Concrete Jacket Theoritical Basis

[Kirkaguel]

Good Day technical support,

May I ask what is the theoritical basis in calculating the strength, stiffness and ductility of a retrofitted member i.e. beam, column or wall using concrete jacket implemented in Seismobuild or Seismostruct. Any code or publication?

[z.gronti]

Dear Kirkaguel,

The Code-based checks and the calculation of the required capacities are calculated according to the selected Code. You may check for the equations used in the User Manual and Help System of the programs.

[Kirkaguel]

Dear Kirkaguel,

The Code-based checks and the calculation of the required capacities are calculated according to the selected Code. You may check for the equations used in the User Manual and Help System of the programs.

Thank you for the reply Z. Gronti, a follow up question though if we use ASCE 41 code for the pushover analysis what code reference is used for the concrete jacket? There is no mention of any US code as reference for concrete jacket?

[z.gronti]

Dear Kirkaguel,

Calculations for jacketed elements for ASCE 41 are based on the same theory as for plain concrete elements. The increase in strength, stiffness and ductility of a retrofitted member results from the consideration of sections with both core and jacket materials (concrete, longitudinal and transverse reinforcement).

[Kirkaguel]

Hi Z. Gronti I think a concrete jacket is more complex than it seems as compared to a plain concrete. It is normal in concrete jacket that the concrete strength of the jacket is much higher than the existing concrete core, in this case the concrete strength of the new jacketed section cannot be assumed to be equal to the new jacket concrete strength this is unconservative assumption (assumption of EN1998-3:2005) as mentioned in the manual.

[z.gronti]

Dear Kirkaguel,

As i mentioned in my previous post, the increase in strength, stiffness and ductility of a retrofitted member results from the consideration of sections with both core, i.e. existing section, and jacket materials (concrete, longitudinal and transverse reinforcement).