Question

A weight of 18,000 lb is supported on a rectangular baseplate that is 9-in. wide and 2-ft long. The baseplate rests on a concrete slab. Determine the stress that the baseplate exerts on the concrete slab. Express your answer in units of (a) lb/in.2 and (b) lb/ft2 (precision of 1 for (a) and of 1000 for (b)).

Answer 1

Step-by-step explanation:

To find the stress that the baseplate exerts on the concrete slab, we need to calculate the pressure distribution on the baseplate. The weight is distributed over an area of 9 in. × 24 in. = 216 in.2.

The stress is the force per unit area, so we can calculate it by dividing the weight by the area:

(a) Stress in lb/in.2:

18,000 lb / 216 in.2 ≈ 83.33 lb/in.2

(b) Stress in lb/ft2:

83.33 lb/in.2 × (12 in./ft)2 × 1 ft2/144 in.2 ≈ 583.3 lb/ft2

Therefore, the stress that the baseplate exerts on the concrete slab is approximately 83.33 lb/in.2 or 583.3 lb/ft2.