How to assess a wall for buckling when using strut & tie? (AS3600)

[Trippelsewe]

Hi all, when you are required to design a wall using strut and tie (AS3600 11.2.1 (b) (i)), how do you check for any buckling effects?

Personally I think the strut should be checked as a column. If that is the case what length and k factor does one adopt for the column? Depending on the wall dimensions you could end up with a 'column' that is very long and slender with little chance of working.

Thanks in advance.

 

[KootK]

Personally I think the strut should be checked as a column.

I feel the same. And I agree that it's a bit of a "hole" in the STM approach. Same for deflection.

If that is the case what length and k factor does one adopt for the column

I'd go with K = 0 in the plane of the wall and k=1.0 from node to node out of plane.

Depending on the wall dimensions you could end up with a 'column' that is very long and slender with little chance of working.

I agree and feel that's a prescient comment. There is definitely a disconnect between how slender an axial loaded wall can be with traditional methods vs an STM designed wall. I switch depending on the scenario. If it's a giant transfer beam of wall, then I make the struts work for buckling. If it needs to a more regular wall and competitively designed, then I usually look at buckling using non-STM methods. I can't be the only guy in town spec'ing 16" walls everwhere.

 

[centondollar]

Wall buckling is more akin to plate buckling than beam buckling. Plate buckling formulas are available in the literature.