EFFECT OF USING HIGH STRENGTH CONCRETE COLUMNS ON THE STRUCTURAL BEHAVIOUR OF R.C BUILDINGS

Strength, durability and stability are the main criteria for material selection and design in the construction industry. Consequently, development and enhancement of construction materials is always an active and attractive field for engineers and researchers. Elevated temperature (fire) is a potential threat for any structural buildings that can cause a major dama ge. Response of construction materials exposed to elevated temperature or fire requires a full study and analysis with lessons learned from previous cases. High strength concrete (HSC) has been used in the lower story columns of high rise buildings owing t o its qualities over normal strength concrete (NSC) in many countries. But, the full structural qualities of the HSC were unable to be used because of insufficient information regarding the structural behaviour of the material and its properties. Columns m oment - curvature curves were developed and maximum inter story drifts were obtained for the different frame models with variation in columns concrete strength. The study shows that frames with HSC columns have got lower stiffness and performed well in sati sfying ductility demand. The maximum inter storey drifts are slightly higher for frames with HSC columns, but the contribution of the concrete strength in resisting the lateral deformations was significant. Economic comparisons were also made and it was fo und that the most economical frame corresponds to frame with the highest columns concrete strength.