期刊文献+
共找到27篇文章
< 1 2 >
每页显示 20 50 100
Aseismic performances of constrained damping lining structures made of rubber-sand-concrete
1
作者 Xiancheng Mei Qian Sheng +4 位作者 Jian Chen Zhen Cui Jianhe Li Chuanqi Li Daniel Dias 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1522-1537,共16页
Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using ... Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is proposed.The aseismic performances of constrained damping structure were investigated by a series of hammer impact tests.The damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were discussed.The hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer one.The aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were investigated.The effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were discussed.The numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m. 展开更多
关键词 Constrained damping structure aseismic performance Hammer impact tests Damping layer Peak ground acceleration Overburden depth
下载PDF
Aseismic ridge subduction and flat subduction:Insights from three-dimensional numerical models 被引量:1
2
作者 Hui Zhao Wei Leng 《Earth and Planetary Physics》 EI CSCD 2023年第2期269-281,共13页
Flat subduction can significantly influence the distribution of volcanism,stress state,and surface topography of the overriding plate.However,the mechanisms for inducing flat subduction remain controversial.Previous t... Flat subduction can significantly influence the distribution of volcanism,stress state,and surface topography of the overriding plate.However,the mechanisms for inducing flat subduction remain controversial.Previous two-dimensional(2-D)numerical models and laboratory analogue models suggested that a buoyant impactor(aseismic ridge,oceanic plateau,or the like)may induce flat subduction.However,three-dimensional(3-D)systematic studies on the relationship between flat subduction and buoyant blocks are still lacking.Here,we use a 3-D numerical model to investigate the influence of the aseismic ridge,especially its width(which is difficult to consider in 2-D numerical models),on the formation of flat subduction.Our model results suggest that the aseismic ridge needs to be wide and thick enough to induce flat subduction,a condition that is difficult to satisfy on the Earth.We also find that the subduction of an aseismic ridge parallel to the trench or a double aseismic ridge normal to the trench has a similar effect on super-wide aseismic ridge subduction in terms of causing flat subduction,which can explain the flat subduction observed beneath regions such as Chile and Peru. 展开更多
关键词 flat subduction aseismic ridge oceanic plateau 3-D numerical simulation
下载PDF
Experimental study on aseismic behaviors of Chinese ancient tenon-mortise joint strengthened by CFRP 被引量:7
3
作者 周乾 闫维明 《Journal of Southeast University(English Edition)》 EI CAS 2011年第2期192-195,共4页
In order to well protect Chinese ancient buildings, aseismic behaviors of Chinese ancient tenon-mortise joints strengthened by carbon fibre reinforced plastic (CFRP) are studied by experiments. Based on the actual s... In order to well protect Chinese ancient buildings, aseismic behaviors of Chinese ancient tenon-mortise joints strengthened by carbon fibre reinforced plastic (CFRP) are studied by experiments. Based on the actual size of an ancient building, a wooden frame model with a scale of 1 : 8 of the prototype structure is built considering the swallow-tail type of tenon-mortise connections. Low cyclic reversed loading tests are carried out including three groups of unstrengthened structures and two groups of structures strengthened with CFRP. Based on experimental data, moment-rotation angle hysteretic curves and skeleton curves for each joint are obtained. The energy dissipation capability, stiffness degradation and deformation performance of the joints before and after being strengthened are also analyzed. Results show that after being strengthened with CFRP, the tenon value pulled out of the mortise is reduced; the bending strength and the energy dissipation capabilities of the joint are enhanced; stiffness degradation of the joint is not obvious; and the deformation performance of the joint remains good. Thus, the CFRP has good effects on strengthening the tenon-mortise joints of Chinese ancient buildings. 展开更多
关键词 tenon-mortise joint aseismic strengthening CFRP(carbon fibre reinforced plastic) wooden construction Chineseancient building
下载PDF
Field investigation on severely damaged aseismic buildings in 2014 Ludian earthquake 被引量:13
4
作者 Lin Xuchuan Zhang Haoyu +2 位作者 Chen Hongfu Chen Hao Lin Junqi 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2015年第1期169-176,共8页
The 2014 magnitude 6.5 Ludian earthquake caused a death toll of 617, many landslides and tens of thousands of collapsed buildings. A field investigation to evaluate the damage to buildings was carried out immediately ... The 2014 magnitude 6.5 Ludian earthquake caused a death toll of 617, many landslides and tens of thousands of collapsed buildings. A field investigation to evaluate the damage to buildings was carried out immediately after the occurrence of the earthquake. Severely damaged aseismic buildings, which were basically observed in the downtown of Longtoushan Town, were carefully examined one by one with the aim to improve design codes. This paper summarizes the damage observed to the investigated aseismic buildings in both the structural and local levels. A common failure mode was observed that most of the aseismic buildings, such as RC frame structures and confined masonry structures, were similarly destroyed by severe damage or complete collapse of the first story. The related strong ground motion, which was recorded at the nearby station, had a short duration of less than 20 s but a very large PGA up to 1.0 g. The RC frames based on the new design codes still failed to achieve the design target for "strong column, weak beam". Typical local failure details, which were related to the interaction between RC columns and infill walls and between constructional columns and masonry walls, are summarized with preliminary analyses. 展开更多
关键词 Ludian earthquake field investigation aseismic buildings structural collapse local failure
下载PDF
Aseismic strengthening techniques of Chinese typical stele relics:A case study of Xi'an Beilin 被引量:5
5
作者 Chun Qing Meng Zhe Hua Yiwei 《Journal of Southeast University(English Edition)》 EI CAS 2018年第3期323-330,共8页
In order to improve the seismic performance of Chinese traditional stele relics, a suitable aseismic strengthening method of Chinese traditional stele relics is proposed. Taking the typical stele relic in Xi'an Beili... In order to improve the seismic performance of Chinese traditional stele relics, a suitable aseismic strengthening method of Chinese traditional stele relics is proposed. Taking the typical stele relic in Xi'an Beilin as an example, the on-site investigations were carried out to obtain the actual geometric size and damage state of the stele relic. Then, the structural performance of the stele relic was analyzed by the finite element software ANSYS. Finally, the two different aseismic strengthening methods of the traditional stele relic are proposed and comparatively analyzed. The results show that in addition to the common problems, such as weathering, and cracks, etc, earthquakes seriously threaten the structural safety of stele relics. Under the rarely-occurring earthquake of eight degree, the unstrengthened stele relic will be overturned, and many cracks will occur at the connection area of stele body and stele pedestal. When the stele relic is strengthened by the stainless angle steel strengthening method, the stele relic will not be overturned, but some cracks will occur at the connection area of stele body and stele pedestal. When the stele relic is strengthened by the base isolation strengthening method, the stele relic will not be overturned, and no cracks will occur at the connection area of stele body and stele pedestal. Therefore, the aseismic strengthening effect of the base isolation strengthening method is obviously better than that of the stainless angle steel strengthening method, and this method is a suitable aseismic strengthening method of Chinese traditional stele relics. 展开更多
关键词 stele relics aseismic strengthening stainlessangle steel base isolation finite element method
下载PDF
Aseismic Reliability Analysis Approach for Offshore Jacket Platform Structures 被引量:3
6
作者 Zhuang, YZ Jin, WL 《China Ocean Engineering》 SCIE EI 1998年第4期375-382,共8页
By means of nonlinear pushover collapse analysis approach, the aseismic reliability analyses of two offshore jacket platforms in the Bohai Gulf in China are studied according to their ocean location and environmental ... By means of nonlinear pushover collapse analysis approach, the aseismic reliability analyses of two offshore jacket platforms in the Bohai Gulf in China are studied according to their ocean location and environmental loadings there. On the basis of those analyses, an aseismic reliability analysis approach is presented. The results show that the aseismic reliability of those platforms is high. Also it is proved that this aseismic reliability analysis approach is simple, practical and reliable. 展开更多
关键词 offshore jacket platform aseismic reliability nonlinear pushover collapse analysis
下载PDF
The subduction of the Copiapó aseismic ridge,is the causing of the formation of metallic minerals deposits in north of Chile and Argentina? 被引量:1
7
作者 Mario Gimenez Gemma Acosta +3 位作者 Orlando Alvarez Agustina Pesce Federico Lince Kinger Andres Folguera 《Geodesy and Geodynamics》 2019年第6期471-476,共6页
The results obtained in this work evince that the metallic mineral deposits located in the northern region of the Chilean-Pampean flat slab(in northern Chile and north-western Argentina),at approximately 27°30’S... The results obtained in this work evince that the metallic mineral deposits located in the northern region of the Chilean-Pampean flat slab(in northern Chile and north-western Argentina),at approximately 27°30’S,would be related to the subduction of the Copiapo aseismic ridge.The analysis of the gravity anomalies and vertical gravity gradient allows inferring a deflection and truncation of the main trend of the Andean structures at the extrapolated zone of the Copiapo ridge beneath South America.Thus,the general NNE-trend of the Andean structures are rotated locally to an ENE-strike within the area of the Ojos del Salado-San Buena Ventura lineament.We explain that this anomalous behavior of the gravity derived anomalies is related to the deformational effects imprinted by the ridge subduction.Regions with a low subduction angle(<30° to horizontal)are related to large mineralization due to fluids released by dehydration of the subducting crust.In addition,a higher degree of mantle melting could be produced by a thicker oceanic crust.Therefore,we interpret that the processes associated to the subduction of the Copiapo aseismic ridge(emplaced on a thickened oceanic crust due to a local compensation of the seamounts)are the cause of formation and emplacement of big metallic mineral deposits in this region of Chile and Argentina. 展开更多
关键词 aseismic RIDGE Satellite gravity Ojos del Salado-San Buena Ventura LINEAMENT Metallic mineral DEPOSITS
原文传递
Aseismic negative dislocation model and deformation analysis of crustal horizontal movement during 1999--2001 in the northeast margin of Qinghai-Xizang block 被引量:1
8
作者 张希 江在森 +2 位作者 王琪 王双绪 张晓亮 《Acta Seismologica Sinica(English Edition)》 CSCD 2003年第4期395-403,共9页
Through numerical simulation for GPS data, aseismic negative dislocation model for crustal horizontal movement during 1999~2001 in the northeast margin of Qinghai-Xizang block is presented, combined with the spatial d... Through numerical simulation for GPS data, aseismic negative dislocation model for crustal horizontal movement during 1999~2001 in the northeast margin of Qinghai-Xizang block is presented, combined with the spatial distribution of apparent strain field in this area, the characteristics of motion and deformation of active blocks and their boundary faults, together with the place and intensity of strain accumulation are analyzed. It is shown that: a) 9 active blocks appeared totally clockwise motion from eastward by north to eastward by south. Obvious sinistral strike-slip and NE-NEE relative compressive motion between the blocks separated by Qilianshan-Haiyuan fault zone was discovered; b) 20 fault segments (most of them showed compression) locked the relative motion between blocks to varying degrees, among the total, the mid-east segment of Qilianshan fault (containing the place where it meets Riyueshan-Lajishan fault) and the place where it meets Haiyuan fault and Zhuanglanghe fault, more favored accumulation of strain. Moreover, the region where Riyueshan-Lajishan fault meets north boundary of Qaidam block may have strain accumulation to some degree. c) Obtained magnitude of block velocities and locking of their boundaries were less than relevant results for observation in the period of 1993~1999. 展开更多
关键词 the northeast margin of Qinghai-Xizang block GPS crustal horizontal movement aseismic negative dislocation model apparent strain field
下载PDF
Aseismic safety analysis of a prestressed concrete containment vessel for CPR1000 nuclear power plant 被引量:1
9
作者 Yi Ping Wang Qingkang Kong Xianjing 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2017年第1期55-67,共13页
Abstract: The containment vessel of a nuclear power plant is the last barrier to prevent nuclear reactor radiation. Aseismic safety analysis is the key to appropriate containment vessel design. A prestressed concrete... Abstract: The containment vessel of a nuclear power plant is the last barrier to prevent nuclear reactor radiation. Aseismic safety analysis is the key to appropriate containment vessel design. A prestressed concrete containment vessel (PCCV) model with a semi-infinite elastic foundation and practical arrangement of tendons has been established to analyze the aseismic ability of the CPR1000 PCCV structure under seismic loads and internal pressure. A method to model the prestressing tendon and its interaction with concrete was proposed and the axial force of the prestressing tendons showed that the simulation was reasonable and accurate. The numerical results show that for the concrete structure, the location of the cylinder wall bottom around the equipment hatch and near the ring beam are critical locations with large principal stress. The concrete cracks occurred at the bottom of the PCCV cylinder wall under the peak earthquake motion of 0.50 g, however the PCCV was still basically in an elastic state. Furthermore, the concrete cracks occurred around the equipment hatch under the design internal pressure of 0.4MPa, but the steel liner was still in the elastic stage and its leak-proof function soundness was verified. The results provide the basis for analysis and design of containment vessels. 展开更多
关键词 nuclear power plant prestressed concrete containment vessel aseismic safety analysis
下载PDF
Aseismic Layer Detected in the Mid-Crust of Nubra-Siachen Region, India Using Local Seismic Data 被引量:1
10
作者 Rajinder Parshad Snehmani   +2 位作者 Pankaj Kumar Srivastva Reeta Rani Ashwagosha Ganju 《International Journal of Geosciences》 2015年第9期993-1006,共14页
The local seismicity observed by seismic network in siachen-nubra region during January 2010-December 2012 shows that the middle part of the crust (17 - 40 km) is aseismic. This aseismic layer (17 - 40 km) is sandwich... The local seismicity observed by seismic network in siachen-nubra region during January 2010-December 2012 shows that the middle part of the crust (17 - 40 km) is aseismic. This aseismic layer (17 - 40 km) is sandwiched between two seismically active layers and depicts a good spatial correlation with the observations of low resistivity reported from magnetotelluric studies for the same region. The local seismicity shows a trend along the Karakoram fault and clustering of events in Shyok Suture zone and Karakoram shear zone. The moment magnitude of these events lies between 1.3 and 4.3. Most of these events have been originated in upper crust. 展开更多
关键词 Shear Zone KARAKORUM LOCAL Events aseismic Nubra-Siachen
下载PDF
Talc-bearing serpentinized peridotites from the southern Mariana forearc:implications for aseismic character within subduction zones
11
作者 汪小妹 曾志刚 +8 位作者 刘长华 陈俊兵 殷学博 王晓媛 陈代庚 张国良 陈帅 李康 欧阳荷根 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第3期667-673,共7页
The serpentinized peridotites overlying the subducted zones in the Izu-Bonin-Mariana(IBM) arc system have been interpret as the cause of the low-velocity layer identified beneath the IBM froearc,in turn few earthquake... The serpentinized peridotites overlying the subducted zones in the Izu-Bonin-Mariana(IBM) arc system have been interpret as the cause of the low-velocity layer identified beneath the IBM froearc,in turn few earthquakes occurred along the plate boundary.Chrysotile,which is a low temperature and highly hydrated phase of serpentine with low frictional strength,has been suggested as the low velocity material in the serpentinized peridotites,besides,brucite is inferred to be likely conducive to stable sliding.However,such idea encounters challenging in our serpentinized peridotites from the southern Mariana forearc,which absent both the above minerals.The presence of talc,which characterized by its weak,low-friction and inherently stable sliding behavior,provides new clue.Here we report the occurrence of talc in serpentinized peridotites collected from the landward trench slope of the southern Mariana forearc.We infer that talc is mainly forming as a result of the reaction of serpentine minerals with silica-saturated fluids released from the subducting slab,and talc also occurs as talc veins sometimes.Due to its unique physical properties,talc may therefore play a significant role in aseismic slip in the IBM subduction zone. 展开更多
关键词 TALC serpentinized peridotites MARIANA aseismic subducfion zone
原文传递
Introduction of structural aseismic research in China in recent four years
12
作者 罗奇峰 石春香 +3 位作者 曹炳政 杨树龙 熊华 李仕栋 《Acta Seismologica Sinica(English Edition)》 CSCD 2003年第6期656-675,共20页
The paper mainly summarized the developments on structural aseismic theory, aseismic analysis and design of reinforced concrete structure, lifeline system, several another kinds of structures, site and structure found... The paper mainly summarized the developments on structural aseismic theory, aseismic analysis and design of reinforced concrete structure, lifeline system, several another kinds of structures, site and structure foundation, structure mitigation and isolation of vibration in China in recent four years. This is the introduction of recent re-search results of Chinese professionals for international organizations and professionals. At the same time, it provides numerous abstract materials for colleagues to realize the trend of the structural aseismic theory and re-search range needing more study. 展开更多
关键词 aseismic theory reinforced concrete structure lifeline system site and foundation mitigation and isolation of vibration
下载PDF
Mechanism on Moho offset induced by aseismic slip of deeply buried faults
13
作者 Zhen Fu Hai-ming Zhang Shu-wen Dong 《Earthquake Science》 2014年第3期247-256,共10页
Recent high-resolution deep seismic reflection profile across the Kunlun fault in northeastern Tibet shows clearly that the Moho is cut off by a complex thrust fault system. Moho offset is a general phenomenon, but li... Recent high-resolution deep seismic reflection profile across the Kunlun fault in northeastern Tibet shows clearly that the Moho is cut off by a complex thrust fault system. Moho offset is a general phenomenon, but little is known about the dynamic mechanism. In this study, contact models with Maxwell materials are used to simulate the mechanical process of Moho offset induced by the aseismic slip of deeply buried faults. Based on the seismic reflection data, we project a single fault model and a complex fault system model with two faults inter- secting. The deformations of the Moho, the aseismic slips, and contact stresses on faults in different models are discussed in detail. Results show that the Moho offset might be produced by aseismic slip of deeply buried faults, and the magnitude is influenced by the friction coefficient of faults and the viscosity of the lower crust. The maximum slip occurs near the Moho on the single fault or at the crossing point of two intersecting faults system. Stress concentrates mainly on the Moho, the deep end of faults, or the crossing point. This study will throw light on understanding the mechanism of Moho offset and aseismic slip of deeply buried faults. The results of complex fault system with two faults intersecting are also useful to understand the shallow intersecting faults that may cause earthquakes. 展开更多
关键词 Moho offset aseismic slip - Deeply buriedfaults Numerical simulation Viscoelastic contact model
下载PDF
Long aseismic slip duration of the 2006 Java tsunami earthquake based on GPS data
14
作者 Rio Raharja Endra Gunawan +2 位作者 Irwan Meilano Hasanuddin Z.Abidin Joni Efendi 《Earthquake Science》 CSCD 2016年第5期291-298,共8页
The Java earthquake occurred on July 17, 2006 with magnitude 7.8 associated to the subduction process of Indo-Australian plate and Sundaland block off southwestern coast of Java. We present postseismic deformation par... The Java earthquake occurred on July 17, 2006 with magnitude 7.8 associated to the subduction process of Indo-Australian plate and Sundaland block off southwestern coast of Java. We present postseismic deformation parameters of the 2006 Java earthquake analyzed using campaign GPS observation from 2006 to 2008 and continuous observation from 2007 to 2014. We use an analytical approach of logarithmic and exponential functions to model these GPS data. We find that the decay time in the order of hundreds of days after the mainshock as observed by 8 years' data after the mainshock for magnitude 7 earthquake is longer than a general megathrust earthquake event. Our findings suggest that the 2006 Java earthquake which is considered as "tsunami earthquake" most probably occurred in the region that has low rigidity and tends to continuously slip for long time periods. 展开更多
关键词 2006 Java earthquake aseismic slip GPS Time series
下载PDF
Stress and Strain Accumulation Due to a Long Dip-Slip Fault Movement in an Elastic-Layer over a Viscoelastic Half Space Model of the Lithosphere-Asthenosphere System
15
作者 Sanjay Sen Subrata Kr. Debnath 《International Journal of Geosciences》 2013年第3期549-557,共9页
Most of the earthquake faults in North-East India, China, mid Atlantic-ridge, the Pacific seismic belt and Japan are found to be predominantly dip-slip in nature. In the present paper a dip-slip fault is taken situate... Most of the earthquake faults in North-East India, China, mid Atlantic-ridge, the Pacific seismic belt and Japan are found to be predominantly dip-slip in nature. In the present paper a dip-slip fault is taken situated in an elastic layer over a viscoelastic half space representing the lithosphere-asthenosphere system. A movement of the dip-slip nature across the fault occurs when the accumulated stress due to various tectonic reasons e.g. mantle convection etc., exceeds the local friction and cohesive forces across the fault. The movement is assumed to be slipping in nature, expressions for displacements, stresses and strains are obtained by solving associated boundary value problem with the help of integral transformation and Green’s function method and a suitable numerical methods is used for computation. A detailed study of these expressions may give some ideas about the nature of stress accumulation in the system, which in turn will be helpful in formulating an earthquake prediction programme. 展开更多
关键词 aseismic Period Dip-Slip Fault Earthquake Prediction MANTLE Convection Plate Movements Stress ACCUMULATION TECTONIC Process Viscoelastic-Layered Model
下载PDF
Discussion on uncertainties,attenuation of ground motion and aseismic design criterion
16
作者 张天中 马云生 舒曦 《Acta Seismologica Sinica(English Edition)》 CSCD 1995年第4期629-637,共9页
The usually calculated exceedance probability curves of ground motion are reduced as cumulative probability curves of normal distribution on some assumptions in this paper. These curves clearly displayed the variation... The usually calculated exceedance probability curves of ground motion are reduced as cumulative probability curves of normal distribution on some assumptions in this paper. These curves clearly displayed the variation of curve shape with the variance of attenuation relation and its physical implication. Similar investigation is also made on uncertainties of hypocenter locations and magnitudes of future earthquakes. The larger the uncertainty,the flatter the exceedance probability curve is. In a broad sense, the less people know future earthquakes, the flatter is the curve. Due to the rich or poor data sets available, the uncertainties of attenuation relation are different from region to region. The acceleration attenuation relations in these regions with no enough strong earthquake records can be obtained by conversion from other region, but with larger uncertainty. The uncertainty contains systematic difference between the two regions in addition to common stochastic error. A method to check and adjust the converted attenuation relation by using the local data is proposed in this paper. If the uncertainty of attenuation relation is too large, the result of seismic hazard assessment may be unaccepted sometimes.In order to realize that the structures do not collapse in large earthquakes, be repairable under moderate ones and without destruction in small earthquakes, this paper suggests that it may be reasonable to get the first and the third levels of aseismic design parameters by some empirical relation on the basis of the second level not by fixing the risk probability levels (63%, 10% and 3%). A particular aseismic design criterion is not only a balance between economic cost and seismic risk but also suited to the human's knowledge of nature. 展开更多
关键词 attenuation uncertainty exceedance probability aseismic design criterion
下载PDF
Rapid afterslip and short-term viscoelastic relaxation following the 2008 M_W7.9 Wenchuan earthquake 被引量:16
17
作者 Zhigang Shao Rongjiang Wang +1 位作者 Yanqiang Wu Langping Zhang 《Earthquake Science》 CSCD 2011年第2期163-175,共13页
Significant postseismic deformation of the 2008 M W 7.9 Wenchuan earthquake has been observed from GPS data of the first 14 days after the earthquake. The possible mechanisms for the rapid postseismic deformation are ... Significant postseismic deformation of the 2008 M W 7.9 Wenchuan earthquake has been observed from GPS data of the first 14 days after the earthquake. The possible mechanisms for the rapid postseismic deformation are assumed to be afterslip on the earthquake rupture plane and viscoelastic relaxation of coseismiclly stress change in the lower crust or upper mantle. We firstly use the constrained least squares method to find an afterslip model which can fit the GPS data best. The afterslip model can explain near-field data very well but shows considerable discrepancies in fitting far-field data. To estimate the effect due to the viscoelastic relaxation in the lower crust, we then ignore the contribution from the afterslip and attempt to invert the viscosity structure beneath the Longmenshan fault where the Wenchuan earthquake occurred from the postseismic deformation data. For this purpose, we use a viscoelastic model with a 2D geometry based on the geological and seismological observations and the coseismic slip distribution derived from the coseismic GPS and InSAR data. By means of a grid search we find that the optimum viscosity is 9×10 18 Pa·s for the middle-lower crust in the Chengdu Basin, 4×10 17 Pa·s for the middle-lower crust in the Chuanxi Plateau and 7×10 17 Pa·s for the low velocity zone in the Chuanxi plateau. The viscoelastic model explains the postseismic deformation observed in the far-field satisfactorily, but it is considerably worse than the afterslip model in fitting the near-fault data. It suggests therefore a hybrid model including both afterslip and relaxation effects. Since the viscoelastic model produces mainly the far-field surface deformation and has fewer degree of freedoms (three viscosity parameters) than the afterslip model with a huge number of source parameters, we fix the viscositiy structure as obtained before but redetermine the afterslip distribution using the residual data from the viscoelastic modeling. The redetermined afterslip distribution becomes physically more reasonable; it is more localized and exhibits a pattern spatially complementary with the coseismic rupture distribution. We conclude that the aseismic fault slip is responsible for the near-fault postseismic deformation, whereas the viscoelastic stress relaxation might be the major cause for the far-field postseismic deformation. 展开更多
关键词 Wenchuan earthquake short-term postseismic deformation aseismic slip viscoelastic relaxation
下载PDF
Synthesis of accelerograms compatible with the Chinese GB 50011-2001 design spectrum via harmonic wavelets: artifi cial and historic records 被引量:3
18
作者 P.D. Spanos A. Giaralis Li Jie 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2009年第2期189-206,共18页
A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent pea... A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent peak factor derived by means of appropriate Monte Carlo analyses is introduced to relate the GB 50011-2001 design spectrum to a parametrically defined evolutionary power spectrum (EPS). Special attention is given to the definition of the frequency content of the EPS in order to accommodate the mathematical form of the aforementioned design spectrum. Further, a one-to-one relationship is established between the parameter controlling the time-varying intensity of the EPS and the effective strong ground motion duration. Subsequently, an efficient auto-regressive moving-average (ARMA) filtering technique is utilized to generate ensembles of non-stationary artificial accelerograms whose average response spectrum is in a close agreement with the considered design spectrum. Furthermore, a harmonic wavelet based iterative scheme is adopted to modify these artificial signals so that a close matching of the signals' response spectra with the GB 50011-2001 design spectrum is achieved on an individual basis. This is also done for field recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In the process, zero-phase high-pass filtering is performed to accomplish proper baseline correction of the acquired spectrum compatible artificial and field accelerograms. Numerical results are given in a tabulated format to expedite their use in practice. 展开更多
关键词 design spectrum Chinese aseismic code artificial accelerograms evolutionary power spectrum peak factor recorded accelerograms WAVELETS
下载PDF
A simplified design method for metallic dampers used in the transverse direction of cable-stayed bridges 被引量:2
19
作者 Niu Jiantao Ding Yang +1 位作者 Shi Yundong Li Zhongxian 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2020年第2期483-497,共15页
The aseismic design of cable-stayed bridges in the transverse direction with newly proposed metallic dampers that can accommodate both longitudinal and transverse movement of the deck has recently been considered.This... The aseismic design of cable-stayed bridges in the transverse direction with newly proposed metallic dampers that can accommodate both longitudinal and transverse movement of the deck has recently been considered.This work focuses on developing a simplified method to design an appropriate metallic damper.The seismic performance of cablestayed bridges with different damper stiffness,main span lengths,tower shapes and types of deck in the transverse direction are investigated.The transverse displacement of the deck of a cable-stayed bridge increases significantly with the increment of the damper stiffness,which proves that the design of the damper stiffness is crucial.A simplified model considering the damper stiffness,cable system and tower in the transverse direction is developed to evaluate the period and lateral displacement of a complicated cable-stayed bridge.Based on the simplified model,a design method is proposed and assessed using two cable-stayed bridges as examples.The results show that metallic dampers can be designed with high efficiency,and the optimal ductility of the damper can be selected. 展开更多
关键词 CABLE-STAYED BRIDGE aseismic design simplified model METALLIC DAMPER TRANSVERSE direction
下载PDF
Seismic force modification factor for ductile structures 被引量:1
20
作者 童根树 黄金桥 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第8期813-825,共13页
The earthquake forces used in design codes of buildings should be theoretically determinable. This work examines the seismic force modification factor R based on elastic-plastic time-history earthquake analysis of SDO... The earthquake forces used in design codes of buildings should be theoretically determinable. This work examines the seismic force modification factor R based on elastic-plastic time-history earthquake analysis of SDOF systems, wherein the hys-teresis models are elastic-perfectly-plastic (EPP), elastic-linearly-hardening (ELH), shear-slipped and bilinear-elastic. The latter two models are analysed for separating the effect of the ductility and the energy-dissipating capacity. Three-hundred eighty-eight earthquake records from different site conditions are used in analysis. The ductility is taken to be 2, 3, 4, 5 and 6, with the damping ratio being 0.02, 0.035 and 0.05 respectively. The post-yield stiffness ratios 0.0, 0.1 and 0.2 are used in the analysis. The R spectra are standardized by the characteristic period of the earthquake records, which leads to a much smaller scatter in averaged numerical results. It was found that the most important factor determining R is the ductility. R increases more than linearly with ductility. The energy-dissipating capacity, damping and the post-yield stiffness are the less important factors. The energy dissipating capacity is important only for structures with short period and moderate period (0.3≤T/Tg<5.0). For EPP and ELH models, R for 0.05 damping is 10% to 15% smaller than for 0.02 damping. For EPP and ELH models, greater post-yield stiffness leads to greater R, but the influence of post-yield stiffness is obvious only when the post-yield stiffness is less than 10% of the initial stiffness. By means of statistical regression analysis the relation of the seismic force modification factor R with the natural period of the system and ductility for EPP and ELH models were established for each site and soil condition. 展开更多
关键词 aseismic design Seismic force modification coefficient DUCTILITY Energy-dissipating capacity
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部