#civil-engineering

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.

api.oanor.com/soil-api

Reinforcement-steel (rebar) maths as an API, computed locally and deterministically. The area endpoint computes the cross-sectional area of a reinforcing bar, a = π/4·d², its mass per metre (a·7850/1e6, steel ρ = 7850 kg/m³), the total area and mass for a number of bars, and — given a required steel area — the number of bars needed and the area provided. The spacing endpoint lays out bars across a section: from the width, the cover, the bar diameter and either a centre-to-centre spacing or a bar count it returns the other, n = floor((width − 2·cover − d)/spacing) + 1, the total steel area and the area per metre of width. The ratio endpoint computes the reinforcement ratio ρ = As/(b·d) of a section from the steel area (or the bars) and the section width and effective depth, as a fraction and a percentage, the single number that governs whether a beam is under- or over-reinforced. Everything is computed locally and deterministically, so it is instant and private. Ideal for structural and site-engineering tools, reinforced-concrete detailing, bar-bending schedules and steel take-off, and civil-engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is rebar geometry and quantities; for concrete mix proportions use a concrete API.

api.oanor.com/rebar-api

Concrete mix-design maths as an API, computed locally and deterministically. The mix endpoint breaks down a volume of concrete into its materials from a nominal mix ratio (cement:sand:aggregate, for example 1:2:4): it applies the 1.54 dry-volume allowance, then returns the cement in cubic metres, kilograms and 50 kg bags, the sand and aggregate volumes and masses, and the water from the water-cement ratio — the complete batch for the pour. The quantity endpoint computes the concrete volume of a slab, footing, or round or square column from its dimensions, adds a wastage allowance and gives the dry material volume. The watercement endpoint solves the water-cement ratio, the water or the cement from the other two — the single most important number for concrete strength and durability. Densities used are cement 1440, sand 1600 and aggregate 1450 kg/m³, with a 50 kg cement bag. Everything is computed locally and deterministically, so it is instant and private. Ideal for construction, estimating and site-engineering tools, material take-off and ordering, DIY and builder apps, and civil-engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is nominal volume-batch concrete estimating; for retaining-wall earth pressure use an earth-pressure API.

api.oanor.com/concrete-api

Structural wind-load maths as an API, computed locally and deterministically. The pressure endpoint computes the velocity (dynamic) pressure of wind, q = ½·ρ·v², from the wind speed and air density — the pressure the wind exerts when it is brought to rest against a surface — and also solves the wind speed back from a given pressure, reporting the speed in m/s, km/h and mph. The force endpoint computes the wind force on a surface, F = q·Cf·A, from the velocity pressure (or wind speed), the exposed area and a force coefficient (≈1.3 for a building wall, ≈1.2 for a flat plate), and — given a height — the overturning moment about the base. The beaufort endpoint converts between a wind speed and the Beaufort scale using v = 0.836·B^1.5, returning the Beaufort number, the standard description from calm to hurricane force and the corresponding pressure. Everything is computed locally and deterministically, so it is instant and private. Ideal for structural and façade-engineering tools, signage, solar-array, scaffold and temporary-structure wind checks, sailing and meteorology apps, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is structural wind pressure and force; for wind-turbine energy output use a wind-power API.

api.oanor.com/windload-api

Lateral earth-pressure maths (Rankine theory) as an API, computed locally and deterministically for retaining-wall design. The active endpoint computes the active earth pressure that pushes a wall outward when the soil is allowed to yield: the coefficient Ka = (1−sinφ)/(1+sinφ) from the soil friction angle, the pressure at the base of the wall σ = Ka·γ·H, the total thrust per metre run ½·Ka·γ·H², plus the contributions of a surface surcharge and of soil cohesion (which reduces the pressure by 2c√Ka and forms a tension crack of depth 2c/(γ√Ka)). The passive endpoint computes the passive resistance Kp = (1+sinφ)/(1−sinφ) that the soil mobilises when a wall is pushed into it — the resisting pressure and thrust, with cohesion adding 2c√Kp. The atrest endpoint computes the at-rest pressure K0 = 1−sinφ (Jaky) for unyielding walls such as basements and braced excavations. Everything is computed locally and deterministically, so it is instant and private. Ideal for geotechnical and civil-engineering tools, retaining-wall, sheet-pile and basement-wall design, excavation-shoring and foundation apps, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is Rankine lateral earth pressure; for slope geometry use a slope API and for open-channel weir flow use a weir API.

api.oanor.com/earthpressure-api

Banked-curve and circular-motion dynamics as an API, computed locally and deterministically. The speed endpoint takes the radius of a curve and its banking (bank) angle and returns the frictionless ideal (design) speed at which the banking alone supplies the centripetal force, v = √(r·g·tanθ); give a coefficient of friction as well and it also returns the maximum safe speed before the vehicle slides outward up the bank, v = √(r·g·(tanθ+μ)/(1−μ·tanθ)), and the minimum speed before it slides inward down the bank — every speed in metres per second, km/h, mph and knots, plus the centripetal acceleration. The bank-angle endpoint inverts this: from a design speed and radius it returns the ideal banking angle θ = atan(v²/(r·g)) and the equivalent superelevation as a ratio and a percentage, the cant a road or railway needs so no side friction is used at that speed. The flat-curve endpoint handles an unbanked curve from the coefficient of friction: the maximum cornering speed v = √(μ·r·g) for a given radius and the minimum radius v²/(μ·g) for a given speed. Gravity defaults to standard 9.80665 m/s² and can be overridden. Everything is computed locally and deterministically, so it is instant and private. Ideal for road and racetrack design tools, vehicle-dynamics and driving-simulator apps, civil and transportation engineering, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is curve banking and cornering dynamics; for projectile and SUVAT kinematics use a physics API.

api.oanor.com/bankedcurve-api

Open-channel flow maths as an API, computed locally and deterministically with the Manning equation. The flow endpoint computes the discharge and velocity of water in an open channel — rectangular, trapezoidal, triangular or circular (a part-full pipe) — from the flow depth, the channel dimensions, the channel slope and the Manning roughness coefficient n: it works out the flow area, the wetted perimeter and the hydraulic radius, then applies Q = (1/n)·A·R^(2/3)·S^(1/2) and V = Q/A, reporting the discharge in cubic metres per second and hour, litres per second, cubic feet per second and US gallons per minute. The normal-depth endpoint reverses it: given a target discharge it solves for the normal depth by bisection and returns the resulting area, velocity and a discharge check. The roughness endpoint is a reference of typical Manning n values, from smooth PVC (0.009) and concrete (0.013) through earth and gravel to rocky natural streams (0.05); pass a material name or an explicit n. Dimensions are metric (metres by default, or cm, mm, ft, in). Everything is computed locally and deterministically, so it is instant and private. Ideal for civil and drainage engineering tools, stormwater and culvert design, irrigation and hydrology apps, and environmental modelling. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is open-channel (Manning) hydraulics; for full-pipe flow rate from diameter and velocity use a pipe-flow API.

api.oanor.com/manning-api