Foundation

Teng Chart – Foundation Calculator (Blogger)

Pre-filled demo values provided. Units fixed: kN/m². Factor of Safety default = 2.

φ (deg)

γ (kN/m³)

c (kN/m²)

q (surcharge at foundation base, kN/m²)

Factor of Safety (FOS)

Target load N (kN)

Footing shape Square (B × B) Rectangular (L/B = 1.5) Circular (diameter = D)

Search B range (min m)

Search B range (max m)

Intermediate values (bearing capacity factors):

Nc = — , Nq = — , Nγ = —

Calculated:

Ultimate bearing capacity (q_ult) = — kN/m²

Safe bearing capacity (q_net = q_ult / FOS) = — kN/m²

Required size B = — m

Note: q in formula is surcharge (γ·Df) — here user-supplied as 'q'.

Notes (Quick guidance)

• Teng’s charts are settlement-based correlations used for preliminary allowable bearing estimates. This tool also computes theoretical Terzaghi-style capacity for demonstration.
• Assumed bearing capacity formula used: qult = c·Nc + q·Nq + 0.5·γ·B·Nγ. Intermediate factors Nc, Nq, Nγ are calculated from φ (standard closed-form approximations).
• Safe/working bearing capacity here is taken as qnet = qult / FOS (FOS default = 2). For final design apply local code procedures (IS 6403/IS 1904 or equivalent), depth corrections, shape and inclination factors, and settlement checks.
• This is a preliminary educational tool — use full geotechnical investigation and standards for project designs.