Vertical Structural Irregularity Type 5
Vertical Structural Irregularity Type 5
(OP)
Fellows...attempting to understand vertical irregularity Type 5a and 5b as listed in ASCE 07-05 Table 12.3-2.
I am uncertain how it is ever possible to have a lower story that is weaker than an upper story, unless the upper story by passes the lower story and transfers some of it's load directly to the ground. However, if the lower story resists all of the story shear above, and the shear at it's own level, this condition does not seem possible.
Would someone kindly shed some light on this topic?
Thank you!
I am uncertain how it is ever possible to have a lower story that is weaker than an upper story, unless the upper story by passes the lower story and transfers some of it's load directly to the ground. However, if the lower story resists all of the story shear above, and the shear at it's own level, this condition does not seem possible.
Would someone kindly shed some light on this topic?
Thank you!






RE: Vertical Structural Irregularity Type 5
As an example, if you have some shearwall in the building that stop mid-height (Because not required above), you might have a lateral stiffness irregularity !
Now imagine that the architect want to do some holes in your shear walls !
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
Maybe a split level building would be an example of Type 5 Vertical irregularity? Still not sure.
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
What am I missing to close the gap between these two irregularity types?
Thanks!
RE: Vertical Structural Irregularity Type 5
Still, Lateral discontinuities in Strengh are linked to the stiffness in a way : Usually, More walls = more stiffness might means more resistance, etc...
All These irregularity must be check case by case for each project !
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
Pico: Thanks for continuing to explain. I do understand the strength and stiffness are related by deflection. What I don't understand why does the code differentiate between stiffnees (Type 1) and strength (Type 5). If the two can be interchanged, why din't they just make type 1a,b,c,d in lieu of type 1 and 5 a,b?
Thanks.
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
If I am wrong in my understanding, then what constitutes variation in stiffness as compared to variation in strength?
Thanks for continued effort to explain.
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
RE: Vertical Structural Irregularity Type 5
In our project, the posts would tranfer shear from upper and lower level...so I would perceive they are stronger than upper level shear walls, but they will be much more flexible...meaning only type 1 would apply. Would you agree with this...or am I still missing something regarding how to evaulate strength?
RE: Vertical Structural Irregularity Type 5
You've only stated you perceive the posts to be stronger, nothing about actually evaluating the strength. You'd have to run the numbers. Shear strength of the shear walls compared to the shear strength at the lowest level based on the controling failure mode of the cantilevered columns. Like flexure at the base, base connection capacity, etc.
RE: Vertical Structural Irregularity Type 5
Agreed?