Montana Department of Transportation


Drilled Shaft Construction Resources

Drilled shaft construction can be challenging and typically requires specialized equipment and methodology. Construction problems occur from time to time. It is in the interest of both the Owner and the Contracting community for MDT to share experiences, "lessons learned", and also external resources, which hopefully will increase knowledge and reduce risk for both parties. This web page is intended to be a technical resource to Contractors who construct Drilled Shafts on MDT projects in order to help avoid problems and to facilitate the repair or mitigation of defects when they do occur.

Case Studies

This MDT document provides examples of drilled shaft problems that have occurred on MDT projects and discusses related construction methods.

Repair Plans

MDT does not maintain any pre-approved drilled shaft repair plans. When a shaft has been found to have a defect, the Contractor will need to submit a plan for correcting a defective shaft as required by the Contract. The following link has information about typical repair plans and would likely be a good starting point for a Contractor who is developing a submittal:

NHI Manual

The following link is an essential resource that covers most aspects of drilled shaft construction and repair as well as design information: