February 5, 2020 ITS Money: Paul Axtell, P.E., D.GE

Paul Axtell, P.E., D.GE | Dan Brown and Associates

Foundation Engineering Revisited to Reduce Bridge Construction Risk

The Sellwood Bridge replacement project involves construction of a bridge over the Willamette River in Portland, Oregon. After award of the construction contract, a value engineering study was proposed to reduce the length of the rock sockets in an effort to mitigate risks associated with construction of very deep sockets in hard rock. The presentation describes the outcome of this study and how risks associated with construction of large diameter drilled shafts can be reduced by qualified foundation engineers along with the necessary QA.

Findings:

• The value engineering study resulted in a substantial reduction of the rock socket lengths.
• The cost of the value engineering study was approximately $200,000, which was more than offset by the direct cost savings of approximately $1 million.
• In addition, the outcome of the value engineering study mitigated construction risks, and these associated benefits must be added to the direct cost savings.