Base Plate Bearing on Concrete

References

American Institute of Steel Construction. 2011. Design Examples V14.1. Chicago, IL:American Institute of Steel Construction. p J-16

Details

From the reference:

An ASTM A992 W12×96 column bears on a 24-in. × 24-in. concrete pedestal with f′c = 3 ksi. The space between the base plate and the concrete pedestal has grout with f′c = 4 ksi. Design the ASTM A36 base plate to support the following loads in axial compression:
  • PD = 115 kips
  • PL = 345 kips

Refer to the figure in the reference for additional details.

Calculations

Calculations

Pu = 1.2(115 kips) + 1.6(345 kips) = 690 kips

Results

Table 1. Comparison with AISC Design Example J-7
Parameter RAM Connection Reference Difference
A1 (in2) 484 484 none
A2 (in2) 576 576 none
m (in) 4.97 4.97 none
n (in) 6.12 6.12 none
ϕPp (kips) 875.161 875 none
Cocnrete brearing strength, LRFD (kips) 875.16 875 < 1%
Concrete bearing strength, ASD (kips) 582.86 583 < 1%

Input

The following data is input into the New Joint dialog:

Joint Data tab
  • Joint = CB
  • Column/Section = W 12x96
  • Column/Material = ASTM A992 Gr50 (from AISC database and according to the reference)
Loads tab
  • Axial = -690 kips

The following data is input into the Connection Pad:

Base Plate group
  • Longitudinal dimension = 22 in.
  • Transverse dimension = 22 in.
  • Thickness = 2 in.
Support group
  • Longitudinal dimension = 24 in.
  • Transverse dimension = 24 in.
  • Material = C 3-40
Anchor group
  • Longitudinal edge distance on the plate = 2 in.
  • Transverse edge distance on the plate = 2 in.