Tools › Civil and Geotechnical › Foundations › Pile Capacity and Lateral Load › Example
HP 12x74 at the FHWA GEC 12 North Abutment: Nordlund shaft and toe resistance in three sand layers, factored resistance, uplift, group, neutral plane, Broms and driving formulas
| Tool | Pile Capacity and Lateral Load |
| Source | Hannigan, P. J., Rausche, F., Likins, G. E., Robinson, B. R., and Becker, M. L. (2016). Design and Construction of Driven Pile Foundations, Volume III: Comprehensive Design Examples. Geotechnical Engineering Circular No. 12, FHWA-NHI-16-064, Federal Highway Administration, Washington, DC (Block 10, North Abutment: Figure D-7, Tables D-4 to D-6); Volume I, FHWA-NHI-16-009 (Section 7.2.1.3.1, Tables 7-6 / 7-7, Figures 7-9 to 7-16, Table 7-1); Volume II, FHWA-NHI-16-010 (Table 13-4). |
| Level | Professional |
Problem
An HP 12x74 (b 12.1 in, steel area 21.8 in², box toe area 1.02 ft²) is driven 60 ft below a pile cap whose bottom is 5 ft below grade through loose silty fine sand (25 ft, 105 pcf, φ′ 33°), medium dense coarse sand (25 ft, 112 pcf, φ′ 36°) and dense gravel with sand (125 pcf, φ′ 36° on the shaft, 40° at the toe); the water table is 15 ft below grade. Find the Nordlund shaft and toe resistances, the nominal and factored resistance (φ 0.45) against a 300-kip factored load, the uplift resistance, the 3 × 4 group at 3 ft, the neutral plane under a 200-kip permanent load, the Broms lateral capacity and the elastic-foundation deflection of a fixed-head pile under 20 kips with n_h 25 pci, and the driving-formula resistances for the ICE I-46 case history (10.15 kips, 8.14 ft stroke, 49 blows/ft).
Inputs to Enter
- Method FHWA (Nordlund / α), LRFD; H-pile, H-section, box toe area; b 12.1 in, A_st 21.8 in², L 60 ft, head 5 ft, water table 15 ft, toe φ′ 40°, E_p 29,000 ksi, I_p 569 in⁴, M_y 391 kip-ft
- Layers: sand 25 ft / 105 pcf / 33° / N 9; sand 25 ft / 112 pcf / 36° / N 17; sand 47 ft / 125 pcf / 36° / N 39
- Loads: Q_c 300 kip, permanent 200 kip, uplift 60 kip, lateral 20 kip at the head; φ_stat 0.45, φ_up 0.35, φ_bl 0.60, φ_ug 0.50; group 3 × 4 at 3 ft; neutral plane with 50 % toe mobilization; E_s 1,416 ksf, μ 0.3, C_p 0.03; fixed head, n_h 25 pci, y_all 0.5 in; ICE I-46: 10.15 kip, 8.14 ft, set 0.245 in, F_eff 0.47
Answers
- Nordlund shaft: δ/φ 0.79 (curve f at V 0.151 ft³/ft), K_δ 1.114 (φ′ 33) / 1.392 (36), C_F 0.92 / 0.90; R_s = 19.1 kips at 10 ft, 51.6 at 20, 105.8 at 30, 172.0 at 40, 343.8 at 60 ft (Table D-6: 19.1, 51.6, 105.9, 172.1, 344.1)
- Toe at 60 ft: α_t 0.75, N′_q 156 (Figure 7-16), σ′_p 4,180 psf limited to 3 ksf: R_p = 355.9 kips (Table D-6 428.1, the DrivenPiles program's chart readings); R_n = 699.7 kips, R_r = 0.45 R_n = 314.9 kips, M.S. +0.05 against 300 kips
- Uplift R_t = 0.35 × 343.8 = 120.3 kips (M.S. +1.01); group η 1.0 (sand), R_ng = 12 × 699.7 = 8,397 kips, group uplift governed by the piles 1,444 kips against the 1H:4V soil block; neutral plane 38.4 ft below the head, drag force 160.9 kips, maximum pile load 360.9 kips; Vesić settlement 0.28 in
- Broms long fixed-head pile in sand (φ′ 35°, γ′ 60.9 pcf averaged): H_u = 77.7 kips, M_max = M_y; elastic foundation n_h 25 pci: T = 4.84 ft, L/T 12.4, y_0 = 0.928 H T³/(E I) = 0.220 in, fixing moment 0.927 H T = 89.7 kip-ft; characteristic load method P_c 3,526 kips, y 0.149 in, M 78.4 kip-ft
- Driving formulas (Table 13-4 case history): Engineering News 2,872, FHWA Gates 710, WSDOT 950 (F_eff 0.47), MPF12 585 kips (printed 2,872 / 710 / 950 / 585)
Notes
The tool's default inputs are this pile; press Submit. The shaft resistances reproduce Table D-6 to 0.1 kip at every depth; the toe differs by the program's reading of Figures 7-15 / 7-16 (N′_q about 190 at 40° in DrivenPiles against 156 digitized here). The group, loads, lateral soil moduli and settlement parameters are illustrative additions to the published example (stated on the page); every formula is checked by test_pile_capacity.php (512 checks) against the GEC 12, NHI-05-042 and GEC 10 printed values and the numpy / scipy script in References/Pile-Capacity/checks/.