High tensile steel as normal reinforcement in concrete

The use of high tensile steel as normal reinforcement in concretemembers necessitates the study of the behaviour of such members under theaction of static, fatigue and sustained loading. The present state ofknowledge of the effects of the type of steel and the type of loading onthe serviceability and strength of concrete members has been reviewed. Froma comparison of structures reinforced with ordinary and high tensile steels,it has been indicated that by increasing the permissible steel stresses greatsavings can be obtained, but the deflection and cracking become more pronounced,especially when the effects of long-term loading are considered. Limitedinformation has been reported on the effect of the static cyoles, subsequentto the first cycle, on these two limit states. In view of the above, theapplicability of the limit state design, and the study of the recommendationsof codes of practice of several countries, it was felt that an experimentalinvestigation was required to study the behaviour, in cracking and deflection,of concrete members reinforced with hiEýi tensile steel and subjected to static,fatigue and sustained loading.A programme of an experimental investigation was designed to study thebehaviour of reinforced concrete beams