Staircase and Brick wall infill as Lateral Bracing

[Enhineyero]

For wind loads and notional loads, can a staircase and/or brick wall infill (assuming non-structural) be considered as a lateral bracing. If so, how do we check in adequacy of these elements against such loads? I have one document that assumed that these elements were to brace the building against these lateral loads. However, no checking was done on these elements for the lateral loads, and no explanation was given on how the loads wind/notional loads transfer to the staircase/brickwall infill. I have attached the design information that I have picked up and appreciate it if someone can explain the rational behind this bracing assumption.

I have been designing in highly seismic areas and so far have only used shear wall or moment frames to resist lateral loads. Now, i have moved into an area with low seismic forces and have been adjusting to the industry practice within the region.

http://files.engineering.com/getfil...9-1b802f2439bc&file=Stair_case_as_bracing.PDF

 

[KootK]

Yeah, I find lateral design to be more frustrating in low seismic zones. In high seismic zones, at least the expectations are clear.

A staircase certainly does act as unintended bracing if not isolated from lateral building movement. It's similar to ramps in parking structures. However, without careful detailing, I suspect that you would find holes in the load path.

The same is true of the masonry infill. It can be designed such that a diagonal strut between columns can form but it requires careful attention to detail.

In my estimation, the building has been poorly engineered laterally, even by low seismic zone standards. It's actually a pretty substantial structure and it's hard to imagine that a staircase and a couple of infill walls would be sufficient as bracing.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Enhineyero]

Hi Kootk, thanks for the response. I have read your idea about the strut action of the brickwall, however no detailed calculation was available for the checks needed in considering such behavior of the wall.

Actually in this region there were no seismic code for the longest time, since there is no significant seismic activity. Buildings only consider notional loads and wind loads, like those in the UK before the introduction of the Eurocodes (if I am not mistaken). I don't know if anyone here (especially those well experienced engineers) have a thorough understanding of this lateral system in a non-seismic zone.