πŸ›οΈ Structural Engineering

Column Load Calculator

Calculate axial load on columns including self-weight, slab load, beam load, wall load, and tributary area β€” for RCC column design in Pakistan and Gulf standards.

πŸ›οΈ

RCC Column Load Calculator

Axial Load Β· Self Weight Β· Tributary Area Method

πŸ“ Column Dimensions
Short side dimension
Long side dimension
Floor-to-floor height
Total floors above this column
πŸ“¦ Tributary Area & Loads
Half span in X-direction
Half span in Y-direction
Slab self wt + finishes (typically 4–6)
Residential: 2–3, Commercial: 3–5
Self weight of beams framing in
9" brick wall = ~12 kN/m @ 3m ht
βš™οΈ Material & Design

πŸ“Š Column Load Results

βœ… Calculated
β€”
mΒ²
Tributary Area
β€”
kN
Load per Floor
β€”
kN
Column Self Wt
β€”
kN
Total Axial Load
β€”
kN
Factored Load Pu
β€”
mmΒ²
Req. Conc. Area
β€”

πŸ“– How Column Load Calculation Works

Column loads are calculated using the Tributary Area Method β€” each column carries the loads from the floor area it supports. This is the standard method used in Pakistani residential and commercial building design.

Step-by-Step Method

1. Tributary Area = Lx Γ— Ly (mΒ²) 2. Floor Load/mΒ² = Dead Load + Live Load (kN/mΒ²) 3. Slab Load = Floor Load Γ— Tributary Area Γ— Floors 4. Beam Load = Beam UDL Γ— (Lx + Ly) Γ— Floors 5. Wall Load = Wall kN/m Γ— (Lx + Ly) Γ— Floors 6. Column Self Wt = b Γ— D Γ— h Γ— 25 kN/mΒ³ Γ— Floors 7. Total Load (P) = Slab + Beam + Wall + Self Weight 8. Factored (Pu) = P Γ— Load Factor (1.5 for IS 456) 9. Required Area = Pu / (0.4 Γ— fck + 0.67 Γ— fy Γ— p) (approx: Ag β‰ˆ Pu / (0.4 Γ— fck) for initial sizing)
Tributary area = the floor area that each column is responsible for supporting. For an interior column on a regular grid: Trib. Area = (Span1/2 + Span2/2) Γ— (Span3/2 + Span4/2)
⚠️ This calculator gives preliminary axial load estimates only. Full column design including eccentricity, slenderness, and reinforcement must be done by a licensed Structural Engineer.

πŸ“‹ Typical Column Sizes for Pakistan Residential Buildings

FloorsTributary AreaApprox LoadMin Column SizeConcrete
G+0 (1 floor)12–16 mΒ²100–200 kN230Γ—230 mmM20
G+1 (2 floors)12–16 mΒ²200–400 kN230Γ—300 mmM20
G+2 (3 floors)12–20 mΒ²400–700 kN300Γ—300 mmM25
G+3 (4 floors)12–20 mΒ²700–1200 kN350Γ—350 mmM25
G+4 (5 floors)15–25 mΒ²1200–2000 kN400Γ—400 mmM30
G+5+ (6+ floors)15–25 mΒ²2000+ kN450Γ—450+ mmM30+

Sizes are indicative only. Actual design depends on loading, eccentricity, and reinforcement details.

❓ Frequently Asked Questions

Tributary area is the portion of floor area that a column is responsible for supporting. For a column on a regular grid, it equals half the distance to each adjacent column in all four directions. For example, a column in a 4m Γ— 5m bay has a tributary area of 4 Γ— 5 = 20 mΒ² (if it is an interior column with equal bays on all sides).
For a typical 5-marla G+2 house in Pakistan (3 floors total), standard column sizes are 230mm Γ— 230mm to 300mm Γ— 300mm using M20 concrete with 4–6 bars of 16mm diameter rebar. For G+3 (4 floors), increase to 300mm Γ— 300mm minimum with M25 concrete. Always consult a structural engineer for the final design.
Per IS 456, ACI 318, and BS 8110: Minimum steel = 0.8% of gross cross-sectional area. Maximum steel = 6% (IS) or 8% (ACI) of gross area. Practical design typically uses 1%–4% steel. For a 300mm Γ— 300mm column: minimum steel = 0.8% Γ— 90,000 = 720 mmΒ² (approx 4 bars of 16mm = 804 mmΒ²).