes the natural disasters and issues related to proper disaster housing for sustainable urban development on the basis of literature.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80246632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-01DOI: 10.4018/IJGEE.2016010102
V. Devi, M. Sharma
Time–Frequency analyses have the advantage of explaining the signal features in both time domain and frequency domain. This paper explores the performance of Time–Frequency analyses on noisy seismograms acquired from seismically active region in NW Himalayan. The Short Term Fourier Transform, Gabor Transform, Wavelet Transform and Wigner-Ville Distribution have been used in the present study to carry out Time-Frequency analyses. Parametric study has been carried out by varying basic parameters viz. sampling, window size and types. Wavelet analysis (Continuous Wavelet Transform) has been studied with different type of wavelets. The seismograms have been stacked in time-frequency domain using Gabor Transform and have been converted using Discrete Gabor Expansion techniques. The Spectrograms reveals better spectral estimation in time-frequency domain than Fourier Transform and hence recommended to estimate dominate frequency components, phase marking and timings of phase. The time of occurrence of frequency component corresponding to maximum energy burst can be identified on seismograms
{"title":"Spectral Estimation of Noisy Seismogram using Time-Frequency Analyses","authors":"V. Devi, M. Sharma","doi":"10.4018/IJGEE.2016010102","DOIUrl":"https://doi.org/10.4018/IJGEE.2016010102","url":null,"abstract":"Time–Frequency analyses have the advantage of explaining the signal features in both time domain and frequency domain. This paper explores the performance of Time–Frequency analyses on noisy seismograms acquired from seismically active region in NW Himalayan. The Short Term Fourier Transform, Gabor Transform, Wavelet Transform and Wigner-Ville Distribution have been used in the present study to carry out Time-Frequency analyses. Parametric study has been carried out by varying basic parameters viz. sampling, window size and types. Wavelet analysis (Continuous Wavelet Transform) has been studied with different type of wavelets. The seismograms have been stacked in time-frequency domain using Gabor Transform and have been converted using Discrete Gabor Expansion techniques. The Spectrograms reveals better spectral estimation in time-frequency domain than Fourier Transform and hence recommended to estimate dominate frequency components, phase marking and timings of phase. The time of occurrence of frequency component corresponding to maximum energy burst can be identified on seismograms","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82303299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-01DOI: 10.4018/IJGEE.2016010104
R. Deendayal, T. Sitharam, K. Muthukkumaran
Piles are often constructed on natural slope such as sea bed slope in off-shore structures. When piles are constructed on sloping ground, the behaviour of piles under earthquake loading is different from the piles on horizontal ground surface. The dynamic response of a pile subjected to external excitation is a complex phenomenon resulting from the interactions between the pile and the surrounding soil. In the present study, a finite element analysis of a single field pile located on sloping ground was carried out. A single pile of length 30m with embedment length to diameter ratios (L/D) 20, 25 and 30 was located on a crest of soft clay of slopes 1V:1H and 1V:5H, and subjected to dynamic earthquake loading (California Earthquake,1990). From the study, the behaviour of acceleration with time, lateral displacement and bending moment behavior along the pile shaft was studied.
{"title":"Effect of Earthquake on a Single Pile Located in Sloping Ground","authors":"R. Deendayal, T. Sitharam, K. Muthukkumaran","doi":"10.4018/IJGEE.2016010104","DOIUrl":"https://doi.org/10.4018/IJGEE.2016010104","url":null,"abstract":"Piles are often constructed on natural slope such as sea bed slope in off-shore structures. When piles are constructed on sloping ground, the behaviour of piles under earthquake loading is different from the piles on horizontal ground surface. The dynamic response of a pile subjected to external excitation is a complex phenomenon resulting from the interactions between the pile and the surrounding soil. In the present study, a finite element analysis of a single field pile located on sloping ground was carried out. A single pile of length 30m with embedment length to diameter ratios (L/D) 20, 25 and 30 was located on a crest of soft clay of slopes 1V:1H and 1V:5H, and subjected to dynamic earthquake loading (California Earthquake,1990). From the study, the behaviour of acceleration with time, lateral displacement and bending moment behavior along the pile shaft was studied.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74665900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-01DOI: 10.4018/IJGEE.2016010103
Mourad A. Khellafi, Z. Harichane, H. Afra, A. Erken
This paper is dedicated to the identification of parameters of soil stratums and earthen dams from accelerometer records by inverse analysis using three kinds of optimization algorithms. The first one is the Levenberg-Marquart (L-M) gradient-based method, the second one is based on a genetic algorithm (G-A) optimization process, and the third one combines the two search algorithms to complete the identification task more efficiently. The efficiency of the two first algorithms is studied by identifying the unknown parameters of a multilayer soil profile. Then, the global -local hybrid scheme is applied to identify the soil profile characteristics and determine some information gaps using experimental data recorded within the Adapazari city during the Kocaeli earthquake of August 17, 1999. Finally, the applicability of the proposed identification procedure is verified through comparison of the parameter identification results and experimental ones at Bradbury dam by using ground motions records during the 1978 Santa Barbara earthquake (in USA).
{"title":"Prediction of Parameters of Soil Stratums and Earthen Dams from Free Field Acceleration Records","authors":"Mourad A. Khellafi, Z. Harichane, H. Afra, A. Erken","doi":"10.4018/IJGEE.2016010103","DOIUrl":"https://doi.org/10.4018/IJGEE.2016010103","url":null,"abstract":"This paper is dedicated to the identification of parameters of soil stratums and earthen dams from accelerometer records by inverse analysis using three kinds of optimization algorithms. The first one is the Levenberg-Marquart (L-M) gradient-based method, the second one is based on a genetic algorithm (G-A) optimization process, and the third one combines the two search algorithms to complete the identification task more efficiently. The efficiency of the two first algorithms is studied by identifying the unknown parameters of a multilayer soil profile. Then, the global -local hybrid scheme is applied to identify the soil profile characteristics and determine some information gaps using experimental data recorded within the Adapazari city during the Kocaeli earthquake of August 17, 1999. Finally, the applicability of the proposed identification procedure is verified through comparison of the parameter identification results and experimental ones at Bradbury dam by using ground motions records during the 1978 Santa Barbara earthquake (in USA).","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82025505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-07-01DOI: 10.4018/IJGEE.2015070102
Arijit Saha, Sima Ghosh
The evaluation of bearing capacity of shallow strip footing under seismic loading condition is an important phenomenon. This paper presents a pseudo-dynamic approach to evaluate the seismic bearing capacity of shallow strip footing resting on c-F soil using limit equilibrium method considering the composite failure mechanism. A single seismic bearing capacity coefficient (N?e) presents here for the simultaneous resistance of unit weight, surcharge and cohesion, which is more practical to simulate the failure mechanism. The effect of soil friction angle(F), soil cohesion(c), shear wave and primary wave velocity(Vs, Vp) and horizontal and vertical seismic accelerations(kh, kv) are taken into account to evaluate the seismic bearing capacity of foundation. The results obtained from the present analysis are presented in both tabular and graphical non-dimensional form. Results are thoroughly compared with the existing values in the literature and the significance of the present methodology for designing the shallow strip footing is discussed.
{"title":"Pseudo-Dynamic Bearing Capacity of Shallow Strip Footing Resting on c-Φ Soil Considering Composite Failure Surface: Bearing Capacity Analysis Using Pseudo-Dynamic Method","authors":"Arijit Saha, Sima Ghosh","doi":"10.4018/IJGEE.2015070102","DOIUrl":"https://doi.org/10.4018/IJGEE.2015070102","url":null,"abstract":"The evaluation of bearing capacity of shallow strip footing under seismic loading condition is an important phenomenon. This paper presents a pseudo-dynamic approach to evaluate the seismic bearing capacity of shallow strip footing resting on c-F soil using limit equilibrium method considering the composite failure mechanism. A single seismic bearing capacity coefficient (N?e) presents here for the simultaneous resistance of unit weight, surcharge and cohesion, which is more practical to simulate the failure mechanism. The effect of soil friction angle(F), soil cohesion(c), shear wave and primary wave velocity(Vs, Vp) and horizontal and vertical seismic accelerations(kh, kv) are taken into account to evaluate the seismic bearing capacity of foundation. The results obtained from the present analysis are presented in both tabular and graphical non-dimensional form. Results are thoroughly compared with the existing values in the literature and the significance of the present methodology for designing the shallow strip footing is discussed.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2015-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84611975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-07-01DOI: 10.4018/IJGEE.2015070104
M. Nayak, T. Sitharam, Sreevalasa Kolathayar
This paper presents the seismic hazard of the state of Uttarakhand in India, located at the foothills of the seismically active Himalayan mountain ranges. In the present study, an updated catalog of earthquakes has been prepared for Uttarakhand which was homogenized into a unified moment magnitude scale after declustering of the catalog to remove aftershocks and foreshocks. Various source zones were identified in the study area to account for local variability in seismicity characteristics. The seismicity parameters were estimated for each of these source zones, which are necessary inputs into seismic hazard estimation of a region. The seismic hazard evaluation of the region based on a state-of-the art PSHA study was performed using the classical Cornell–McGuire approach with different source models and attenuation relations. The most recent knowledge of seismic activity in the region was used to evaluate the hazard, incorporating uncertainty associated with different modeling parameters as well as spatial and temporal uncertainties. The PSHA was performed with currently available data and their best possible scientific interpretation using an appropriate instrument such as the logic tree to explicitly account for epistemic uncertainty by considering alternative models. The hazard maps were produced for horizontal ground motion at the bedrock level and an attempt was done to bring the hazard at surface level using appropriate amplification factors. The maximum PHA value at bedrock level for 10% Probability of exceedance (PE) in 50 years is 0.34g and same for 2% PE in 50 years is 0.54g.
本文介绍了位于地震活跃的喜马拉雅山脉山麓的印度北阿坎德邦的地震危险性。本研究为北阿坎德邦编制了一份更新的地震目录，该目录在剔除余震和前震后，被统一为一个统一的矩震级。在研究区内确定了不同的震源带，以解释地震活动特征的局部变化。对每个震源区的地震活动性参数进行了估计，这是对一个地区进行地震危险性估计的必要输入。基于最先进的PSHA研究，采用经典的cornell - McGuire方法，采用不同的震源模型和衰减关系，对该地区进行了地震危险性评估。利用该地区地震活动的最新知识来评估灾害，其中纳入了与不同建模参数相关的不确定性以及空间和时间的不确定性。PSHA是用当前可用的数据和它们最好的科学解释来执行的，使用适当的工具，如逻辑树，通过考虑替代模型来明确地解释认知的不确定性。绘制了基岩水平地面运动的危险图，并尝试使用适当的放大系数将危险带到地表。10% PE 50年基岩层最大PHA值为0.34g, 2% PE 50年基岩层最大PHA值为0.54g。
{"title":"A Revisit to Seismic Hazard at Uttarakhand","authors":"M. Nayak, T. Sitharam, Sreevalasa Kolathayar","doi":"10.4018/IJGEE.2015070104","DOIUrl":"https://doi.org/10.4018/IJGEE.2015070104","url":null,"abstract":"This paper presents the seismic hazard of the state of Uttarakhand in India, located at the foothills of the seismically active Himalayan mountain ranges. In the present study, an updated catalog of earthquakes has been prepared for Uttarakhand which was homogenized into a unified moment magnitude scale after declustering of the catalog to remove aftershocks and foreshocks. Various source zones were identified in the study area to account for local variability in seismicity characteristics. The seismicity parameters were estimated for each of these source zones, which are necessary inputs into seismic hazard estimation of a region. The seismic hazard evaluation of the region based on a state-of-the art PSHA study was performed using the classical Cornell–McGuire approach with different source models and attenuation relations. The most recent knowledge of seismic activity in the region was used to evaluate the hazard, incorporating uncertainty associated with different modeling parameters as well as spatial and temporal uncertainties. The PSHA was performed with currently available data and their best possible scientific interpretation using an appropriate instrument such as the logic tree to explicitly account for epistemic uncertainty by considering alternative models. The hazard maps were produced for horizontal ground motion at the bedrock level and an attempt was done to bring the hazard at surface level using appropriate amplification factors. The maximum PHA value at bedrock level for 10% Probability of exceedance (PE) in 50 years is 0.34g and same for 2% PE in 50 years is 0.54g.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2015-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80458259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-07-01DOI: 10.4018/IJGEE.2015070101
B. Gordan, A. Adnan
Due to the performance of embankment under the earthquake, relative displacement at both edges of the crest is very important for body cracks. It can be computed by dynamic analysis. In this way, response spectrum analysis and Rayleigh damping coefficient are dependent factors to dominant frequency. Based on the new technology using advanced programs to compute frequency, free vibration analysis as the basic technique and considering of different vibration modes is accessible. This research tried to evaluate the distribution of dominant frequencies for short embankment (H=30 meter) using Finite-Element Method (ANSYS 13). To evaluate of the frequency, elasticity modulus ratio and foundation depth ratio were the main objectives. Both were defined by the ratio between the embankment and foundation. As a result, maximum and minimum vertical displacements were located on both slopes, and maximum horizontal displacement was exposed at the crest. The dominant frequency increased as the modulus ratio decreased. In addition, dominant frequency decreased as the depth ratio increased. The impact of the modulus ratio to enhance frequency was greater than the depth ratio. In terms of contributing engineering, the amplitude of the dominant frequency (Hz) was finally optimized for modulus ratios (0.25-1.00) and depth ratios (0.1-1.00). For critical situation, modulus ratio was more than three, and the depth ratio was half of the unit. More research about medium embankment is recommended.
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