Assignment
You are designing a square footing to support a 65-kip column load from a highway overpass pier. Due to a low project budget, limited site investigation was performed. The boring logs show a generally homogeneous medium-dense sand deposit beneath the surface. Based on SPT correlations, you have estimated the effective angle of internal friction to be 34 degrees. You have also estimated the moist and saturated unit weights to be 110 pcf and 125 pcf, respectively. During drilling operations, the groundwater table was encountered at a depth of 6 feet.
If the footing is to be embedded 42 inches below the ground surface, what is the optimum footing width using the Terzaghi bearing capacity theory?
A. What factor of safety should you use for this design
B. Assume an initial guess for the footing width, B, in feet (ft)
C. What is the effective vertical stress at the depth of embedment of the footing, σzD′, in pounds per square foot (psf)
D. What is the effective unit weight of the soil within the zone of influence beneath the footing, 'γ′, in pounds per cubic foot (pcf)
E. What is the Terzaghi bearing capacity factor associated with the depth term, Nq
F. What is the Terzaghi bearing capacity factor associated with the unit weight term, Nγ?
G. Based on your initial guess for B, what is the ultimate bearing capacity, qult, in pounds per square foot (psf).
H. Based on your initial guess for B, what is the allowable bearing capacity, q_{all}qall, in pounds per square foot (psf)
I. What is the optimized footing width, Breq, in feet (ft)
J. What is the optimum footing width using the Vesic/Meyerhof bearing capacity theory? Assume an initial guess for the footing width, B, in feet (ft)
K. What is the effective unit weight of the soil within the zone of influence beneath the footing, 'γ′, in pounds per cubic foot (pcf)
L. What is the Vesic/Meyerhof bearing capacity factor associated with the depth term, Nq
M. What is the Vesic/Meyerhof bearing capacity factor associated with the unit weight term, Nγ
N. What is the shape factor associated with the depth term, Fqs
O. What is the shape factor associated with the unit weight term, Fγs
P. What is the depth factor associated with the depth term, Fqd
Q. What is the depth factor associated with the unit weight term, Fγd
R. Based on your initial guess for BB, what is the ultimate bearing capacity, qult, in pounds per square foot (psf)
Based on your initial guess for B, what is the allowable bearing capacity, qall, in pounds per square foot (psf)?
What is the optimized footing width, Breq, in feet (ft)