STRUCTURAL ENGINEERING CHARACTERISTICS OF LOCALLY AVAILABLE STEEL REINFORCING BARS IN NIGERIA

Abstract

Investigation was carried on the locally available (Locally manufactured and imported) high yield steel bars of different diameters in Nigeria. The investigation involved the determination of their chemical constituents, mechanical characteristics as well as their behaviour in concrete beams. The steel specimens were tested in their original state. without machining.

The results showed that the imported high yield steel bars contained higher values of ferrous and carbon contents than the corresponding locally produced ones, thus resulting in higher yield and ultimate strength as well as higher transverse load bearing capacity of concrete beams, reinforced with them. The locally produced steel bars behaved like mild steel in terms of the elongation while their yield stresses were very low, ranging between 63.76 10 204 N/mm². The behaviour of the reinforcing bars in concrete was consistent with their initial chemical characteristics. 

It is recommended that in design, only high yield imported bars with diameter not less than 16mm should be used for structural concrete works while the yield stress should be around 280-300 N/mm². The locally manufactured high yield reinforcing bars would only be used for minor structural works. It is also recommended that samples of proposed steel bars should be tested prior to their use.