azcats
Structural
- Oct 17, 1999
- 693
2018 IBC & ASCE 7-16
This ASCE now lists "Ground-supported cantilever walls or fences" in table 15.4-2. In the previous version of ASCE 7, screen walls were not specifically listed so there was some question as to whether they should be designed per Chapter 13 or Chapter 15. IMO, this places it squarely in chapter 15 and the table shows to use R = 1.25. I plan to use the equivalent lateral force procedure as allowed in 15.1.3.
So I run thru section 12.8 and come up with my base shear.
12.8.3 discusses the vertical distribution of lateral forces. Is it the intent of this section that I turn my base shear into a triangular distribution that is zero at grade and maximized at top of wall? Or apply the base shear at 2/3*h from grade?
How would you all apply the force?
I want to follow the intent of the code but I don't want go beyond what's required. You don't have to be too deep into seismic land before this starts to matter and the triangular load would result in 1/3 more moment than an equal distribution.
Thoughts welcome.
This ASCE now lists "Ground-supported cantilever walls or fences" in table 15.4-2. In the previous version of ASCE 7, screen walls were not specifically listed so there was some question as to whether they should be designed per Chapter 13 or Chapter 15. IMO, this places it squarely in chapter 15 and the table shows to use R = 1.25. I plan to use the equivalent lateral force procedure as allowed in 15.1.3.
So I run thru section 12.8 and come up with my base shear.
12.8.3 discusses the vertical distribution of lateral forces. Is it the intent of this section that I turn my base shear into a triangular distribution that is zero at grade and maximized at top of wall? Or apply the base shear at 2/3*h from grade?
How would you all apply the force?
I want to follow the intent of the code but I don't want go beyond what's required. You don't have to be too deep into seismic land before this starts to matter and the triangular load would result in 1/3 more moment than an equal distribution.
Thoughts welcome.
