Experimental Study On Flexural Property Of Concrete Slabs Reinforced By CRB600H Cold-rolled Ribbed Steel Wires With Improved Elongation

Cold-rolled ribbed steel wires with improved elongation is a new type of cold-rolled steel wires,has developed at home and abroad in recent years.Increasing the heat treatment in its production process,a clear yield point,elongation index of the wires were significantly increased.This paper presents the test results of 6 concrete slabs reinforced by the cold-rolled ribbed steel wires with improved elongation under flexure,the flexural characteristics,bearing capacity,deflection and cracking of these slabs under flexure are analyzed,the formulas for calculating the flexural bearing capacity,the deflection and crack width of the slabs are suggested.This may be as a reference for the applications of this new type of cold-rolled steel wires,and for the revision of Chinese Code《Technical specification for concrete structures with cold-rolled ribbed steel wires》JGJ95-2011.The main contents of the thesis are:First,6 concrete slabs reinforced by the cold-rolled ribbed steel wires with improved elongation for the longitudinal reinforcement and distribution reinforcement were designed and produced,and the slabs were tested by inverted way of loading.Test results show that the bending behavior of concrete slabs reinforced by cold-rolled ribbed steel wires with improved elongation is almost the same as that of slabs reinforced by ordinary hot-rolled steel bars.The flexural bearing capacity of the slabs can be calculated by the equations suggested in Chinese Code《Technical specification for concrete structures with cold-rolled ribbed steel wires》JGJ95-2011,take the tensile design value of fy=415N/mm2 for the wires,the calculated results are in the safe side.Second,the property of concrete slabs reinforced by the cold-rolled ribbed steel wires with improved elongation under flexure,such as the steel and concrete strain,load-deflection curve,the cracking moment and flexural failure modes are analyzed,the formulas for calculating the deflection of the slabs are suggested.which show a good agreement with the "Regulations" and control the deformation ensures in the safe side.Third,the crack distribution and crack width of which were more detailed statistics and analysis,the concrete slabs reinforced by the cold-rolled ribbed steel wires with improved elongation.and cut the slab along the longitudinal and between longitudinal direction observing the internal cracks,the formulas for calculating the crack width of the slabs may be the stipulations in the Chinese Code《Technical specification for concrete structures with cold-rolled ribbed steel wires》and in the safe side.Through statistical analysis,there is linear relationship between crack width and the distance from the steel to surface w =ws+0.03s the crack width at the steel surface is roughly the width of about 3/5 the slab surface,and both in the range of 3/10 to 3/4.