The Geotechnical Program works with CDOT designers to investigate and develop foundations for highway structures.


Every structure (bridge, retaining wall, concrete box culvert, etc.) in the state highway system sits on a foundation. The Geotechnical Program performs drilling operations at selected locations to determine the geologic engineering characteristics. This allows the designers to properly determine the type, size and number of foundation types required and to what depth. Common foundation types include drilled caisson, driven pile, and spread footing.

Foundations for the Maroon Creek Bridge on CO 82

CO 82 over Maroon Creek by Aspen


Caissons, also called drilled shafts, are deep foundations constructed by placing fluid concrete and steel rebar into a drilled hole.

View from the old bridge looking down on the new caisson foundations being drilled.

Rebar cage placed in caisson boring.

Driven Piles

Driven piles are deep foundations constructed by driving a pre-fabricated concrete, steel or timber pile into the ground.

Driven pile installation.

Load test on Maroon Creek bridge foundation, SH-82.