Following several damaging earthquakes in China, research has been devoted to find the causes of the collapse of reinforced concrete （RC） building sand studying the vulnerability of existing buildings. The Chinese C...Following several damaging earthquakes in China, research has been devoted to find the causes of the collapse of reinforced concrete （RC） building sand studying the vulnerability of existing buildings. The Chinese Code for Seismic Design of Buildings （CCSDB） has evolved over time, however, there is still reported earthquake induced damage of newly designed RC buildings. Thus, to investigate modern Chinese seismic design code, three low-, mid- and high-rise RC frames were designed according to the 2010 CCSDB and the corresponding vulnerability curves were derived by computing a probabilistic seismic demand model （PSDM）.The PSDM was computed by carrying out nonlinear time history analysis using thirty ground motions obtained from the Pacific Earthquake Engineering Research Center. Finally, the PSDM was used to generate fragility curves for immediate occupancy, significant damage, and collapse prevention damage levels. Results of the vulnerability assessment indicate that the seismic demands on the three different frames designed according to the 2010 CCSDB meet the seismic requirements and are almost in the same safety level.展开更多
The seismic behavior of a large diameter extended pile shaft founded on a dense sandy site is investigated in this paper. First, a deterministic analysis is conducted including both nonlinear dynamic analysis （NDA） ...The seismic behavior of a large diameter extended pile shaft founded on a dense sandy site is investigated in this paper. First, a deterministic analysis is conducted including both nonlinear dynamic analysis （NDA） and pushover analysis to gain insights into the behavior of the pile and make sure an appropriate modeling technique is utilized. Then a probabilistic analysis is performed using the results of NDA for various demands. To this end a set of 40 pulse-like ground motions are picked and subsequently 40 nonlinear dynamic and pushover analyses are performed. The data obtained from NDA are used to generate probabilistic seismic demand model （PSDM） plots and consequently the median line and dispersion for each plot are computed. The NDA and pushover data are also plotted against each other to find out to what extent they are correlated. These operations are done for various engineering demand parameters （EDPs）. A sensitivity analysis is done to pick the most appropriate intensity measure （IM） which would cause a minimum dispersion in PSDM plots out of 7 different IMs. Peak ground acceleration （PGA） is found to be the most appropriate IM. Pushover coefficient equations as a function of PGA are proposed which can be applied to the pushover analysis data to yield a better outcome with respect to the NDA. At the end, the pacific earthquake engineering research （PEER） center methodology is utilized to generate the fragility curves using the properties obtained from PSDM plots and considering various states of damage ranging from minor to severe. The extended pile shaft shows more vulnerability with a higher probability with respect to minor damage compared to severe damage.展开更多
Identifying the optimal intensity measures(IMs)of ground motion is a critical step in the seismic fragility analysis of slopes using probabilistic seismic demand models.In this study,we investigated various IMs of ear...Identifying the optimal intensity measures(IMs)of ground motion is a critical step in the seismic fragility analysis of slopes using probabilistic seismic demand models.In this study,we investigated various IMs of earthquake ground motions,considering both vertical and horizontal components that can trigger landslides,through numerical simulations.A set of 19 IMs was examined for three heights of slopes.The optimal IMs were assessed using the maximum permanent displacement as an engineering demand parameter.The findings reveal that acceleration-related parameters specifically sustained maximum acceleration(SMA)and root-mean-square of acceleration,and velocity-related parameters namely sustained maximum velocity(SMV)and peak ground velocity,are the most effective IMs for slopes subjected to both vertical and horizontal ground motions.For slopes subjected exclusively to horizontal ground motion,SMA is recommended as the optimal IM for lower-height slopes,while SMV is more suitable for the taller slope.In contrast,for models subjected to combined horizontal and vertical ground motions,SMA is consistently identified as the optimal IM for slope across all heights.Notably,the study concludes that peak ground acceleration,a commonly used parameter in seismic analysis,is unsuitable for the considered slopes.展开更多
In AC microgrids(ACMG),hierarchical control is widely adopted,and conventionally,communication links are required between converters to transmit control instructions.However,establishing these communication links incr...In AC microgrids(ACMG),hierarchical control is widely adopted,and conventionally,communication links are required between converters to transmit control instructions.However,establishing these communication links increases system complexity and introduces communication delays.Consequently,there is an urgent need for highly integrated communication schemes in ACMG.Power and signal dual modulation(PSDM)offers an integrated communication solution that simultaneously modulates and transmits power and data in power electronic systems.In contrast,existing research primarily focuses on DC systems.In this paper,PSDM for cascaded H-Bridge multilevel inverters is proposed.The communication function is integrated into the power conversion process by modulating the data around the zero-crossing point of AC bus voltage,without interfering with power transmission.The harmonic effect and power losses introduced by this novel strategy in power transmission are further explored,offering theoretical guidance for designing DCAC PSDM systems.The proposed method has been implemented in an experimental platform of ACMG.The experimental results validated the proposed modulation scheme for full-duplex communication with a bit rate of 300bps.展开更多
Proven research output on the behavior of structures made of waste copper slag concrete can improve its utilization in the construction industry and thereby help to develop a sustainable built environment.Although num...Proven research output on the behavior of structures made of waste copper slag concrete can improve its utilization in the construction industry and thereby help to develop a sustainable built environment.Although numerous studies on waste copper slag concrete can be found in the published literature,no research has focused on the structural application of this type of concrete.In particular,the variability in the strength properties of waste copper slag concrete,which is required for various structural applications,such as limit state design formulation,reliability-based structural analysis,etc.,has so far not attracted the attention of researchers.This paper quantifies the uncertainty associated with the compressive-,flexural-and split tensile strength of hardened concrete with different dosages of waste copper slag as fine aggregate.Best-fit probability distribution models are proposed based on statistical analyses of strength data generated from laboratory experiments.In addition,the paper presents a reliability-based seismic risk assessment of a typical waste copper slag incorporated reinforced concrete framed building,considering the proposed distribution model.The results show that waste copper slag can be safely used for seismic resistant structures as it results in an identical probability of failure and dispersion in the drift demand when compared with a conventional concrete building made of natural sand.展开更多
基金National Natural Science Foundation of China Under Grant No.51108105,90815029,50938006 Research Fund for the Doctoral Program of Higher Education of China Under Grant No.20094410120002+3 种基金 Major Program of National Natural Science Foundation of China Under Grant No.90815027Key Projects in the National Science&Technology Pillar Program during the Eleventh Five-Year Plan Period Under Grant No.2009BAJ28B03Fund for High School in Guangzhou (10A057)the Open Foundation of State Key Laboratory of Subtropical Building Science(2011KB15)
文摘Following several damaging earthquakes in China, research has been devoted to find the causes of the collapse of reinforced concrete （RC） building sand studying the vulnerability of existing buildings. The Chinese Code for Seismic Design of Buildings （CCSDB） has evolved over time, however, there is still reported earthquake induced damage of newly designed RC buildings. Thus, to investigate modern Chinese seismic design code, three low-, mid- and high-rise RC frames were designed according to the 2010 CCSDB and the corresponding vulnerability curves were derived by computing a probabilistic seismic demand model （PSDM）.The PSDM was computed by carrying out nonlinear time history analysis using thirty ground motions obtained from the Pacific Earthquake Engineering Research Center. Finally, the PSDM was used to generate fragility curves for immediate occupancy, significant damage, and collapse prevention damage levels. Results of the vulnerability assessment indicate that the seismic demands on the three different frames designed according to the 2010 CCSDB meet the seismic requirements and are almost in the same safety level.
文摘The seismic behavior of a large diameter extended pile shaft founded on a dense sandy site is investigated in this paper. First, a deterministic analysis is conducted including both nonlinear dynamic analysis （NDA） and pushover analysis to gain insights into the behavior of the pile and make sure an appropriate modeling technique is utilized. Then a probabilistic analysis is performed using the results of NDA for various demands. To this end a set of 40 pulse-like ground motions are picked and subsequently 40 nonlinear dynamic and pushover analyses are performed. The data obtained from NDA are used to generate probabilistic seismic demand model （PSDM） plots and consequently the median line and dispersion for each plot are computed. The NDA and pushover data are also plotted against each other to find out to what extent they are correlated. These operations are done for various engineering demand parameters （EDPs）. A sensitivity analysis is done to pick the most appropriate intensity measure （IM） which would cause a minimum dispersion in PSDM plots out of 7 different IMs. Peak ground acceleration （PGA） is found to be the most appropriate IM. Pushover coefficient equations as a function of PGA are proposed which can be applied to the pushover analysis data to yield a better outcome with respect to the NDA. At the end, the pacific earthquake engineering research （PEER） center methodology is utilized to generate the fragility curves using the properties obtained from PSDM plots and considering various states of damage ranging from minor to severe. The extended pile shaft shows more vulnerability with a higher probability with respect to minor damage compared to severe damage.
基金funded by the National Natural Science Foundation of China(Grant No.52422807).
文摘Identifying the optimal intensity measures(IMs)of ground motion is a critical step in the seismic fragility analysis of slopes using probabilistic seismic demand models.In this study,we investigated various IMs of earthquake ground motions,considering both vertical and horizontal components that can trigger landslides,through numerical simulations.A set of 19 IMs was examined for three heights of slopes.The optimal IMs were assessed using the maximum permanent displacement as an engineering demand parameter.The findings reveal that acceleration-related parameters specifically sustained maximum acceleration(SMA)and root-mean-square of acceleration,and velocity-related parameters namely sustained maximum velocity(SMV)and peak ground velocity,are the most effective IMs for slopes subjected to both vertical and horizontal ground motions.For slopes subjected exclusively to horizontal ground motion,SMA is recommended as the optimal IM for lower-height slopes,while SMV is more suitable for the taller slope.In contrast,for models subjected to combined horizontal and vertical ground motions,SMA is consistently identified as the optimal IM for slope across all heights.Notably,the study concludes that peak ground acceleration,a commonly used parameter in seismic analysis,is unsuitable for the considered slopes.
基金supported in part by the National Natural Science Foundation of China under Grant 52350003in part by the Royal Society Research Grant(RG/R1/251624).
文摘In AC microgrids(ACMG),hierarchical control is widely adopted,and conventionally,communication links are required between converters to transmit control instructions.However,establishing these communication links increases system complexity and introduces communication delays.Consequently,there is an urgent need for highly integrated communication schemes in ACMG.Power and signal dual modulation(PSDM)offers an integrated communication solution that simultaneously modulates and transmits power and data in power electronic systems.In contrast,existing research primarily focuses on DC systems.In this paper,PSDM for cascaded H-Bridge multilevel inverters is proposed.The communication function is integrated into the power conversion process by modulating the data around the zero-crossing point of AC bus voltage,without interfering with power transmission.The harmonic effect and power losses introduced by this novel strategy in power transmission are further explored,offering theoretical guidance for designing DCAC PSDM systems.The proposed method has been implemented in an experimental platform of ACMG.The experimental results validated the proposed modulation scheme for full-duplex communication with a bit rate of 300bps.
文摘Proven research output on the behavior of structures made of waste copper slag concrete can improve its utilization in the construction industry and thereby help to develop a sustainable built environment.Although numerous studies on waste copper slag concrete can be found in the published literature,no research has focused on the structural application of this type of concrete.In particular,the variability in the strength properties of waste copper slag concrete,which is required for various structural applications,such as limit state design formulation,reliability-based structural analysis,etc.,has so far not attracted the attention of researchers.This paper quantifies the uncertainty associated with the compressive-,flexural-and split tensile strength of hardened concrete with different dosages of waste copper slag as fine aggregate.Best-fit probability distribution models are proposed based on statistical analyses of strength data generated from laboratory experiments.In addition,the paper presents a reliability-based seismic risk assessment of a typical waste copper slag incorporated reinforced concrete framed building,considering the proposed distribution model.The results show that waste copper slag can be safely used for seismic resistant structures as it results in an identical probability of failure and dispersion in the drift demand when compared with a conventional concrete building made of natural sand.
