Slender RC columns (BS or EC2)

[GioC]

Hi,

I am just trying to get my head around slender RC columns and any help would be much appreciated.

Both BS and EC (eurocodes) give rigorous methods of calculating second order effects and induced moments by calculating the deflection of the columns at the ultimate limit state. However, when required to assess the deflection of say a cantilevering concrete column someone could use the service (unfactored) moment and check whether section is cracked or not and thus by that check deflection using the reduced stiffness (?). These too values are nowhere close to each other. I will have a closer look to basic principles, however, any thoughts are more than welcome.

 

[Lion06]

One is a strength level check, the other is a serviceability level check. The level of cracking, the effective section properties, and teh resulting deflections will vary significantly from serviceability to strength level loading. I don't know anyone who checks deflections or drifts at strength level loads (except for max seismic drift).