Nie X.,Tsinghua University |
Nie X.,Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education |
Fan J.,Tsinghua University |
Fan J.,Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education |
And 2 more authors.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2013
The use of flexible shear connectors without longitudinal shear resistance between steel and concrete is an efficient method to reduce the tensile stress in negative moment segment of steel-concrete composite bridge. The elastic partial differential equation of simply supported composite beam without composite action was established and its solutions under different loading conditions and with different boundary conditions were then derived. Furthermore, an approximate computing method for continuous beams with local-released combined action was proposed, and its accuracy was verified by numerical models. A parametric study of continuous composite bridge was performed, and it was shown that the tensile strain may be decreased sharply by increasing the length of released segment so that the crack resistance of negative moment segment of steel-concrete composite bridge can be enhanced, but its influence on structural stiffness was not significant. When the width of concrete plate was larger, the reduction in stiffness caused by the increased length of released segment became more remarkable.
Qian J.,Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education |
Li N.,Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education |
Ji X.,Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education |
Cao W.,Beijing University of Technology
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2014
Quasi-static tests on six specimens were conducted to investigate the cumulative damage performance of composite-sectioned high strength concrete-filled steel tubular (CSCFT) columns. The column specimen was subjected to axial compressive force and lateral reversal loading with ten cycles at each drift level. The test indexes include the axial force ratio, thickness of square steel tube and its width-to-thickness ratio, diameter and thickness of circular steel tube. The failure modes of the six CSCFT column specimens are almost same. Local buckling of square steel tube, crushing of concrete between the two steel tubes, and local buckling of circular steel tube were occurred within a height of 300mm from the column base. The damage extent of specimens was a little bit severe than the specimens loaded with three cycles at each drift ratio. The lateral force-displacement hysteretic loops of all specimens were plump. The nominal yield drift ratio was 1/154 to 1/124, the peak drift ratio was over 1/80, and the ultimate drift ratio was greater than 1/60. The seismic behavior of the specimens was about the same as that of the specimens loaded with three cycles at each drift ratio. It means that the seismic behavior of the CSCFT column is stable. At the drift ratios of 1/150 and 1/100, cumulative damage of the specimens was minimal. At the drift ratios of 1/75, 1/50 and 1/33, the specimens experienced cumulative damage to which the extent was not significantly severe. Increasing the thickness of square steel tube and the thickness of circular steel tube would lead to a reduction of degeneration extent of load-carrying capacity of specimens caused by cumulative damage.