Construction Supervisor License Practice Exam

A 4 x 4 concrete pad is placed on dense gravel. What is the net allowable bearing pressure the soil can support from a load placed on that pad, in tons?

1. 32

2. 48

3. 64

4. 96

The correct answer is: 96

To determine the net allowable bearing pressure that the soil can support from a load placed on a concrete pad, the size of the pad and the characteristics of the base material need to be considered. In this case, the pad measures 4 feet by 4 feet, which is a total area of 16 square feet. The net allowable bearing pressure is typically determined by dividing the total load on the pad by the area of the pad. The dense gravel base can typically support a higher load compared to other types of soil, often allowing for significant bearing pressures. In general, dense gravel can support an allowable bearing pressure in the range of 4,000 to 8,000 pounds per square foot, depending on various factors, including compaction and moisture content. When calculating the weight that this bearing pressure translates into, you can determine the total load supported by the pad and subsequently find the allowable load that corresponds to the given options. For a 4 x 4 pad (16 square feet), if we consider an allowable bearing pressure at the high end of 6 tons per square foot, we'd multiply that by the area (16 sq ft). This results in: 6 tons/sq ft * 16 sq ft = 96 tons This