Eccentric loading experiment of 13 steel tube-reinforced concrete columns and a reinforced concrete column is implemented. The whole process from the start load on the steel tube-reinforced concrete column until damage has been researched. Change of ultimate bearing capacity with eccentricity, longitudinal reinforcement ratio, position coefficient has been studied, and deflection curve and load-vertical displacement curve under eccentric compressive load were obtained. Failure characteristics of steel tube-reinforced concrete were divided into two different type, small eccentric damage and big eccentric damage. With the same conditions, when steel tube ratio of steel tube-reinforced concrete was 2%, its ultimate bearing capacity was nearly double of reinforced concrete columns.
Wire rope transmission is very efficient because of the small total moving object mass. The wire rope could only transmit pulling force. Therefore it has to be kept in a tightened state during transmission; in high speed applications the dynamic performance depends on the rope's stiffness, which can be adjusted by the wire rope tension. To improve the system dynamic performance output, this paper proposes a novel pull-pull method based on dual motors connected by wire ropes, for precise, high speed position control applications. The method can regulate target position and wire rope tension simultaneously. Wire ropes remain in a pre-tightening state at all times, which prevents the influence of elasticity and reduces the position tracking error in the changing direction process. Simulations and experiments were conducted; the results indicate that both position precision and superior dynamic performance can be synchronously achieved. The research is relevant to space craft precision pointing instruments.
Nonlinear constitutive law was used in this paper. On the basis of plain section assumption, through isoparametric element theory, nonlinear secant and tangent stiffness matrices of section were derived. Nonlinear equation was solved by Newton-Raphson method. The bearing mechanism under the eccentric compression was revealed by changing eccentricity and position coefficient. The result is found to be in good agreement with the experimental data, and it shows that large and minor eccentricity failure mode, which are similar to reinforced concrete, are existed in steel tube-reinforced concrete column. In addition, force-moment correlation curve is derived. By calculation and comparison. The ultimate capacity is found to be greatly underestimated in the current technical specification.
The improvement effect of the external concrete to stability of the core steel-tube was demonstrated by the steel-tube replacement ratio through experimental study. The test results show that, with the steel-tube replacement ratio increasing, the ultimate bearing capacity of composite columns increased correspondingly, and the ductility of composite columns was improved obviously also. Therefore, the steel-tube replacement ratio should be involved in the formula for calculating the ultimate bearing capacity of composite columns. By finite element method and regression analysis, the slenderness ratio is amended by the steel-tube replacement ratio and the calculation results of the eccentric compression bearing capacity agreed well with the test results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.