1. Introduction
The GB 1499-1998 hot-rolled ribbed steel bars are used for reinforcing concrete structures in civil engineering projects. It is an important structural material for the construction of buildings, bridges, and other concrete structures. The hot-rolled ribbed steel bars are produced in two grades – grade I and grade II. They are manufactured to a certain standard depending on the size, shape and material used. The characteristics of each grade are specified by Chinese National Standards (GB).
2. Properties of Hot-Rolled Ribbed Steel Bars
The properties of the hot-rolled ribbed steel bars differ according to the grade of the bars. Grade I bars are made from high strength steel with ductile behavior and greater thermal conductivity. Grade II bars are made from low strength steel which has low stretching and low thermal conductivity. Both grades of the bars have ribbed shapes which increases their friction and gives them better support to the concrete structure. The ribs help in better distribution of loads and uniform bonding with the concrete.
3. Chemical Composition of Hot-Rolled Ribbed Steel Bars
The chemical composition of the hot-rolled ribbed steel bars is as below: Grade I steel bars contain carbon, silicon, and trace amounts of other elements like manganese, phosphorus, and sulfur. Tolerance limits for each element is specified in the Chinese National Standards. Grade II steel bars consist of carbon, manganese, phosphorus, and sulfur. The tolerance limits for each element is specified in the Chinese National Standards.
4. Standard Sizes of Hot-Rolled Ribbed Steel Bars
The standard sizes of hot-rolled ribbed steel bars are specified in the GB 1499-1998 Chinese National Standards. The rounds bars, which are available in grade I and grade II, have diameters in the range of 6mm to 50mm. The hexagons bars, which are only available in grade I, have sides in the range of 8mm to 32mm. The bulging bars, which are only available in grade I, have sides in the range of 10mm to 25mm. All the bars have lengths in the range of 6m to 12m.
5. Conclusion
The GB 1499-1998 hot-rolled ribbed steel bars are an important reinforcing material used in concrete structures. They are produced to a certain standard with different chemical compositions and standard sizes. The grade I bars are made from high strength steel with large ribs for better jointing adhesion and structure strength, while the grade II bars are made from low strength steel and have lesser ribs for lesser friction.