# Wind question



## Engineer22 (Mar 13, 2018)

Brittle veneer like masonry would be easiest to break when there is which one of the following conditions?: excess drift, uplift, low frequency vibration?


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## User1 (Mar 14, 2018)

I feel like low frequency vibration would be the only out of plane situation. drift wouldn't be dynamic, uplift would be "in plane"


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## MA_PE (Mar 14, 2018)

tj_PE said:


> I feel like low frequency vibration would be the only out of plane situation. drift wouldn't be dynamic, uplift would be "in plane"


not sure I agree with that.  Depends on the amplitude of the vibration.  How does one "drift" a masonry wall?


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## User1 (Mar 14, 2018)

MA_PE said:


> not sure I agree with that.  Depends on the amplitude of the vibration.  How does one "drift" a masonry wall?


I don't understand what you're not agreeing with. I was intending to say that I believe vibration is most likely. 

Thinking more about this, excess story drift maybe in plane could cause cracking due to shear. And if your building is overturning/uplifting a piece of veneer, maybe the shear would cause cracking in the other direction, still in plane.

As David Connor commented on another problem, a lot of these questions you have been sharing are very vague and cause a lot of unnecessary speculation. I feel like an actual study guide would be more helpful in studying for the exam


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## MA_PE (Mar 14, 2018)

If the question relates to seismic loadings then unquestionably the answer is inter-story drift.  Vibration doesn't necessarily harm structures, it's the displacement that cracks/harms structures.  The problem with low frequency vibration is that if the excitation frequency is at the natural frequency of the structure which may cause resonance which leads to amplified magnitude along with amplified displacement


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## sayed (Mar 15, 2018)

Engineer22 said:


> Brittle veneer like masonry would be easiest to break when there is which one of the following conditions?: excess drift, uplift, low frequency vibration?


easy, excess drift

'excess,' which implies some form of failure mode.

perhaps the syntax is this sample problem is erroneous.


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