Eurocode 8 Estimation of effective stiffness of reinforced concrete ductile bridge piers

Note: The ratio J_cr / J_un can be obtained by the following procedure:

• Perform cross-section analysis considering the final reinforcement to obtain the bending resistance M_Rd = M_yd at the yield point of the tensile reinforcement. Depending on the type of cross-section, the following calculations can be used: circular, tubular, rectangular, I-shaped, T-shaped, or box-shaped, with the following modifications:
  • The design value of reinforcement ultimate strain ε_ud should be set equal to the reinforcement design yield strain ε_yd
  • The coefficient taking account of long term effects and loading effects on the compressive strength of concrete α_cc should be set equal to the value coresponding to seismic design situations according to the National Annex (if different from static design situations)
• In the table of the results the value of the effective bending stiffness ratio (EI)_eff / (EI)_gross should be considered and input as J_cr / J_un in this calculation