AS3600 Column detailing contradiction

[li0ngalahad]

It seems there's a contradiction between clauses in the concrete code regarding column detailing.

Clause 10.7.4.3 (b) (iii) states, "where Lu < 5D, the spacing of the fitments shall not exceed the requirements of Section 14.5."

Clause 14.4.3 indicates, "Any column in an Ordinary Moment Resisting Frame (OMRF) that is part of the lateral force resisting system and where the unsupported length Lu < 5D, where D is the dimension of the column in the direction of the span, shall be detailed according to Clauses 14.5.4 and 14.5.5."

The contradiction lies in the applicability of the 14.5 detailing for columns with Lu < 5D. Clause 10.7.4.3 implies that the detailing applies universally, whereas clause 14.4.3 specifies it only for columns in a moment resisting frame that are part of the lateral system (i.e., attracting more than 20% of earthquake actions, as clarified in the commentary).

My interpretation is that clause 14.4.3 is more precise and clearly delineates when this detailing should be applied, effectively superseding the general requirement of 10.7.4.3, but I know some may disagree.

I'm interested in hearing how other engineers are handling this.

 

[the_Dominator]

@li0ngalahad,

The commentary on Clause 10.7.4.3 addresses this as well, where it notes that the additional confinement ties are not required for columns in structures designed for a mu of 1.

 

[li0ngalahad]

The commentary on Clause 10.7.4.3 addresses this as well, where it notes that the additional confinement ties are not required for columns in structures designed for a mu of 1.

I can't quite believe I haven't checked in the commentary before posting. I feel like an idiot now haha. Thanks for pointing that out.

 

[rscassar]

The location of a few items are a bit confusing. High strength concretes seem to have a higher requirement for confinement reinforcement & ties due to concrete brittleness, which I think would be better placed in the relative locations of section 10 & 11 instead of being placed in section 14.

 

[rapt]

The requirements for Brittleness are in 10.7.

The extra requirement for Seismic are in 14.5.4 which refers back to 10.7 for checks on Brittleness based on strength to make sure you check both.