Allowable bearing pressures for wall and columns
Allowable bearing pressures for wall and columns
(OP)
Hi, I have a 2-story structure with high column loads (D+L=1,050kN). The wall loads are around 90kN/m. The structure will be like a box (rectangular-shaped building with continous footings for walls and independent footings for columns)
I have CL and CH soils for this site and am planning to provide 2 allowable bearing pressures: one for the columns (independent footings) and other for the walls (continuos footings). My intent is to provide higher allowable bearing pressures for the walls than the columns in order to keep differential settlements lesser than the typical 12 mm. I do not know the column spacing so I have not calculated the deflection ratios (delta/L) yet.
My question is: do you think that providing 2 allowable bearing pressures for the same structure is acceptable? Do you think that this can cause confusion to the structural designer?
I have CL and CH soils for this site and am planning to provide 2 allowable bearing pressures: one for the columns (independent footings) and other for the walls (continuos footings). My intent is to provide higher allowable bearing pressures for the walls than the columns in order to keep differential settlements lesser than the typical 12 mm. I do not know the column spacing so I have not calculated the deflection ratios (delta/L) yet.
My question is: do you think that providing 2 allowable bearing pressures for the same structure is acceptable? Do you think that this can cause confusion to the structural designer?





RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns
What I have done in my arid to semi-arid, heavily irrigated area for small to medium loads is specify a maximum allowable bearing for the structure foundation, call for the interior footings to be balanced for about 300 to 500 psf less for settlement issues (500 psf more for expansive issues). The other requirement is for the foundation to be balanced within about 200-400 psf for small structures, after satisfying the interior versus exterior requirements. Larger structures are have about the same balancing requirements, at my discretion.
I must add that these requirements change in different areas of my practice & may radically change for certain Architects & Structural Engineers. The concept of good foundation balancing is not appreciated by many.
RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns
Attached is a rough start on such a graph I made years and years and years ago - it just happened to have been following me around Asia for the last 20 odd years. Obviously, this is made for a particular set of strata and undrained shear strengths.
RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns
RE: Allowable bearing pressures for wall and columns