{"openapi":"3.1.0","info":{"title":"Soil Bearing Capacity API","version":"1.0.0","description":"Geotechnical foundation maths as an API, computed locally and deterministically. The factors endpoint computes the Terzaghi/Vesic bearing-capacity factors Nc, Nq and Nγ from a soil friction angle — Nq = e^(π·tanφ)·tan²(45+φ/2), Nc = (Nq−1)·cotφ and Nγ = 2(Nq+1)·tanφ. The bearing-capacity endpoint computes the ultimate, net and allowable bearing capacity of a strip, square or circular footing from the cohesion, friction angle, soil unit weight, footing width and founding depth, qu = sc·c·Nc + γ·D·Nq + sγ·γ·B·Nγ, breaking it into its cohesion, surcharge and self-weight components and dividing by a factor of safety (default 3) for the allowable value. The settlement endpoint computes the immediate elastic settlement of a footing, s = q·B·(1−ν²)·I / E, from the applied pressure, the footing width, the soil elastic modulus and Poisson's ratio. Cohesion and pressures are in kilopascals, unit weight in kN/m³ and lengths in metres. Everything is computed locally and deterministically, so it is instant and private. Ideal for civil-engineering, geotechnical, foundation-design and construction app developers, footing-sizing and feasibility tools, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is foundation bearing capacity; for lateral earth pressure on walls use an earth-pressure API and for open-channel flow a Manning API.","contact":{"name":"PremiumApi","url":"https://www.oanor.com/by/premiumapi"}},"servers":[{"url":"https://api.oanor.com/soil-api","description":"oanor gateway"}],"tags":[{"name":"Soil"},{"name":"Meta"}],"components":{"securitySchemes":{"oanorKey":{"type":"apiKey","in":"header","name":"x-oanor-key","description":"Get your key at https://www.oanor.com/developer/keys"}}},"security":[{"oanorKey":[]}],"paths":{"/v1/bearing-capacity":{"get":{"operationId":"get_v1_bearing_capacity","tags":["Soil"],"summary":"Bearing capacity","description":"","parameters":[{"name":"friction_angle","in":"query","required":true,"description":"Friction angle φ (degrees)","schema":{"type":"string"},"example":"30"},{"name":"cohesion","in":"query","required":false,"description":"Cohesion c (kPa)","schema":{"type":"string"},"example":"0"},{"name":"unit_weight","in":"query","required":true,"description":"Soil unit weight γ (kN/m³)","schema":{"type":"string"},"example":"18"},{"name":"width","in":"query","required":true,"description":"Footing width B (m)","schema":{"type":"string"},"example":"2"},{"name":"depth","in":"query","required":false,"description":"Founding depth D (m)","schema":{"type":"string"},"example":"1"},{"name":"shape","in":"query","required":false,"description":"strip, square or circular","schema":{"type":"string"},"example":"strip"},{"name":"factor_of_safety","in":"query","required":false,"description":"Factor of safety","schema":{"type":"string"},"example":"3"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"qu = sc·c·Nc + γ·D·Nq + sγ·γ·B·Nγ. Allowable = qu ÷ factor of safety (default 3). Pressures in kPa.","inputs":{"shape":"strip","depth_m":1,"width_m":2,"unit_weight":18,"cohesion_kpa":0,"factor_of_safety":3,"friction_angle_deg":30},"factors":{"Nc":30.1396,"Nq":18.4011,"Ngamma":22.4025},"components_kpa":{"cohesion":0,"surcharge":331.2202,"self_weight":403.2448},"ultimate_bearing_capacity_kpa":734.465,"allowable_bearing_capacity_kpa":244.8217,"net_ultimate_bearing_capacity_kpa":716.465,"net_allowable_bearing_capacity_kpa":238.8217},"meta":{"timestamp":"2026-06-05T03:09:00.974Z","request_id":"c2e52489-db2b-4f32-bd17-f22e319ad586"},"status":"ok","message":"Bearing capacity","success":true}}}},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}},"/v1/factors":{"get":{"operationId":"get_v1_factors","tags":["Soil"],"summary":"Bearing-capacity factors","description":"","parameters":[{"name":"friction_angle","in":"query","required":true,"description":"Friction angle φ (degrees)","schema":{"type":"string"},"example":"30"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"Nc":30.1396,"Nq":18.4011,"note":"Bearing-capacity factors: Nq = e^(π·tanφ)·tan²(45+φ/2), Nc = (Nq−1)·cotφ, Nγ = 2(Nq+1)·tanφ (Vesic).","Ngamma":22.4025,"inputs":{"friction_angle_deg":30}},"meta":{"timestamp":"2026-06-05T03:09:01.049Z","request_id":"28b8fb78-bf7d-4701-a678-b3bd2a17579f"},"status":"ok","message":"Bearing factors","success":true}}}},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}},"/v1/settlement":{"get":{"operationId":"get_v1_settlement","tags":["Soil"],"summary":"Elastic settlement","description":"","parameters":[{"name":"pressure","in":"query","required":true,"description":"Applied pressure (kPa)","schema":{"type":"string"},"example":"100"},{"name":"width","in":"query","required":true,"description":"Footing width B (m)","schema":{"type":"string"},"example":"2"},{"name":"elastic_modulus","in":"query","required":true,"description":"Soil elastic modulus E (kPa)","schema":{"type":"string"},"example":"20000"},{"name":"poisson_ratio","in":"query","required":false,"description":"Poisson's ratio ν","schema":{"type":"string"},"example":"0.3"},{"name":"influence_factor","in":"query","required":false,"description":"Influence factor I","schema":{"type":"string"},"example":"1.12"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"Elastic settlement s = q·B·(1−ν²)·I / E. 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