Type 4 Plan/Vertical Irregularity
Type 4 Plan/Vertical Irregularity
(OP)
For the type of irregularity of title, the UBC says
1630A.8.2.1 General. Where any portion of the lateral-load-
resisting system is discontinuous, such as for vertical irregularity Type 4 in Table 16A-L or plan irregularity Type 4 in Table 16A-M,concrete, masonry, steel and wood elements supporting such dis-continuous systems shall have the design strength to resist thecombination loads resulting from the special seismic load com-binations of Section 1612A.4.
Does this inlcude any element from the uplift location downward? ie, wood shear panels of the lower level, foundation, etc.?
codes seems to be vague.
1630A.8.2.1 General. Where any portion of the lateral-load-
resisting system is discontinuous, such as for vertical irregularity Type 4 in Table 16A-L or plan irregularity Type 4 in Table 16A-M,concrete, masonry, steel and wood elements supporting such dis-continuous systems shall have the design strength to resist thecombination loads resulting from the special seismic load com-binations of Section 1612A.4.
Does this inlcude any element from the uplift location downward? ie, wood shear panels of the lower level, foundation, etc.?
codes seems to be vague.





RE: Type 4 Plan/Vertical Irregularity
2. Concrete slabs supporting light-frame wood shear wall systems or light-frame steel and wood structural panel shear wall systems.
does this mean that wherever wood structural shear walls are used, the increase for plan/vertical irregularity is not necessary?
RE: Type 4 Plan/Vertical Irregularity
2. Concrete slabs supporting light-frame wood shear wall systems or light-frame steel and wood structural panel shear wall systems. (ubc1997 1630.8.2.1)
does this mean that wherever wood structural shear walls are used, the increase for plan/vertical irregularity is not necessary?