Cold Rolled Ribbed Steel Prestressed Concrete Hollow Slab And Composite Board Structure And Properties Of The Study

Cold-rolled ribbed steel bars adopt common low-steel bars or low-alloy hot-rolled steel bars which have lower strength and better plastics as a row and processed materials, is a sort of steel which is cold-rolled two-sides or three-sides crossing rib in surface through cold stretching. Cold-rolled ribbed steel bars has better basic mechanical property, is a sort of excellent steel bar in capability as non-pre-stressed or pre-stressed steel bars. In recent years it is especially recommended to be used by state-planned committee, metallurgy ministry and constructed ministry.Firstly, we analyze their bending behaviors, failure processions and important influenced-factors in details through tests of 20 single supported pre-stressed concrete hollow slabs with cold-rolled ribbed steel bars, of 4 single supported pre-stressed concrete hollow laminated slabs with cold-rolled ribbed steel bars, and 4 pre-stressed concrete continuous hollow laminated slabs with cold-rolled ribbed steel bars. The ultimate bearing capacity of crossing section and the calculation about rigidity and cracking width of service ability is deeply researched and analyzed based in the finite element nonlinear thesis . The moment adjusting values is proposed in designing cold-rolled ribbed pre-stressed continuous hollow laminated slabs.Secondly, thtough the test research and theory analysis of the relationship in cracking moment and ultimate moment between pre-stressed concrete hollow slabs and pre-stressed concrete hollow laminated slabs, we not only put forward the calculation model and formula about the relationship in cracking moment and ultimate moment of hollow laminated slabs, but also put forward a completed new calculation model and method which is provided as reference for pre-stressed concrete hollow slabs and pre-stressed concrete hollow laminated slabs with cold-rolled ribbed steel bars in production and construction and working out of general standard gallery.Finally, through the theory analysis and calculation, it can be obtained that the strength of concrete, the strength and ductility of steel wires, reinforcement ratio, stretching controlling stress and span-to-depth ratio are important factors whichinfluence the ductility of pre-stressed concrete hollow slabs.