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