A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate...A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders is investigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.展开更多
An optical temperature sensor based on infrared-to-visible upconversion emission in Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbØ9(BTN)ceramics is reported.The fluorescence intensity ratio of the green upconversion photolum...An optical temperature sensor based on infrared-to-visible upconversion emission in Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbØ9(BTN)ceramics is reported.The fluorescence intensity ratio of the green upconversion photoluminescence(UC−PL)around 524 nm and 545 nm depends on temperature.The operating temperature range and the maximum sensitivity of Er ^(3+)/Yb ^(3+)co−doped Bi_(3)TiNbO_(9) ceramics are 123–693 K and 0.0032 K^(−1),respectively.BTN:Er3+/Yb3+ceramic has good thermal,physical and chemical stability,great UC−PL intensity and low cost fabrication.The results imply that Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbO9 ceramic is promising for applications in wide-temperature-range sensors.展开更多
文摘A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders is investigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.
基金by the National Natural Science Foundation of China under Grant No 10704021the Natural Scientific Research Innovation Foundation at the Harbin Institute of Technology(2009055).
文摘An optical temperature sensor based on infrared-to-visible upconversion emission in Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbØ9(BTN)ceramics is reported.The fluorescence intensity ratio of the green upconversion photoluminescence(UC−PL)around 524 nm and 545 nm depends on temperature.The operating temperature range and the maximum sensitivity of Er ^(3+)/Yb ^(3+)co−doped Bi_(3)TiNbO_(9) ceramics are 123–693 K and 0.0032 K^(−1),respectively.BTN:Er3+/Yb3+ceramic has good thermal,physical and chemical stability,great UC−PL intensity and low cost fabrication.The results imply that Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbO9 ceramic is promising for applications in wide-temperature-range sensors.
