Amplification for Accidental Torsion Per UBC97 and ASCE
Amplification for Accidental Torsion Per UBC97 and ASCE
(OP)
Hi all:
First, I tried to look for a thread discussing what I am about to pose but I wasn't able to find any so here it goes:
For discussion sake, suppose I have a building with applied earthquake and gravity loads and thus producing displacement on ends having a magnitude of -20mm and +20mm respectively from it's undeformed shape. Is it correct if I solve for the average displacement algebraically, which would render Ax as infinite? Or will the correct approach be a relative displacement (delta min = 0 and delta max = 20 + 20 = 40mm) in order to get a value?
I have a gut feel that the building has a torsional irregularity but I cannot seem to figure otherwise through computations. Is there something I am missing here?
Would appreciate if anyone would shed some light here.
Thanks!
First, I tried to look for a thread discussing what I am about to pose but I wasn't able to find any so here it goes:
For discussion sake, suppose I have a building with applied earthquake and gravity loads and thus producing displacement on ends having a magnitude of -20mm and +20mm respectively from it's undeformed shape. Is it correct if I solve for the average displacement algebraically, which would render Ax as infinite? Or will the correct approach be a relative displacement (delta min = 0 and delta max = 20 + 20 = 40mm) in order to get a value?
I have a gut feel that the building has a torsional irregularity but I cannot seem to figure otherwise through computations. Is there something I am missing here?
Would appreciate if anyone would shed some light here.
Thanks!






RE: Amplification for Accidental Torsion Per UBC97 and ASCE
Your hypothetical case of -20mm & +20mm is a bit much and probably could only occur if the diaphragm was subject to torsional force only and no horizontal shear.
I think your -20mm & +20mm probably comes more from a calculation or modelling error.
RE: Amplification for Accidental Torsion Per UBC97 and ASCE