Updating Bearing Capacity – SPT Graphs - Maryland State Highway ...

x 1 and x 2 Factors as a Function of SPT N-value for a Wall FootingN x 1 x 2 N x 1 x 22 14.11 7.91 28 35.08 25.674 15.06 8.62 30 37.75 28.156 16.09 9.41 32 40.85 31.128 17.22 10.28 34 44.12 34.2810 18.40 11.20 36 47.73 37.8312 19.74 12.28 38 51.74 41.8614 21.14 13.42 40 55.96 46.1216 22.67 14.69 42 60.90 51.2718 24.34 16.10 44 66.14 56.7920 26.09 17.59 46 71.96 63.0322 28.10 19.36 48 78.49 70.1824 30.21 21.23 50 85.38 77.7726 32.53 23.32x 1 and x 2 Factors as a Function of SPT N-value for a Square FootingN x 1 x 2 N x 1 x 22 21.49 4.75 28 60.02 15.404 23.13 5.17 30 65.19 16.896 24.94 5.65 32 71.20 18.678 26.91 6.17 34 77.61 20.5710 29.02 6.72 36 84.77 22.7012 31.41 7.37 38 92.77 25.1214 33.95 8.05 40 101.23 27.6816 36.73 8.81 42 111.26 30.7718 39.79 9.66 44 122.03 34.0720 43.02 10.56 46 134.06 37.8222 46.76 11.61 48 147.72 42.1124 50.72 12.74 50 162.22 46.6726 55.14 13.99Ultimate Bearing Capacity as a Function of SPT N-value for a Wall FootingSoil Type Range of q ult in psf Average of q ult in psfClays of High Plasticity (CH) (1059 to 1613) N 1336 NClays of Medium Plasticity (CL) (505 to 1059) N 782 NClays of Low Plasticity and Clayey Silt (SC-ML) (275 to 505) N 390 NUltimate Bearing Capacity as a Function of SPT N-value for a Square FootingSoil Type Range of q ult in psf Average of q ult in psfClay of High Plasticity (CH) (1265 to 1927) N 1596 NClay of Medium Plasticity (CL) (603 to 1265) N 934 NClay of Low plasticity and Clayey silt (SC-ML) (329 to 603) N 466 Nvi