kennyb04
Structural
- Jun 17, 2011
- 33
I am working on a project with an interesting site. It is a PEMB the we are doing the foundations for, so moment frame in one direction and rod braces in the other. Our site class is F due to liquefiable soils and seismic Design Category is D. The geotech recommends helical piers and slab NOT supported on grade.
The plan is to use grade beams across the pier caps in the moment frame direction and a one way slab perpendicular. The question I run into is using the Sesimic Tie requirements of IBC 2009 1810.3.13 or IBC 2006 1808.2.23.1. From my understanding, I can use the beams in the moment frame direction to also act as the seismic tie (so that the beam would be subject to bending and axial force). Does anyone have a recommendation on how to meet the requirement in the brace direction? Do I need to put a grade beam in this direction as well? Or design the reinforcement in the slab to carry these loads without having to use a beam?
I'm also not completely familiar with the seismic ties in genereal since I have been fortunate enough to not need them much. So, if anyone has any other comments or suggestions besides what I asked feel free to comment.
Also, when looking at ACI-318-08 21.12.3.2 for the grade beams designed as horizontal ties, it seems like for an 18" wide beam I would need ties at 9" o.c for the length of all the beams. Does this seem correct? Thanks for any input.
The plan is to use grade beams across the pier caps in the moment frame direction and a one way slab perpendicular. The question I run into is using the Sesimic Tie requirements of IBC 2009 1810.3.13 or IBC 2006 1808.2.23.1. From my understanding, I can use the beams in the moment frame direction to also act as the seismic tie (so that the beam would be subject to bending and axial force). Does anyone have a recommendation on how to meet the requirement in the brace direction? Do I need to put a grade beam in this direction as well? Or design the reinforcement in the slab to carry these loads without having to use a beam?
I'm also not completely familiar with the seismic ties in genereal since I have been fortunate enough to not need them much. So, if anyone has any other comments or suggestions besides what I asked feel free to comment.
Also, when looking at ACI-318-08 21.12.3.2 for the grade beams designed as horizontal ties, it seems like for an 18" wide beam I would need ties at 9" o.c for the length of all the beams. Does this seem correct? Thanks for any input.
