The calculation of ultimate bearing capacity is a significant issue in the design of Concrete Filled Steel Tubular (CFST) arch bridges. Based on the space beam theory, this paper provides a calculation method for dete...The calculation of ultimate bearing capacity is a significant issue in the design of Concrete Filled Steel Tubular (CFST) arch bridges. Based on the space beam theory, this paper provides a calculation method for determining the ultimate strength of CFST structures. The accuracy of this method and the applicability of the stress-strain relationships were validated by comparing different existing confined concrete uniaxial constitutive relationships and experimental results. Comparison of these results indicated that this method using the confined concrete uniaxial stress-strain relationships can be used to calculate the ultimate strength and CFST behavior with satisfactory accuracy. The calculation results are stable and seldom affected by concrete con-stitutive relationships. The method is therefore valuable in the practice of engineering design. Finally, the ultimate strength of an arch bridge with span of 330 m was investigated by the proposed method and the nonlinear behavior was discussed.展开更多
In order to investigate the size effect and other effects on the stress-strain relationship of confined concrete, 42 specimens with different sizes and section shapes were placed under axial compression loading. Effec...In order to investigate the size effect and other effects on the stress-strain relationship of confined concrete, 42 specimens with different sizes and section shapes were placed under axial compression loading. Effects of key parameters such as size of specimens, tie configuration, transverse reinforcement ratio, and concrete cover were studied. The results show that for specimens with the same configuration and the same volumetric ratio of the transverse reinforcement, along with the increasing specimen size, the peak stress, peak strain and deformation of the post-peak show a down trend, however, the volumetric ratio of the transverse reinforcement is lowered, the decreasing of the peak stress is accelerated, but the decreasing of the deformation is slow down. For specimens with the same volumetric ratio but different configurations of transverse reinforcement, though the transverse reinforcement configuration becomes more complicated, the peak stress of the large size specimen does not improve more than that of the small size. However, the deformation occurs before the stress declines to 85% of peak stress, and the improvement with the grid pattern tie configuration is much greater due to size effect.展开更多
This paper work aims to present the effect of the soil stiffness （k）, boundary conditions of piles and embedded length of piles （L） on a buckling force of a fully embedded pile and subject to an axial compression ...This paper work aims to present the effect of the soil stiffness （k）, boundary conditions of piles and embedded length of piles （L） on a buckling force of a fully embedded pile and subject to an axial compression force only, based on the finite difference method. Based on this method, MATLAB sottware is used to calculate the buckling forces of piles. Effect of the soil stiffness （k）, boundary conditions of piles and embedded length of piles （L） on a buckling force have been studied for reinforced concrete pile, whereas the modulus of horizontal subgrade reaction is adopted constantly with depth, increasing linearly with depth with zero value at the surface and increasing linearly with depth with nonzero value at the surface.展开更多
The radiation of noise from a parallelly rib-stiffened skin plate of aircraft cabin fuselage in the presence of external mean flow is theoretically investigated.An aero-acoustic-elastic model is developed and used to ...The radiation of noise from a parallelly rib-stiffened skin plate of aircraft cabin fuselage in the presence of external mean flow is theoretically investigated.An aero-acoustic-elastic model is developed and used to calculate the radiated sound pressure level(SPL) versus frequency curves with reference to sound radiation of a bare plate immersed in a steady fluid.The flexural and rotational motions of the rib stiffeners are described by applying the Euler-Bernoulli beam theory and torsional wave equation,respectively.Therefore,the coupling forces and moments between the ribs and the face-panel,caused separately by flexural and rotational motion of the ribs,are both taken into account.Given the periodicity of the structure,the Fourier transform technique is employed to solve panel vibration equations and acoustic equations.Systematic parametric investigation demonstrates that the presence of mean flow as well as rib spacings play significant roles in the sound radiation behavior of parallelly rib-stiffened plates.The proposed model provides a convenient and efficient tool for the factual engineering design of this kind of periodic structures with acoustic requirements.展开更多
文摘The calculation of ultimate bearing capacity is a significant issue in the design of Concrete Filled Steel Tubular (CFST) arch bridges. Based on the space beam theory, this paper provides a calculation method for determining the ultimate strength of CFST structures. The accuracy of this method and the applicability of the stress-strain relationships were validated by comparing different existing confined concrete uniaxial constitutive relationships and experimental results. Comparison of these results indicated that this method using the confined concrete uniaxial stress-strain relationships can be used to calculate the ultimate strength and CFST behavior with satisfactory accuracy. The calculation results are stable and seldom affected by concrete con-stitutive relationships. The method is therefore valuable in the practice of engineering design. Finally, the ultimate strength of an arch bridge with span of 330 m was investigated by the proposed method and the nonlinear behavior was discussed.
基金Project(50838001) supported by the National Natural Science Foundation of China
文摘In order to investigate the size effect and other effects on the stress-strain relationship of confined concrete, 42 specimens with different sizes and section shapes were placed under axial compression loading. Effects of key parameters such as size of specimens, tie configuration, transverse reinforcement ratio, and concrete cover were studied. The results show that for specimens with the same configuration and the same volumetric ratio of the transverse reinforcement, along with the increasing specimen size, the peak stress, peak strain and deformation of the post-peak show a down trend, however, the volumetric ratio of the transverse reinforcement is lowered, the decreasing of the peak stress is accelerated, but the decreasing of the deformation is slow down. For specimens with the same volumetric ratio but different configurations of transverse reinforcement, though the transverse reinforcement configuration becomes more complicated, the peak stress of the large size specimen does not improve more than that of the small size. However, the deformation occurs before the stress declines to 85% of peak stress, and the improvement with the grid pattern tie configuration is much greater due to size effect.
文摘This paper work aims to present the effect of the soil stiffness （k）, boundary conditions of piles and embedded length of piles （L） on a buckling force of a fully embedded pile and subject to an axial compression force only, based on the finite difference method. Based on this method, MATLAB sottware is used to calculate the buckling forces of piles. Effect of the soil stiffness （k）, boundary conditions of piles and embedded length of piles （L） on a buckling force have been studied for reinforced concrete pile, whereas the modulus of horizontal subgrade reaction is adopted constantly with depth, increasing linearly with depth with zero value at the surface and increasing linearly with depth with nonzero value at the surface.
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2011CB610300)the National Natural Science Foundation of China (Grant Nos. 11102148,11072188,11021202 and 10825210)the Fundamental Research Funds for the Central Universities
文摘The radiation of noise from a parallelly rib-stiffened skin plate of aircraft cabin fuselage in the presence of external mean flow is theoretically investigated.An aero-acoustic-elastic model is developed and used to calculate the radiated sound pressure level(SPL) versus frequency curves with reference to sound radiation of a bare plate immersed in a steady fluid.The flexural and rotational motions of the rib stiffeners are described by applying the Euler-Bernoulli beam theory and torsional wave equation,respectively.Therefore,the coupling forces and moments between the ribs and the face-panel,caused separately by flexural and rotational motion of the ribs,are both taken into account.Given the periodicity of the structure,the Fourier transform technique is employed to solve panel vibration equations and acoustic equations.Systematic parametric investigation demonstrates that the presence of mean flow as well as rib spacings play significant roles in the sound radiation behavior of parallelly rib-stiffened plates.The proposed model provides a convenient and efficient tool for the factual engineering design of this kind of periodic structures with acoustic requirements.
