Axial capacity (AASHTO in-situ SPT or BNBC 2020 Table 3.11.3.3), lateral capacity from a Winkler beam-on-elastic-foundation solve with a Broms closed-form cross-check, circular or rectangular P-M section design, and reinforcement detailing (confinement, shear, precast handling moments) for a single pile from a bore log.
BNBC 2020ACI 318-08
Pile type & geometry
Bore log (24 rows)
z (ft)
N
Type
γ (kcf)
γ blank = automatic (above GWT uses the "above" unit weight, below uses the "below" value).
Axial capacity method
AASHTO in-situ parameters
Everything you have entered is in the address bar, so the link reproduces this exact calculation.
Qa = 154.1 kip · Qult = 462.3 kip
Allowable compression
154.1 kip
Allowable uplift
129.1 kip
Ultimate capacity
462.3 kip
Calculation
1Cumulative skin friction at the pile tip
Q_s
Q_s = 408.2
Q_s=408.2 kip
2End bearing at the pile tip
Q_p
Q_p = 91.6
Q_p=91.6 kip
3Ultimate axial capacity
Q_{ult} = Q_p + Q_s - W_p
Q_{ult} = 91.6 + 408.2 - 37.6 = 462.3
Q_{ult}=462.3 kip
4Allowable compression, FS = 3
Q_a = Q_{ult}/FS_c
Q_a = 462.3/3 = 154.1
Q_a=154.1 kip
70.0 metric ton
5Allowable uplift, FS = 2.5
Q_t = (0.7 Q_s + W_p)/FS_t
Q_t = 129.1
Q_t=129.1 kip
58.7 metric ton
Assumptions
AASHTO in-situ method: effective-stress β method for skin friction in sand/silt, α (adhesion) method in clay, SPT-N correlated end bearing — capped throughout at the entered ceiling values.
BNBC 2020 Table 3.11.3.3 method: driven-precast static formula with N60 corrected for hammer energy, rod length and sampler when the bore log's N is field-measured.
What this calculator does not check
The AASHTO in-situ method treats the pile as circular using the entered diameter, regardless of the selected pile shape — a square or rectangular pile needs an equivalent diameter entered directly for that method. The BNBC method uses the true perimeter and area of whichever shape is selected.
The BNBC method's pile self-weight deduction uses a fixed water unit weight of 18 kN/m³ carried verbatim from the source implementation rather than water's actual unit weight (9.81 kN/m³); the deduction is smaller than physically correct, so the reported allowable capacity is mildly on the unconservative side by that amount.
This is a port of the owner's own reference implementation; no published worked example has been reproduced against it. Treat results as indicative and check them against a hand calculation before relying on them.
Results are for preliminary sizing and educational use. They are not a design and must be reviewed, verified and sealed by a licensed or registered engineer before being used in construction.