For sandy gravel soils, what is the maximum foundation pressure allowed in PSF?

The maximum foundation pressure for sandy gravel soils is typically set at 3000 Pounds per Square Foot (PSF). This value is based on the engineering properties of sandy gravel, which generally include good drainage and high load-bearing capacities. Sandy gravel soils can support larger loads compared to other soil types due to their granular nature, which allows for better interlocking of particles and minimizes the risk of excessive settlement under load.

Understanding soil mechanics and the characteristics of different soil types is crucial for deciding safe load limits in construction. Sandy gravel, being a coarse-grained soil, has a relatively high angle of internal friction, contributing to its strength when compacted. This allows it to bear significant pressure without leading to failure, which is reflected in the standard engineering guidelines that establish 3000 PSF as a maximum pressure threshold for foundations on this type of soil.

In contrast, other soil types may have lower bearing capacities due to higher moisture retention, particle shape, or density issues, which can necessitate lower maximum pressure limits. Thus, the selection of 3000 PSF for sandy gravel is consistent with practices aimed at ensuring structural integrity and safety in construction.