GRADE BEAM DESIGN
GRADE BEAM DESIGN
(OP)
Our office has had much debate about this one.
The scenario is you have a grade beam spanning from drilled pier to drilled pier, supporting more rigid load bearing concrete walls (several levels) above. Do you design the grade beam taking into account the stiffer wall elements above will deflect less than the beam and try to transfer the loads directly to the piers? Or do you design the grade beam as it if is transfering the full load to the piers? The two approaches can yield significantly different grade beam design results, not to mention pier reactions.
Your thoughts & input are greatly appreciated.
The scenario is you have a grade beam spanning from drilled pier to drilled pier, supporting more rigid load bearing concrete walls (several levels) above. Do you design the grade beam taking into account the stiffer wall elements above will deflect less than the beam and try to transfer the loads directly to the piers? Or do you design the grade beam as it if is transfering the full load to the piers? The two approaches can yield significantly different grade beam design results, not to mention pier reactions.
Your thoughts & input are greatly appreciated.






RE: GRADE BEAM DESIGN
The walls are more than capable of spanning between piers.
RE: GRADE BEAM DESIGN
RE: GRADE BEAM DESIGN
It is difficult to predict field conditions and means and methods the sub-contractor may employ during construction. We always design grade beams to support load from at least one or two storys without counting on the underlying soil.
RE: GRADE BEAM DESIGN
If the first story wall is continuous, it may be relied upon to support the upper stories. If there are door or window openings, engineering judgment is required as to what portion of load is carried by the grade beam.
BA
RE: GRADE BEAM DESIGN
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: GRADE BEAM DESIGN
RE: GRADE BEAM DESIGN
We once had a building plans reviewer, rightly so, do a strut-and-tie analysis for a planar shear wall that was supported by pile caps at each end. A finite element stress analysis indicated that this wall acted as a purely compression member until the first floor (about 10 feet) high and then as a deep beam, looking at the compression struts. The wall was 30 feet long. We ended up providing some hooked #8 bars at the base.
RE: GRADE BEAM DESIGN