Foundation Analysis of Drilled Piers and Grade Beams
Foundation Analysis of Drilled Piers and Grade Beams
(OP)
I am analyzing a slab-on-grade foundation for a project that is about to go into construction. It is an office addition (See attachment:http://files.engineering.com/getfile.aspx?folder=3... ) . The spacing for the drilled piers are 31'-10",26'-2"& 30'-11". One side of the building has 4 steel columns and the other side is using a CMU load bearing wall. Based on my calculations, I determine that at it's current spacing that 20/60 shaft & bell pier would work instead of 16/48 (this is mainly for the side of the CMU wall). This is primarily due to the spacing of the piers. My main issue is with the Grade Beams. I have analyzed the grade beams as spanning from pier to pier. I checked for the 31'-10" span. Due to the applied loads (wt. of grade beam, 8" CMU Wall @ 12'-0" ht, roof dead and live loads) the grade beam is not passing for strength. I am trying to think of what other acceptable solutions to this issue besides adding additional piers (due to cost) to reduce the span. Am I view the analysis of the grade beam correctly? I have been told it is good to span underreamed footings at 15'-0" o.c. or a max of 20'-0" to avoid these types of situation. What are the potential problems that may arise if it is left as is? Could I count on the soil the grade beams are resting on to help carry the load in this situation? Any suggestions and/or comments are appreciated.






RE: Foundation Analysis of Drilled Piers and Grade Beams
Dik
RE: Foundation Analysis of Drilled Piers and Grade Beams
For masonry support usually try to keep to L/600 on total load deflection to avoid cracking per dik's statement.
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RE: Foundation Analysis of Drilled Piers and Grade Beams
RE: Foundation Analysis of Drilled Piers and Grade Beams
@JAE- the grade beam dimensions are 16"x24" with (3)- #6 top & Bottom
RE: Foundation Analysis of Drilled Piers and Grade Beams
RE: Foundation Analysis of Drilled Piers and Grade Beams
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RE: Foundation Analysis of Drilled Piers and Grade Beams
Dik
RE: Foundation Analysis of Drilled Piers and Grade Beams