Which anchor is used for hardpan or rocky, crumbly damp soil?

Study for the BICSI OSP Design Test. Prepare using multiple choice questions, with hints and explanations to enhance understanding. Succeed in your exam journey!

When choosing an anchor for hardpan or rocky, crumbly damp soil, the goal is to get the anchor to bite into dense material and develop strong resistance along a conical surface. A cone anchor is driven into the ground and its tapered shape cuts through the dense layer, causing surrounding soil to compact and shear against the cone. This creates high friction and a solid anchorage, which is especially effective in hard or rocky conditions where other anchors can struggle to seat or gain traction.

Expansion anchors need space to expand, which is unreliable in hardpan or rocky soils and can lead to poor holding power. Screw anchors rely on threading into the soil, but rigid, rocky ground can bind or resist advancement, reducing effectiveness. Plate anchors spread load over a flat plate, but in dense or rocky soils they may not seat properly or provide as much pullout resistance.

So, the cone anchor offers the best combination of penetration, friction, and holding power for hardpan or rocky, crumbly damp soil.