Challenge 4: Bridge Design
Cost Model
| Materials | Quantity | Unit Cost/Item | Cost | |
| Mass of structure (kg) | 60/kg | |||
| Pop rivets | 0.1 | |||
| Bolts | M4 | 0.6 | ||
| M5 | 0.9 | |||
| M6 | 1.2 | |||
| Total cost for materials (a) | ||||
| Labour | Quantity | Unit Cost/Item | Cost | |
| All drilled holes (rivet holes and bolt holes) but see note 1 below | 2 | |||
| Bars/rods (see note 2 below) | Total used | 4 | ||
| Extra bends | 8 | |||
| Steel metal items | Total used | 4 | ||
| Bends < 300 mm in length | 6 | |||
| Bends ³ 300 mm in length | 64 | |||
| Lengths of wire | Total used | 8 | ||
| Total cost for labour (b) | ||||
| Total cost for materials (a) | |
| Total cost for labour (b) | |
| Total cost for bridge (a+b) |
Note 1: a hole drilled through several sheets counts as one hole, and the holes for the 13 mm loading attachment are free.
Note 2: any length of steel angle counts as a bar; rods include lengths of rod, tube and studding.