--- title: "RCC column with footing: concrete and steel" subject: "Estimating and Costing" chapter: 6 key: "semester_7/estimating_and_costing:rcc-column-footing-h" source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/rcc-column-footing-h site: BCT Engineering --- # RCC column with footing: concrete and steel Estimating and Costing · Chapter 6: Detailed Estimate - Asked in: 2078 Bhadra, 3+5 marks - Video: [Lecture 13 Estimate of R.C.C Column & Footing ( Part-1)](https://www.youtube.com/watch?v=W8SobtsZquc) — GECJ CIVIL - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/rcc-column-footing-h - Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-6 ## Question From the attached drawing (figure 2) of RCC column, estimate the following items. (i) RCC 1:2:4 in column (ii) Steel reinforcement work excluding formwork [Figure 2: Column footing 1.5 m × 1.5 m in plan, RCC 1:2:4, 20 cm thick at edge (sloping up to column) with 10 cm PCC 1:3:6 below; column 30 cm × 30 cm, 3.50 m above GL and 70 cm below GL; footing reinforcement 12 mm main bars @ 10 cm c/c and 10 mm distribution bars @ 10 cm c/c; column reinforcement 4–16 mm dia and 4–12 mm dia vertical bars; 6 mm dia stirrups @ 15 cm c/c; anchorage/development 45 times bar dia.] ## Short answer Column RCC 1:2:4: 0.337 m³ (0.3×0.3×3.75 m). Footing RCC: edge slab 0.45 m³ + frustum 0.232 m³ = 0.682 m³. Total 1.02 m³. Steel: main 12 mm (15 nos), distribution 10 mm (15), vertical 16 mm (4) and 12 mm (4), stirrups 6 mm (29 nos @15 cm), total mass 86.3 kg. ## Answer The footing thickness at the column face is not given, so **0.45 m** is assumed (0.20 m at the edge, sloping up 0.25 m to the column). The 1.5 m × 1.5 m footing has its bottom (of the RCC) 0.70 m below GL, and the 0.30 × 0.30 m column rises 3.50 m above GL. #### i) RCC 1:2:4 Column (above footing top, height = 0.70 − 0.45 + 3.50 = 3.75 m): 0.30 × 0.30 × 3.75 = **0.337 m³** Footing (a slab plus a sloping pyramid frustum): - Edge slab: 1.5 × 1.5 × 0.20 = 0.450 m³ - Frustum (prismoidal formula, $h=0.25$ m, $A_1=2.25$, $A_2=0.09$): $\frac{0.25}{3}\left(2.25+0.09+\sqrt{2.25\times0.09}\right)=0.2325$ m³ - Footing total = 0.682 m³ Total RCC 1:2:4 (footing + column) = 0.337 + 0.682 = **1.020 m³**. (PCC 1:3:6, 10 cm under footing = 1.5 × 1.5 × 0.10 = 0.225 m³.) #### ii) Steel reinforcement (formwork excluded) Cover 50 mm in footing, 25 mm in column; weight per metre = $d^2/162$ kg (d in mm). | Bar | Working | Length (m) | Weight (kg) | |---|---|---|---| | 12 mm main, 15 bars | 15 × (1.5 − 0.10) | 21.00 | 18.67 | | 10 mm distribution, 15 bars | 15 × 1.40 | 21.00 | 12.96 | | 16 mm vertical, 4 bars | 4 × (4.20 − 0.05 + 45 × 0.016) | 19.48 | 30.78 | | 12 mm vertical, 4 bars | 4 × (4.20 − 0.05 + 45 × 0.012) | 18.76 | 16.68 | | 6 mm stirrups, 29 nos. | 29 × (4 × 0.25 + 2 × 10 × 0.006) | 32.48 | 7.22 | | **Total** | | | **86.31** | Number of stirrups = (4.20 − 0.10)/0.15 + 1, rounded up = 29. Bars per layer in the footing = 1.40/0.10 + 1 = 15. (Each column bar includes one 45d anchorage (development) allowance; hooks and bend allowances are ignored.) **Answer:** RCC 1:2:4 = 1.02 m³ (column 0.337 m³, footing 0.682 m³); steel ≈ **86.3 kg**. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. How is the column RCC height 3.75 m above footing top found? A. 3.50 + 0.70 - 0.45 B. 3.50 + 0.70 + 0.45 C. 3.50 - 0.70 D. 3.50 + 0.45 Answer: A. Column runs 3.50 m above GL plus 0.70 m below GL, less the 0.45 m footing thickness. (Key point: Column height) 2. How is the sloping footing part computed? A. Edge slab plus frustum by the prismoidal formula B. Full 1.5 x 1.5 x 0.45 C. Slab only D. Column area x 0.45 Answer: A. Footing = edge slab 1.5x1.5x0.20 plus frustum (h/3)(A1 + A2 + sqrt(A1A2)) = 0.682 m3. (Key point: Footing RCC volume) 3. Which formula gives unit weight of steel bar in kg/m? A. d^2/162 with d in mm B. d/162 C. d^2/81 D. d^2 x 7850 Answer: A. Weight per metre = d^2/162 kg for d in mm. (Key point: Bar weight) 4. How many 12 mm bars are in one footing layer at 10 cm c/c over 1.40 m? A. 14 B. 15 C. 10 D. 16 Answer: B. Number = 1.40/0.10 + 1 = 15. (Key point: Number of footing bars) ## Related in Estimating and Costing - [Underground RCC tank: brickwork 1:4, M20 PCC, steel](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aug-tank-e-fig1) — Estimating and Costing, chapter 6 - [RCC slab culvert 1.5 m span: four items](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aslab-culvert-n-four-items) — Estimating and Costing, chapter 6 - [T-beam decking: PCC for RCC and steel](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3At-beam-pcc-rcc-reinforcement) — Estimating and Costing, chapter 6 - [RCC slab culvert (u): four items](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aslab-culvert-u-four-items) — Estimating and Costing, chapter 6 - [Underground RCC tank: brick, PCC, steel (1% steel)](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aug-tank-b-fig1) — Estimating and Costing, chapter 6 - [Underground RCC tank: brickwork, steel (fig a)](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aug-rcc-tank-a) — Estimating and Costing, chapter 6 ## Related in other subjects - [Footing for 30x35 cm column, M25](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Afooting-for-30x35-cm-column-m25) — Design of RCC Structure, chapter 11 - [Footing, 450x500 column, 6#20, uniaxial moment](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Afooting-450x500-column-6-20-uniaxial) — Design of RCC Structure, chapter 11 - [Footing 300x400 column, factored moment 120 kNm](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Afooting-300x400-column-factored-moment-120) — Design of RCC Structure, chapter 11 - [Footing, 1250 kN column load, depth 1.8 m](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Afooting-1250-kn-column-load-depth) — Design of RCC Structure, chapter 11