diagonal compression criterion on compression reinforcement ratio in flexural hsrc members

limit to the tension reinforcement ratio ( ρ) in flexural high strength reinforced concrete (hsrc) members is based on the requirement that tension failure as sufficient rotation capacity are ensured at ultimate limit state. however, the provisions for the total amount of longitudinal reinforcement ratio ( ρ and ρ’) are not associated with any rational derivation. in this paper, a quantitative measure to evaluate an upper limit to the compression reinforcement ratio ρbmax of flexural hsrc members is proposed. the quantitative criterion to ρbmax can be derived from i) steel congestion and ii) considerations that are related to the diagonal compression bearing capacity of the members. in this paper it is shown that, when shear loading is dominant, the limit to is set by the diagonal compression criterion. parameters that affect this limit are deeply investigated and the expressions were derived for different end conditions, to provide an additional tool for a better design and assessment of the flexural capacity of hsrc members.