This article presents an experimental study on the flexural performance of reinforced concrete(RC)beams with fiber reinforced cementitious composites(FRCC)and hybrid fiber reinforced cementitious composites(HFRCC)in t...This article presents an experimental study on the flexural performance of reinforced concrete(RC)beams with fiber reinforced cementitious composites(FRCC)and hybrid fiber reinforced cementitious composites(HFRCC)in the hinge portion.Beam specimens with moderate confinement were used in the study and tested under monotonic loading.Seven diverse types of FRCC including hybrid composites using fibers in different profiles and in different volumes are employed in this study.Companion specimens such as cylindrical specimens and prism specimens are also used to study the physical properties of composites employed.The moment?curvature,stiffness behavior,ductility,crack pattern and modified flexural damage ratio are the main factors considered in this study to observe the efficacy of the employed hybrid composites.The experimental outputs demonstrate the improved post yield behavior with less rate of stiffness degradation and better damage tolerance capacity than conventional technique.展开更多
Seismologists have begun to investigate the earthquake damage and assess the economic losses on the spot in the Yunnan area since the earthquakes with M_S6.7 and M_S6.9 that occurred on the boundary between China and ...Seismologists have begun to investigate the earthquake damage and assess the economic losses on the spot in the Yunnan area since the earthquakes with M_S6.7 and M_S6.9 that occurred on the boundary between China and Myanmar west of Menglian county,Yunnan Province,on April 23,1992.From 1992 to 2003,50 destructive earthquakes occurred in Yunnan,and large amounts of data on seismic hazard have been accumulated.With focus on the major building structures,the paper makes statistical analysis on the earthquake damage ratio,loss ratio and seismic hazard index in the areas with different seismic intensity of the 50 events,and presents the seismic hazard matrix of buildings for the Yunnan area.展开更多
Hurricane Ike,which struck the United States in September 2008,was the ninth most expensive hurricane in terms of damages.It caused nearly USD 30 billion in damage after making landfall on the Bolivar Peninsula,Texas....Hurricane Ike,which struck the United States in September 2008,was the ninth most expensive hurricane in terms of damages.It caused nearly USD 30 billion in damage after making landfall on the Bolivar Peninsula,Texas.We used the Delft3dFM/SWAN hydrodynamic and spectral wave model to simulate the storm surge inundation around Galveston Bay during Hurricane Ike.Damage curves were established through the relationship between eight hydrodynamic parameters(water depth,flow velocity,unit discharge,flow momentum flux,significant wave height,wave energy flux,total water depth(flow depth plus wave height),and total(flow plus wave)force)simulated by the model and National Flood Insurance Program(NFIP)insurance damage data.The NFIP insurance database contains a large amount of building damage data,building stories,and elevation,as well as other information from the Ike event.We found that the damage curves are sensitive to the model grid resolution,building elevation,and the number of stories.We also found that the resulting damage functions are steeper than those developed for residential structures in many other locations.展开更多
The neutronic calculations and activation behavior of the proposed helium cooled ceramic breeder（HCCB） blanket were predicted for the Chinese Fusion Engineering Testing Reactor（CFETR） design model using the MCNP m...The neutronic calculations and activation behavior of the proposed helium cooled ceramic breeder（HCCB） blanket were predicted for the Chinese Fusion Engineering Testing Reactor（CFETR） design model using the MCNP multi-particle transport code and its associated data library. The tritium self-sufficiency behavior of the HCCB blanket was assessed, addressing several important breeding-related arrangements inside the blankets. Two candidate first wall armor materials were considered to obtain a proper tritium breeding ratio（TBR）. Presentations of other neutronic characteristics, including neutron flux, neutron-induced damages in terms of the accumulated dpa and helium production were also conducted. Activation, decay heat levels and contact dose rates of the components were calculated to estimate the neutron-induced radioactivity and personnel safety. The results indicate that neutron radiation is efficiently attenuated and slowed down by components placed between the plasma and toroidal field coil.The dominant nuclides and corresponding isotopes in the structural steel were discussed. A radioactivity comparison between pure beryllium and beryllium with specific impurities was also performed. After a millennium cooling time, the decay heat of all the concerned components and materials is less than 1？×？10-4 k W, and most associated in-vessel components qualify for recycling by remote handling. The results demonstrate that acceptable hands-on recycling and operation still require a further long waiting period to allow the activated products to decay.展开更多
Aiming at the progressive damage phenomenon in geotechnical field,it attempts to study the effect of progressive damage on the macro-bearing capacity.Firstly,based on the theoretical analysis of a two-dimensional plan...Aiming at the progressive damage phenomenon in geotechnical field,it attempts to study the effect of progressive damage on the macro-bearing capacity.Firstly,based on the theoretical analysis of a two-dimensional plane inside representative volume element,it is proposed that progressive damage will occur if the bearing capacity of microplanes is different.Besides,“damage-aggravation effect”is proposed according to the difference between the macro-bearing capacity of entire plane and the sum of bearing capacity of all microplanes when progressive damage occurs.Secondly,progressive damage ratio K_(t)is proposed to quantify“damage-aggravation effect”.Finally,based on the rod model,the correspondence between K_(t),and some influence factors is studied by theoretical analysis and numerical simulation.The results show that“damage-aggravation effect”does exist,and the macro-bearing capacity of entire plane is less than the sum of bearing capacity of all microplanes when progressive damage occurs.If the bearing capacity of rods in the rod model obeys uniform distribution,as the minimum of bearing capacity increases linearly,the macro-bearing capacity increases linearly,and K_(t)decreases inversely.展开更多
This paper presents experimental and theoretical methods to study the damage layer evolution of a breakwater made with concrete hollow squares in marine environment.Wetting time was directly related to the performance...This paper presents experimental and theoretical methods to study the damage layer evolution of a breakwater made with concrete hollow squares in marine environment.Wetting time was directly related to the performance degradation of the breakwater by observation.The thickness of damage layer was detected by means of ultrasonic testing.Meanwhile,some samples drilled from concrete hollow squares were analyzed by SEM and XRD in order to illustrate the damage mechanism.Subsequently,a theoretical model containing wetting time ratio was established to simulate the damage layer evolution based on Fick’s second law,which could be suggested to predict the service life of concrete structures in marine environment.展开更多
基金support of Reliance Industries and Bakaert Industries, India for providing fiber for the experimental work
文摘This article presents an experimental study on the flexural performance of reinforced concrete(RC)beams with fiber reinforced cementitious composites(FRCC)and hybrid fiber reinforced cementitious composites(HFRCC)in the hinge portion.Beam specimens with moderate confinement were used in the study and tested under monotonic loading.Seven diverse types of FRCC including hybrid composites using fibers in different profiles and in different volumes are employed in this study.Companion specimens such as cylindrical specimens and prism specimens are also used to study the physical properties of composites employed.The moment?curvature,stiffness behavior,ductility,crack pattern and modified flexural damage ratio are the main factors considered in this study to observe the efficacy of the employed hybrid composites.The experimental outputs demonstrate the improved post yield behavior with less rate of stiffness degradation and better damage tolerance capacity than conventional technique.
基金This project was sponsored by the provincial tenth"Five-Year Plan"(Yunnan Provincial Plan2002-54-02-02),China
文摘Seismologists have begun to investigate the earthquake damage and assess the economic losses on the spot in the Yunnan area since the earthquakes with M_S6.7 and M_S6.9 that occurred on the boundary between China and Myanmar west of Menglian county,Yunnan Province,on April 23,1992.From 1992 to 2003,50 destructive earthquakes occurred in Yunnan,and large amounts of data on seismic hazard have been accumulated.With focus on the major building structures,the paper makes statistical analysis on the earthquake damage ratio,loss ratio and seismic hazard index in the areas with different seismic intensity of the 50 events,and presents the seismic hazard matrix of buildings for the Yunnan area.
基金funded by NSF award 2228486 under the program Strengthening America’s Infrastructurefunding from the China Scholarship Council,Grant No.202206140090。
文摘Hurricane Ike,which struck the United States in September 2008,was the ninth most expensive hurricane in terms of damages.It caused nearly USD 30 billion in damage after making landfall on the Bolivar Peninsula,Texas.We used the Delft3dFM/SWAN hydrodynamic and spectral wave model to simulate the storm surge inundation around Galveston Bay during Hurricane Ike.Damage curves were established through the relationship between eight hydrodynamic parameters(water depth,flow velocity,unit discharge,flow momentum flux,significant wave height,wave energy flux,total water depth(flow depth plus wave height),and total(flow plus wave)force)simulated by the model and National Flood Insurance Program(NFIP)insurance damage data.The NFIP insurance database contains a large amount of building damage data,building stories,and elevation,as well as other information from the Ike event.We found that the damage curves are sensitive to the model grid resolution,building elevation,and the number of stories.We also found that the resulting damage functions are steeper than those developed for residential structures in many other locations.
文摘The neutronic calculations and activation behavior of the proposed helium cooled ceramic breeder（HCCB） blanket were predicted for the Chinese Fusion Engineering Testing Reactor（CFETR） design model using the MCNP multi-particle transport code and its associated data library. The tritium self-sufficiency behavior of the HCCB blanket was assessed, addressing several important breeding-related arrangements inside the blankets. Two candidate first wall armor materials were considered to obtain a proper tritium breeding ratio（TBR）. Presentations of other neutronic characteristics, including neutron flux, neutron-induced damages in terms of the accumulated dpa and helium production were also conducted. Activation, decay heat levels and contact dose rates of the components were calculated to estimate the neutron-induced radioactivity and personnel safety. The results indicate that neutron radiation is efficiently attenuated and slowed down by components placed between the plasma and toroidal field coil.The dominant nuclides and corresponding isotopes in the structural steel were discussed. A radioactivity comparison between pure beryllium and beryllium with specific impurities was also performed. After a millennium cooling time, the decay heat of all the concerned components and materials is less than 1？×？10-4 k W, and most associated in-vessel components qualify for recycling by remote handling. The results demonstrate that acceptable hands-on recycling and operation still require a further long waiting period to allow the activated products to decay.
基金The authors would like to acknowledge the financial support of the National Key Research and Development Project of China,the Ministry of Science and Technology of China(Grant 2018 YFC1505504).
文摘Aiming at the progressive damage phenomenon in geotechnical field,it attempts to study the effect of progressive damage on the macro-bearing capacity.Firstly,based on the theoretical analysis of a two-dimensional plane inside representative volume element,it is proposed that progressive damage will occur if the bearing capacity of microplanes is different.Besides,“damage-aggravation effect”is proposed according to the difference between the macro-bearing capacity of entire plane and the sum of bearing capacity of all microplanes when progressive damage occurs.Secondly,progressive damage ratio K_(t)is proposed to quantify“damage-aggravation effect”.Finally,based on the rod model,the correspondence between K_(t),and some influence factors is studied by theoretical analysis and numerical simulation.The results show that“damage-aggravation effect”does exist,and the macro-bearing capacity of entire plane is less than the sum of bearing capacity of all microplanes when progressive damage occurs.If the bearing capacity of rods in the rod model obeys uniform distribution,as the minimum of bearing capacity increases linearly,the macro-bearing capacity increases linearly,and K_(t)decreases inversely.
基金The authors would like to acknowledge the financial support by the National Natural Science Foundation of China(11832013,11772164)the National Basic Research Program of China(973 Program,2009CB623203)+1 种基金the Key Research Program of Society Development of Ningbo(2013C51007)K.C.Wong Magna Fund in Ningbo University.
文摘This paper presents experimental and theoretical methods to study the damage layer evolution of a breakwater made with concrete hollow squares in marine environment.Wetting time was directly related to the performance degradation of the breakwater by observation.The thickness of damage layer was detected by means of ultrasonic testing.Meanwhile,some samples drilled from concrete hollow squares were analyzed by SEM and XRD in order to illustrate the damage mechanism.Subsequently,a theoretical model containing wetting time ratio was established to simulate the damage layer evolution based on Fick’s second law,which could be suggested to predict the service life of concrete structures in marine environment.
