Fig. 1
Variables included in the models_
| Models variables | Type of variable |
|---|---|
| Y = reinforcement steel quantity, in kilograms | Dependent variable |
| X1 = flat slab volume, in cubic metres (for flat slab with beams) | Independent variable |
| X2 = flat slab volume, in cubic metres (for flat slab without beams) | Independent variable |
| X3 = hollow block slab volume, in cubic metres (with hidden beams) | Independent variable |
| X4 = hollow block slab volume, in cubic metres (with drop beams) | Independent variable |
| X5 = solid slab volume, in cubic metres (with drop beams) | Independent variable |
| X6 = isolated footing volume, in cubic metres | Independent variable |
| X7 = strip footing volume, in cubic metres | Independent variable |
| X8 = column volume, in cubic metres | Independent variable |
| X9 = beam volume, in cubic metres | Independent variable |
| X10, X11, X12, X13, X14, = floor area in square metres (based on number of floors) | Independent variable |
Summary of the developed regression models_
| Model no. | Regression model |
|---|---|
| 1 | Y1 = 92.25X1 |
| 2 | Y2 = 139.52X2 |
| 3 | Y3 = 122.36X3 |
| 4 | Y4 = 88.96X4 |
| 5 | Y5 = 102.36X5 |
| 6 | Y6 = 75.16X6 |
| 7 | Y7 = 90.58X7 |
| 8 | Y8 = 124.13X8 |
| 9 | Y9 = 100.42X9 |
| 10 | Y10 = 31.24X10 |
| 11 | Y10 = 40.36X11 |
| 12 | Y10 = 35.76X12 |
| 13 | Y10 = 33.73X13 |
| 14 | Y10 = 31.25X14 |
Results of multiple regression for total steel quantity and floor area_
| Regression statistics | Variables | Coefficient | P-value | |
|---|---|---|---|---|
| R2 | 0.56 | Floor area (m2) | 31.24 | 9.43E–05 |
| Observations | 158.0 | |||
| F | 120.5 | |||
MAPE results for the developed regression models_
| Model no. | MAPE (%) |
|---|---|
| 1 | 24.31 |
| 2 | 26.13 |
| 3 | 21.89 |
| 4 | 22.21 |
| 5 | 21.81 |
| 6 | 25.12 |
| 7 | 23.58 |
| 8 | 23.97 |
| 9 | 24.83 |
| 10 | 36.13 |
| 11 | 28.12 |
| 12 | 27.30 |
| 13 | 29.14 |
| 14 | 30.16 |
Examples to illustrate the models in Table 4_
| Example no. | Floor area (m2) | No. of floors | Total area | Model used | Steel quantity (kg) |
|---|---|---|---|---|---|
| 1 | 150 | 1 | 150 | 11 | 40.36 × 150 = 6,054 |
| 2 | 150 | 2 | 300 | 12 | 35.76 × 300 = 10,728 |
| 3 | 150 | 3 | 450 | 13 | 33.73 × 450 = 15,178.5 |
| 4 | 150 | 4 | 600 | 14 | 31.25 × 600 = 18,750 |
Regression models for total steel quantity and floor area based on number of building floors_
| Model no. | Regression model | Notes | R2, P-value |
|---|---|---|---|
| 11 | Y10 = 0.36X11 | One floor building | 0.72, 0.00 |
| 12 | Y10 = 35.76X12 | Two-floor building | 0.73, 0.00 |
| 13 | Y10 = 33.73X13 | Three-floor building | 0.71, 0.00 |
| 14 | Y10 = 31.25X14 | Four-floor building | 0.69, 0.00 |
The developed models (steel quantity as a function of structural element volume)_
| Model no. | Structural element | Range of reinforcement steel quantity (kg/m3 of element volume) | Regression model | Notes |
|---|---|---|---|---|
| 1 | Flat slab with beams | 80–100 | Y1 = 92.25X1 (R2 = 0.77, P = 0.00) | Average slab thickness = 17 cm |
| 2 | Flat slab without beams | 130–150 | Y2 = 139.52X2 (R2 = 0.74, P = 0.00) | Average slab thickness = 20 cm |
| 3 | Hollow block slab (with hidden beams) | 110–130 | Y3 = 122.36X3 (R2 = 0.80, P = 0.00) | Average slab thickness = 27 cm |
| 4 | Hollow block slab (with drop beams) | 80–100 | Y4 = 88.96X4 (R2 = 0.80, P = 0.00) | Average slab thickness = 27 cm |
| 5 | Solid slab (with drop beams) | 90–110 | Y5 = 102.36X5 (R2 = 0.82, P = 0.00) | Average slab thickness = 14 cm |
| 6 | Isolated footings | 70–90 | Y6 = 75.16X6 (R2 = 0.76, P = 0.000006) | |
| 7 | Strip footings | 80–100 | Y7 = 90.58X7 (R2 = 0.78, P = 0.00) | |
| 8 | Columns | 90–140 | Y8 = 124.13X8 (R2 = 0.77, P = 0.00) | |
| 9 | Beams | 70–120 | Y9 = 100.42X9 (R2 = 0.76, P = 0.00) |