---
title: "Slab culvert: excavation and brickwork"
subject: "Estimating and Costing"
chapter: 6
key: "semester_7/estimating_and_costing:slab-culvert-l-brick-earthwork"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/slab-culvert-l-brick-earthwork
site: BCT Engineering
---

# Slab culvert: excavation and brickwork

Estimating and Costing · Chapter 6: Detailed Estimate

- Asked in: 2075 Asoj, 4+6 marks
- Video: [ESTIMATION OF 2.0M *1.5M R.C.C. SLAB CULVERT.#rccslabculvert #culverts](https://www.youtube.com/watch?v=LVxIDj1TRwA) — MR. CIVIL ENGINEER
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/slab-culvert-l-brick-earthwork
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-6

## Question

Workout quantity of (i) earth work excavation and (ii) brick work of slab culvert. (Fig. 2)
[Figure 2: slab culvert. Sectional elevation: 300 thick RCC slab, 100 thick wearing coat, 200 thick kerb, bed/ground level, PCC (1:3:6) foundation; dimensions 590, 710, 1010, 1410 mm, clear span 2000, 295, 300, 150, 280, 230, 350. Sectional plan: 5000 total length, 2000 width, 590 abutment width. Cross-section: 5000 roadway width. Dimensions in mm, hard to read in the scan.]

## Short answer

Excavation:2×1.41×5.00×0.90 =12.69 m³. Brickwork volume including shaft and two offsets:11.060 m³.

## Answer

#### Reading of Fig. 2 (dimensions are hard to read; stated values are assumed where unclear)

- Roadway width $5.00$ m, which is the length of each abutment (measured across the road); clear span $2.00$ m.
- Each abutment: brick shaft $0.59$ m thick $\times$ $1.00$ m high; first offset $0.71$ m $\times$ $0.30$ m; second offset $1.01$ m $\times$ $0.30$ m; PCC (1:3:6) bed $1.41$ m wide $\times$ $0.30$ m thick.
- Ground level is at the top of the first offset, so the excavation depth to the bottom of the PCC is $0.30 + 0.30 + 0.30 = 0.90$ m.

#### (i) Earthwork in excavation

$V = 2 \times 1.41 \times 5.00 \times 0.90 = 12.69$ m³

#### (ii) Brickwork

| Part | Working | Area of section (m²) |
|---|---|---:|
| Shaft | $0.59 \times 1.00$ | 0.5900 |
| Offset 1 | $0.71 \times 0.30$ | 0.2130 |
| Offset 2 | $1.01 \times 0.30$ | 0.3030 |
| **Total** | | **1.1060** |

$V = 2 \times 5.00 \times 1.1060 = 11.060$ m³

**Answer: excavation = 12.69 m³; brickwork = 11.060 m³.**

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Excavation depth 0.90 m comes from
   A. Shaft height alone
   B. Shaft height + PCC
   C. Sum of the thicknesses of offset 1, offset 2 and the PCC bed (0.30 each)
   D. Clear span / 2
   Answer: C. Ground is at the top of the first offset, so the excavation reaches the bottom of the PCC bed. (Key point: Excavation depth)

2. Why are the volumes multiplied by 2?
   A. There are two layers of brick
   B. Bricks are laid in two courses
   C. To allow for wastage
   D. The culvert has two abutments
   Answer: D. Each abutment has the same cross-section, so total = 2 x length x area. (Key point: Why factor 2)

3. The brickwork cross-section area is
   A. Shaft area + offset 1 area + offset 2 area = 1.106 m2
   B. Shaft area only
   C. Widest offset width x total height
   D. PCC width x 0.9
   Answer: A. The wall is made of the shaft and the two offset footings, whose areas add. (Key point: Brickwork section)

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