December 2, 2020 ITS Money: Jesus Gomez, Ph.D., P.E.

Jesús E. Gómez, Ph.D., P.E. | GEI Consultants, Inc.

Power Plant Foundations in Highly Seismic Zone

Fast-track construction of two gas-turbine power plants at Huntington and Los Alamitos in California required the development of preliminary and final foundation design documents in a carefully coordinated, staged sequence with other portions of the project as construction was commencing. This presentation summarizes the key geotechnical site conditions and details of the pre-construction exploration. It also illustrates how the exploration information was used to optimize the foundation design, resulting in cost savings and schedule reduction.

Findings

• Strategic contractor-driven, pre-construction exploration and testing resulted in significant cost and schedule reductions as well as a better managed risk.
• As a result of testing, deep mixing methods were selected over the use of a diaphragm wall, resulting in savings between $5 – 8 Million.
• The testing all resulted in pile length reductions for a savings of $2 Million.
• Finally, the testing showed that the lateral capacity of the foundations was significantly underestimated.