Question about 1997 UBC

[HannaZ]

I am trying to calculate a non-structural component seismic anchorage. The 1997 UBC says "Forces shall be applied in the horizontal directions". Does it mean the Fp needs to apply to both x and y directions or should I just pick one worst case, like smaller dimension direction?

I appreciate your help.

Hong

 

[JAE]

Seismic is in ALL horizontal directions. In most cases, you can select the two primary (x and y) directions, but you cannot ignore any if they might control the design.

 

[HannaZ]

Thank you Jae for your response.

I guess the answer is to apply Fp(calculated from formula 32-1) to ANY direction that will result worst condition for anchors. It might be more correct to combine Fp in two orthogonal directions on a SRSS basis. But I see no one does that. The code did say to use 100% of force in one direction and 30% of force in the other direction, but I don't know if it applies to non-structural component calculations.

 

[AlohaBob]

I would think you would see plenty of engineers combining accellerations in two directions. Maybe looking the wrong direction. I think the basis of some of the load combinations consider 3 directions.

I heard there's a sticky wax that the storeowners with fragile displaywares use to keep it from tumbling off the shelves. I forget what it's called.