- 2080 Bhadra · 3+4+3 marks
RCC frame building: excavation, brick, plaster
Short answer
Centre-line method from the figure gives foundation excavation 10.92 m³, brickwork in 1:4 up to plinth 4.04 m³, and 12 mm inside plaster 63.05 m² (mortar volume 0.757 m³).
Prepare detailed estimate for the following items of works for RCC frame structured building (Fig. 2.) i) Earthwork in excavation in foundation ii) Brickwork in 1:4 c/s mortar up to plinth level iii) 1:4 (c/s) mortar inside the room [Figure 2: two-room building. Overall 7000 mm × 4700 mm outer; Room 1 3180 × 3040 mm, Room 2 3130 × 3040 mm, verandah 7000 × 1200 mm. Openings: D1 1000 × 2100 mm, W1 1500 × 1350 mm, W2 1000 × 1350 mm. Plinth tie-beam 300 × 300 mm; superstructure wall thickness 230 mm (same section for exterior and partition walls). Section A-A: height 2850 mm, M20 RCC slab 125 mm with 600 mm projection, brickwork 1:6 in superstructure, 1:4 brickwork in plinth (450 mm), foundation with 75 mm PCC, brick soling, compacted earth, PCC (1:2:4); footing widths 600/400/300 mm; heights 300/150/350/150 mm. All dimensions in mm, not to scale.]
Reading of the figure
The outer building is 7000 × 4700 mm including the 1200 mm verandah, so the rooms (and walls) occupy 7000 × 3500 mm (3040 + 2 × 230 = 3500; 3180 + 3130 + 3 × 230 = 7000). Walls are 230 mm. The verandah is open and not walled. Assumptions: one door D1 in each room, W1 in Room 1, W2 in Room 2.
Foundation: concrete 0.60 m wide × 0.30 m thick, brick step 0.40 m × 0.15 m, 230 mm wall; trench depth taken as 0.30 + 0.15 + 0.35 = 0.80 m; plinth 0.45 m above GL; 300 × 300 RCC tie beam at the top of the plinth.
Centre-line length of outer walls = 2[(7.0 − 0.23) + (3.5 − 0.23)] = 20.08 m. The partition is 3.04 + 0.23 = 3.27 m between the outer-wall centre lines; at its two T-junctions it is shortened by half the width of the outer-wall item at each end: trench 3.27 − 0.60 = 2.67 m, brick step 3.27 − 0.40 = 2.87 m, wall 3.27 − 0.23 = 3.04 m.
i) Earthwork in excavation in foundation
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| Trench, outer walls | 1 | 20.080 | 0.600 | 0.800 | 9.638 |
| Trench, partition (3.27 − 0.60) | 1 | 2.670 | 0.600 | 0.800 | 1.282 |
| Total | 10.920 |
ii) Brickwork in 1:4 c/s mortar up to plinth level
Wall height = 0.35 (below GL) + 0.45 (plinth) − 0.30 (tie beam) = 0.50 m. Brickwork below plinth level runs continuously under the doors, so no deduction is made for door openings.
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| Brick step 0.40 × 0.15 (20.08 + 2.87) | 1 | 22.950 | 0.400 | 0.150 | 1.377 |
| Wall 0.23 up to plinth tie beam (20.08 + 3.04) | 1 | 23.120 | 0.230 | 0.500 | 2.659 |
| Total | 4.036 |
iii) 1:4 cement-sand plaster inside the rooms (12 mm assumed)
Clear height 2.85 m.
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m²) |
|---|---|---|---|---|---|
| Room 1 walls | 1 | 12.440 | 2.850 | – | 35.454 |
| Room 2 walls | 1 | 12.340 | 2.850 | – | 35.169 |
| Deduct D1 1.0 × 2.1 (2 nos.) | -2 | 1.000 | 2.100 | – | -4.200 |
| Deduct W1 1.5 × 1.35 | -1 | 1.500 | 1.350 | – | -2.025 |
| Deduct W2 1.0 × 1.35 | -1 | 1.000 | 1.350 | – | -1.350 |
| Total | 63.048 |
Mortar volume at 12 mm = 63.05 × 0.012 = 0.757 m³.
Answer: Excavation 10.92 m³; brickwork to plinth 4.04 m³; inside plaster 63.05 m².
✓ Answer checked by Claude Opus 5.5 (high effort)
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