Fire Resistance of Columns

[structbureau]

Hi All,

I have a situation where I have 22 meter columns that are required to abide by a 120 min fire. In accordance with CL 5.6.4 General tabular method to determine structural adequacy of columns a slenderness limit under the fire condition is <30. My columns are running at approximately 40.

Due to the limitations of AS3600 I have adopted the 500 degree isotherm approach from Eurocode 2 which is referenced in AS3600 Clause 5.3.1 General Performance Criteria Notes 1 & 2.

When we go to the Eurocode 2 there is additional requirements for spalling not covered under AS3600, for instance high strength concretes or when the axis distance of the bar is greater than 70mm from the edge additional mesh is required for spalling.

The question is, can we waive these spalling requirements whilst adopting EC2 500 Degree Isotherm Method?

Thanks in advance.

 

[rowingengineer]

22m columns that is long, I really can't help at all, as I am no longer an as3600 expert. But as a performance solution under NCC you would need to provide either certification to as3600 or EC2 for fire. Once you have decided this element you must comply with the requirements of said code for all fire elements.

Often codes have a long process to getting to a solution, so be careful in splicing codes.