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Running safety assessment of a train traversing a three-tower cable-stayed bridge under spatially varying ground motion 被引量:9
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作者 Wei Gong Zhihui Zhu +3 位作者 Yu Liu Ruitao Liu Yongjiu Tang Lizhong Jiang 《Railway Engineering Science》 2020年第2期184-198,共15页
To explore the influence of spatially varying ground motion on the dynamic behavior of a train passing through a three-tower cable-stayed bridge,a 3D train–track–bridge coupled model is established for accurately si... To explore the influence of spatially varying ground motion on the dynamic behavior of a train passing through a three-tower cable-stayed bridge,a 3D train–track–bridge coupled model is established for accurately simulating the train–bridge interaction under earthquake excitation,which is made up of a vehicle model built by multi-body dynamics,a track–bridge finite element model,and a 3D rolling wheel–rail contact model.A conditional simulation method,which takes into consideration the wave passage effect,incoherence effect,and site-response effect,is adopted to simulate the spatially varying ground motion under different soil conditions.The multi-time-step method previously proposed by the authors is also adopted to improve computational efficiency.The dynamic responses of the train running on a three-tower cablestayed bridge are calculated with differing earthquake excitations and train speeds.The results indicate that(1)the earthquake excitation significantly increases the responses of the train–bridge system,but at a design speed,all the running safety indices meet the code requirements;(2)the incoherence and site-response effects should also be considered in the seismic analysis for long-span bridges though there is no fixed pattern for determining their influences;(3)different train speeds that vary the vibration characteristics of the train–bridge system affect the vibration frequencies of the car body and bridge. 展开更多
关键词 EARTHQUAKE spatially varying ground motion Long-span bridges Nonlinear wheel-rail contact Running safety
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Vertical coherency function model of spatial ground motion 被引量:5
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作者 Ye Jihong Pan Jinlong Liu Xianming 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2011年第3期403-415,共13页
Many studies have focused on horizontal ground motion, resulting in many coherency functions for horizontal ground motion while neglecting related problems arising from vertical ground motion. However, seismic events ... Many studies have focused on horizontal ground motion, resulting in many coherency functions for horizontal ground motion while neglecting related problems arising from vertical ground motion. However, seismic events have demonstrated that the vertical components of ground motion sometimes govern the ultimate failure of structures. In this paper, a vertical coherency function model of spatial ground motion is proposed based on the Hao model and SMART 1 array records, and the validity of the model is demonstrated. The vertical coherency function model of spatial ground motion is also compared with the horizontal coherency function model, indicating that neither model exhibits isotropic characteristics. The value of the vertical coherency function has little correlation with that of the horizontal coherency function. However, the coherence of the vertical ground motion between a pair of stations decreases with their projection distance and the frequency of the ground motion. When the projection distance in the wave direction is greater than 800 meters, the coherency between the two points can be neglected. 展开更多
关键词 spatial ground motion vertical coherency model coherence law of vertical ground motion coherence law of horizontal ground motion
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A coherency function model of ground motion at base rock corresponding to strike-slip fault 被引量:4
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作者 丁海平 刘启方 +1 位作者 金星 袁一凡 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第1期64-69,共6页
At present, the method to study spatial variation of ground motions is statistic analysis based on dense array re-cords such as SMART-1 array, etc. For lacking of information of ground motions, there is no coherency f... At present, the method to study spatial variation of ground motions is statistic analysis based on dense array re-cords such as SMART-1 array, etc. For lacking of information of ground motions, there is no coherency function model of base rock and different style site. Spatial variation of ground motions in elastic media is analyzed by deterministic method in this paper. Taking elastic half-space model with dislocation source of fault, near-field ground motions are simulated. This model takes strike-slip fault and earth media into account. A coherency func-tion is proposed for base rock site. 展开更多
关键词 elastic media spatial variation of ground motion coherency function strip-fault stochastic vibration
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Simulation of multi-support depth-varying earthquake ground motions within heterogeneous onshore and offshore sites 被引量:6
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作者 Li Chao Li Hongnan +2 位作者 Hao Hong Bi Kaiming Tian Li 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2018年第3期475-490,共16页
This paper presents a novel approach to model and simulate the multi-support depth-varying seismic motions(MDSMs) within heterogeneous offshore and onshore sites.Based on 1 D wave propagation theory,the three-dimens... This paper presents a novel approach to model and simulate the multi-support depth-varying seismic motions(MDSMs) within heterogeneous offshore and onshore sites.Based on 1 D wave propagation theory,the three-dimensional ground motion transfer functions on the surface or within an offshore or onshore site are derived by considering the effects of seawater and porous soils on the propagation of seismic P waves.Moreover,the depth-varying and spatial variation properties of seismic ground motions are considered in the ground motion simulation.Using the obtained transfer functions at any locations within a site,the offshore or onshore depth-varying seismic motions are stochastically simulated based on the spectral representation method(SRM).The traditional approaches for simulating spatially varying ground motions are improved and extended to generate MDSMs within multiple offshore and onshore sites.The simulation results show that the PSD functions and coherency losses of the generated MDSMs are compatible with respective target values,which fully validates the effectiveness of the proposed simulation method.The synthesized MDSMs can provide strong support for the precise seismic response prediction and performance-based design of both offshore and onshore large-span engineering structures. 展开更多
关键词 seismic motion simulation onshore and offshore sites ground motion spatial variation depth-varying motions transfer function
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On time-step in structural seismic response analysis under ground displacement/acceleration 被引量:3
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作者 TianYuji~+ and Yang Qingshan~(++) School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China +Associate Professor ++Professor 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2009年第3期341-347,共7页
There are two models in use today to analyze structural responses when subjected to earthquake ground motions, the Displacement Input Model (DIM) and the Acceleration Input Model (AIM). The time steps used in dire... There are two models in use today to analyze structural responses when subjected to earthquake ground motions, the Displacement Input Model (DIM) and the Acceleration Input Model (AIM). The time steps used in direct integration methods for these models are analyzed to examine the suitability of DIM. Numerical results are presented and show that the time-step for DIM is about the same as for AIM, and achieves the same accuracy. This is contrary to previous research that reported that there are several sources of numerical errors associated with the direct application of earthquake displacement loading, and a very small time step is required to define the displacement record and to integrate the dynamic equilibrium equation. It is shown in this paper that DIM is as accurate and suitable as, if not more than, AIM for analyzing the response of a structure to uniformly distributed and spatially varying ground motions. 展开更多
关键词 integration time step multi-supported structure displacement input model acceleration input model spatially varying ground motions
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An extended multiple-support response spectrum method incorporating fluid-structure interaction for seismic analysis of deep-water bridges 被引量:1
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作者 Wu Kun Li Ning Li Zhongxian 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第1期211-223,共13页
The effects of ground motion spatial variability(GMSV)or fluid-structure interaction(FSI)on the seismic responses of deep-water bridges have been extensively examined.However,there are few studies on the seismic perfo... The effects of ground motion spatial variability(GMSV)or fluid-structure interaction(FSI)on the seismic responses of deep-water bridges have been extensively examined.However,there are few studies on the seismic performance of bridges considering GMSV and FSI effects simultaneously.In this study,the original multiple-support response spectrum(MSRS)method is extended to consider FSI effect for seismic analysis of deep-water bridges.The solution of hydrodynamic pressure on a pier is obtained using the radiation wave theory,and the FSI-MSRS formulation is derived according to the random vibration theory.The influence of FSI effect on the related coefficients is analyzed.A five-span steel-concrete continuous beam bridge is adopted to conduct the numerical simulations.Different load conditions are designed to investigate the variation of the bridge responses when considering the GMSV and FSI effects.The results indicate that the incoherence effect and wave passage effect decrease the bridge responses with a maximum percentage of 86%,while the FSI effect increases the responses with a maximum percentage of 26%.The GMSV and FSI effects should be included in the seismic design of deep-water bridges. 展开更多
关键词 response spectrum method seismic response of bridge ground motion spatial variability fluid-structure interaction rdiation wave theory
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Generation of endurance time excitation functions using spectral representation method
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作者 Parsa Parvanehro Mohammad Safi 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第2期441-452,共12页
In this study,application of the spectral representation method for generation of endurance time excitation functions is introduced.Using this method,the intensifying acceleration time series is generated so that its ... In this study,application of the spectral representation method for generation of endurance time excitation functions is introduced.Using this method,the intensifying acceleration time series is generated so that its acceleration response spectrum in any desired time duration is compatible with a time-scaled predefined acceleration response spectrum.For this purpose,simulated stationary acceleration time series is multiplied by the time dependent linear modulation function,then using a simple iterative scheme,it is forced to match a target acceleration response spectrum.It is shown that the generated samples have excellent conformity in low frequency,which is useful for nonlinear endurance time analysis.In the second part of this study,it is shown that this procedure can be extended to generate a set of spatially correlated endurance time excitation functions.This makes it possible to assess the performance of long structures under multi-support seismic excitation using endurance time analysis. 展开更多
关键词 endurance time analysis endurance time excitation functions spatial variation of seismic ground motions multi-support excitation spectral representation method
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Response of a transmission tower-line system at a canyon site to spatially varying ground motions
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作者 Hong-nan LI Feng-long BAI +1 位作者 Li TIAN Hong HAO 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2011年第2期103-120,共18页
Collapses of transmission towers were often observed in previous large earthquakes such as the Chi-Chi earthquake in Taiwan and Wenchuan earthquake in Sichuan,China. These collapses were partially caused by the pullin... Collapses of transmission towers were often observed in previous large earthquakes such as the Chi-Chi earthquake in Taiwan and Wenchuan earthquake in Sichuan,China. These collapses were partially caused by the pulling forces from the transmission lines generated from out-of-phase responses of the adjacent towers owing to spatially varying earthquake ground motions. In this paper,a 3D finite element model of the transmission tower-line system is established considering the geometric nonlinearity of transmission lines. The nonlinear responses of the structural system at a canyon site are analyzed subjected to spatially varying ground motions. The spatial variations of ground motion associated with the wave passage,coherency loss,and local site effects are given. The spatially varying ground motions are simulated stochastically based on an empirical coherency loss function and a filtered Tajimi-Kanai power spectral density function. The site effect is considered by a transfer function derived from 1D wave propagation theory. Compared with structural responses calculated using the uniform ground motion and delayed excitations,numerical results indicate that seismic responses of transmission towers and power lines are amplified when considering spatially varying ground motions including site effects. Each factor of ground motion spatial variations has a significant effect on the seismic response of the structure,especially for the local site effect. Therefore,neglecting the earthquake ground motion spatial variations may lead to a substantial underestimation of the response of transmission tower-line system during strong earthquakes. Each effect of ground motion spatial variations should be incorporated in seismic analysis of the structural system. 展开更多
关键词 Transmission tower-line system Canyon site spatially varying ground motions Coherency loss Local site effect
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A Rapid Estimation Method for Post-earthquake Building Losses
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作者 Dengke Zhao Zifa Wang +3 位作者 Jianming Wang Dongliang Wei Yang Zhou Zhaoyan Li 《International Journal of Disaster Risk Science》 SCIE CSCD 2023年第3期428-439,共12页
Rapid estimation of post-earthquake building damage and loss is very important in urgent response efforts.The current approach leaves much room for improvement in estimating ground motion and correctly incorporating t... Rapid estimation of post-earthquake building damage and loss is very important in urgent response efforts.The current approach leaves much room for improvement in estimating ground motion and correctly incorporating the uncertainty and spatial correlation of the loss.This study proposed a new approach for rapidly estimating post-earthquake building loss with reasonable accuracy.The proposed method interpolates ground motion based on the observed ground motion using the Ground Motion Prediction Equation(GMPE)as the weight.It samples the building seismic loss quantile considering the spatial loss correlation that is expressed by Gaussian copula,and kriging is applied to reduce the dimension of direct sampling for estimation speed.The proposed approach was validated using three historical earthquake events in Japan with actual loss reports,and was then applied to predict the building loss amount for the March 2022 Fukushima Mw7.3 earthquake.The proposed method has high potential in future emergency efforts such as search,rescue,and evacuation planning. 展开更多
关键词 Earthquake building loss estimation Fukushima earthquake 2022 Gaussian copula sampling Japan Spatial correlation of earthquake losses Spatial interpolation of ground motion
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