How to model conc filled column STAAD

[steve101]

I have a 10m column, 1m dia 10mm thick. I need stiffen it by filling it with grout. How do I model that combined property? One member with the equivalent stiffness (not sure how) or model an unreinforced conc column and put rigid links to the steel column?

 

[ishvaaag]

From

https://netfiles.uiuc.edu/jfhajjar/

http://www/home/Hajjar -- CFT -- PSEM Vol 2 No 1 2000.pdf

SSRC[20] proposed a modified elastic modulus that is the sum of the moduli of elasticity for the steel and concrete, with a reduction factor of 0.4 imposed on the initial modulus of the concrete to account for creep and tensile cracking. This has been adopted as a design recommendation in, for example, AISC[21]. Other authors have proposed summing the individual rigidities of each component material[25*], which generally matches better with experiments and is thus appropriate for representing initial axial stiffness in a linear or nonlinear analysis[15*]. Stability behavior of CFTs is summarized in ref.[26].

 

[steve101]

thanks. Yep, I had actually just tried that equivalent E x x I value from a Corus ref. for Design Guide for SHS concrete filled Columns.

Thanks for the AISC references.