The Study Of The Mechanical Behavior Of Pre-stressed And Hollow Concrete Slabs With Mid-strength (1270MPa) Spiral-ribs Steels

As a new variety of steel wire in our country, the mid-strength (1270MPa) spiral-ribs steel wire has many excellences such as high strength, good ductility, credible felting and anchoring capability witn concrete and so on. The pre-stressed concrete slab with this sort of steel wire has good mechanical property. So it is an ideal substitute to the cold-processed wires traditionally adopted in pre-stressed concrete slabs.Based on the nonlinear analysis theory of the reinforced concrete flexural member, this paper explores a numerical analysis program for the pre-stressed and hollow-core concrete slabs with mid-strength spiral-ribs steel wires. Contrast with the experimental results which were made by Wei Xing of Zhengzhou University of Technology, the numerical analysis results show a good agreement with the experimental results. Thus the numerical analysis testifies that the service stages of the pre-stressed and hollow concrete slabs with mid-strength spiral-ribs steel wires can also be separated to the elastic stage, cracking stage and failure stage.175 slabs with different parameters such as the ratio of span to rise, the ratio of reinforcement and the stretching controlling stress are analyzed by the numerical analysis program. The results indicate that the ratio of span to rise, the ratio of reinforcement and the stretching controlling stress are the three primary influencing factors to the failure pattern of the slab. In addition, the relationships between the ratio of deflection to span and the ratio of span to rise and the stretching controlling stress submit to linear curves, the relationship between the ratio of deflection to span and the ratio of reinforcement submits to a quadratic parabola curve. Furthermore, using the regress analysis method, the regress equation of the ratio of deflection to span and the above three parameters are resulted.Taking an ultimate deflection more than 1/50 of calculating span as the determinant term, by the means of numerical analysis and regress equationrespectively, this paper discusses the reasonable stretching controlling stress of usual span and reinforcement slabs for design reference.