Standards regulations and divergences
Current structural codes permit yield strength of reinforcement bars up to fy = 500 N/mm² (DIN 1045-1) respectively fy ≤ 600 N/mm² (EN 1992-1-1). Reinforcement ratio is limited with r ≤ 9% (DIN 1045-1) respectively r ≤ 8% (EN 1992-1-1). Further constraints are given for maximum diameter for main bars and minimum diameter and maximum span for stirrups.
For the design of high strength columns (HPCM – High performance compression members, predominantly stressed) all those constraints will be surpassed:
» Yield strength fy = 670 N/mm²
» Reinforcement ratio r ≤ 20%