Wall Buckling Effective Length

[Trenno]

With reference to sketch below, say you have a riser opening on each floor at the back of the lift shaft wall. Say we're also designing the core as 4 separate piers.

In terms of the blue wall effective length for buckling, I know the answer lies somewhere between:

a) Wall supported on each vertical edge only (ie the return walls).
b) Wall supported on all 4 sides, with a pinned connection between top/btm edge and slab.
c) Wall supported on all 4 sides, with a semi-rigid connection between top/btm edge and slab.

Are there any somewhat codified methods of refining the accurate wall buckling length?

The Eurocode (see below) will only allow you to take advantage of a semi-rigid connection between top/btm edge of wall and the slab. How about side edge connection with the return walls? It's likely given usual return wall lengths and slab spans, could one argue the side edge - wall return connection is more rigid than top/btm edge - slab connection?

 

[HTURKAK]

This subject is mentioned at 12.6.5 ULS induced by structural deformation (buckling). Pls notice that the clear height of the member (lw ) is shown as (B) the storey height at Table 12.1 and for all supporting conditions , and the floor slab ( A) is continuous...

The return walls may be considered as a bracing wall if satisfies the conditions mentioned in item (3).

The in-plane bending will not be an issue for the wall ( blue colored ) for seismic event , since the both ends will experience compression and has satisfactory bracing against buckling with return walls and partial slab. However, the wall ( blue colored ) will also experience full compression for out of plane direction since it is a flange of the lift shaft.

In order to discuss and obtain better responds, will you pls clarify the ULS loading, and sketch which shows the boundary of floor slab, dimensions of the bldg , no. of storeys ?..