Civil & Structural Calculators
Concrete, walls, and welds.
- Beam DeflectionMaximum deflection for the two textbook cases: cantilever and simply-supported.δ = PL³ / 3EI (cantilever) δ = PL³ / 48EI (simple, center load)
- Linear Thermal ExpansionΔL = αLΔT for common structural materials.ΔL = α · L · ΔT
- Axial Stress & Strainσ = F/A and ε = σ/E, with an optional yield-strength safety check.σ = F/A ε = σ/E
- Euler Column BucklingCritical buckling load Pcr = π²EI/(KL)² with standard end conditions.Pcr = π²·E·I / (K·L)²
- Gravitational Potential EnergyPE = mgh — energy banked by height.PE = m · g · h
- Rectangular Section ModulusS = bh²/6 and I = bh³/12, with optional bending stress from a moment.S = b·h²/6 I = b·h³/12 σ = M/S
- Fillet Weld Throat StressShear on the throat, a = 0.707z — the plane where fillet welds actually fail.a = 0.707·z τ = F / (a · l)
- Manning Open-Channel FlowDischarge in a rectangular channel from geometry, slope, and roughness n.Q = (1/n) · A · R^(2/3) · S^(1/2) (SI units; R = A/P)
- Water Hammer (Joukowsky)Pressure surge from a sudden velocity change: ΔP = ρ·a·Δv.ΔP = ρ · a · Δv (valid when closure time < 2L/a)
- Area & Volume Converterm², ft², in² and L, gal(US), ft³, m³ — enter either or both.1 ft² = 0.09290304 m² 1 gal(US) = 3.785412 L 1 ft³ = 28.31685 L
- Concrete Slab VolumeSlab volume from length, width, and thickness — plus bag counts and a waste allowance.V = L × W × t (order ≈ 1.10 × V)
- Concrete Column VolumeVolume for round or square columns, any count — with bag equivalents.V = (π/4)·d²·h (round) V = s²·h (square)
- Concrete Block WallCMU count and mortar bags for a wall — standard 8×16 block.blocks = 1.125 × area(ft²) mortar ≈ 1 bag / 28 blocks
- Rebar WeightTotal weight for a run of US bar sizes #3–#8.W = (unit weight lb/ft) × length × count
- Aggregate TonnageTonnes of gravel, sand, or crushed stone from area and depth.m = area × depth × ρ_bulk
- Rankine Earth PressureActive earth pressure coefficient and resultant force on a retaining wall.Ka = (1 − sin φ)/(1 + sin φ) Pₐ = ½·Ka·γ·H²
- Horizontal Tank VolumePartial-fill volume of a horizontal cylindrical tank from the dip level.A = r²·cos⁻¹((r−h)/r) − (r−h)·√(2rh−h²) V = A·L
- Vertical Tank VolumeFill volume of a vertical cylindrical tank from the level.V = (π/4)·D²·h
- Heat Conduction (Fourier)Steady heat flow through a flat layer — Q = k·A·ΔT/L.Q = k · A · ΔT / L
- Corrosion Rate (Mass Loss & mm/y ⇄ mpy)Turn a coupon mass-loss test into a corrosion rate, or convert straight between mm/y and mils per year.CR(mm/y) = 8.76×10⁴ · W / (A·T·ρ) , W in g, A in cm², T in h, ρ in g/cm³ , 1 mpy = 0.0254 mm/y
- Charpy V-Notch Impact EnergyTurn pendulum release and rise angles into absorbed impact energy — J, ft·lbf, and J/cm² over the notch ligament per ASTM E23.KV = m·g·R·(cos β − cos α) v₀ = √(2·g·R·(1 − cos α)) KV/A = KV ÷ A_ligament
- R-Value / U-Value (Series Wall)Stack up to five layer R-values, get the assembly U-value plus heat flux — SI and US units side by side.R_total = ΣRᵢ U = 1 / R_total q = U · ΔT Q = q · A
- Cipoletti Weir FlowOpen-channel flow over a trapezoidal (Cipoletti) weir from crest length and head.Q = 1.859 · L · H^(3/2) (SI: Q in m³/s, L and H in m)
- ASCE 7-22 Wind PressureVelocity pressure and design wind pressure on a building surface using the ASCE 7-22 directional method.qz = 0.613·Kz·Kzt·Kd·Ke·V² (SI, Pa) , p = q·G·Cp − qi·(GCpi)
- Seismic Base Shear (ASCE 7 ELF)Equivalent lateral force base shear per ASCE 7-22 §12.8 — Cs with upper and lower bounds, plus which equation governed.V = Cs·W Cs = S_DS/(R/Iₑ) ≤ S_D1/(T·R/Iₑ) for T ≤ T_L , ≤ S_D1·T_L/(T²·R/Iₑ) for T > T_L Cs ≥ max(0.044·S_DS·Iₑ, 0.01) ; if S₁ ≥ 0.6g, Cs ≥ 0.5·S₁/(R/Iₑ)
- Bolt Shear (Lap Joint)Shear capacity of a bolted lap joint per AISC J3 — LRFD and ASD strengths plus utilization against your applied load.Rn = Fnv · Ab · m · n , Ab = π·d²/4 φ = 0.75 (LRFD) , Ω = 2.00 (ASD)
- Flitch Beam Composite DeflectionSize a wood-and-steel-plate flitch beam by summing parallel EI — midspan deflection, steel share, and span ratio for a uniformly loaded simple span.ΣEI = n·E_w·(b·d³/12) + E_s·(t·h³/12), δ = 5·w·L⁴ / (384·ΣEI)
- Plate Critical Buckling StressElastic critical buckling stress of a thin rectangular plate — pick the k for your edge conditions and load case, get σ_cr and load per unit width.σ_cr = k · π² · E / [12(1 − ν²)] · (t/b)²
- Footing Bearing Pressure (Eccentric)Soil pressure under a rectangular spread footing carrying axial load plus moment — checks for uplift and reports peak/min pressure.e = M/P, kern = B/6 , full contact: q = P/A ± 6M/(L·B²) , partial (e>B/6): q_max = 2P/[3L(B/2 − e)]
- Shear-Wall Cantilever Deflection (SDPWS)Wood shear-wall deflection per the AWC SDPWS three-term equation — bending, panel shear via Ga, and anchorage slip, with drift ratio.δsw = 8vh³/(E·A·b) + vh/(1000·Ga) + (h/b)·Δa (v in plf, h & b in ft, E in psi, A in in², Ga in kips/in, Δa in in → δ in in)
- Bolt Preload vs YieldTarget preload and installation torque for a fastener at a chosen fraction of proof or yield strength.F_preload = frac · σ_y · A_t , T = K · F · d