Study On Bond Performance Of Cold-rolled Spirals Steel Bars And The Bend Behavior Of Cold-rolled Spiral Steel Bars RC Slabs

Based on cold-rolled ribbed steel bars, cold-rolled spiral steel bars is developed and produced as a new building material. In this paper, in order to get the actual characteristics and working performance of cold-rolled spiral steel bars RC components, the bond performance of cold-rolled spiral steel bars and the bending behaviors of cold-rolled spiral steel bars RC slabs are investigated by experimental research and theoretical analysis. An example concerning the engineering using of cold-rolled spiral steel bars is offered in the end. The major contents are summarized as follows:1. The pullout specimens of 4 different surface configurations of reinforcements are tested under monotonic loading. By analyzing and comparing the P-s curves of the above specimens and curves' characteristics at different stages, bond performances of cold-rolled spiral steel bars are summarized, the reinforcement's shape characteristics is analyzed and its bond mechanisms between the reinforcements and concrete can be explored. Finally, some suggested values on the shape parameters of cold-rolled spiral steel bars are given.2. Four groups of concrete one-way slab specimens are made to carry out bending performance tests of reinforced concrete one-way slabs with rectangular cross-section under the equivalent concentrated loads. By analyzing and comparing of every slab's responses, such as its concrete strain, mid-span deflection, steel strain, and the crack appearing situation of slab bottom, cold-rolled spiral steel bars RC slabs' craze status, deformation and failure characteristics are researched. And the empirical formulas are given for the calculation of cracking moment, mid-span deflection and crack width of concrete flexural members with cold-rolled spiral steel bars.3. An example concerning the engineering using of cold-rolled spiral steel bars is offered, in which the feasibility and economy of applying cold-rolled spiral steel bars as the stressed steel bars of concrete floors are analyzed with contrast method.