# Comparison of Axial Capacity of CFRT Columns using ABAQUS and AS5100 Equation Essay Example

us) that can be calculated according to AS 5100. The formula that is used to calculate is shown below. In the equation reinforcement contribution is not factored NA rectangular concrete that has been filled with tabular steel stub column that is under compressional force has an ultimate section capacity (

φ Asfy + φc Ac f’cus = N

Where As= steel area

= area of concrete sectionAc

= steel nominal yield strength fy

= compressive strength of concretefc

capacity reduction for steel with value of 0.9φ=

reduction capacity for concrete with value of 0.6Φc=

/10 the extra increase in the strength of the concrete slab strength as a result of confinement effect should be put into consideration. The ultimate section capacity changes when the effect of confinement is considered and it is depicted by the formula:do) is less than 0.5 and eccentricity loading under design bending momentum is less than λrThe above equation can be applied also for circular concrete filled steel tubular stub column. On the other hand if relative slenderness ( φ Asη2fy + φc Ac f’cus = N

are the coefficients for reflecting confinement effectη2 and η1

is the concrete strength increase= η1 Where

steel strength reduction as a result of confinement effect= η2

The procedure of calculating the coefficients is provided in Clause 10.6.2.2 of AS 5100.

of concrete that is filled with steel tabular is calculated using the formula Nuc ≤ 4 can be ignored because it does not have any effect on the final results. When these slenderness are put into consideration the b /Leor do /Le is put into consideration. Stub column defined by c) is to be calculated, slenderness effect represented by a slenderness reduction factor, NucWhen ultimate member capacity (

usNus NcucN

) is calculated using the formulac(Slenderness reduction factor ξc =

= compression member factorξ Where

= function of relative slendernessλ

crN/ us N is give by λ

is is calculated by the formula Ncris calculated using previous formulas, capacity factors are taken as unity. us Nwhere Ncr =

cIcEcs EIe EI

= second momentum of steel areas sectionsIs Where

=second momentum of uncracked steel sections areas. Ic

= capacity factors. φcand φ